Reducing the scrap rate is a key goal in high-precision machining processes, which requires comprehensive management and control from multiple aspects. Here are some effective methods:

1、 In terms of processing equipment

Equipment selection and accuracy matching

Select appropriate precision grade processing equipment based on the accuracy requirements of the processed parts. For example, for parts with precision requirements at the micrometer level, high-precision CNC machining centers or grinders should be selected, and their positioning accuracy and repeatability accuracy should be able to meet the machining requirements. Before purchasing equipment, it is necessary to have a detailed understanding of the technical parameters of the equipment, such as the straightness, flatness, roundness and other geometric accuracy indicators of the machine tool, to ensure that the accuracy of the equipment itself can provide a basic guarantee for precision machining.

Avoid pursuing high-precision equipment excessively, which may result in cost waste, or using equipment with insufficient precision for high-precision machining. For some complex shaped precision parts, it is possible to consider using machining equipment with multi axis linkage function to better achieve the machining of complex surfaces and reduce machining errors caused by equipment functional limitations.

Equipment maintenance and upkeep

Establish a strict equipment maintenance plan and regularly inspect, clean, lubricate, and calibrate processing equipment. For example, for CNC lathes, it is necessary to regularly check and adjust the preload of the ball screw to ensure its transmission accuracy; For the spindle of the machining center, regular dynamic balance testing and accuracy testing should be carried out, and worn bearings should be replaced in a timely manner.

Record the operating status and maintenance history of the equipment, analyze this data to predict possible equipment failures, and carry out preventive maintenance in advance. For example, by monitoring parameters such as motor current and vibration signals of the equipment, when abnormal changes are detected, timely maintenance of the equipment can be carried out to avoid the production of waste due to sudden equipment failures.

2、 In terms of processing technology

Process planning and optimization

Before processing, develop a detailed and reasonable processing technology route. For high-precision parts, the influence of machining sequence, cutting parameters, tool paths, and other factors on machining accuracy should be fully considered. For example, for a part with complex inner cavity and outer contour, rough machining of the inner cavity should be carried out first to remove most of the excess, followed by outer contour machining, and finally precision machining of the inner cavity, which can reduce deformation during the machining process.

Optimize cutting parameters through experiments and simulations based on the material, shape, and precision requirements of the parts. When processing aluminum alloy parts, choose appropriate cutting speed, feed rate, and cutting depth to avoid excessive cutting force that can cause part deformation. Cutting force models and finite element analysis software can be used to simulate the machining process under different cutting parameters, in order to determine the optimal combination of process parameters.

Tool selection and management

Select appropriate tool materials, tool geometries, and tool coatings based on processing material and process requirements. For example, when processing alloy steel with high hardness, hard alloy cutting tools or cubic boron nitride (CBN) cutting tools are used; For high-precision surface machining, use ball end milling cutters and select the appropriate tool radius based on the curvature radius of the surface.

Establish a tool life management system to record the usage time of tools, the number of processed parts, etc. Timely replace worn tools to avoid a decrease in machining accuracy caused by tool wear. For example, by monitoring the amount of cutting edge wear or changes in cutting force of the tool, when the tool wear reaches a certain level, an automatic alarm is triggered and the tool is replaced.

3、 In terms of raw materials

Raw material quality control

Strictly control the procurement process of raw materials and select suppliers with reliable quality. Inspect each batch of raw materials to check whether their chemical composition, physical properties, and dimensional accuracy meet the requirements. For example, for steel raw materials, it is necessary to test their carbon content, alloy element content, hardness, grain size and other indicators to ensure the stability of material quality.

During the storage and transportation of raw materials, appropriate protective measures should be taken to avoid damage or contamination of the materials. For example, for easily oxidizable metal materials, vacuum packaging or filling with protective gas should be used for storage; For high-precision bar materials, specialized fixtures and packaging should be used during transportation to prevent deformation.

4、 Personnel operation aspect

Operator training

Provide professional training for operators engaged in high-precision machining, including skills in operating machining equipment, knowledge of machining processes, and awareness of quality control. Operators should be familiar with the control panel and programming instructions of the equipment, and be able to correctly set machining parameters and tool paths. For example, through training, operators can proficiently master the programming and operation of CNC machining centers, and accurately understand the various requirements in the process documents.

Regularly conduct skill assessments and knowledge update training for operators to keep up with the development of precision machining technology. For example, with the emergence of new tool materials and processing techniques, timely training should be provided to operators to enable them to master new operating methods and technical points.

Operating standards and execution

Develop detailed operating specifications and quality inspection standards, and operators must strictly follow the specifications during the processing. For example, during the clamping process of parts, it is necessary to operate according to the prescribed clamping method and clamping force to ensure the positioning accuracy of the parts; During the machining process, it is necessary to strictly follow the cutting parameters and machining sequence in the process documents, and not to change them arbitrarily.

Establish a quality traceability mechanism, which can trace the occurrence of waste products to specific operational links and responsible persons through operation and inspection records, in order to analyze the reasons and take improvement measures.