China Shenzhen Perfect Precision Product Co., Ltd. company news

Due to the complexity of NC processing (such as different machine tools, different materials, different tools, different cutting methods, different parameter settings, etc A summary of experience in monitoring and other aspects of the processing process is available for your reference. Q1: How to divide processing operations? Answer: NC processing procedures can be divided according to the following methods: (1) The centralized tool sorting method is to divide the process according to the tool used, and use the same tool to process all the parts that can be completed on the part. Use the second knife and the third knife to complete other parts that they can complete. This can reduce the number of tool changes, compress the idle time and reduce unnecessary positioning errors. (2) For parts with many processing contents, the processing part can be divided into several parts according to its structural characteristics, such as internal shape, shape, curved surface or plane. Generally, the plane and positioning surface are processed first, and then the hole is processed; First process simple geometric shapes, then process complex geometric shapes; The parts with lower accuracy shall be processed first, and then the parts with higher accuracy requirements shall be processed. (3) For the parts that are easy to be deformed by rough and finish machining in sequence, due to the possible deformation after rough machining, they need to be calibrated, so generally, the processes should be separated for rough and finish machining. To sum up, when dividing processes, it is necessary to flexibly master the structure and processability of parts, the function of machine tools, the number of NC machining contents of parts, the number of installation times and the production organization of the unit. In addition, it is suggested to adopt the principle of process centralization or process decentralization, which should be determined according to the actual situation, but must be reasonable. Q2: What principles should be followed in arranging the processing sequence? Answer: The processing sequence should be arranged according to the structure of the part and the blank condition, as well as the need for positioning and clamping. The key is that the rigidity of the workpiece will not be damaged. The sequence shall generally follow the following principles: (1) The processing of the previous process shall not affect the positioning and clamping of the next process, and the processing of general machine tools interspersed between them shall also be considered comprehensively. (2) . Perform the internal cavity processing first, and then perform the contour processing. (3) It is better to connect the processes of the same positioning, clamping method or the same knife processing to reduce the times of repeated positioning, tool change and moving the pressing plate. (4) . For multiple processes in the same installation, the process with small rigid damage to the workpiece shall be arranged first. Q3: What aspects should be paid attention to when determining the workpiece clamping mode? Answer: Pay attention to the following three points when determining the positioning datum and clamping scheme: (1) Strive for design (2) . Try to reduce the clamping times, and make sure that all the surfaces to be machined can be machined after one positioning. (3) Avoid using manual adjustment scheme for machine occupation. (4) The fixture shall be open smoothly, and its positioning and clamping mechanism shall not affect the tool path during processing (such as collision). In such cases, it can be clamped with a vise or by adding a base plate to draw screws. Q4: How to determine a reasonable tool setting point? What is the relationship between the workpiece coordinate system and the programming coordinate system? 1. The tool setting point can be set on the part to be processed, but it should be noted that the tool setting point must be the reference position or the finished part. Sometimes the tool setting point is damaged after the first process, which will lead to no way to find the tool setting point in the second process and the subsequent process. Therefore, when setting the tool in the first process, it should be noted that a relative tool setting position should be set at a place with a relatively fixed dimension relationship with the positioning reference, In this way, the original tool setting point can be found according to the relative position relationship between them. This relative tool setting position is usually set on the machine tool workbench or fixture. The selection principles are as follows: (1) Easy to find. (2) Easy programming. (3) The tool setting error is small. (4) It is convenient to check during processing. 2. The origin position of the workpiece coordinate system is set by the operator. After the workpiece is clamped, it is determined by tool setting. It reflects the distance position relationship between the workpiece and the machine tool zero point. Once the workpiece coordinate system is fixed, it is generally unchanged. The workpiece coordinate system and the programming coordinate system must be unified, that is, during processing, the workpiece coordinate system and the programming coordinate system are consistent. Q5: How to choose the cutting route? Tool path refers to the path and direction of the tool relative to the workpiece in the process of NC machining. The reasonable choice of machining route is very important, because it is closely related to the machining accuracy and surface quality of parts. The following points are mainly considered when determining the tool path: 1) Ensure the machining accuracy requirements of parts. 2) It is convenient for numerical calculation and reduces programming workload. 3) Seek the shortest processing route to reduce the empty tool time to improve the processing efficiency. 4) Minimize the number of program segments. 5) Ensure the roughness requirements of the workpiece contour surface after machining. The final contour shall be processed continuously with the last cutter. 6) The route of tool advance and retreat (cut in and cut out) should also be carefully considered to minimize tool marks caused by tool stop at the contour (elastic deformation caused by sudden change of cutting force), and to avoid scratching the workpiece by cutting vertically on the contour surface The process and programming calculation shall be unified. Q6: How to monitor and adjust during processing? The workpiece can enter the automatic processing stage after the alignment and program debugging are completed. In the automatic machining process, the operator shall monitor the cutting process to prevent the workpiece quality problems and other accidents caused by abnormal cutting. The monitoring of cutting process mainly considers the following aspects: 1. The main consideration of the rough machining process monitoring is the rapid removal of the surplus allowance on the workpiece surface. In the automatic machining process of the machine tool, the tool automatically cuts according to the predetermined cutting path according to the set cutting parameters. Operation at this time The operator shall observe the change of cutting load in the automatic machining process through the cutting load table, and adjust the cutting parameters according to the bearing force of the tool to maximize the efficiency of the machine tool. 2. Monitoring of cutting sound in the cutting process In the automatic cutting process, the sound of the tool cutting the workpiece is stable, continuous, and light at the beginning of cutting, and the machine tool movement is stable at this time. With the progress of the cutting process, when there are hard spots on the workpiece or the tool is worn or the tool is clamped, the cutting process becomes unstable. The unstable performance is that the cutting sound changes, the tool and the workpiece will collide with each other, and the machine tool will vibrate. At this time, the cutting parameters and cutting conditions should be adjusted in time. When the adjustment effect is not obvious, the machine tool should be paused to check the condition of the tool and workpiece. 3. The finishing process is monitored to ensure the machining size and surface quality of the workpiece. The cutting speed is high and the feed rate is large. At this time, attention should be paid to the influence of chip buildup on the machined surface. For cavity machining, attention should also be paid to over cutting and tool passing at corners. To solve the above problems, first, pay attention to adjusting the spraying position of cutting fluid, so that the machined surface is always in the best cooling condition; Second, pay attention to the quality of the machined surface of the workpiece, and try to avoid quality changes by adjusting the cutting parameters. If the adjustment still has no obvious effect, stop the machine to check whether the original program is reasonable. In particular, pay attention to the position of the tool when suspending inspection or stopping inspection. If the tool stops in the cutting process and the spindle stops suddenly, tool marks will be generated on the workpiece surface. In general, shutdown shall be considered when the tool leaves the cutting state. 4. The quality of the tool monitoring tool largely determines the processing quality of the workpiece. In the process of automatic machining and cutting, it is necessary to judge the normal wear condition and abnormal damage condition of tools by means of sound monitoring, cutting time control, pause inspection during cutting, workpiece surface analysis, etc. Tools shall be handled in time according to the processing requirements to prevent the processing quality problems caused by the tools not being handled in time. Q7: How to reasonably select machining tools? How many elements are there in the cutting parameters? How many materials are there? How to determine the tool speed, cutting speed, cutting width? 1. The non regrinding carbide end milling cutter or end milling cutter shall be selected for plane milling. In general milling, try to use the second tool path for processing. The first tool path is better to use the end milling cutter for rough milling, and the tool path is continuous along the workpiece surface. The recommended width of each tool path is 60% - 75% of the tool diameter. 2. End milling cutter and end milling cutter with carbide insert are mainly used for machining boss, groove and box mouth surface. 3. Ball knife and round knife (also known as round nose knife) are commonly used to process curved surfaces and variable angle contour shapes. The ball cutter is mostly used for semi finishing and finishing. The round cutters with carbide inserts are mostly used for roughening. Q8: What is the function of the processing program sheet? What should be included in the processing program sheet? Answer: (1) The processing program list is one of the contents of the NC processing process design, is also a procedure that needs to be observed and implemented by the operator, and is a specific description of the processing program. The purpose is to let the operator know the content of the program, the clamping and positioning methods, and the problems that should be paid attention to when selecting the tools for each processing program. (2) In the processing program list, it should include: drawing and programming file name, workpiece name, clamping sketch, program name, the tool used in each program, the maximum depth of cutting, processing nature (such as rough machining or finish machining), theoretical processing time, etc. Q9: How to prepare for NC programming? Answer: After determining the processing technology, we should understand the following before programming: 1. Workpiece clamping method; 2. Size of work-piece rough - to determine the processing range or whether multiple clamping is required; 3. The material of the workpiece - in order to choose which tool to use for processing; 4. What are the tools in stock? Avoid modifying the program when there is no such tool. If you must use this tool, you can prepare in advance. Q10: What are the principles for setting the safe height in programming? Answer: The setting principle of safe height is generally higher than the highest surface of the island. Or set the programming zero point at the highest plane, so as to avoid the danger of knife collision to the greatest extent. Q11: Why should post processing be carried out after the tool path is compiled? Answer: Because the address code recognized by different machine tools is different from the NC program format, the correct post-processing format must be selected for the machine tool used to ensure that the compiled program can run. Q12: What is DNC communication? Answer: There are two ways of program transmission: CNC and DNC. CNC refers to that the program is stored in the memory of the machine tool through the media (such as floppy disk, tape reader, communication line, etc.), and the program is called out from the memory for processing. Because the memory capacity is limited by the size, when the program is large, the DNC method can be used for processing. Because the machine tool reads the program directly from the control computer (that is, it is not limited by the size of the memory capacity) during DNC processing. There are three elements of cutting parameters: cutting depth, spindle speed and feed speed. The general principles for selecting cutting parameters are: Less cutting and fast feed (i.e. small cutting depth and fast feed speed) According to the classification of materials, tools are generally divided into ordinary hard white steel tools (made of high-speed steel), coated tools (such as titanium plating), and alloy tools (such as tungsten steel, boron nitride tools, etc.).

Integral impeller is the core component of turbo engine and turbocharged engine. It is widely used in energy power, aerospace, petrochemical, metallurgy and other industries. It is a typical channel type complex part with standardized modeling. The machining means, machining accuracy and machining surface quality of its profile directly affect the aerodynamic performance and mechanical efficiency of the engine, and have a decisive impact on the engine performance. Integral impeller has become a typical difficult to machine part because of its complexity of curved surface and high machining accuracy. With the increasing demand for turbine engines in the market, it is increasingly necessary to achieve efficient machining of integral impellers. At present, the common materials of integral impeller are aluminum alloy, titanium alloy, stainless steel, etc. The complexity of impeller machining mainly lies in the complexity of blade surface modeling, which can be divided into ruled surface and non ruled surface according to the molding principle, and ruled surface can be divided into developable ruled surface and non developable ruled surface. Five axis NC milling is one of the commonly used methods for machining integral impeller with good flexibility, high machining efficiency and wide application. According to the different surface shapes of impellers, two kinds of methods are usually used for machining on CNC machine tools, namely, point milling method and side milling method. Due to the complex shape of the integral impeller and the large distortion of the blade, the machining of the integral impeller is very easy to interfere, so the machining difficulty lies in the rough and finish machining of the runner and blade. In the process of NC machining of integral impeller, taper ball end milling cutter is often used to minimize over cutting and interference caused by the cutter, and the cutter can still have good rigidity when machining narrow runner. In order to make the impeller meet the requirements of aerodynamics, the blade often adopts the structure of large twist angle and variable fillet at the root, which puts forward higher requirements for the processing of the impeller. The machining technical requirements of integral impeller include the requirements of size, shape, location, surface roughness and other geometric aspects, as well as the requirements of mechanical, physical and chemical properties. The impeller blade must have good surface quality, and the accuracy is generally concentrated on the blade surface, hub surface and blade root surface. The surface roughness value should be less than Ra0.8um. In order to meet the above requirements, the following problems are often encountered in the processing of integral impeller: ① The integral impeller has narrow flow passage, relatively long blade and low stiffness, which belongs to thin-walled parts and is easily deformed during processing. In the process of machining, due to the role of its own structure and external cutting force, the inlet of the runner and the upper end of the blade will produce vibration lines. Sometimes, in order to avoid chatter marks, it is necessary to change the sharpness of the tool, which will cause burrs at the inlet, outlet and blade edges of the runner. In order to ensure the surface quality of the integral impeller, it is required that the cutter has enough rigidity, enough chip removal space and appropriate sharpness. ② The blade depth at the narrowest part of the runner is far more than the tool diameter, and the adjacent blade space is very small. The tool diameter is small during angle cleaning, and the tool is easy to break. The control of the cutting depth is also a key technology for machining. ③ The surface of the integral impeller is a free surface, with narrow flow passage, severe blade distortion, and a clear tendency to lean back. It is very easy to cause interference during processing, which is difficult to process. Some impellers have auxiliary blades. In order to avoid interference, the curved surface must be machined in sections. Therefore, it is difficult to ensure the consistency of the machined surface. ④ Considering that the overall impeller rotates at a high speed in actual work, with a speed of 30000-50000 revolutions, it is necessary to prevent vibration and reduce noise, so the requirements for dynamic balance are high, which improves the requirements for machine tools and tools. It is necessary to save the processing time, and ensure the stability and symmetry of cutting. Considering the rigidity of machine tool, cutter, fixture and integral impeller, designing reasonable cutter structure and selecting appropriate manufacturing process can meet the manufacturing requirements of integral impeller.

The positioning accuracy of CNC machine tools refers to the position accuracy that can be achieved by the movement of each coordinate axis of the machine tools under the control of CNC devices. The positioning accuracy of CNC machine tools can also be understood as the kinematic accuracy of machine tools. The common machine tool is fed manually, and the positioning accuracy is mainly determined by the reading error, while the movement of the CNC machine tool is realized by the digital program command, so the positioning accuracy is determined by the CNC system and mechanical transmission error. The movement of each moving part of the machine tool is completed under the control of the numerical control device. The accuracy of each moving part under the control of the program command directly reflects the accuracy of the processing part. Therefore, the positioning accuracy is a very important detection content. 1. Linear motion positioning accuracy detection The positioning accuracy of linear motion is generally carried out under the no-load condition of the machine tool and the workbench. According to the national standards and the provisions of the International Organization for Standardization (ISO standards), the detection of CNC machine tools should be based on laser measurement. In the absence of a laser interferometer, ordinary users can also use a standard scale and an optical reading microscope for comparative measurement. However, the accuracy of the measuring instrument must be 1~2 grades higher than the measured accuracy. In order to reflect all the errors in multiple positioning, the ISO standard stipulates that each positioning point is a positioning point dispersion zone composed of the average value and dispersion - 3 dispersion zone calculated according to five times of measured data. 2. Repetitive positioning accuracy detection of linear motion The instrument used for detection is the same as that used for detection of positioning accuracy. The general detection method is to measure at any three positions close to the midpoint and both ends of the travel of each coordinate. Each position is positioned by rapid movement, and the positioning is repeated 7 times under the same conditions. The stop position value is measured and the maximum difference between readings is calculated. One half of the maximum difference value of the three positions is attached with positive and negative symbols as the repeated positioning accuracy of the coordinate, which is the most basic index to reflect the stability of axis motion accuracy. 3. Detection of the Return Accuracy of the Origin of Linear Motion The origin return accuracy is essentially the repeated positioning accuracy of a special point on the coordinate axis, so its detection method is completely the same as the repeated positioning accuracy. 4. Reverse Error Detection of Linear Motion The reverse error of linear motion, also known as loss of momentum, includes the comprehensive reflection of the reverse dead zone of the drive parts (such as servo motor, servo hydraulic motor and stepping motor) on the feed transmission chain of the coordinate axis, the reverse clearance and elastic deformation of the mechanical motion transmission pairs. The larger the error is, the lower the positioning accuracy and repeated positioning accuracy are. The reverse error detection method is to move a distance forward or backward in advance within the stroke of the measured coordinate axis and take the stop position as the reference, then give a certain movement command value in the same direction to move it for a distance, and then move the same distance in the opposite direction to measure the difference between the stop position and the reference position. Carry out multiple measurements (generally 7 times) at three positions near the middle point and two ends of the stroke, and calculate the average value at each position. The maximum of the average value is the reverse error value. 5. Positioning accuracy detection of rotary table Measuring tools include standard turntable, angle polyhedron, circular grating and collimator (collimator), which can be selected according to specific conditions. The measurement method is to turn the workbench forward (or backward) for an angle and stop, lock, and locate it. This position is used as the reference, and then quickly turn the workbench in the same direction, lock and locate it every 30 for measurement. The forward rotation and reverse rotation shall be measured for one cycle respectively, and the maximum difference between the actual angle of each positioning position and the theoretical value (command value) is the indexing error. If it is a CNC rotary table, it should take every 30 as a target position. For each target position, it should be quickly positioned 7 times from the positive and negative directions. The difference between the actual position and the target position is the position deviation. Then, the average position deviation and standard deviation should be calculated according to the method specified in GB10931-89 Evaluation Method for the Position Accuracy of Digitally Controlled Machine Tools, The difference between the maximum value of all average position deviations and the standard deviation and the sum of the minimum value of all average position deviations and the standard deviation is the positioning accuracy error of the NC rotary table. Considering the actual use requirements of dry-type transformers, generally focus on the measurement of 0, 90, 180, 270 and other right angle equally divided points. The accuracy of these points is required to be one level higher than that of other angle positions. 6. Repetitive indexing accuracy detection of rotary table The measurement method is to select three positions at random within one week of the rotary table to repeat the positioning for three times, and detect them under the rotation in the positive and negative directions respectively. The maximum indexing accuracy of the difference between all readings and the theoretical value at the corresponding position. If it is a CNC rotary table, take one measuring point every 30 as the target position, and quickly locate each target position for five times from the positive and negative directions, measure the difference between the actual position reached and the target position, that is, the position deviation, and then calculate the standard deviation according to the method specified in GB10931-89. Six times of the maximum standard deviation of each measuring point is the repeated indexing accuracy of the CNC rotary table. 7. Zero point reset precision detection of rotary table The measurement method is to carry out the original point reset once from 7 arbitrary positions, measure the stop position, and take the maximum difference read as the original point reset accuracy. It should be pointed out that the existing positioning accuracy is measured under the condition of fast and positioning. For some CNC machines with poor feed system style, different positioning accuracy values will be obtained when positioning at different feed speeds. In addition, the measurement result of the positioning accuracy is related to the ambient temperature and the working state of the coordinate axis. At present, most CNC machine tools use a semi closed loop system, and the position detection elements are mostly installed on the drive motor. It is not surprising that the error of 0.01~0.02mm occurs within 1m travel. This is the error caused by thermal elongation. Some machine tools adopt pre stretching (pre tightening) to reduce the impact. The repeated positioning accuracy of each coordinate axis is the most basic accuracy index reflecting the axis, which reflects the stability of the motion accuracy of the axis. It cannot be assumed that the machine tool with poor accuracy can be stably used in production. At present, due to the increasing functions of the NC system, systematic compensation can be made for the systematic errors of the movement accuracy of each ejector mark, such as the pitch accumulation error and the reverse clearance error. Only the random error can not be compensated. The repetitive positioning accuracy reflects the comprehensive random error of the feed drive mechanism, which cannot be corrected by the CNC system compensation. When it is found that it is out of tolerance, only the fine adjustment and correction of the feed drive chain can be made. Therefore, if the machine tool is allowed to be selected, it is better to select the machine tool with high repeated positioning accuracy.

If a drill is used to process the cross holes of steel parts, it is a headache for many tool manufacturers and engineers. After R&D, the Antimony Mast Tool finally solved this problem, providing an optimized process plan and a special drill for such processing. For the drilling of cross holes of steel parts, the impact at the broken hole causes uneven stress on the drill bit, which is prone to blade breakage, tool breakage and rapid wear. As a result, tool users have high cost and low efficiency, and the quality is difficult to control stably. A well-known domestic axle manufacturer has been puzzled by this problem for a long time. Product working conditions and processing conditions are as follows: The material to be machined is 50 # steel, HRC28-32, with holes drilled on the blank surface, roughness of 3.2, one piece with two holes, vertical CNC machining center, machine tool with internal cooling, hydraulic fixture, hydraulic tool handle. The hole depth, diameter and hole breaking are shown in Figure 1: Fig. 1 Cross hole size of axle pin hole At present, there are many well-known brands of suppliers providing solutions and tools for this axle manufacturer, but the effect is not satisfactory. The following situations are summarized: Scheme 1: The world's top brand replaceable drill bit or U-drill is used. When the drill bit is processed to the hole breaking point, the interchangeable head will often fall off. This scheme is unstable. Scheme 2: The standard cemented carbide internal cooling bit of the world's top brand is used to complete the drilling directly in one sequence. The practice has proved that the machining is unstable, the service life is low, the tool is often broken, and the straightness and roughness are difficult to guarantee. Scheme 3: Adopt the world's top brand of cemented carbide internal cooling flat bottom drilling. Practice has proved that the efficiency is low, the tool wear is fast, and frequent tool change is required. Scheme 4: Increase the pilot drill, use the world's top brand drill bit, feed in sections, and reduce the speed at the half hole, so that the size and requirements of the processed product are still stable, but the drill bit is still rapidly worn, and the number of regrinding is only one or two times. For such a low life, the customer's cost is also very high. Obviously, the above schemes have obvious shortcomings. The scheme provided by Sima Tools has achieved the following four points: 1. The drill bit is normally worn, the processing condition is stable, and the hole size and all requirements can be continuously guaranteed; 2. The service life is stable at 210-230 pieces (38-40M), which is twice the best use of imported brand bits mentioned above; 3. Increase efficiency by 1/3; 4. The number of regrinding can be 5-7, and the cost reduction is also considerable. After several improvements in bit design and processing technology, the above effects have been achieved. First of all, the drill bit is designed ingeniously, especially the transverse edge form, tip protection and negative chamfer design of the groove are just right, and the edge passivation further improves the wear resistance, as shown in Figure 2. Fig. 2 Perfect groove, edge and edge treatment Secondly, through many tests, we have summarized a reasonable cutting scheme - guide drill+hole breaking drill, as follows: Process 1: guide the drilling to a certain depth to guide the hole breaking drill. Procedure 2: ￠ 15 hole breaking drill processing, Vc=70M/min, feed is divided into three sections, and F=0.25mm/r is used when processing to 30MM depth. When processing to 60MM depth (i.e. hole breaking processing section), the feed speed is reduced by F=0.1mm/r, and then it is restored to F=0.25mm/r after the hole breaking processing, until the whole hole processing is completed.

Question raising Fixed plate (material: 45 steel, overall dimension: 1005 × seven thousand × 20mm), a total of 1071 pieces need to be drilled φ 24mm 30 ° inclined hole, and the surface roughness of the hole wall is required to reach Ra6.3 μ m。 When drilling, the thickness of the workpiece is 3mm greater than the nominal size (reserved as fine planning allowance). When the standard fried dough twist drill is used to drill the fixed plate on the z3550 universal rocker drilling machine, the following process problems occur: 1) When drilling a 30 ° oblique hole with a standard fried dough twist drill bit, the included angle between the drill bit and the workpiece is small. In order to ensure the processing length, it is necessary to lengthen the drill rod and drill bit, thus reducing the rigidity of the drill bit. In addition, when drilling inclined holes, the drill bit is in intermittent cutting state for quite a long time and has a large radial resistance. In order to avoid blade breakage and ensure normal processing, the cutting amount must be reduced, which directly affects the processing efficiency and production progress. 2) When drilling straight holes, the drilling and expanding process can be used to reach Ra6.3 μ M surface roughness requirements. However, when drilling 30 ° inclined holes, due to intermittent cutting and radial resistance, the drill bit always has vibration in the drilling process. Although the radial resistance can be partially reduced by using the drill sleeve guidance, the vibration will still accelerate the wear of the drill bit, causing the external edge of the drill bit to break, which seriously affects the normal drilling and drilling quality. In order to solve the above problems, the oblique hole drilling technology and the standard fried dough twist drill structure used for processing were improved. 2. Improvement of drilling technology 1) . Change the drilling process of inclined hole from direct drilling to reaming after drilling, i.e φ One more in 24mm drill sleeve φ 21mm drill sleeve, first use φ Drill holes with a 21mm drill bit and then use φ Reaming with 24mm drill. 2) In order to ensure the dimensional accuracy of the fixed plate hole spacing and improve the stability of the drill at the beginning of drilling, a special oblique hole drilling die is designed. 3) In order to eliminate the radial resistance generated by the drill tip at the moment of just drilling through the workpiece, a layer of A3 material process plate is set under the workpiece during drilling. 4) Selection of drill type: in order to improve the rigidity and drilling accuracy of the drill bit, the long edge fried dough twist drill bit with thickened core and parabolic cutting edge groove is selected, and the drill tip of the drill bit is ground by machine to ensure that the angles of the two edges are symmetrical and the cutting edges are evenly stressed. 5) Grinding of bit angle: for drilling φ 21mm drill bit. At the beginning of drilling inclined holes, the drill bit is in intermittent cutting state, and the cutting area is from small to large to continuous cutting state. The processing length at this stage is 48 mm. In the intermittent cutting stage, the friction between the edge of the drill bit and the inner wall of the drill sleeve is large under the action of the radial resistance. To reduce the friction φ The geometric angle of the 21mm drill point is grinded into the group drill type. Because the change of the bit sharp angle (main deflection angle) will change the size ratio of the radial cutting force Py and the axial cutting force (cutting force) Px, that is, the radial cutting force Py will decrease with the increase of the sharp angle, so it is necessary to increase the two sharp angles when grinding the bit. At the same time, the transverse edge of the drill point is sharpened to reduce the axial cutting force; Grind the arc edge low, and the arc bottom is close to the side edge of the drill bit to narrow the width of the external straight edge, reduce the axial height between A and B, so as to increase the annular rib, enhance the centering effect of the drill bit side tip, and achieve the purpose of improving the cutting stability. In this way, when the drilling length exceeds A and B, the radial cutting force near the drill point is opposite to and smaller than the radial component of the external straight edge. 3. Improved processing effect After the geometric angle of the drill bit is determined, the reasonable cutting parameters (rotating speed n=160r/min, feed rate f=0.08~0.10mm/r) are selected through the cutting test. After the oblique hole on the fixed plate is drilled, it needs to be manually grinded with a grinding wheel (the diameter after grinding is φ 24 ～ 24.5mm), and then polish with emery cloth to make the surface roughness of each hole basically reach Ra6.3 μ m。 After processing, it is found that the generatrix of the hole wall at the drill opening of some holes is not straight. Through analysis, this is because the misalignment between the guide rail of the machine tool, the angle of the machine tool spindle and the drill template results in the inconsistent feed direction of the drill bit and the axis of the inner hole of the drill sleeve on the drill template. To solve this problem, each machine tool is equipped with a aligning mandrel. After each hole is drilled, move the position of the head of the machine, insert the aligning mandrel installed in the spindle hole of the machine tool into the drill sleeve of the drill template, adjust the position of the spindle of the machine tool, so that the spindle can rotate freely in the drill sleeve, and then take out the spindle and install the drill to drill. Through production verification, when using the improved drilling technology and fried dough twist drill to process 30 ° oblique holes of fixed plate parts, the processing effect is good, and the drilling quality and processing efficiency are significantly improved. Each shift can drill 30 ~ 35 holes.

Precision mechanical parts processing will inevitably have noise, noise will not only interfere with the normal work of the relevant personnel, but also a kind of pollution. So how to reduce the noise of precision mechanical parts processing? The following editor to tell you! 1. Civilized production.   Gear transmission noise has more than 30% of the reasons from the burr, bump injury. Some precision machinery parts processing factory in the gear box assembly before the removal of burrs and bump injuries, is a passive practice.   2, to ensure the accuracy of the tooth blank.   The accuracy of the size of the gear hole requirements in the hole deviation value of the middle difference around the distribution, set at ± 0.003 ~ ± 0.005mm; if the excess difference and within the design requirements of the hole, must be classified, respectively, transferred to the gear cutting process. 3、Control the accuracy of gears.   The basic requirements of gear accuracy: proven by practice, gear accuracy must be controlled in GB10995-887 ~ 8 levels, linear speed higher than 20m / s gear, tooth pitch limit deviation, tooth ring radial runout tolerance, tooth tolerance must be stable to 7 levels of accuracy.

At present, China's labor force is in shortage and labor cost is greatly increased. Especially the lack of skilled personnel is serious. Enterprises to be more competitive in the market must improve production efficiency. So how should we improve the efficiency of mechanical parts processing? The following is to introduce how to improve the efficiency of parts processing. 1. To improve the efficiency of parts processing must use more advanced CNC lathe processing to produce. CNC lathe processing in the production of more intelligent and fast, as long as a one-time design of the production program design can be a one-time batch of parts processing. 2. The hardness, toughness, etc. of the production cutting tools for parts processing will directly affect the efficiency of parts processing   3. The rationality of the production process when using CNC lathe processing will also directly affect the efficiency of parts processing.

Mechanical parts processing industry is the pillar of the national economy, with a very promising future. In the processing of precision mechanical parts, processing plant will have many requirements and regulations on the processing process to ensure the qualification rate of the factory parts. So we know the requirements of precision mechanical parts processing technology processing? Let's take a look below! 1, parts to remove oxidation, parts processing surface, there should be no scratches, scrapes and other defects that damage the surface of the parts, remove burrs flying edge;   2, by tempering, parts for high-frequency quenching, 350 ~ 370 ℃ tempering, HRC40 ~ 45, carburizing depth of 0.3mm, high-temperature aging treatment.   3, not injected shape tolerance should be consistent with the requirements of GB1184-80, not injected length size allowable deviation ± 0.5mm, casting tolerance zone symmetry in the basic size configuration of the blank casting; 4, not injected rounded radius R5, not injected chamfer are 2 × 45 °, acute angle inverted blunt;   5, the temperature shall not exceed 100 ℃, gear assembly, tooth surface contact spots and side clearance should comply with the provisions of GB10095 and GB11365;   6, assembly of the hydraulic system allows the use of sealing filler or sealant, but should be prevented from entering the system, into the assembly of parts and components (including outsourced parts, outsourced parts), all must have the inspection department's certificate of compliance before assembly.

In the mechanical parts processing industry, the standard, specifications, precision of the parts has always been the most important to the enterprise, but also the most important to the customer, for mechanical parts processing the accuracy of the good or bad directly related to the processing of products. So we know what to pay attention to mechanical parts processing materials? Here we take a look! Mechanical parts machining accuracy requirements first mechanical machining parts material to pay attention to, the material needs to meet the requirements of the drawings provided by the customer, in line with the national standards for materials. Commonly used specifications are "stainless steel material specification", "aluminum alloy material specification", "carbon structural steel material specification" . Mechanical parts of new products in the expansion of the market should take the initiative to look for opportunities to enter the market, and looking for opportunities requires mechanical parts processing enterprises have a good observation, comprehensive analysis and imagination. The relevant experts pointed out that in recent years, with the implementation of the policy of joint development of a variety of ownership, mechanical parts processing industry is experiencing the development process from the scattered to gradually set intensive. And in this process, small and medium-sized enterprises should pay particular attention to the improvement of their own competitive strength, because the market competition is fierce, the market rules do not advance or retreat also applies to the parts processing industry.

The general layout of the machining of mechanical parts is required to follow certain principles, so do you know what errors and wear and tear of its tool manufacturing? Let's take a look below! 1, fixed size tools (such as drills, reamers, keyway milling cutters and round broaches, etc.) of the size accuracy directly affect the size accuracy of the workpiece.   2, forming tools (such as forming turning tools, forming milling tools, forming grinding wheels, etc.) shape accuracy will directly affect the shape accuracy of the workpiece   3、Spreading tools (such as gear hobs, spline hobs, gear shaping tools, etc.) shape error of the cutting edge will affect the shape accuracy of the processed surface.   4, general tools (such as turning tools, boring tools, milling tools), its manufacturing accuracy has no direct impact on machining accuracy, but the tool is easy to wear.   Mechanical parts machining process protocol design principles.   1, the designed process procedures should be able to ensure the processing quality of machine parts (or machine assembly quality), to achieve the technical requirements specified on the design drawings.   2, should make the process has a high productivity, so that the product as soon as possible to market.   3, try to reduce manufacturing costs. 4, pay attention to reduce the labor intensity of workers, to ensure production safety. Scope of application of mechanical parts processing.   1、All kinds of metal parts processing;   2、Sheet metal, box, metal structure;   3, titanium alloy, high-temperature alloy, non-metallic machining;   4, wind tunnel combustion chamber design and manufacturing;   5, non-standard equipment design and manufacturing;   6、Mold design and manufacturing.