How to ensure that the machining tolerance of the mold is within a reasonable range?

How to ensure that the machining tolerance of the mold is within a reasonable range?

To ensure that the machining tolerances of Dalian die-casting molds are within a reasonable range, the following aspects can be taken into account:

1、 Mold design stage

Accurate calculation

During design, use computer-aided design (CAD) software for precise dimensional calculations and simulations. Fully consider factors such as thermal expansion and stress deformation of the mold during operation, and make reasonable compensation and reservation for dimensions to ensure that the processed mold can meet tolerance requirements under actual working conditions.

For molds with complex shapes, 3D modeling technology is used for detailed design and analysis to avoid processing tolerances exceeding the range due to design errors.

tolerance allocation 

Reasonably allocate tolerances between various components of the mold. Determine critical and non critical dimensions based on the function and assembly requirements of the mold, and set corresponding tolerance levels for the dimensions of different parts. For example, for the cavity dimensions of the mold, tolerances should be controlled more strictly, while for some non critical appearance dimensions, tolerances can be appropriately relaxed.

Considering the processing technology and cost factors of the mold, reasonable tolerance optimization should be carried out while ensuring the performance of the mold, in order to avoid overly strict tolerance requirements leading to a significant increase in processing difficulty and cost.

2、 Dalian Die Casting Processing Equipment and Process Selection

High precision machining equipment

Choose high-precision machining equipment, such as CNC machining centers, electrical discharge machining machines, wire cutting machines, etc. These devices have high positioning accuracy and repeatability, which can ensure the dimensional accuracy of mold processing.

Regularly maintain and calibrate processing equipment to ensure that its accuracy remains at a stable level. For example, check key parameters such as the accuracy of the machine tool's guide rails and spindle runout, and develop a reasonable maintenance plan based on the equipment's usage and accuracy changes.

Appropriate processing technology

Select the appropriate processing technology based on the material and structural characteristics of the mold. For example, for mold steel with high hardness, electrical discharge machining or wire cutting can be used to ensure machining accuracy; For complex curved surfaces, five axis linkage machining technology can be used to improve machining accuracy and surface quality.

Optimize machining process parameters, such as cutting speed, feed rate, cutting depth, etc. By conducting process experiments and data analysis, determine the combination of processing parameters to reduce errors during the machining process. For example, in milling, reducing the feed rate appropriately can improve surface smoothness and dimensional accuracy.

3、 Tool and fixture selection

High quality cutting tools

Choosing high-quality cutting tools, the geometric shape, hardness, wear resistance, etc. of the tools will affect the machining accuracy. For example, using coated cutting tools can improve their wear resistance and cutting performance, reducing the impact of tool wear on machining accuracy.

Select appropriate tool types and specifications based on processing materials and process requirements. For different machining processes, such as rough machining, semi precision machining, and precision machining, different cutting tools should be selected to ensure the machining accuracy at each stage.

Precision fixtures

Use precision fixtures to ensure the positioning accuracy and uniform clamping force of mold parts during the machining process. The design of fixtures should consider the shape, size, and processing requirements of the mold parts to ensure that the parts will not undergo displacement or deformation during the processing.

Regularly inspect and maintain fixtures to ensure their accuracy and reliability. For example, check the wear of key components such as the positioning pin and clamping mechanism of the fixture, and replace or repair them in a timely manner.

4、 Dalian Die Casting Quality Inspection and Control

Online detection

During the processing, online detection technology is used to monitor the machining dimensions in real-time. For example, using the online measurement system of CNC machining centers, real-time measurement and feedback of dimensions during the machining process can be carried out, and machining parameters can be adjusted in a timely manner to ensure dimensional accuracy within the tolerance range.

For some critical dimensions, sensors or measuring instruments can be used for real-time monitoring. Once the dimensional deviation exceeds the allowable range, the machine should be stopped immediately for adjustment.

Offline detection

After processing, use precision measuring tools such as coordinate measuring instruments, optical projectors, micrometers, etc. to conduct a comprehensive dimensional inspection of the mold. By comparing with the tolerance requirements on the design drawings, determine whether the machining tolerance of the mold meets the requirements.

Establish strict quality inspection standards and processes, and record and analyze inspection data in detail. For non-conforming products, timely cause analysis and rework should be carried out to ensure the quality of the mold.