When machining mechanical parts, if the workpiece is too high, it shall be roughened layer by layer with a knife of different lengths. After roughening with a big knife, the surplus material shall be removed with a small knife. The flat end cutter is used to process the plane, and the ball cutter is used less, so as to reduce the processing time; If there is slope and it is an integer, the slope cutter shall be used for machining.
At the same time, the tolerance should be set reasonably to balance the processing accuracy with the computer calculation time, and more procedures should be done to reduce the empty tool time; The hardness of the blank material is high, so the reverse milling is selected; The hardness of the blank material is low, so the forward milling is selected. Rough machining up milling, finishing down milling; The tool material has good toughness and low hardness for rough machining, while the tool material has poor toughness and high hardness for fine machining.
The clamping method of machined parts on CNC machine tools shall also reasonably select the positioning datum and clamping scheme. When selecting the precision datum, the two principles of "datum unification" and "datum coincidence" shall be generally followed. In addition to these two principles, the machining of all surfaces in one positioning clamping shall be considered as much as possible. Therefore, the positioning method that facilitates the machining of all surfaces shall be selected.
When the workpiece is clamped at one time, it shall be able to finish machining all surfaces of the workpiece; When determining the placement position of the workpiece on the workbench, consideration should be given to the processing of each station, the influence of the length of the tool and the stiffness of the tool on the processing quality. Fixtures used in control processing shall be assembled by universal components and adjustable to shorten the production preparation cycle.
When arranging the machining sequence, the basic principles must be observed, including "face before hole", "rough before finish", etc. It is processed according to the centralized process of tools to avoid repeated use of the same tool for many times and reduce the number and time of tool change.
For the hole system with high coaxiality requirements, the hole system at other coordinate positions shall be processed after the whole processing of the hole system is completed after one positioning, so as to eliminate the error caused by repeated positioning and improve the coaxiality of the hole system. The tool point and tool change point shall be determined. Once determined, they shall not be replaced.
