Cnc processing, CNC lathe processing, metal precision parts processing, machining processing manufacturing plant, thousands of parts produced a car. The quality of the parts determines the quality of the car. The processing quality of auto parts affects the service life, working performance and reliability of auto parts. Ensuring the cnc machining quality of automobile shaft parts is an extremely important link to ensure the quality of the entire vehicle. In order to ensure the quality and safe operation of vehicles, manufacturing and processing enterprises should continuously improve the processing quality of automobile shaft parts. This article analyzes and discusses how to improve the processing quality of automobile shaft parts.
Keywords: shafts; handling errors; quality
1. Characteristics of automobile shaft parts
Shaft parts are common typical parts that support transmission components, carry loads, transmit torque and power in automotive mechanical structures. The failure modes of shaft parts include fatigue, overload fracture, excessive deformation and excessive journal wear. From the perspective of the performance requirements of shaft parts, the selection of materials should have higher rigidity and strength margin, appropriate impact toughness and higher fatigue strength, and the friction parts at the journal should have higher strength and wear resistance . Technical workability and hardenability.
2. Processing technology analysis of automobile shaft parts
Alloy steels such as 30Mn2, 40MnB and 40Cr are usually used as raw materials for manufacturing shaft parts, while rough parts are usually steel die forgings. First check the size of the sawn material, and then change the metallographic structure of the steel by heating to improve the pressing performance and processing performance. After the raw material is pressed, it is stamped.
(2) Mechanical processing, heat treatment and quality control procedures
1. Determine the content of the process, analyze the CNC process of the part drawing, determine the mathematical processing and programming size settings of the part drawing, select the type of CNC machine tool, and formulate the CNC process route, such as process division, processing sequence arrangement, benchmark selection, and NAND CNC machining china technology connection, etc. Design CNC technology, such as determining work steps, tool selection, fixture positioning and installation, determining feed route, measuring, determining cutting amount, etc. Compile, check and modify machining programs, adjust CNC machining process programs, such as tool setting and tool compensation.
2. Heat treatment is generally applied to parts after rough machining, that is, high temperature quenching and tempering after quenching to obtain higher shaft strength and hardness, better plasticity and toughness, that is, good comprehensive mechanical properties.
3. Hardness testing and tissue flaw detection. Test the hardness of the parts after heat treatment with a Brinell hardness tester, and measure the hardness value according to the indentation depth. Then use the ultrasonic flaw detector to detect the internal tissue defects of the parts, and observe whether the internal tissue has cracks, pores, wrinkles and other defects.
4. Metallographic examination. Sampling and slicing the finished product, and then inspecting the slice with a metallurgical microscope, and observing whether the metallographic structure of the test sample meets the relevant grade evaluation standards.
5. Final inspection. According to the requirements of the technical documents, complete the dimensional inspection and special characteristics inspection of the finished product, and record the process records as required. 3. From manufacturing process and process to good quality.
Measures to improve the machining quality of shaft parts
In order to ensure and improve the processing quality of automobile shaft parts, the processing error of parts must be reduced. According to different causes of errors, different measures can be taken or combined to ensure and improve the machining accuracy of parts.
1. Measures to reduce the mechanical deformation of the process system
(1) Improve contact rigidity
Common methods to improve contact stiffness include: first, improve the matching quality of the contact surfaces of the main components of the process system; second, pre-load to reduce the deformation after stress.
(2) Improve the rigidity of the workpiece and reduce stress and deformation
For shaft parts, especially slender shaft and fork parts, deformation is very easy. The main measure is to reduce the distance between the cutting force point and the supporting surface of the workpiece to increase the rigidity of the workpiece during the processing. In mechanical processing, some auxiliary devices can be used to increase the rigidity of machine tool parts.
(3) Reasonably clamp the workpiece and reduce the clamping deformation. For processing various shaft parts, especially thin-walled or small-sized parts, an appropriate machining method should be selected to reduce the shape error.
2. The main measures to reduce the thermal deformation of the process system
(1) Reduce heating and heat insulation
The heat can be dispersed by changing the structure of the machine tool or the lubrication method.
(2) Enhance heat dissipation capacity
In order to eliminate the influence of the heat source inside the machine tool, forced cooling can be used to absorb the heat of the heat source, thereby controlling the temperature rise and thermal deformation of the machine tool.
(3) Thermal compensation method to reduce the influence of thermal deformation
In order to make the overall temperature of the machine tool uniform, instead of promoting a single heat reduction, the thermal compensation method can make the temperature field of the machine tool more uniform and produce uniform thermal deformation to reduce errors.
(4) Control temperature changes
The temperature change in the workshop affects the accuracy of the machine tool. The engine bed can be preheated in advance to reduce temperature changes. The manufacture and installation of auto parts is the most important cause of product failure. Through the breakdown of manufacturing issues, we can see that auto parts and raw materials are extremely critical parts, so the assembly process should also be considered. In addition, relevant personnel should take a variety of effective measures when continuously supervising the quality of auto parts to continuously improve the quality of purchased auto parts. For example, the following measures can be taken to optimize the supervision and management model. First, strengthen supervision and management and expand the scope of supervision. Second, establish a component quality supervision system for the manufacturing system and make full use of information resources to supervise auto parts. Third, establish a linkage mechanism to enable suppliers to provide quality assurance for auto parts. At the same time, suppliers should be dynamically managed. Fourth, establish an auto parts quality supervision and control expert database, and continue to improve in practice. At the same time, it is necessary to establish a strong supervision team to strengthen the management of auto parts. Finally, it is necessary to continuously optimize the auto parts management mode, and at the same time combine development, innovate the grid auto parts supervision mode, and strengthen the supervision of the quality of life of auto parts. Only by doing this well can large-scale bidding be conducted to ensure the quality and management of auto parts.
In short, before processing shaft parts, production enterprises should fully understand and analyze the impact of processing accuracy and quality, find and solve problems in actual operation, timely summarize the experience and lessons of processing and manufacturing, and continuously improve the quality of processing to make machinery manufacturing enterprises stable , Healthy and sustainable development.
Analysis of factors affecting the machining quality of shaft parts
1. Blank quality
The quality of any product must first be controlled from a blank source. Selecting raw materials that meet production standards is a critical first step in ensuring the quality of parts.
2. Geometric error of the process system
Mainly include: first, the error of the spindle rotation movement directly affects the machining accuracy, especially in finishing, this error is often the main factor affecting the roundness error of the workpiece. The second is the error of the guide rail. The positioning, clamping, installation and tool setting errors of the tool will affect the machining error of the part.
3. Errors caused by thermal deformation of the process system
The internal heat source includes cutting heat and frictional heat; the external heat source includes ambient temperature and radiant heat. Cutting heat and friction heat are the main heat sources of the process system. Due to the influence of cutting temperature, workpieces, tools and fixtures will deform and produce machining errors.
4. Errors caused by mechanical deformation of the process system
The main influencing factors are: one is insufficient rigidity of workpiece; second, insufficient rigidity of tool; third, insufficient rigidity of machine tool parts. Fourth, the effect of process system stiffness on machining accuracy.
5. Error caused by the internal stress of the workpiece
After casting, forging and cutting, the workpiece will have various internal stresses. The redistribution of the internal stress of the parts will not only affect the machining accuracy of the parts, but also have a great influence on the assembly accuracy. Slim shaft parts are easy to bend and deform during processing and transportation. Under normal circumstances, the stress is in equilibrium, but the blank or the processed workpiece is stressed. When the stress of the workpiece returns to equilibrium, the workpiece will be deformed, resulting in processing errors.
6. Measurement error
The accuracy of measurement methods and measurement tools affects the errors caused by the accuracy of measurement results. In the processing system, the mutual position accuracy of the workpiece and the tool on the machine tool is guaranteed by adjusting the machine tool, tool, fixture, or workpiece. In order to adjust the error, the accuracy of the measurement method and measurement tool must be strictly specified and required.