Precautions for CNC machining
(1) When the workpiece is too high, it should be roughed with different length knifes in layers. After roughing with a big knife, the remaining material should be removed with a small knife.
(2) Use flat-bottomed knives to process planes and use less ball knives in order to reduce processing time; if there is an inclination and it is an integer, use an inclination knife to process.
(3) Set tolerances reasonably to balance the machining accuracy and computer calculation time. Do more procedures to reduce the time of empty tools.
(4) If the rough material has high hardness, choose up-cut milling; if the rough material has low hardness, choose down milling. Roughing up milling, finishing down milling.
(5) The tool material has good toughness and low hardness, which is suitable for rough machining. The tool material has poor toughness and high hardness and is suitable for finishing.
2. CNC machining process
(1) Part clamping method and fixture selection
The clamping method of the processed 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 "standard unification" and "standard overlap" should be 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, choose a positioning method that is convenient for all surfaces 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 workbench, 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. The fixtures used in the control processing should be assembled from common components as much as possible, and can be adjusted 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 repeated use of the same tool multiple times, 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.