Improving the Machining Precision of Graphite Mold Fixtures and Jigs
In mechanical processing, errors in graphite mold fixtures and jigs are inevitable. However, if they exceed the permissible range, measures must be taken to reduce these errors and improve the machining precision of graphite mold fixtures and jigs.
Methods to Improve the Machining Precision of Graphite Mold Fixtures and Jigs
1.Reducing Original Errors To improve machining precision, the original errors causing these inaccuracies must be analyzed, and different methods should be adopted to address different situations. For example, in the machining of precision parts, the geometric precision, rigidity, and control of thermal deformation of the machine tools should be enhanced. For parts with forming surfaces, efforts should be made to reduce the shape errors of forming tools and setup errors. By analyzing the causes of the original errors, these factors can be eliminated or minimized.
2.Compensating for Original Errors Error compensation involves artificially counteracting the original errors in the processing system. If the original error is negative, the artificial error should be positive, and vice versa, aiming to make their magnitudes equal. One type of original error can also be used to offset another, again striving to balance their magnitudes and directions, thereby reducing machining errors and improving the machining precision of graphite mold fixtures and jigs.
3.Transferring Original Errors Transferring original errors involves relocating geometric errors, thermal deformation, and stress deformation of the processing system. For example, if the machine tool’s precision does not meet the fixture’s machining requirements, in addition to improving the machine tool’s precision, measures should be taken in the process and fixtures to transfer the machine tool’s geometric errors to areas that do not affect machining precision.
4.Equalizing Original Errors When machining graphite mold fixtures and jigs, errors in the workpiece blank or previous processes can lead to errors in the current process. Changes in workpiece material properties or process changes in previous steps can cause significant original errors. This issue can be addressed by using a grouping and adjustment method to equalize errors. This means dividing the original error magnitude into n groups, reducing the error range of each blank to 1/n of the original, and then adjusting and machining each group accordingly.
5.Homogenizing Original Errors In grinding processes, high precision is not inherently required, but the process can perform fine cutting on the workpiece through relative movement, gradually wearing down high points and achieving high precision. This friction and wear process reduces errors, known as the error homogenization method. This involves closely linked surfaces comparing and inspecting differences, correcting each other, or using each other as a reference for machining, continuously reducing and homogenizing fixture surface errors.
6.On-Site Machining Method In the machining and installation of graphite mold fixtures and jigs, some precision issues relate to the mutual relationships between parts and components. Thus, merely improving the precision of individual parts or components may not be sufficient. The on-site machining method, also known as self-machining and fitting, can address these precision issues by ensuring accurate relationships between interconnected parts and components.