(1) Part clamping method and fixture selection
The clamping method of the machined parts on the CNC machine tool should also reasonably choose the positioning datum and the clamping plan. When selecting the precise datum, the two principles of "benchmark uniformity" and "benchmark coincidence" are generally followed, except for these two This principle, we also need to consider:
a. Try to finish the processing of all surfaces in one positioning and clamping. Therefore, it is necessary to choose a positioning method that is convenient for each surface to be processed.
b. When the workpiece is clamped once, it should be able to finish the processing of all the surfaces of the workpiece.
c. When determining the placement position of the workpiece on the worktable, consideration should be given to the processing of each station, the length of the tool and the impact of the rigidity of the tool on the processing quality.
d. Fixtures used in control processing should be assembled from common components as much as possible and adjustable fixtures to shorten the production preparation cycle.
(2) Arrangement of processing sequence
When arranging the processing sequence, the basic principles must be followed, including "face first, hole second", "rough first then fine", etc. In addition to these basic principles, we should also follow the following principles, as:
a. According to the tool centralized process processing, to avoid multiple repeated use of the same tool, reduce the number of tool changes and time.
b. For the hole system that requires high coaxiality, after one positioning, the processing of the hole system should be completed, and then the hole system of other coordinate positions should be processed, which can eliminate the error caused by repeated positioning and improve Coaxiality of the hole system.
c. Choose to determine the tool point and tool change point. Once determined, it is not suitable to change.
