When machining precision mechanical parts, there are many requirements and regulations for processing to ensure the pass rate of factory parts.

Remove the jaws of the vise, make another two M4 threaded holes, put two steel plates with a thickness of 1.5mm flush with the jaws, rivet the hard brass plate with a thickness of 0.8mm with aluminum countersunk rivet, and fasten it to the jaws with M4 countersunk screw 1 to form a durable soft jaws. This can also protect the hardware parts from being pinched, but also has interchangeability.

For a workpiece first clamping and positioning, because the clamping will certainly test the workpiece deformation, so it should be first clamping and positioning, for 6 points positioning, find to limit its freedom. When the hexagon wrench handle is short and cannot be focused, the tube with an inner diameter slightly larger than the wrench can be inserted into the slot from a section of milling groove and can be used as a long handle.

In the process of mechanical manufacturing, errors mainly include spindle rotation error, guide rail error and transmission chain error. Spindle rotation error refers to the actual rotation axis of the spindle at each moment relative to its average rotation axis change, it will directly affect the precision of the workpiece to be machined.

The main causes of spindle rotation error include spindle coaxiality error, bearing error, bearing coaxiality error, spindle winding and so on. The guide rail is the benchmark to determine the relative position relationship of each machine tool component on the machine tool, and it is also the benchmark of the machine tool movement. The manufacturing error of the guide rail itself, the uneven wear of the guide rail and the installation quality are the important factors causing the error of the guide rail. Transmission chain error refers to the relative motion error between the two ends of the transmission chain. It is caused by the manufacturing and assembly errors of the various components of the transmission chain, as well as wear during use.

The experience of mechanical processing plants points out that the tool is inevitably worn during the cutting process, which causes the size and shape of the workpiece to change. The influence of machining error on machining error varies with the type of tool: When machining with a fixed size tool, the manufacturing error of the tool will directly affect the machining accuracy of the workpiece; For the general tool, the manufacturing error has no direct influence on the machining error.

The function of the fixture is to make the workpiece equivalent to the tool and the machine tool have the correct position, so the geometric error of the fixture has a great influence on the machining error (especially the position error). The influence of thermal deformation of the process system on the machining error is relatively large, especially in the precision machining and large parts machining, the processing error caused by thermal deformation can sometimes account for 50% of the total error of the workpiece.