Things to pay attention to during CNC machining

Because it is a large piece of processing, there is no high requirement in terms of precision. After giving a rough CNC precision machining plan, the purchasing manager is also very satisfied, but still a little hesitant. The director of the technical department sent a video of the cases and processing we have done, and described the functions of these devices in detail.

Small-sized precision parts are easy to make, and large-sized ones generally require suppliers to have specific processing equipment, so half of them are more difficult to find.

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) Flat-bottomed cutters are used to process the plane, and ball cutters are used sparingly to reduce the processing time;

(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 machining process

(1) Parts clamping method and fixture selection

CNC machining parts The clamping method 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 need to consider :

a. Try to complete all the surface processing in one positioning and clamping, therefore, it is necessary to choose a positioning method that is convenient for all surfaces to be processed.

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 the influence of the machining of each station, the length of the tool and the stiffness of the tool on the machining quality.

d. The fixtures used in the control processing should be selected as far as possible, and the fixtures that are assembled by common 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 machining 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 tool change point. Once determined, it should not be replaced.

Similar mechanical parts processing plants can actually process them, but due to equipment reasons, they need to be disassembled and processed, and the strength of the products produced is not very good.