Table of Contents
CNC machine tools, known for their high precision, efficiency, and automation, are particularly well-suited for processing irregular parts. Due to the complex shapes of these parts and the challenges they present in manufacturing, advanced processing technologies are essential to maintain quality and efficiency. However, the intricate nature of irregular parts necessitates that the processing techniques employed by CNC machine tools be carefully adjusted and optimized to achieve the desired outcomes.
Difficulties in processing
1. Complex process
Due to the complex shape and irregular geometric structure of irregular parts, the processing is difficult, so detailed process planning and organization are required before processing, including process route design, tool selection, processing parameter setting, processing sequence arrangement, etc.
2. High precision requirements
The processing precision requirements of irregular parts are usually very high, even reaching 0.1mm or even a micron level. During the processing process, the control of processing parameters, the stability of processing equipment, the selection of processing tools, etc. all put forward extremely high requirements for processing accuracy and stability. Once the processing accuracy and stability cannot meet the requirements, the quality of the parts will not meet the standards, affecting the quality and performance of the entire product.
3. Low processing efficiency
Irregular parts have complex structures. When processing these parts, CNC machine tools may require more complex programming and tool path planning to ensure that the desired shape is accurately processed. This may increase processing time and difficulty, resulting in relatively low efficiency.
Process design
1. Selection of machining toolsSince the cutting tool is cutting for a long time, its cutting performance and service life are important indicators that must be considered when selecting the cutting tool. Typically, you can choose an equilateral diamond-shaped coated insert with a specific angle (80°or 35°) to obtain better-cutting results. Among them, the 80° equilateral diamond-shaped coated insert is more suitable for processing harder materials or situations requiring greater cutting force, because it provides greater tip strength and cutting force. The 35° insert is more suitable for machining softer materials or situations where finer cutting is required because it can provide less cutting force and better surface quality. We usually use three methods to determine whether a processing tool should be replaced: (1) Observe the wear of the tool flank surface. When serious wear marks appear on the flank surface, which usually manifests as severe peeling of the coating, severe wear of the coating, or significant changes in the color of the coating, we should replace the tool in time; (2) Observe the surface of the processed parts. Under the same cutting conditions, if the shape of the chips changes greatly, for example, the cutting changes from long strips to short pieces or even chips, or if the color of the chips is directly observed, if it changes from silver to white, If it turns yellow or black, it indicates that the tool has been severely worn; (3)Judge by the sound of processing. If during the cutting process, the tool produces a sound that is different from normal cutting, such as loud noise, harsh sound, obvious change in timbre, etc., the tool should be replaced in time.
2. Selection of cutting parameters
The selection of cutting parameters should take into account the hardness and toughness of the processed material. For materials with higher hardness, the tool needs to withstand greater cutting force, so the cutting parameters need to be appropriately increased to improve cutting efficiency and ensure the service life of the tool. For materials with higher toughness, the cutting parameters need to be reduced to prevent excessive cutting force from causing deformation of the workpiece or damage to the tool. The selection of cutting parameters should also take into account the material and type of the tool. Tools of different materials and types have different wear resistance and rigidity, so when selecting cutting parameters, it is necessary to adjust according to the characteristics of the tool. Generally speaking, carbide tools can withstand greater cutting parameters, while coated tools need to reduce cutting parameters to avoid peeling of the coating on the tool surface. The type of tool will also affect the selection of cutting parameters, such as milling tools and turning tools will have different cutting parameters. In addition, processing requirements are also one of the important factors affecting the selection of cutting parameters.
3. Design of mechanical fixtures
For parts with complex shapes, the design of the fixture needs to be able to fully fix the parts to avoid displacement or deformation during processing. This requires that the clamping force of the fixture should be large enough, and at the same time, excessive stress on the parts should be avoided to avoid damage to the parts. The design of the fixture also needs to take into account the size of the parts. Parts with irregular sizes may have problems such as poor symmetry and difficulty in positioning in the fixture design. When designing a fixture, it is necessary to consider how to ensure that the position of the part in the fixture is accurate through appropriate positioning methods. The material and surface treatment of the fixture are also factors that cannot be ignored. The material of the fixture should have sufficient hardness and strength to ensure that the fixture does not deform or damage during long-term use. At the same time, the surface treatment of the fixture should also take into account the surface requirements of the parts to avoid damage or wear to the parts during the clamping process.
4. Determination of the benchmark
By carefully studying the drawings and technical requirements of the parts, determine the key parameters such as the geometry, dimensional tolerance, and surface roughness requirements of the parts. These parameters will become the basis for determining the benchmark, and the staff needs to operate strictly by these requirements. In the actual processing process, the determination of the benchmark involves many aspects. The first is the positioning benchmark of the part. The positioning benchmark refers to determining the specific position and direction of the part on the CNC machine tool. The second is the processing benchmark of the part. The processing benchmark refers to determining the relative position relationship between the part and the tool or workpiece table during processing. By accurately determining the positioning benchmark and the processing benchmark, it can be ensured that the part will not deviate during the processing process, thereby ensuring the dimensional accuracy of the part. Determination of the process benchmark, the process benchmark includes the setting of processing parameters such as cutting speed, feed speed, and cutting depth. The determination of these parameters directly affects the surface quality and processing efficiency of the part.
5. Workpiece clamping problem
Workpieces of different shapes and sizes require different clamping methods to ensure that the workpiece will not be displaced or deformed during the processing, thereby ensuring processing accuracy and quality. When clamping the workpiece, the staff needs to do a good job of workpiece clamping alignment, that is, to ensure that the position and direction of the workpiece in the clamping fixture are correct to reduce processing errors. At the same time, the staff also needs to consider the size and direction of the clamping force to prevent the workpiece from moving or deforming during the processing. When clamping the workpiece, it is necessary to ensure that the contact surface between the workpiece and the fixture is fully in contact and that the clamping force of the fixture is evenly distributed. Poor contact surface and uneven clamping force will cause the workpiece to be displaced or deformed during the processing, affecting the processing accuracy. When installing the fixture on the self-centering, it is necessary to ensure that the rotation axis of the control clamp and the main axis of the lathe are controlled within 0.01mm.
6. Processing wheel frame issues
When selecting a processing wheel frame, you need to consider the shape, size, weight, and processing requirements of the parts. The design of the processing wheel frame should be stable and reliable to ensure that the parts will not be displaced or deformed during the processing. When installing the processing wheel frame, it is necessary to ensure that it is fixedly connected to the workbench of the CNC machine tool to avoid shaking or displacement during the processing. At the same time, it is necessary to reasonably adjust the height, angle, and position of the processing wheel frame according to the shape of the part and the processing requirements to ensure that the parts can be properly fixed and processed. The material and surface treatment of the processing wheel frame also need to be paid attention to. The processing wheel frame should be made of high-strength and high-hardness materials to ensure that it will not be deformed or damaged during the processing. In addition, the surface of the processing wheel frame needs to be smoothed to reduce the friction resistance when in contact with the parts and improve the processing accuracy. During the processing, it is necessary to constantly check the fixing of the processing wheel frame to ensure its stability. If the processing wheel frame is found to be loose or deformed, it should be stopped for inspection immediately to avoid affecting the processing of the parts.
Conclusion
As advanced processing equipment, CNC machine tools are highly suitable for processing irregular parts with the advantages of high precision, high efficiency, and high automation. However, the research on CNC machine tool processing technology for irregular parts is a relatively complex subject. We can achieve this through the reasonable selection of processing tools and cutting amounts, scientific design of mechanical fixtures, and accurate determination of benchmarks. At the same time, we should pay attention to the problems of workpiece clamping and processing wheel frames, improve the processing efficiency and quality of irregular parts, reduce production costs, and enhance the competitiveness of enterprises.
Keyword: cnc machining lathe