Things to pay attention to in the process of CNC precision machining

The contents of CNC machining are many, including many aspects, especially in the machinery industry, this term is often used.

1. Precautions for CNC precision machining

(1) When the workpiece is too high, it should be roughed with knives of different lengths in layers. Use a knife to remove any leftovers.

(2) Use a flat-bottomed knife to process the plane, and use a ball knife less to reduce the processing time; if there is a slope, and it is an integer, use a sloped tool for processing.

(3) Reasonably set tolerances to balance the machining accuracy and computer calculation time, and do more processes to reduce the time for empty tools.

(4) If the hardness of the blank material is high, choose up-cut milling; if the hardness of the blank material is low, choose down-cut milling. Roughing up milling, finishing down milling.

(5) Tool material with good toughness and low hardness is suitable for rough machining, while tool material with poor toughness and high hardness is suitable for finishing.

2.CNC precision machining process

(1) Parts clamping method and fixture selection

CNC machining The clamping method of the machined parts should also reasonably select the positioning datum and clamping scheme. When selecting the precise datum, generally follow the two principles of 'datum unification' and 'datum coincidence'. In addition to these two principles, we also To consider:

a. Try to complete the machining of all surfaces in one positioning and clamping. Therefore, choose a positioning method that facilitates all surfaces to be machined.

b. When the workpiece is clamped at one time, it should be able to complete the machining of all surfaces of the workpiece.

c. When determining the placement position of the workpiece on the worktable, consideration should be given to taking into account the processing of each station, the influence of the length of the tool and the stiffness of the tool on the processing quality.

d. The fixtures used in the control processing should be selected as far as possible from general-purpose components and can be adjusted to shorten the production preparation cycle.

(2) Arrangement of machining sequence

When arranging machining sequence, the basic principles must be followed, including 'face first and then holeIn addition to these basic principles, we should also follow the following principles:

a. Process according to the tool centralized process, avoid repeated use of the same tool, and reduce the number and time of tool changes.

b. For holes with high requirements on coaxiality, after one positioning, the processing of the holes should be completed, and then the holes at other coordinate positions should be processed, which can eliminate duplication. The error generated during positioning improves the coaxiality of the hole system.

c. Choose to determine the tool point and the tool change point. Once determined, it is not suitable to replace.