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Abstract: Deep hole machining is overlapped under the closed sill state, and the cutting condition of the tool cannot be directly observed. The metal plastic forming simulation software DEFORM-3D is used to simulate the deep hole drilling process dynamically with the finite element method, predict the temperature and stress changes in the processing process, compare the changes of temperature and equivalent stress under different drilling parameters, and obtain the change curves of cutting temperature and equivalent left force under different cutting speeds. The results show that the cutting temperature increases with the increase of the cutting depth, and tends to be stable gradually; The cutting temperature is proportional to the cutting speed, while the effect force does not change much with the change of cutting parameters. Key words: deep hole Rugong; D eform -3D; Drilling Deep hole machining is one of the most difficult processes in hole machining, and deep hole solid drilling technology is recognized as the key technology of deep hole machining technology. The traditional processing method is time-consuming and labor-intensive, and the precision of deep hole processing is not high, there is also the problem of frequent tool change and the risk of tool breakage [1]. Gun drilling is an ideal processing method at present. In the process of deep hole processing, the drill pipe is thin and long, easy to deflect, generate vibration, and the generated heat and cutting shoulder are not easy to discharge. It is not possible to directly observe the cutting condition of the tool. At present, there is no ideal way to monitor the temperature change and distribution in the cutting area in real time [w]. Only experience can be used to judge whether the cutting process is normal by listening to the cutting sound, watching the chips, touching the vibration and other appearance phenomena. In recent years, with the rapid development of computer hardware technology and numerical simulation, simulation technology provides an efficient scientific and technological way to solve this problem [4]. Simulation drilling is of great significance for improving the machining accuracy, stability and efficiency of deep holes. At present, some scholars can indirectly judge or predict the processing process in advance through some advanced measurement methods and software analysis. For example, Ding Zhenglong of Xi'an Jiaotong University and other scholars set up an online measurement platform to measure the inner diameter of deep holes [5], but the processing process could not be monitored online; some engineers improved the processing technology of deep holes by changing the traditional structure of the machine tool. For example, in order to prevent the cutting shoulder from scratching the hole wall after processing, the machine tool spindle was used in an inverted structure, and the self weight of the cutting fluid and the cutting shoulder was used to make the chips more smoothly discharged from the V-shaped groove of the drill pipe [6] and other measures, Effectively improve drilling quality. In this paper, Def 〇 rm-3D metal plastic forming simulation software is used to dynamically simulate the drilling process; The temperature and stress changes under different cutting speeds are obtained, and the processing effect of deep hole is predicted in advance, which provides a basis for the design and implementation of deep hole processing coolant. 1. Working principle and drilling technology of gun drill 1.1 Working principle of gun drill Gun drill is the main tool for machining deep holes. It has the characteristics of good accuracy and low surface roughness after one drilling [7]. The basic structure of gun drill is shown in Figure 1. Figure 1 Basic Structure of Gun Drill Gun drill consists of head, drill pipe and handle. The head is the key part of the whole gun drill, which is generally made of cemented carbide. There are two types: integral type and welded type, which are usually welded with the drill pipe. The drill pipe of gun drill is generally made of special alloy steel and heat treated to make it have good strength and rigidity, and must have sufficient strength and toughness; The handle of the gun drill is used to connect the tool with the machine tool spindle, and is designed and manufactured according to certain standards. 1.2 Gun drilling process During operation, the handle of the gun drill is clamped on the spindle of the machine tool, and the drill bit enters the workpiece through the guide hole or guide sleeve for drilling. The unique structure of the drill blade plays the role of self guidance, ensuring the cutting accuracy. First process the pilot hole, and then reach 2~5 m m on the pilot hole at a certain feed speed, that is, the point in Figure 2. At the same time, open the coolant by intercooling; Start machining at normal speed after the pilot hole is reached. During the machining process, adopt intermittent feeding, and feed every time! 2 depth, realizing deep hole and short shoulder; When the machining is finished and leaves the entity, first withdraw the tool at a fast speed to a certain distance from the hole bottom, then exit the pilot hole at a low speed, and finally quickly leave the machining workpiece and turn off the coolant. The whole process is shown in Figure 2. The dotted line in the figure represents rapid feed, and the solid line represents slow feed. 2. Analysis of deep hole drilling force Compared with other metal cutting methods, the most significant difference between deep hole drilling and other metal cutting methods is that the deep hole drilling uses the positioning and support of the guide block to drill in the closed cavity. The contact between the tool and the workpiece is not the single contact of the blade+91, but also the contact between the additional guide block on the tool and the workpiece. As shown in Figure 3. The deep hole drill is composed of three parts: cutting tool body, cutter tooth and guide block. The cutter body is hollow. The cutting shoulder enters from the front end and discharges through the drill pipe cavity. The rear thread is used to connect with the drill pipe. The main cutting edge on the cutter teeth is divided into two, namely, the outer edge and the inner edge. Taking the cobalt in the deep hole of the multi blade inner shoulder as an example, the auxiliary blade and two guide blocks are on the same circumference, and the three-point fixed circle is self guided. The force on it is analyzed. The simplified mechanical model is shown in Figure   4. (1) Cutting force F. The cutting force on deep hole tools can be decomposed into mutually perpendicular tangential forces F,,, and radial forces F, And axial force radial force will directly lead to tool bending deformation, axial force increases tool wear, while tangential force on cutting edge mainly produces torque. In the process of processing, it is always hoped to reduce the axial force and torque as much as possible on the premise of ensuring the processing quality and efficiency. Generally, the service life of the tool is directly linked to the axial force and torque. Excessive axial force makes the drill bit easier to break, and excessive torque will also accelerate the wear and break of the tool until it is scrapped [1 °]. (2) Friction F/. Friction/and/2 are generated when the guide block rotates relative to the hole wall; The axial friction between the guide block and the hole wall when it moves along the axis is/lu and 7L; (3) Extrusion force The extrusion force is caused by the elastic deformation of the hole wall. The extrusion force between the guide block and the hole wall is M and ^ 2. According to the principle of force system balance, it can be known that: Where: is the resultant force of vertical cutting force; F ,. Is the resultant of the radial cutting force; F is the resultant of circumferential cutting force. Assuming that only Coulomb friction coefficient is considered, the axial friction and circumferential friction on the guide block are equal. It can be straight through experiment Connect the torque M and F a measured during deep hole processing. For a given drill bit, its nominal diameter is and the position angle of the guide block is determined. In addition, the empirical axial force of the cutting force is half of the main cutting force. By synthesizing the above formula, the cutting force components and the force on the guide block can be calculated. 3. Drilling simulation of gun drill The deep hole drilling of inner shoulder is carried out in a closed or semi closed condition. The cutting heat is not easy to disperse, the shoulder is difficult to arrange, and the rigidity of the process system is poor. When the coolant produced in drilling cannot enter the cutting area, resulting in poor cooling and lubrication, the tool temperature will rise sharply, accelerating tool wear; With the increase of the drilling depth, the tool overhang increases, and the rigidity of the drilling process system decreases. All these put forward some special requirements for the deep hole drilling process with internal chip removal. This paper predicts the heat and cutting force generated in the cutting process through the reproduction simulation of the actual processing conditions, which provides a basis for optimizing the deep hole drilling process. 3.1 Definition of drilling parameters and material properties DEFORM is a set of finite element based process simulation system for analyzing metal forming process. By simulating the whole processing process on the computer, engineers and designers can predict the adverse factors under various working conditions in advance and effectively improve the processing process nM2]. In this paper, the 3D modeling software Pm/E is used to draw the simulation tool model, and the model is saved as The STL format is imported into Defo rm - 3 D. The set cutting parameters and conditions are shown in Table 1. (1) Setting of working conditions: select drilling as the machining type, the unit standard is SI, input the cutting speed and feed rate, the ambient temperature is 20t:, the friction factor of the workpiece contact surface is 0.6, the heat transfer coefficient is 45 W/m2. 0C, and the thermal melting is 15 N/mm2/X. (2) Setting of tool and workpiece: the tool is rigid, the material is 45 steel, the workpiece is plastic, and the material is WC carbide. (3) Set the relationship between objects: The master slave relationship of D e fo rm is that rigid body is the main part and plastic body is the slave, so the tool is active and the workpiece is driven. Table 1 Main Parameters of Workpiece and Tool In order to compare the influence of different process parameters on the changes of temperature, stress and strain in the cutting process, the simulation is carried out under different drilling parameters as shown in Table 2, and the results are observed. Table 2 Gun drilling parameters 3.2 Drilling simulation and result analysis (1) Temperature Most of the energy consumed in metal cutting is converted into heat energy. This heat causes the temperature of the cutting zone to rise It directly affects the tool wear, machining accuracy and surface quality of the workpiece. In high-speed metal cutting, severe friction and fracture make local temperature rise to very high temperature in a short time. In gun drilling, the heat mainly comes from the deformation of the metal cutting shoulder, the friction between the drill support pad and the workpiece hole pad, and the friction of the cutting shoulder on the tool rake face [13]. All these heat needs to be cooled by the cutting fluid. By simulating the drilling process, the temperature changes in the contact area of the workpiece at different speeds and feeds are obtained. These data provide a design basis for optimizing the cooling system during deep hole machining. Due to the high performance requirements of the computer for simulating drilling process, it takes a long time to simulate the complete hole processing process. By setting the step size of drilling simulation, the depth of simulation is controlled to achieve stable processing. Simulation condition setting The number of simulation steps is set as 1000, the number of simulation interval steps is set as 50, and the data is automatically saved every 50 steps; Deform-3D adopts adaptive mesh generation technology. The workpiece is a plastic body. The mesh generation is used to calculate the cutting force. The absolute element type is shown in Figure 5, and the simulation results are shown in   Table 3. Fig. 5 Finite element model and drilling process of deep hole drill Table 3 Data Collection of Cutting Speed and Temperature with Steps By analyzing and processing the data in Table 3, the curves of the temperature change of the workpiece cutting area with the number of steps under three working conditions are obtained as shown in Figure 6. Fig. 6 shows that the drilling speed has a great influence on the temperature of the workpiece contact area. At the beginning of drilling, the drill bit and the workpiece begin to contact, and the feed rate is large. The sharp impact of the tool on the workpiece causes the initial temperature to change greatly and rise rapidly. As the drilling tends to be stable, the curve generally becomes gentle but still fluctuates, which is normal for deep hole processing. Because the drill bit diameter is small and the feed rate is large, the vibration will persist. It can also be seen from Fig. 6 that drilling speed has a great influence on temperature. As the speed increases The drilling temperature is getting higher and higher. From the results of the finite element model, the maximum temperature generated at different drilling speeds occurs in the local deformation area near the drill point, because this is where plastic deformation and friction of the tool shoulder are concentrated. Fig. 6 Variation Curve of Contact Area Temperature with Cutting Speed (2) Equivalent stress distribution Von Mises stress is an equivalent stress based on shear strain energy and a yield criterion. After the introduction of equivalent stress, no matter how complex the stress state of the element body is, it can be imagined as the stress when bearing a unidirectional tension on the numerical value. The corresponding relationship between the equivalent stress and the equivalent strain obtained from the analysis reflects the work hardening of the workpiece material caused by plastic deformation through finite element analysis The equivalent stress changes of gun drill at different drilling speeds are obtained. The simulation interval is 50 steps, and the results are automatically saved every 50 steps, as shown in Table 4. Table 4 Data Collection of Cutting Speed and Equal Force with Steps The analysis of the relationship between the equivalent stress and the number of steps is shown in Figure 7. It can be seen that different spindle speeds have little influence on the equivalent stress of the workpiece during processing, and fluctuate within a certain range, but the trend of the maximum equivalent stress change under the three processing conditions is very similar. The curve in Figure 7 of drilling equivalent stress shows that the stress in the initial stage of drilling is large. As the drilling depth becomes stable, the curve generally drops and becomes gentle. At the same time, through the stress and strain analysis, the maximum equivalent stress of the gun drill is 1550 M Pa, and the overall maximum displacement is 0.0823 m m. 4. Conclusion The deep hole cutting process is effectively simulated by using the software of Defo rm. The temperature change and stress change in the cutting process are analyzed, and the change curve between the cutting temperature and the cutting speed is obtained. This provides a certain basis for the study of the cutting mechanism of deep hole machining, the selection of cutting parameters and the design of the cooling system in actual machining.

Phosphating is a process of chemical and electrochemical reaction to form a phosphate chemical conversion film, which is called phosphating film. The purpose of phosphating is mainly to provide protection for the base metal and prevent the metal from corrosion to a certain extent; It is used for priming before painting to improve the adhesion and corrosion resistance of the paint film; It is used for antifriction lubrication in metal cold working process. 1. Rationale: The phosphating process includes chemical and electrochemical reactions. The phosphating reaction mechanism of different phosphating systems and materials is complex. Although scientists have done a lot of research in this area, they have not yet fully understood it. A long time ago, the phosphating film formation mechanism was simply described by a chemical reaction equation: 8Fe+5Me (H2PO4) 2+8H2O+H3PO4Me2Fe (PO4) 2 · 4H2O (membrane)+Me3 (PO4) · 4H2O (membrane)+7FeHPO4 (sediment)+8H2 ↑ Me is Mn, Zn, etc. Machu, etc. believed that steel immersed in a high-temperature solution containing phosphoric acid and dihydrogen phosphate will form a crystalline phosphating film composed of phosphate deposits, and produce phosphate iron hydrogen sediment and hydrogen. The explanation of this mechanism is rather rough and cannot completely explain the film forming process. With the gradual deepening of phosphating research, today, scholars agree that the phosphating film forming process mainly consists of the following four steps: ① Acid etching reduces the H+concentration on the surface of the base metal Fe – 2e→ Fe2+ 2H2－+2e→2[H] (1) H2 ② Accelerating agent (oxidant) [O]+[H] → [R]+H2O Fe2++[O] → Fe3++[R] In the formula, [O] is the accelerator (oxidant), and [R] is the reduction product. Because the accelerator oxidizes the hydrogen atom generated in the first step of the reaction, the speed of reaction (1) is accelerated, which further leads to a sharp drop in the H+concentration on the metal surface. At the same time, Fe2+in the solution is oxidized to Fe3+. ③ Multistage dissociation of phosphate H3PO4 H2PO4－+H+ HPO42－+2H+ PO43－+3H－ （3） Due to the sharp drop of H+concentration on the metal surface, the dissociation equilibrium of phosphate at all levels moves to the right, and finally PO43 -. ④ Phosphate precipitates and crystallizes into phosphating film When PO43 - dissociated from metal surface reaches the solubility product constant Ksp with metal ions (such as Zn2+, Mn2+, Ca2+, Fe2+) in solution (metal interface), phosphate precipitation will be formed Zn2++Fe2++PO43－+H2O→Zn2Fe(PO4)2·4H2O↓ （4） 3Zn2++2PO43－+4H2O=Zn3(PO4)2·4H2O↓ （5） Phosphate precipitation and water molecules together form phosphating crystal nucleus, which continues to grow into phosphating grains, and countless grains are closely stacked to form a phosphating film metaphysically. The side reaction of phosphate precipitation will form phosphating sediment Fe3++PO43－=FePO4 （6） The above mechanism can not only explain the phosphating film forming process of zinc series, manganese series and zinc calcium series, but also guide the design of phosphating formula and process. From the above mechanism, it can be seen that appropriate oxidants can improve the speed of reaction (2); Lower H+concentration can make the dissociation equilibrium of phosphate dissociation reaction (3) more easily move to the right to dissociate PO43 -; If there is active point surface binding on the metal surface, the precipitation reaction (4) (5) can form phosphate precipitation nuclei without too much supersaturation; The generation of phosphating sediment depends on reaction (1) and reaction (2). High concentration of H+in solution and strong accelerator will increase the sediment. Accordingly, in the actual phosphating formula and process implementation, the surface is: an appropriate strong accelerator (oxidant); High acid ratio (relatively low free acid, i.e. H+concentration); Adjusting the metal surface to have an active point can improve the phosphating reaction speed, and can quickly form a film at a lower temperature. Therefore, the above mechanism is generally followed in the design of low temperature rapid phosphating formula, and strong accelerator, high acid ratio, surface adjustment process, etc. are selected. About phosphating sediment. Because the phosphating sediment is mainly FePO4, the amount of Fe3+must be reduced in order to reduce the amount of sediment. That is, two methods are adopted: reduce the H+concentration of phosphating solution (low free acidity) to reduce the oxidation of Fe2+to Fe3+. The phosphating mechanism of zinc and aluminum is basically the same as above. The phosphating speed of zinc material is fast, and the phosphating film is only composed of zinc phosphate, and there is little sediment. Generally, more fluorine compounds are added to aluminum phosphating to form AlF3 and AlF63 -. The mechanism of aluminum phosphating step polymerization is basically the same as above. 2. Phosphating classification There are many classification methods for phosphating, but they are generally classified according to phosphating film forming system, phosphating film thickness, phosphating temperature and accelerator type. 2.1 Classification according to phosphating film system According to the phosphating film forming system, it is mainly divided into six categories: zinc system, zinc calcium system, zinc manganese system, manganese system, iron system and amorphous iron system. The main components of zinc phosphating bath solution are: Zn2+, H2PO3 -, NO3 -, H3PO4, accelerant, etc. The main composition of the formed phosphating film (steel parts): Zn3 (po4) 2 · 4H2O, Zn2Fe (PO4) 2 · 4H2O. Phosphated grains are dendritic, acicular and porous. It is widely used for priming before painting, anti-corrosion and cold working antifriction lubrication. The main components of zinc calcium phosphating bath solution are: Zn2+, Ca2+, NO3 -, H2PO4 -, H3PO4 and other additives. The main composition of phosphating film (steel parts): Zn2Ca (PO4) 2 · 4H2O, Zn2Fe (PO4) 2 · 4H2O, Zn3 (PO4) 2 · 4H2O. Phosphated grains are compact granules (sometimes with large needle like grains) with few pores. It is used for priming and anti-corrosion before painting. The main composition of zinc manganese phosphating bath solution: Zn2+, Mn2+, NO3 -, H2PO4 -, H3PO4 and other additives. The main composition of the phosphating film: Zn2Fe (PO4) 2 · 4H2O, Zn3 (PO4) 2 · 4H2O, (Mn, Fe) 5H2 (PO4) 4 · 4H2O. The phosphating grains are in granular needle dendritic mixed crystal form with few pores. It is widely used for priming before painting, anti-corrosion and antifriction lubrication during cold working. The main composition of manganese phosphating bath solution: Mn2+, NO3 -, H2PO4, H3PO4 and other additives. The main composition of phosphating film formed on steel parts: (Mn, Fe) 5H2 (PO4) 4 · 4H2O. The phosphating film is thick with few pores, and the phosphating grains are dense. It is widely used in anti-corrosion and cold working antifriction lubrication. The main composition of iron phosphating bath solution: Fe2+, H2PO4, H3PO4 and other additives. The main composition of the phosphating film (steel workpiece): Fe5H2 (PO4) 4 · 4H2O. The phosphating film is thick, the phosphating temperature is high, the treatment time is long, the film has many pores, and the phosphating grains are granular. It is used for anti-corrosion and cold working antifriction lubrication. The main components of amorphous iron phosphating bath solution: Na+(NH4+), H2PO4, H3PO4, MoO4 - (ClO3 -, NO3 -) and other additives. The main composition of phosphating film (steel parts): Fe3 (PO4) 2 · 8H2O, Fe2O3. The phosphating film is thin, and the micro film structure is planar distribution of amorphous phase, which is only used for priming before painting. 2.2 Classification according to the thickness of phosphating film According to the thickness of phosphating film (weight of phosphating film), it can be divided into four types: sub lightweight, lightweight, sub heavyweight and heavyweight. The weight of the secondary lightweight film is only 0.1~1.0g/m2. Generally, it is amorphous iron system phosphating film, which is only used for priming before painting, especially for large deformed workpieces. The lightweight film weighs 1.1~4.5 g/m2, and is widely used for priming before painting, but less used in anti-corrosion and cold processing industries. The thickness of the sub heavy phosphating film is 4.6 ～ 7.5 g/m2. Due to the large film weight, the film is thick (generally>3 μ m) It is less used as the primer before painting (only used as the primer before painting for basically non deformed steel parts), and can be used for corrosion prevention and cold processing to reduce friction and lubrication. The heavy film weighs more than 7.5 g/m2 and is not used as primer before painting. It is widely used for anti-corrosion and cold working. 2.3 Classification according to phosphating treatment temperature According to treatment temperature, it can be divided into normal temperature, low temperature, medium temperature and high temperature. Normal temperature phosphating is no heating phosphating. The general treatment temperature of low temperature phosphating is 30-45 ℃. Medium temperature phosphating is generally 60~70 ℃. High temperature phosphating is generally greater than 80 ℃. The temperature division method itself is not strict. Sometimes there are sub medium temperature and sub high temperature methods, depending on the wishes of each person, but the above division method is generally followed. 2.4 Classification according to accelerator type Since there are only a few kinds of phosphating accelerants, it is helpful to understand the bath solution according to the type of accelerants. The phosphating treatment temperature can be generally determined according to the type of accelerant, for example, NO3 accelerant is mainly medium temperature phosphating. Accelerators are mainly divided into nitrate type, nitrite type, chlorate type, organic nitride type, molybdate type and other main types. Each accelerator type can be used together with other accelerators, and there are many branch series. Nitrate type includes: NO3 - type, NO3 -/NO2 - (autogenous type). Chlorate types include: ClO3 －, ClO3 －/NO3 －, ClO3 －/NO2 －. Nitrite includes: nitroguanidine R - NO2 -/ClO3 -. Molybdate type includes MoO4 -, MoO4 -/ClO3 -, MoO4 -/NO3 -. There are many ways to classify phosphating, for example, it can be divided into steel parts, aluminum parts, zinc parts and mixed parts by material. 2、 Pretreatment before phosphating In general, phosphating treatment requires that the workpiece surface should be clean metal surface (except for two in one, three in one and four in one). Before phosphating, the workpieces must be pretreated to remove grease, rust, oxide skin and surface adjustment. In particular, the phosphating for priming before painting requires surface adjustment to make the metal surface have certain "activity", so as to obtain a uniform, fine and dense phosphating film, and meet the requirements of improving the adhesion and corrosion resistance of the paint film. Therefore, phosphating pretreatment is the basis for obtaining high-quality phosphating film. 1. Degrease The purpose of grease removal is to remove the grease and greasy dirt on the surface of the workpiece. Including mechanical method and chemical method. Mechanical method mainly includes manual brushing, sand blasting and shot blasting, flame burning, etc. Chemical method mainly includes solvent cleaning, acid cleaning agent cleaning, strong alkaline solution cleaning and low alkaline cleaning agent cleaning. The following describes the chemical degreasing process. 1.1 Solvent cleaning The solvent method is generally used to remove grease by non flammable halohydrocarbon vapor method or emulsification method. The most common method is to use trichloroethane, trichloroethylene and perchloroethylene vapor to remove grease. Steam degreasing is fast, efficient, clean and thorough, and has a very good removal effect on all kinds of oil and grease. Adding a certain amount of emulsion into chlorinated hydrocarbons has good effect both in soaking and spraying. Due to the toxicity of chlorinated halogens and high vaporization temperature, as well as the appearance of new water-based low alkaline cleaning agents, solvent steam and lotion degreasing methods are rarely used now.

With the growing maturity of microelectronics and computer technology, the development of CNC technology in China has been promoted. The successful development of domestic CNC systems has ensured the quality and performance of CNC machine tools in China. CNC machine tools have been widely used in various fields due to their strong adaptability to workpiece modification, high machining accuracy, and improved productivity. CNC technology has been widely used in sheet metal machine tools. It solves the problems of high precision, complex shape and large batch of parts in sheet metal processing. CNC sheet metal machine tools include CNC shearing machine, CNC laser cutting machine, CNC punch, CNC bending machine, welding machine, flame cutting machine, etc. Their application in production greatly improves the processing capacity of sheet metal, ensures the quality and output of sheet metal parts, and greatly reduces the labor intensity of workers. Cutting is the first process in the process of sheet metal processing. The accuracy of cutting directly affects the processing quality of the following processes. The application of numerical control plate shears ensures the size of cutting and the work error of cutting diagonal. Numerical control plate shearing machine is composed of numerical control device, servo system, measuring device and machine tool. The servo system is composed of three servo motors and servo drive devices. There are two servo motors positioned in front of the machine tool. Generally, one main motor works independently, with a processing range of 2-500mm. If the bevel is processed, the auxiliary motor works. The CNC system gives two different instructions to form the bevel. There is a servo motor in the rear positioning, which is mainly used to process large plate products, with the processing range of 150~4000mm. For example, the QC12K series numerical control plate shears made in Shanghai are equipped with the Swiss CYBELEC DNC60 series, which can store 36 sequences, and the internal memory capacity is 100 sequences. S stamping is an important link in sheet metal processing, and the CNC punch can replace the processing capacity of the past three punches. The productivity has been greatly improved. CNC punch press is a machine tool with a wide range of uses, including single punch and turret. This paper takes CNC1000 as an example, which is produced in Italy. Machine tool of C-type structure, processing range: 1270 × 1000mm, the turret has 19 mold stations, which are divided into upper and lower parts to install the punch and die respectively. The external dimensions of the die are 25.4mm, 47.62mm, 88.9mm, 125.43mm, 158.4mm and 210.00mm in diameter. The CNC punch generally has X, Y and Z axes. The X axis is the 0 degree direction of the machine tool, the Y axis is the 90 degree direction of the machine tool, and the Z axis is installed on the turret to control the mold angle. The machine tool operator shall determine the processing plan according to the part drawing and process requirements, and prepare the program sheet. The operator directly writes the program into the program memory in EDIT mode through the operation panel of the machine tool; With the development of CAD/CAM and CIMS technology, the operator can input graphics into the computer to generate programs through computer related software, copy them into disks, and input them into the CNC system through disk drives. It can also be input by computer and numerical control system serially. The programming instructions of the CNC punch are divided into G code and M code. G code is used to instruct the machine tool to carry out processing movement and interpolation mode. For example, G91 incremental command, G90 absolute command, G29 arc punching, G68 step punching circular arc. M code is the code that instructs the machine tool to do some auxiliary actions. If M30 program stops. After the inspection procedure is correct, release the caliper and put in the workpiece to close the caliper. Start the oil pump and punch to complete the processing. CNC punch has the following characteristics: (1) Full automatic centralized lubrication; (2) 、 Automatic cooling and lubrication of punch die (3) Screen display and automatic reset of hydraulic overload protector; (4) Equipped with pneumatic/hydraulic operated variable pressure plate clamp; (5) An extra large worktable that can fully support large plates; (6) Hydraulic CNC punch with high accuracy, high speed and low noise; (7) Sliding worktable that can easily replace the mold and safely interlock; (8) The polyurethane free ball device can prevent the material surface from scratching. The processing technology of CNC punch has the following characteristics: (1) High processing precision. The tolerance of hole edge distance is 0.2mm, and the tolerance of hole distance is 0.5mm/m. (2) . Because there are many kinds of molds installed on the turret, the workpiece can be clamped once to complete all the processing contents immediately. (3) The machine tool can process workpieces individually or batch process workpieces with G98 group command to improve productivity. The workpiece reaches the bending process after going through two processes of blanking and stamping. CNC bending machine has the advantages that ordinary machine tools can not compare. For example, CASPRINI is produced in Italy and Siemens CNC system. The input method is manual programming. (1) Through the control panel, directly input the plate thickness, mold number, tensile strength, X-axis size, angle, workpiece length and stroke height to complete the preparation. (2) For some workpieces with complex shape and high precision requirements, 2D or 3D graphics, plate thickness and die number are input through the control panel. The function of man-machine dialogue is used to determine the bending sequence generation program. After the program is generated, it is stored in the program buffer area. If it is to be used in the future, it is stored in the machine tool memory. If the program needs to be used repeatedly, it should be copied out for backup through a special disk. The CNC bending machine usually has two towing racks in front and back. The CNC system controls the bending angle to determine the lifting height of the towing rack, which reduces the labor intensity of the operator. The common CNC bending machine has two servo motors to drive the X axis and Y axis of the machine tool. The detection component adopts a grating ruler, inductosyn, encoder, etc., which are usually installed on the lead screw of the machine tool. The detection feedback device converts the displacement of the lead screw into an electrical signal and feeds it back to the numerical control device. If there is an error of 0.02mm with the command value, the lead screw is controlled to make adjustments. The high-performance bending machine is equipped with a motor on both sides of the X axis, so that the X axis can be used to process beveled edges. A motor is installed on each shaft to process workpieces with different angles on both sides. A motor is added under the tailgate so that the tailgate can move up and down, which is more convenient for operation and processing. As the hydraulic system of the ordinary upward bending machine has been used on the machine tool for a long time, the lower die is bent. Therefore, the CNC bending machine is equipped with a hydraulic system under the machine tool. When the upper and lower dies work together, the system applies force to the lower die to reduce the deformation of the lower die and extend the service time of the lower die. Features of CNC bending machine: (1) After the program is established, it can work automatically or semi-automatically. The automatic cycle of the program enables the workpiece to be processed at one time, thus changing the inconvenience of large batch of workpieces and complex processes in semi-automatic processing. (2) The numerical control system automatically calculates the oil pressure to avoid damage to the machine tool caused by overpressure. (3) The introduction of 2D, 3D graphics input functions facilitates the processing of complex workpieces and improves the processing efficiency. (4) The increase of various devices improves the processing technology and reduces the labor intensity of operators. With the wide application of sheet metal machinery in aerospace, railway transportation, environmental protection equipment, air conditioning appliances, tobacco machinery, packaging and printing, engineering machinery, textile machinery and many other industries. The sheet metal processing also needs more high-tech workers to operate. Only good equipment and excellent staff can produce good products, making more excellent products made in China in the world.

1. The connection between the servo motor shaft and the lead screw is loose, causing the lead screw and the motor to be out of sync, resulting in dimensional error. During detection, it is only necessary to make marks on the coupling between the servo motor and the lead screw, and move the workbench (or tool rest) back and forth with a faster magnification. Due to the inertial action of the workbench (or turret), the two ends of the coupling will move relatively obviously. This kind of fault usually shows that the machining size only changes in one direction, and it can be eliminated by uniformly tightening the coupling screws 2. The lubrication between the ball screw and the nut is poor, which increases the movement resistance of the workbench (or tool rest) and makes it impossible to completely and accurately execute the movement command. This kind of fault usually shows that the size of the part changes irregularly within the range of several wires, and the fault can be eliminated by improving the lubrication. 3. The moving resistance of the machine tool workbench (or tool rest) is too large, which is generally caused by the tight adjustment of the inserts and poor lubrication of the machine tool guide rail surface. This fault phenomenon generally shows that the part size changes irregularly within the range of several wires. The inspection can be carried out by observing the size and change of the position deviation of DGN800-804. Generally, the difference is large when the positive and negative directions are stationary. This kind of fault only needs to readjust the insert and improve the lubrication of the guide rail. 4. The rolling bearing is worn or adjusted improperly, resulting in excessive movement resistance. This fault phenomenon also usually shows that the size changes irregularly within a few wires. The inspection can be conducted through the position deviation of DGN800-804, and the method is the same as above. Such faults can be eliminated by replacing and carefully adjusting the worn bearing.

In the process of deep hole machining, problems such as dimensional accuracy, surface quality and tool life often occur. How to reduce or even avoid these problems is an urgent problem to be solved. ◆ Problem ①: The aperture increases and the error is large Causes: The design value of the reamer outer diameter is too large or the reaming cutting edge has burrs; Cutting speed is too high; Improper feed rate or excessive machining allowance; The main deflection angle of reamer is too large; Reamer bending; Chip beading is adhered to the reaming cutting edge; The runout of reaming cutting edge is out of tolerance during grinding; The cutting fluid is not suitable; When installing the reamer, the oil stain on the surface of the taper shank is not wiped clean or the cone surface is bruised; The taper interference of the taper shank after the offset of the flat tail of the taper shank is installed into the machine tool spindle; The main shaft is bent or the main shaft bearing is too loose or damaged; Reamer floating is not flexible; When reaming holes with different axes from the workpiece and hands, the force of both hands is uneven, causing the reamer to shake left and right. Solution: appropriately reduce the external diameter of the reamer according to the specific situation; Reduce cutting speed; Properly adjust the feed rate or reduce the machining allowance; Reduce the main deflection angle appropriately; Straighten or scrap the bent and unusable reamer; Carefully trim with an oilstone until it is qualified; Control the swing error within the allowable range; Select cutting fluid with good cooling performance; Before installing the reamer, the internal oil stain of the reamer taper handle and the taper hole of the machine tool spindle must be wiped off, and the cone surface with bumps shall be polished with an oilstone; Repair and grind the flat end of reamer; Adjust or replace the main shaft bearing; Readjust the floating clip and adjust the coaxiality; Pay attention to correct operation. ◆ Problem ②: Hole diameter reduction Cause: the design value of the external diameter of the reamer is too small; Cutting speed is too low; Excessive feed rate; The main deflection angle of reamer is too small; The cutting fluid is not suitable; When sharpening, the worn part of the reamer is not worn off, and the elastic recovery reduces the aperture; When reaming steel parts, if the allowance is too large or the reamer is not sharp, it is easy to produce elastic recovery, which will reduce the hole diameter, make the inner hole out of round, and make the hole diameter unqualified. Solution: Replace the external diameter of the reamer; Properly increase the cutting speed; Properly reduce the feed rate; Increase the main deflection angle appropriately; Select oily cutting fluid with good lubricating performance; Exchange reamers regularly, and grind the cutting part of reamers correctly; When designing the reamer size, the above factors shall be taken into account, or the value shall be taken according to the actual situation; Make experimental cutting, take appropriate allowance, and sharpen the reamer. ◆ Problem ③: The reamed inner hole is not round Causes: The reamer is too long, the rigidity is insufficient, and vibration occurs during reaming; The main deflection angle of reamer is too small; Narrow hinge cutting edge band; Reaming allowance deviation; There are notches and cross holes on the inner hole surface; There are sand holes and air holes on the hole surface; The main shaft bearing is loose and there is no guide sleeve, or the fitting clearance between the reamer and the guide sleeve is too large, and the thin-walled workpiece is clamped too tightly, so the workpiece is deformed after removal. Solution: The reamer with insufficient rigidity can adopt the reamer with unequal pitch, and the installation of the reamer should adopt rigid connection to increase the main deflection angle; Select qualified reamers and control the hole position tolerance of the pre processing process; Unequal pitch reamer and longer and more precise guide sleeve are adopted; Select qualified blank; When reaming more precise holes with equal pitch reamers, the machine tool spindle clearance shall be adjusted. The fitting clearance of the guide sleeve shall be higher or appropriate clamping method shall be adopted to reduce the clamping force. ◆ Problem ④: The inner surface of the hole has obvious edges Cause: excessive reaming allowance; The rear angle of reamer cutting part is too large; The reaming cutting edge belt is too wide; There are air holes and sand holes on the workpiece surface and the spindle runout is too large. Solution: reduce reaming allowance; Reduce the back angle of the cutting part; Width of grinding blade belt; Select qualified blank; Adjust the machine spindle. ◆ Problem ⑤: The surface roughness of the inner hole is high Cause: too high cutting speed; The cutting fluid is not suitable; The main deflection angle of the reamer is too large, and the reaming cutting edge is not on the same circumference; Reaming allowance is too large; The reaming allowance is uneven or too small, and the local surface is not reamed; The runout of the reamer cutting part is out of tolerance, the cutting edge is not sharp, and the surface is rough; The reaming cutting edge belt is too wide; Poor chip removal during reaming; The reamer is excessively worn; The reamer is bumped, and the cutting edge is left with burrs or broken edges; The cutting edge has chip accretion; It is not applicable to zero or negative rake reamers due to material relationship. Solution: reduce cutting speed; Select cutting fluid according to processing materials; Properly reduce the main deflection angle, and correctly grind and ream the cutting edge; Reduce reaming allowance appropriately; Improve the position accuracy and quality of the bottom hole before reaming or increase the reaming allowance; Select qualified reamers; Width of grinding blade belt; According to the specific situation, reduce the number of reamer teeth, increase the chip holding slot space or use the reamer with edge inclination angle to ensure smooth chip removal; Replace the reamer regularly, and remove the grinding area when grinding; Protective measures shall be taken for reamers during grinding, use and transportation to avoid bumping; For the damaged reamer, the damaged reamer shall be repaired with extra fine oilstone, or the reamer shall be replaced; The reamer with a front angle of 5 °~10 ° shall be used when the trimming is qualified with an oilstone. ◆ Problem ⑥: The service life of the reamer is low Cause: unsuitable reamer material; The reamer is burnt during grinding; The cutting fluid is not properly selected, the cutting fluid fails to flow smoothly, and the surface roughness value at the cutting point and after grinding the hinge cutting edge is too high. Solution: The reamer material can be selected according to the processing material, and the carbide reamer or coated reamer can be used; Strictly control the grinding and cutting parameters to avoid burns; Always select the cutting fluid correctly according to the processing materials; The chips in the chip groove shall be removed frequently, and the cutting fluid with sufficient pressure shall be used to meet the requirements after fine grinding or grinding. ◆ Problem ⑦: The position accuracy of reamed hole is out of tolerance Cause: wear of guide sleeve; The bottom of the guide sleeve is too far from the workpiece; The length of the guide sleeve is short, the precision is poor, and the main shaft bearing is loose. Solution: Replace the guide sleeve regularly; Lengthen the guide sleeve to improve the fitting accuracy of the clearance between the guide sleeve and the reamer; Timely maintain the machine tool and adjust the spindle bearing clearance. ◆ Problem ⑧: reamer tooth breakage Cause: excessive reaming allowance; The hardness of workpiece material is too high; The swing difference of cutting edge is too large, and the cutting load is uneven; The main deflection angle of reamer is too small, which increases the cutting width; When reaming deep holes or blind holes, there are too many chips, which have not been removed in time, and the cutter teeth have been worn and cracked when sharpening. Solution: Modify the pre processed hole size; Reduce material hardness or change to negative rake angle reamer or carbide reamer; Control the runout within the acceptable range; Increase the main deflection angle; Pay attention to the timely removal of chips or the use of reamers with edge inclination; Pay attention to the grinding quality. ◆ Problem ⑨: The reamer shank is broken Cause: excessive reaming allowance; When reaming tapered holes, the allocation of rough and fine reaming allowance and the selection of cutting parameters are inappropriate; Reamer teeth have small chip space and chip is blocked. Solution: Modify the pre processed hole size; Modify the allowance allocation and reasonably select the cutting parameters; Reduce the number of reamer teeth, increase the chip space or grind off one tooth of the cutter tooth clearance. ◆ Problem ⑩: The centerline of the reamed hole is not straight Cause: The original bending degree cannot be corrected due to the poor rigidity of the reamer when the drilling hole is deflected before reaming, especially when the hole diameter is small; The main deflection angle of reamer is too large; Poor guidance makes the reamer easy to deviate from the direction during reaming; The chamfer of the cutting part is too large; The reamer moves at the middle clearance of the intermittent hole; During hand reaming, excessive force is exerted in one direction, forcing the reamer to deflect towards one end, which destroys the verticality of the reamed hole.

The random error of the machine tool is caused by external conditions, and is greatly affected by the external conditions. It can be divided into: positioning accuracy error, geometric accuracy error, thermal deformation error, etc. Let's briefly understand these three errors. 1. Error caused by load deformation of the process system: When turning, the workpiece is often affected by cutting force, clamping force, inertial force, gravity, etc., which will produce corresponding deformation, and ultimately destroy the correct relative position between the tool and the workpiece, reducing the machining precision of the workpiece. For example, when the rigidity of the workpiece is far less than the rigidity of the tool and fixture, the workpiece will be deformed due to insufficient rigidity under the action of the cutting force, thus reducing the machining accuracy. On the contrary, when the rigidity of the workpiece is far greater than the rigidity of the tool and fixture, the tool and fixture will be deformed during the processing of the workpiece, which will also reduce the accuracy of the workpiece. Therefore, it is necessary to reasonably select the tool material, increase the rake angle and main deflection angle of the tool, and reasonably heat treat the workpiece material to improve its machining performance. At the same time, it is necessary to improve the rigidity of the process system, reduce the cutting force and compress their variation amplitude. 2. Error caused by redistribution of internal stress: the so-called internal stress is the stress that exists inside the part without the effect of external force. Once internal stress is generated on the workpiece, it will make the workpiece in an unstable state of high energy level, thus instinctively transforming to a stable state of low energy level, and with the deformation of the workpiece, the workpiece will eventually lose its original machining accuracy. For example, after heat treatment, internal stress is generated due to uneven wall thickness and uneven cooling of workpieces, which leads to deformation and ultimately reduces machining accuracy. Therefore, when designing parts, we should try to achieve uniform wall thickness and symmetrical structure to reduce the generation of internal stress. 3. Error caused by thermal deformation: In precision machining and large piece machining, the thermal deformation of the process system has a great impact on the machining accuracy of the workpiece, and the machining error caused by thermal deformation can sometimes account for 40%~70% of the total error of the workpiece. Machine tools, cutting tools and workpieces are affected by various heat sources, and the temperature will gradually rise. At the same time, they transfer heat to the surrounding materials and space. Thus, the workpiece and the whole process system will be deformed. When the heat input per unit time is equal to the heat released, the process system will reach the thermal equilibrium state. For example, in the process of turning large parts, the temperature of the spindle bearing and the Z-axis lead screw increases due to excessive cutting force, resulting in large deformation, which affects the machining accuracy of the workpiece.

When it comes to the matching of tools and machine tools, you may first think of the matching of shape and size. Indeed, the matching of the shape and size is the basis for the correct installation of the tool on the machine tool. Without this foundation, the tool cannot be correctly installed on the machine tool, so it is impossible to complete any processing task. However, this alone is not enough. After the tool is installed on the machine tool, it is necessary to complete certain processing tasks. In the process of completing this machining task, it is necessary to ensure the machining accuracy, bear and transfer the cutting force and cutting torque, bear, transfer and export the cutting heat, consider the possible transmission of cutting waste (chips and heads) and even the workpiece, as well as the digital transmission of modern tool parameters. Although some of these tasks are not common, they are also possible tasks for the tool. If we can consider the matching between tools and machine tools when selecting tools, it will increase our thinking to solve processing problems. To ensure the machining accuracy, transfer cutting force and torque, and provide the channel for cutting fluid are the problems we often encounter after ensuring the matching of shape and size. For example, on machining centers, we often use cylindrical (usually called straight shank) as the clamping method. As for the cylindrical tool handle, in addition to the typical complete cylindrical shape, there are also some changes that add some other elements to the cylindrical shape, such as the flat straight handle (the milling cutter is divided into single cutting plane and double cutting plane according to the diameter, and the common full cutting plane is drilled, which is called the side pressing type), the inclined flat handle with 2 ° inclination, and the straight handle with a flat tail (commonly used for drills), Straight shank with square body (commonly used for taps and reamers), etc. As far as the connection mode of this kind of tool handle and machine tool is concerned, it is not rare that only the cylindrical part is used for positioning and clamping. Spring sleeve systems of various pressure angles, powerful collet systems, hydraulic locking systems, thermal expansion clamping systems, and force deformation locking systems are all used to lock cylindrical tool handles. However, each clamping method has its advantages and disadvantages. Take the most common spring sleeve system as an example. A large pressure angle (defined here as the angle between the positive pressure of the cone surface locking and the cylinder axis), that is, a large cone angle represents a short locking stroke, which is conducive to rapid locking and loosening. However, the positive pressure decomposed to the cylinder surface under the same locking torque is small, resulting in a small friction distance and a correspondingly small cutting force distance that can be resisted, The tool is easy to slip in the tool handle, which affects the stability of the machining process and the quality of the machined surface; At the same time, the tool handle diameter that can be clamped by this kind of chuck has a wide range of changes, which is conducive to reducing the inventory of spring sleeves and optimizing management. A small pressure angle is the opposite. The spring sleeve with small pressure angle can clamp a small range of tool handle diameter, and the locking stroke is long during clamping, which is not conducive to rapid clamping and loosening. However, its clamping accuracy is slightly higher, the clamping force is large, and it can withstand greater cutting load. The hydraulic locking system is a new clamping system, which uses the incompressibility of high viscosity hydraulic oil to make the inner wall of the tool clamping chamber produce elastic deformation, thus locking the tool. The hydraulic locking system has high accuracy, and it is convenient to lock and release without special equipment. The locking torque is usually better than that of the spring sleeve system, but its inner wall can only work within the range of elastic deformation. Once the range is exceeded, irreversible plastic deformation will occur on the inner wall, which will cause permanent failure of the clamping cavity of the tool handle. Therefore, the flat tool handle, especially the full cut flat tool handle commonly used for drilling tools, cannot be used in the hydraulic locking system. The common reasons for damage and failure of the system are the pressure applied to the cavity and the tool handle not inserted into the bottom of the chamber. The thermal expansion clamping system usually requires special equipment, which can control heating and cooling according to multiple predetermined modes. Non professional heating equipment (even flame heating) may be used, but the temperature and heating curve cannot be well controlled, which will affect other parts of the tool handle, or even change its metallographic structure, so that the system will soon become invalid. In addition, the tool length of the thermal expansion clamping system is difficult to adjust, and special auxiliary tools are required, which adds some trouble to the situation where multiple tools need to work synchronously. On the other hand, the tool clamping mode may also determine the possible value of production efficiency. Cylindrical tool shank, hydraulic pressure and thermal expansion are all balanced designs that can adapt to high speed, while the flat clamping is a typical unbalanced design, which is not recommended for high-speed cutting by tool manufacturers. As far as the tool shank itself is concerned, when a part of the material is milled (or ground) to form a pressure surface, the center of gravity of the tool shank is not coincident with the rotation center of the tool. In the process of tool clamping, the flattening handle is pushed to the side that has deviated from the center by the locking screw, and the center of gravity of the tool will further deviate from the rotation center of the tool on the machine tool, which increases the imbalance of the tool. In addition, some users often do not care about the length of a screw after the original locking screw is damaged or lost, which also adds uncertainty to the balance performance of the tool. Therefore, the flat type (including the bevel type) is not recommended to be used at high speed. However, the flattening type is a tool handle with forced driving property, which is more reliable than the pure cylinder driven by friction force at high torque. Therefore, it is suitable for rough machining (rough machining generally has large torque, but low speed).

In addition to overcoming the resistance of the workpiece material, the tool geometry will also affect the actual cutting effect and even the result. Choosing proper tool geometry can increase tool life, maintain machining accuracy, reduce cutting power, etc. Common tool related geometry is as follows: 1. Tool edge angle; 2. Chip discharge groove; 3. Over center and over center tools; 4. Number of blades 01 Tool edge angle 1.1 Tool edge angle --- rake angle The bevel can be changed from a positive value to a negative value, as shown in the following figure. In terms of cutting force and required power, the tool tip angle formed by positive and oblique angles is small, the tool can easily cut into the workpiece, and the chip flows out smoothly, which can reduce the cutting pressure, so the cutting efficiency is high. However, too large positive bevel angle forms a sharp blade, so the blade is fragile and easy to wear or crack. On the contrary, the negative bevel angle has a strong cutting edge, which is suitable for cutting high-strength materials. 1.2 Tool edge angle clearance angle It is also called clearance angle, which is positive. Its function is to avoid the interference of single friction or physical phenomena between the cutter belly and the workpiece surface when the cutter cuts into the workpiece, as shown in the following figure. The small clearance angle gives the cutting edge greater support, which is generally used for work-piece materials with high strength mechanical properties. Large clearance angle can make the blade sharp, but the strength of the blade is reduced, which is easy to wear or crack. It is suitable for soft or low strength workpiece materials. 1.3 Tool edge angle Helix Angle The groove of milling cutter is spiral, which can be divided into left spiral and right spiral, as shown below. When the cutting edge enters the workpiece during cutting, as shown in the figure below on the right, the cutting force F will instantly increase to the maximum. When the cutting edge leaves the workpiece, the cutting force will rapidly decrease, which is the reason for the vibration during cutting. The effect of helix angle at this time can prevent the cutting force from concentrating too much in one direction and scattering it in the other two directions - the horizontal component FH and the vertical component FV. When helix angle γ The larger the value is, the larger the horizontal component FH will become, causing the tool to swing during cutting; Helix angle γ The smaller the value is, the greater the vertical component FV will become. When the force holding the tool is insufficient during cutting, the tool will disengage from the handle, which is very dangerous when rotating at high speed. The common helix angle is 30 ˚、 thirty-eight ˚、 forty-five ˚、 sixty ˚。 02 Chip discharge chute The ideal chip processing condition is that the chip will not interfere with or scratch the workpiece surface or impact the tool and hurt the worker when it flows out, so the chip should be able to naturally break into small pieces and be discharged to other places. Therefore, the chip control should not only consider the chip flow direction, but also make the chip break automatically. In order to meet this requirement, a design is generally made on the top surface of the tool. The mechanism that can automatically limit the chip length is called chip chute or chip breaker. The purpose is to enable the chip to curl rapidly and force the chip to break by the curling stress. The general chip removal groove design is shown in the lower right: Groove width W: curl is formed when chips are generated. If the groove width is too large, the curl radius is large, and the curl stress generated is not enough to break the chips; If it is too small, on the contrary, when the generated stress is too large, the cutting edge is easy to crack. Groove depth H: it affects the stability of chip flow. If it is too deep, the force required for the chip to curl when flowing to the groove shoulder is large, which is easy to cause the blade to break; If it is too shallow, the chip may leave automatically when it does not flow to the slot shoulder, making the chip flow difficult to control. Groove shoulder R: refers to the part where the chip rolls up from the chip breaking groove, which directly affects the size of the curling force. If the radius is too large, the chip is easy to slide up, and the curling stress may not be enough to break the chip; If the radius is too small, the chips are easy to be blocked and slide on, which will produce great extrusion stress. 03 Tools passing the center and not passing the center When making a discarding round nose knife, the diameter D of the knife is usually much larger than the R angle of the blade, so the blade will not cross the center at the middle of the bottom and there will be a region without a blade, that is, there is no cutting capacity in this region, as shown in the left figure. When the workpiece in the shape of machining hole or groove is encountered, the processing problem in the lower right figure will occur. Although the size of the tool can enter these areas, because the blade does not cross the center, the blade will not cut the material in the middle and leave the yellow columnar residual material in the figure. With the deeper processing, the height of the residual material will increase, and finally it will hit the bottom of the tool, causing damage to the tool. The tool that passes through the center means that its blade passes through the center, so there is no such problem, so it is also called drilling tool. 04 Number of blades The relationship between the number of cutting edges of a milling cutter and the cutting effect will vary depending on the workpiece material, the shape of the milling cutter, the brightness of the machining surface, and so on. A milling cutter with more cutting edges can obtain a more smooth and smooth machining surface because it has more cutting edges. However, because there is not enough chip space to accommodate the chips, it is vulnerable to chip interference, and the strength of the blade will be weak. Therefore, for general rough cutting, high feed, especially for soft materials, large chip space is required, and the best way to provide chip space is to reduce the number of edges and increase the blade, which can not only increase the chip space, but also increase the strength of the blade, and the number of regrinding times and life of the milling cutter can also be increased. Therefore, when considering the processing method, heavy and rough cutting should choose the milling cutter with fewer blades and coarse teeth; For fine and finish machining, the milling cutter with more blades and finer teeth should be selected.

Now the automation boom in the mold industry is unstoppable, which is certainly a good thing from the perspective of development. The mold industry really needs to eliminate some backward manual modes. However, if automation is used in the mold industry, do not simply think that as long as you spend money on the most advanced automation technology, you can replace technicians to make high-quality molds. This is a big mistake. Mold managers and senior managers can clearly distinguish, and the most afraid is that the investment after a fever will return a pile of equipment that can not operate! The mold factory should not be in a hurry to automate, but use human brains to solve problems first We have all seen many automation cases in the western world. Why do foreigners come to China and other countries with relatively abundant human resources and relatively low labor quality to place mold orders? Why don't they use the method of Industry 4.0 to manufacture molds in automated unmanned factories? This also shows that not all molds can be made by automatic methods. It seems that the application of mold automation is pessimistic. To be sure, for some products with high similarity, or for a certain product that requires a batch of molds, the manufacturing of these molds can completely achieve a high degree of automation to enhance the competitiveness of mold factories. However, for single set of mold manufacturing and ever-changing mold manufacturing, there are still some problems if you want to apply mold automation production! The mold factory should not be in a hurry to automate, but use human brains to solve problems first After seeing many mold manufacturing plants, I think the profit of mold depends on two guarantees: the best design scheme and the best processing efficiency. There is no inevitable relationship between the efficient processing and automation of typical single piece flow workpieces such as molds. The core of automation is numerical control, and the core of numerical control is programming. The programming here refers to the data generation and control of the whole process. However, the quantification of 3D objects with high complexity such as molds and the huge quantized data stream are exactly completed with the actual workpiece according to the process sequence and quality requirements of mold processing, so as to achieve satisfactory results judged by the human brain. At this stage, it is absolutely impossible to complete the task. I can see that the problems in countless mold workshops are mainly slow, from finding things to processing to logistics, which can not be solved by automation. Automation refers to the limited digital transfer of the knowledge system in the human brain to the computer, which is just a very stiff, no sense to complete a series of actions, of course, they do not know the meaning and purpose of these actions. Automation at this stage is in fact rigid. We all feel sorry that there are no craftsmen in the workshop, so we can't make a good mold. Similarly, we can't expect a robot without perception to do a good mold. Do they know what is good? Just like PM software can't program a good path by itself and UG software can't draw a good graph by itself, it still needs high-quality designers and programmers to use the software well. Then we need a high-quality team to solve all the problems on the production site first, make customers satisfied, and then quantize the satisfied results with data to form the instructions that can be executed by the automation equipment. Only when the results after the automation equipment executes the instructions are closest to the results of manual operation can we achieve the role of the automation equipment. When a team cannot rely on the knowledge system and practical ability of the human brain to achieve customer satisfaction, how can we talk about using automation equipment to achieve customer satisfaction? A mold factory that can operate normally must start from the human-machine material method measuring ring of 5M1E, and improve all aspects step by step, including water, electricity, gas and liquid, cutting tool measuring card, logistics, design, process, plant planning, supply chain optimization, information management and other issues. It is not too late to talk about automation after the problem is solved by human brain.

❑ General technical requirements 1. Remove oxide scale from parts. 2. There shall be no scratch, scratch and other defects that damage the part surface on the part processing surface. 3. Remove burrs and fins. ❑ Heat treatment requirements 1. After quenching and tempering, HRC50~55. 2. Parts shall be subject to high-frequency quenching, 350~370 ℃ tempering and HRC40~45. 3. Carburizing depth 0.3mm. 4. Carry out high temperature aging treatment. ❑ Tolerance requirements 1. Undeclared shape tolerance shall meet the requirements of GB1184-80. 2. The allowable deviation of unspecified length is ± 0.5mm. 3. The casting tolerance zone is symmetrical to the basic dimension configuration of the blank casting. ❑ Edge angle of parts 1. Undeclared fillet radius R5. 2. Undeclared chamfers are all 2 × 45°。 3. Sharp corner/sharp corner/sharp edge rounding off. ❑ Assembly requirements 1. All seals must be soaked with oil before assembly. 2. It is allowed to use oil heating for hot assembly of rolling bearings, and the oil temperature shall not exceed 100 ℃. 3. After the gear is assembled, the contact pattern and backlash of the gear surface shall comply with the provisions of GB10095 and GB11365. 4. When assembling the hydraulic system, it is allowed to use sealing filler or sealant, but it should be prevented from entering the system. 5. The parts and components (including purchased parts and outsourced parts) to be assembled must have the qualification certificate of the inspection department before assembly. 6. The parts must be cleaned and cleaned before assembly, without burrs, fins, oxide skin, rust, chips, oil stains, colorants, dust, etc. 7. Before assembly, the main fit dimensions of parts and components, especially the interference fit dimensions and relevant accuracy shall be rechecked. 8. Parts shall not be knocked, bumped, scratched or rusted during assembly. 9. When fastening screws, bolts and nuts, it is forbidden to strike or use inappropriate screwdrivers and wrenches. The screw groove, nut, screw and bolt head shall not be damaged after fastening. 10. For fasteners with specified tightening torque requirements, torque wrenches must be used and tightened according to the specified tightening torque. 11. When the same part is fastened with multiple screws (bolts), all screws (bolts) shall be tightened crosswise, symmetrically, step by step and evenly. 12. The taper pin shall be painted with the hole during assembly, and its contact rate shall not be less than 60% of the fitting length, and shall be evenly distributed. 13. The flat key and two sides of the keyway on the shaft shall be in uniform contact, and there shall be no gap between their mating surfaces. 14. The number of tooth surfaces contacted by spline assembly at the same time shall not be less than 2/3, and the contact rate shall not be less than 50% in the direction of length and height of key teeth. 15. After the assembly of the flat key (or spline) of the sliding fit, the corresponding accessories can move freely without uneven tightness. 16. Excess adhesive shall be removed after bonding. 17. The semicircle hole of bearing outer ring, open bearing seat and bearing cover shall not be stuck. 18. The outer ring of the bearing shall be in good contact with the semicircular hole of the open bearing seat and bearing cover. During the color inspection, it shall be in uniform contact with the bearing seat within 120 ° symmetrical to the centerline and with the bearing cover within 90 ° symmetrical to the centerline. When checking with a feeler gauge within the above range, the 0.03mm feeler gauge shall not be inserted into 1/3 of the outer ring width. 19. The bearing outer ring shall contact the end face of the locating end bearing cover evenly after assembly. 20. The rolling bearing shall rotate flexibly and stably by hand after installation. 21. The joint surface of the upper and lower bearing pads shall be close to each other and cannot be checked with a 0.05mm feeler gauge. 22. When fixing bearing pads with locating pins, drill, ream and match pins under the condition that the pad mouth surface and end face are flush with the opening and closing surfaces and end faces of relevant bearing holes. The pin shall not be loose after driving. 23. The bearing body and bearing seat of spherical bearing shall be in uniform contact, and the contact shall not be less than 70% when checked by painting method. 24. When the surface of alloy bearing liner is yellow, it is not allowed to use it. There is no nucleation within the specified contact angle. The nucleation area outside the contact angle shall not be greater than 10% of the total area of the non-contact area. 25. The reference end face of the gear (worm gear) should fit with the shaft shoulder (or the end face of the positioning sleeve), and cannot be checked with a 0.05mm feeler gauge. The perpendicularity between the gear reference end face and the axis shall be ensured. 26. The interface between the gearbox and the cover shall be in good contact. 27. Before assembly, strictly check and remove the sharp corners, burrs and foreign matters left during part processing. Ensure that the seal is not scratched during installation. ❑ Requirements for castings 1. The casting surface is not allowed to have cold shut, crack, shrinkage cavity, penetrating defects and serious defects (such as under casting, mechanical damage, etc.). 2. The casting shall be cleaned without burr and flash, and the gate and riser on the non machining indication shall be cleaned and flush with the casting surface. 3. The casting words and marks on the non machined surface of the casting shall be clear and legible, and the position and font shall meet the requirements of the drawing. 4. Roughness of non machined surface of casting, sand casting R, not greater than 50 μ m。 5. The casting shall be cleaned of the sprue, riser, flying thorn, etc. The residual amount of gating and riser on the non machined surface shall be leveled and polished to meet the surface quality requirements. 6. The molding sand, core sand and core bone on the casting shall be cleaned. 7. The dimensional tolerance zone of castings with inclined parts shall be symmetrically arranged along the inclined plane. 8. Moulding sand, core sand, core bone, fleshy, sticky sand, etc. on the casting shall be scraped and cleaned. 9. The wrong type and boss casting deviation shall be corrected to achieve smooth transition and ensure the appearance quality. 10. The wrinkle on the non machined surface of the casting shall be less than 2mm deep and more than 100mm apart. 11. The non machined surfaces of machine product castings shall be shot blasted or roller treated to meet the requirements of cleanliness Sa2 1/2. 12. Castings must be treated with water toughening. 13. The casting surface shall be flat, and the gate, burr, sand, etc. shall be removed. 14. The casting shall be free from cold shut, crack, hole and other casting defects detrimental to use. Coating requirements 1. Rust, oxide skin, grease, dust, soil, salt and dirt must be removed from the surface of all steel products to be coated before painting. 2. Before rust removal, use organic solvent, lye, emulsifier, steam, etc. to remove grease and dirt on the surface of steel products. 3. The time interval between the surface to be painted after shot blasting or manual derusting and the primer shall not be more than 6h. 4. The surfaces of riveted parts in contact with each other must be coated with a thickness of 30-40 before connection μ M Anti rust paint. The overlapping edges shall be sealed with paint, putty or adhesive. The primer damaged due to processing or welding shall be repainted. ❑ Piping requirements 1. Before assembly, all pipes shall be free of flash, burr and chamfer. Use compressed air or other methods to clear the sundries and floating rust attached to the inner wall of the pipe. 2. Before assembly, all steel pipes (including prefabricated pipes) shall be subject to degreasing, pickling, neutralization, water washing and rust prevention. 3. During assembly, screw down the pipe clamp, support, flange, joint and other parts fixed by threaded connection to prevent looseness. 4. The welding parts of prefabricated pipes shall be subject to pressure test. 5. When piping is replaced or transferred, the pipe separation port must be sealed with tape or plastic pipe to prevent any foreign matter from entering, and a label must be attached. Requirements for repair weldments 1. The defects must be completely removed before welding, and the groove surface should be smooth and smooth without sharp corners. 2. According to the defects of steel castings, the defects in the welding area can be removed by digging, grinding, carbon arc gouging, gas cutting or machining. 3. Sand, oil, water, rust and other dirt in the welding area and within 20mm around the groove must be thoroughly cleaned. 4. During the whole welding process, the temperature of the preheating area of the steel casting shall not be lower than 350 ° C. 5. If conditions permit, welding shall be carried out in horizontal position as far as possible. 6. During repair welding, the welding rod shall not swing laterally. 7. When the surface of steel casting is welded, the overlap between weld beads shall not be less than 1/3 of the weld bead width. The welding flesh is full, and the welding surface is free of burns, cracks and obvious nodules. The appearance of the weld is beautiful, and there is no undercut, slag, air hole, crack, splash and other defects; The welding wave is uniform. Requirements for forgings 1. The nozzle and riser of the ingot shall have enough removal to ensure that the forgings are free of shrinkage cavity and serious deflection. 2. The forgings shall be forged and formed on a forging press with sufficient capacity to ensure full internal penetration of the forgings. 3. Forgings are not allowed to have visible cracks, folds and other appearance defects affecting use. Local defects can be removed, but the cleaning depth shall not exceed 75% of the machining allowance. Defects on the non machined surface of forgings shall be cleaned and smoothly transited. 4. Forgings are not allowed to have white spots, internal cracks and residual shrinkage cavities. Requirements for machining parts 1. Parts shall be inspected and accepted according to the process, and can be transferred to the next process only after the previous process passes the inspection. 2. The machined parts are not allowed to have burrs. 3. The finished parts shall not be placed directly on the ground, and necessary support and protection measures shall be taken. The machined surface shall be free of rust and other defects that may affect the performance, service life or appearance. 4. The surface for rolling finishing shall be free of peeling after rolling. 5. There shall be no oxide skin on the surface of parts after heat treatment in the final process. The finished mating surface and tooth surface shall not be annealed. 6. The machined thread surface shall be free of defects such as black skin, bump, random thread and burr.