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

What is the source of milling force in precision machining In precision parts processing, the milling process is the interaction between the milling cutter and the workpiece, and therefore consumes power. Milling force directly affects the generation of cutting heat, and further affects tool wear, tool life and the quality of machined surfaces. In production, the milling force is also the necessary basis for determining the power of the computer machine and the clamping force. Therefore, it is of practical significance to study the variation law of the milling force and estimate the milling force and power. The source of milling force There are two aspects of the source of milling force: one is the resistance caused by the elastic deformation and plastic deformation of the cutting layer metal, cutting and surface layer metal of the workpiece; The second is the friction resistance between the milling cutter and the chip and the workpiece surface. As the number of teeth, cutting thickness and milling position involved in the milling process in precision parts processing are constantly changing, the size, direction and action point of cutting force are also constantly changing. In order to facilitate the analysis, the total milling force on a pair of force bearing bodies (milling cutter and workpiece) is generally decomposed in a certain direction, and the change of each milling force component is analyzed, so that the change rule of milling force can be mastered.

How to observe the fault phenomenon and cause analysis in precision parts processing In the process of precision parts processing, the fixture of the milling machine breaks down, and there are some obvious faults, such as the machining accuracy of the parts cannot be guaranteed, the clamping of the parts is not firm, some components of the fixture are damaged and seriously worn, and the device and mechanism cannot realize the operation function. At this time, it is mainly through detection, observation and experimental operation to preliminarily determine the main part causing the fault. Failure cause analysis Various failures of the milling machine fixture, if caused by a single reason, the analysis can be carried out according to the general rules, such as the displacement of parts during processing, and the cause may be the clamping part failure; The dimensional accuracy of precision parts processing has regular deviation, which may be caused by the decline and looseness of the positioning element accuracy of parts; The machining accuracy deviation of the parts is consistent, which may be caused by the failure of the tool setting device. If it is caused by multiple reasons, it is necessary to further analyze the relevant reasons after analyzing the above single reason. For example, the position accuracy of the plane milling fixture decreases, which may be caused by wear on the top of the support limiting element, misalignment of the linkage clamping mechanism and other reasons.

What are the process design principles of turning milling 1. Turning and milling process The turning milling compound processing process consists of one or more programs arranged in sequence, which can be subdivided into work steps or tool paths. Process refers to a part of the process in which a worker (or group of workers) continuously completes the same (or several) workpieces on the machine tool (or work site). Process flow is the basic component of process flow and the basic unit of production plan. 2. Steps and tool feeding An operation is one that is completed continuously under the conditions of the same machining surface, the same machining tool and the same cutting amount. A process consists of one or more steps. If the metal layer to be cut in one process step is very thick, it must be cut several times, and each cut is one time. A step can include one or more passes. 3. Installation and station Installation refers to the process completed after the workpiece (or assembly unit) is clamped. A process can include one or more installations. Station refers to the process completed at each position occupied by clamping on the machine tool at one time. When the indexing fixture, turntable or multi axis machine tool is used in the turning milling compound processing in Dongguan, the workpiece needs to pass through multiple stations for one clamping.

What are the selection principles of turning milling composite machining process benchmark 1. Selection principle of rough datum (1) The principle of uniformity of important surface margins. First, it is necessary to ensure that the important surface of the workpiece has a small and uniform machining allowance. (2) Principle of mutual position requirements of workpiece surfaces. The mutual position requirements of the machined surface and the unmachined surface on the workpiece must be guaranteed, and the unmachined surface is taken as the rough machining datum. (3) The principle of sufficient margin. If all surfaces on the part need to be machined, the surface with small machining allowance shall be taken as the rough datum. (4) The principle of reliable positioning. As a rough datum plane, a relatively reliable, smooth and clean surface shall be selected to ensure accurate positioning and reliable clamping. (5) Non reuse principle. The coarse datum positioning accuracy is low. The same dimension direction can only be used once and cannot be used repeatedly, otherwise the positioning error is too large. 2. Selection principle of precise benchmark When selecting the precision base, the key point to be considered is how to reduce the error and ensure the precision of Dongguan turning milling composite processing and convenient installation. The selection principles of precise benchmark include: (1) Principle of datum coincidence. The design datum of the part shall be selected as the datum as far as possible to avoid the misalignment error of the datum. (2) The principle of unified datum. The precision datum selected as far as possible shall be used for positioning and processing each surface to ensure the mutual position accuracy between the surfaces. (3) Self reference principle. Some finishing or finishing processes require small and even machining allowance, so the machined surface itself should be selected as the finishing benchmark. (4) The principle of mutual reference and repeated processing. Some surfaces with relatively high mutual position accuracy requirements can be guaranteed by the principle of mutual reference and repeated turning milling in Dongguan. (5) Positioning reliability principle. The precision datum shall be flat and smooth, with certain accuracy, to ensure simple positioning, easy installation and reliable clamping. The selection principles of benchmarks are summarized from production practice, and must be analyzed and applied in combination with specific production conditions, production types and processing requirements.

The Geometric Angles of Cutting Tools and the Types of Their Reference Systems in Precision Parts Processing There are two types of geometric angles of tools in precision parts processing: one is that the tool is regarded as a geometric entity, which is used to determine the angle of the geometric position of the cutting edge and tool face relative to the positioning datum of the tool during manufacturing, grinding and measurement, which is the angle marked on the tool working drawing, and this kind of angle is called the static angle or marked angle of the tool; The other is used to determine the geometric angle of cutting edge and cutter face relative to the tool in the cutting process, which is the actual geometric angle in the process of tool working. This angle is called the tool working angle. In order to define the working angle of the tool, a reference system consisting of two sets of corresponding planes must be established for the tool in precision part machining. One is the static reference system that defines the static angle of the tool, and the other is the working reference system that defines the working angle of the tool. Its constituent planes should be defined according to the direction of the composite cutting force and the direction of the feed movement in the actual cutting process. When establishing the static reference system, it is necessary to assume that the tool is in a certain working state, and the assumed main motion direction and assumed feed motion direction of the tool are perpendicular to the milling cutter axis. Tool static angle and static reference are widely used, while tool dynamic geometric angle is more complex. Dongguan Yamei Precision Machinery Parts Co., Ltd. focuses on CNC precision machining supporting services for automation, aviation, basic scientific research, optical fiber, communication, semiconductor, electronics, medical devices, auto parts suspension and other equipment accessories. Processed materials: aluminum alloy, stainless steel, magnesium alloy, titanium alloy, nickel base alloy (invar invar alloy/invar alloy, kovar kovar alloy/kovar alloy), high-temperature alloy, tungsten copper alloy, engineering plastics and other special difficult to process materials. Processed products: precision mechanical parts, medical precision parts, aviation parts, instrument and meter parts, optical fiber communication parts, electronic product parts, auto parts, shock absorbers, suspension parts, non-standard components, connectors, alloy parts, hardware shells, heat sinks and other high standard products in the industry.

The Role of Positioning Operation Specifications in Precision Parts Processing Be familiar with the positioning method and wear rule of precision reference positioning elements in precision parts processing, and conduct workpiece positioning operation according to the process operation instructions. For example, when using the fixture with side and horizontal precision datum positioning, pay attention to cleaning the surface of the positioning element. The chip on the surface of the horizontal support plate is difficult to remove, so it should be carefully cleaned. During the installation of workpieces, the method of long distance movement on the positioning element shall not be used for positioning, so as to avoid damaging the accuracy of the workpiece datum and fixture positioning datum. Generally, thin feeler gauge is used to detect the fitting degree between the workpiece reference plane and the fixture locating surface. It is forbidden to impact or strike the locating element when the workpiece is placed. The method of slight movement and slow approaching is used to make the precision reference plane of the workpiece contact and fit the fixture locating surface. Due to the workpiece movement and the impact of each placement on the edges and corners of the positioning surface of the support plate, the wear of the support plate is generally at the edges and corners. Another example is to use the horizontal axis of the cylindrical positioning shaft to position the sleeve parts, because each time the workpiece is placed, the workpiece will hit the circumference edge of the guide part when it is sleeved into the positioning shaft. However, due to the gravity of the workpiece when disassembling the workpiece in the process of precision parts processing, the cylindrical surface and the edge of the positioning shaft will be more worn due to the large friction. Therefore, the parts with large wear of the horizontal positioning shaft should be located at the edge of the connecting part between the shaft end guide part and the positioning cylindrical surface and the upper part of the positioning cylinder. Therefore, for the fixture with such positioning elements, attention should be paid to overcoming the influence of gravity on the increase of local friction of the positioning elements, so as to extend the service life of the positioning elements of the fixture.

The Structural Characteristics of Three sided Milling Cutter with Staggered Teeth in Precision Parts Processing The structural characteristics of circumferential grooves and cutter teeth in precision parts processing are shown in the figure The tooth grooves on the circumference are spiral, and have two directions of rotation with staggered intervals. Half of the tooth grooves are right-handed and the other half is left-handed. The teeth of the main cutting edge, the rake face and the rake face with a certain angle are formed by the polygonal tooth back and the tooth space containing the chips. The cutter teeth are also divided into right and left rotation, and the left and right cutter teeth are staggered on the circumference. The structural characteristics of the end face gear groove and cutter teeth The structural characteristics of the end face gear groove distribution of the staggered three edge milling cutter. Because the circumferential gear groove has left and right rotations, on the same end face, half of them are the end cutting edges with positive rake angle and the other half are the end cutting edges with negative rake angle. The staggered three side milling cutter retains the end cutting edge with positive rake angle and cancels the end cutting edge with negative rake angle. It is recessed into the two end faces, so as to form the tooth grooves and cutter teeth that are staggered and evenly distributed at both ends of the staggered three side milling cutter. In the process of precision parts processing, the cutting edges at both ends of the cutter have good cutting ability and spacious chip holding grooves.

What are the characteristics of centralized and decentralized turning milling combined machining processes Centralization and dispersion of turning milling processes are two different options for the preparation of process routes. The process dispersion is to divide the processing of each surface of the part into very fine parts, with many processes and long process routes. On the contrary, the processing of parts is only concentrated in a few processes, while each process contains a lot of processing content. 1. Characteristics of process concentration (1) It is convenient to use efficient special equipment and process equipment to greatly improve productivity. (2) The number of equipment is reduced, and the production area of operators is correspondingly reduced. (3) The number of processes is reduced, the workload of transportation is reduced, the production planning is simplified, and the production cycle is shortened. (4) The number of workpiece installation times is reduced, which is not only conducive to improving productivity, but also easy to ensure the mutual position accuracy between them because many surfaces are processed in one installation. (5) Because the number of special equipment and special process equipment used is large and complex, the adjustment and maintenance of machine tools and process equipment are time-consuming, and the production preparation workload is large. 2. Characteristics of decentralized processes (1) Simple machine tools and process equipment are used, which is easy to adjust. (2) Because the process content is simple, it is conducive to selecting reasonable cutting parameters, arranging process time and organizing flow production. (3) The production preparation workload is small, and it is easy to adapt to product replacement. (4) Low technical requirements for operators. (5) The number of equipment is large, the number of operators is large, and the production area is large.

Three working procedures in turning milling compound processing Dongguan turning milling compound processing process of a complex part consists of machining process, heat treatment process and auxiliary process. 1. Machining process: (1) Benchmark before others. At the beginning of processing, always arrange the processing of the fine base plane first and then use the fine base plane to process other surfaces (2) Coarse before refined. Rough machining is arranged first, semi finishing is arranged in the middle, and finishing and finishing are arranged finally. (3) First primary, then secondary. First arrange the processing of the main surface, and then arrange the processing of the secondary surface. 2. Heat treatment procedure Heat treatment is used to improve the properties of materials and eliminate internal stress. The arrangement of heat treatment in the process route mainly depends on the materials of parts and the purpose requirements of heat treatment. (1) Prepare for heat treatment. Before machining, the main purpose is to improve the cutting performance and eliminate the internal stress during blank manufacturing. (2) Final heat treatment. It is mainly used to improve the strength and hardness of materials after semi finishing and before grinding. (3) Stress relief treatment. It is better to arrange after rough machining and before finish machining, such as artificial aging and annealing. 3. Auxiliary process The auxiliary processes include inspection, deburring, demagnetization, cleaning and oiling of workpieces. The inspection process is the main auxiliary process, which is the main measure to monitor the quality of Dongguan turning milling compound processing products.

What are the characteristics of repetitive positioning accuracy of linear motion in precision parts processing The positioning accuracy of CNC lathe in precision parts processing is to measure the position accuracy of the moving parts of the machine tool under the control of the CNC system. According to the measured positioning accuracy value of a CNC lathe, the best machining accuracy of the workpiece can be determined. The main detection contents of positioning accuracy include: linear motion positioning accuracy, linear motion repetitive positioning accuracy, etc. What we need to know today is linear motion repetitive positioning accuracy. The accuracy is the basic index reflecting the stability of coordinate axis movement, and the stability of machine tool movement determines the quality stability and error consistency of precision parts processing. The general inspection method is to measure at any three positions close to the midpoint of each coordinate stroke and at both ends. Each position is positioned by rapid movement. Under the same circumstances, the positioning is repeated 7 times, the coordinate value of the positioning point is measured, and the maximum difference between readings is calculated. Take 2/1 of the maximum difference of the three positions as the repeated positioning accuracy of the coordinate after taking the ± sign.