What is the process of machining parts?
After the third scientific and technological revolution, the world ushered in the era of rapid development of information technology. The advancement of science and technology has played an increasingly important role in politics, economy, and society, and it has also made international competition more and more fierce. As part of the mechanical processing technology of parts is included in the science and technology, the level and popularity of the mechanical processing technology of parts have become one of the important indicators to measure the comprehensive national strength and industrial modernization level of a country. As an advanced processing technology, parts machining technology has greatly promoted the development of my country’s parts processing industry and the development of my country’s manufacturing industry.
First, about the machining process of parts
The main content of the machining process of parts In modern society, the machining of parts is generally processed in the form of numerical control. Therefore, when processing parts, you must first understand the relevant processing technology and formulate appropriate processing plans. In-depth research and analysis of CNC machining technology. First of all, when performing CNC machining on parts, choose a suitable CNC machine tool, perform operations on the CNC machine tool, and determine what the processing procedure is. Then formulate a suitable processing plan for the CNC machining of the parts, analyze the drawings of the parts to be processed, perform the parts for the processing content of the parts and adopt the appropriate processing technology. The most important thing in the machining of parts is to design the process of parts processing, which is related to the quality of the parts. We must be clear about the steps of the part processing procedures, the selection of benchmarks, the selection of processing tools, the selection and installation of fixtures and processing The strategy and process parameters are determined so as to formulate the most suitable processing technology. In addition, we need to compile and test the NC programming programs for machining parts, control programming errors, and improve programming quality and efficiency.
The characteristics of the machining process of parts The machining of parts is generally carried out in the form of numerical control, so it is inevitable to have the characteristics of numerical control processing, but also has its own characteristics.
(1) CNC machining of parts requires that the content of the machining process be detailed and specific. When performing CNC machining on parts, a CNC machining plan will be formulated in advance, and then operated on the CNC machine tool, including the machining program, the selected tool, the machining method and the corresponding machining parameters, etc. These requirements are required for the machining of the parts. There must be a concrete and detailed plan, the plan is analyzed, and finally the processing procedure of the part is formed.
(2) The CNC machining of parts requires more rigorous and precise machining. The CNC machining mode is adopted for the machining process of parts, which makes the machining precision and quality of the parts higher, and does not require too many people during the machining process, which saves manpower, but on the other hand, human intervention Reduced, so that if there is a problem in the processing of the part, it cannot be adjusted artificially. Therefore, the setting of the CNC machining process of the part should be more rigorous and accurate, and no small error should occur, because the existence of the error is likely to be As a result, the processing technology is not up to the standard, the parts are discarded, and even mechanical accidents are caused.
(3) When performing mechanical numerical control processing on parts, mathematical calculations should be performed on the part graphics and the set value of the programming size. Because the machining of the parts adopts the numerical control mode, it is necessary to program and design before processing, the geometric mode of the size of the part, and the mathematical calculation of the size of the part processing, so comprehensive consideration should be given to all aspects when programming To design more optimized parts.
Second, analysis of the design principles of parts machining technology
The principle of positioning datum selection Positioning datum refers to the surface of the relative position of the part to the machine tool and the tool when the part is machined, and the original unprocessed surface is used when the part is processed for the first time. It is the rough datum. If the processed positioning datum is used after the original processing, this is the fine datum. So, what kind of surface should be selected as the positioning reference when performing parts machining? This must be carefully considered when performing part machining processes. The choice of positioning datum will affect the quality of parts processing and the complexity of the fixture structure of the machine tool. So what are the principles for choosing coarse benchmarks and fine benchmarks?
The principle of choosing the rough datum to follow When selecting the rough datum to process parts, ensure that the material is sufficient, the machined surface has sufficient margin, and the size and position of the machined surface of the unmachined side of the part must conform to the processing drawing Require. If you choose a rough datum, you must ensure that the surface of the part is easy to locate, easy to clamp and process, and the selected fixture should be as simple as possible. When choosing the rough datum, you must determine the machined surface and the unmachined surface, and there must be a precise location selection. Generally, the unmachined surface is used as the rough datum. When selecting the rough reference, it is generally to satisfy the important surface that the margin is small and uniform after roughing. When selecting the unprocessed surface, the position error of the rough reference should be evenly distributed on the unprocessed surface, and the rough reference surface is as good as possible. It may be flat and complete, without gaps, which is helpful for setting the position.
Principles to follow when selecting a fine datum When selecting a fine datum, first observe whether the fine datum is convenient for positioning and clamping processing, and if a certain surface is selected as a fine datum, the positioning of the selected surface can be uniformly used when selecting other surfaces Ways to improve processing efficiency, so careful consideration should be given to positioning the precise surface. The precision datum adopts the principle of precise coincidence, that is, the unified positioning principle is used to position and finish other surfaces.
The principle of selecting the surface processing method of parts For different parts surface and different parts processing requirements, part structure characteristics, material properties, etc., it is necessary to select a suitable processing method to process the surface of the part. When determining the processing method of a part, it is generally to determine the final processing method of the part first, and then from back to forward, derive and determine the processing method of the previous related procedures.
(1) The principle of economic applicability
When processing parts, first analyze the processing economy of the processing method, that is, select and analyze the equipment, technology, skilled workers, and processing time, that is, determine the suitability of the processing, determine the accuracy range of the processing, and the accuracy range It must be compatible with the accuracy requirements and surface roughness requirements of the surface processing of the parts, so as to ensure that the processed parts meet the requirements.
(2) The principle of adaptation to production types
Different processing methods should be selected for different types of production. When mass production is carried out, high-efficiency machine tools and advanced processing methods are often used. For small-batch production parts, the production methods of ordinary machine tools and conventional processing are generally adopted. method.
(3) The matching principle of processing methods
The machining method selected for machining parts must match the shape accuracy and surface position accuracy of the machined surface, be compatible with the material of the part, and be compatible with the existing equipment conditions and the skill level of the workers. Specific problems should be analyzed in detail, and processing should be performed according to processing requirements and existing resources. Do not blindly match and cause processing failures.
Third, the principle of selecting the order of parts processing
Types of processing sequence The machining process of parts is divided into different processing stages according to different processing properties and functions. Generally there are roughing stages, semi-finishing stages and finishing stages. In the rough machining stage, it is mainly to cut the remaining material on the surface of the machined part to complete the basic part processing. In the semi-finishing stage, it is mainly to perform secondary surface processing on the surface of the rough-machined part. In the finishing stage, the parts are precisely processed to meet the requirements of part processing. For some high-demand parts processing, it is necessary to go through a more refined processing stage.
The principle of combination of parts processing procedures After preliminary analysis of the parts and selection of the appropriate processing sequence, the further processing sequence should be determined according to the specific production conditions such as the structural characteristics of the parts, production types, technical requirements, equipment selection, etc., and the formulation is reasonable Processing technology. The principle of process dispersion. The mechanical processing of parts must follow the principle of process dispersion. The processed parts often need to go through multiple processes. The process of the processing technology is relatively long, and the processing content required for each process is relatively simple. On the basis of the principle of process dispersion, the selection of reasonable process equipment can reduce processing time and facilitate product replacement. The principle of process concentration. The processing of each surface of the part is concentrated in a few processes, and each process has more steps, which belongs to the principle of process concentration. Processing parts in this way facilitates the use of funny special equipment and improves processing efficiency and productivity. The principle of process concentration greatly simplifies production planning and production organization, reduces the number of workers required for parts processing, and improves processing efficiency. However, it has increased the difficulty of equipment adjustment and maintenance, increased the workload of production preparations, and increased the difficulty of replacing new products.
In actual production, the principle of process concentration is often used when processing small batches of parts. When processing large batches of parts, the principle of process dispersion can be used for assembly line production mode, and the principle of process concentration can also be used. Carry out parts machining.