Mastars is a metal prototype maker, provide rapid prototyping, CNC parts processing, 3D printing, laser molding, manufacturing, mass production and mold reproduction, etc., to provide customers with comprehensive and professional product manufacturing needs..With 5 axis machining equipment, we have rich experience in CNC machining

Processing process planning refers to the whole process, which cannot be judged according to the nature of the process and surface processing. For example, some positioning datum planes need to be accurately machined in semi finishing stage or even rough machining stage. Sometimes, in order to avoid dimension chain conversion, semi finishing of some secondary surfaces can also be arranged in the finishing stage.

After the processing method and processing stage of the part surface are determined, the processing of each surface in the same processing stage can be combined into multiple steps.

1. Method for dividing machining process

The parts processed on CNC machine tools are generally divided according to the principle of centralized process. The division method is as follows:

(1) By tool used

This division method is applicable to the case where there are many surfaces to be machined. This method is usually used in machining centers.

(2) Divided by workpiece installation times

Take the process of clamping parts at one time as the process. This method is suitable for parts with less processing content. On the premise of ensuring the processing quality of parts, all processing contents shall be completed by clamping at one time.

(3) Divided by rough and fine processing

One part of the rough machining process is regarded as one process, and the other part of the finish machining process is regarded as another process. The division method is applicable to parts with strength and hardness requirements, which need heat treatment or high-precision requirements, need to effectively remove internal stress, and the parts have large deformation after processing, so it needs to be divided according to the coarse and fine processing stages.

(4) The process flow of completing the same profile is divided into one process according to the processing part.

For parts with complex machining surface, the sequence of NC machining, heat treatment and auxiliary processes shall be reasonably arranged to solve the connection problem between processes. The part is composed of multiple surfaces and has its own accuracy requirements. There are corresponding accuracy requirements between each surface. In order to meet the design accuracy requirements of parts, the processing sequence should follow certain principles.

(1) The principle of first rough and then fine

The machining sequence of each surface shall be in the order of rough machining, semi finishing machining, finishing machining and finishing machining, so as to gradually improve the accuracy and quality of the machined surface of parts. If all surfaces of parts are processed by CNC machine tools, the process arrangement is generally carried out in the order of rough machining, semi finishing machining and finishing machining, that is, semi finishing machining and finishing machining are carried out after rough machining. During rough machining, most of the machining allowance can be removed quickly, and then finish each surface in turn, which can improve the production efficiency and ensure the machining accuracy and surface roughness of parts. This method is suitable for machining surfaces with high position accuracy. This is not absolute. For example, for some machined surfaces with high dimensional accuracy requirements, considering the stiffness, deformation and dimensional accuracy of parts, these machined surfaces can also be completed in the order of rough machining, semi finishing and finishing. For the machined surface with high precision requirements, it is best to put the parts aside for a period of time to completely release the stress on the rough machined part surface, which is conducive to improving the degree of stress and deformation of the parts.

(2) Principle of datum first processing

At the beginning of machining, it is always used as the finish machining reference surface. Due to the accurate positioning reference surface and small clamping error, the machining process of any part is always rough machining and semi finish machining, and finish machining when necessary. For example, the shaft part is always rough machining and semi finish machining, and then finish machining. For example, shaft parts always process the central hole first, and then process the hole system and other surfaces based on the central hole surface and positioning hole. If there is more than one accurate datum surface, the machining of datum surface shall be arranged according to the sequence of datum conversion and the principle of gradually improving machining accuracy.

(3) Principle of "face before hole"

For box type, support type, body type and other parts, the plane contour size is large, and the plane positioning is relatively stable and reliable, so the plane should be processed first and then the hole. In this way, it not only makes the subsequent processing have a stable and reliable plane as the positioning reference plane, but also processes the hole on the flat surface, which makes the processing easier, but also helps to improve the machining accuracy of the hole. Generally, the process can be divided according to the processing part of the part. Generally, the simple geometry is processed first, and then the complex geometry is processed; First process the parts with low precision, and then process the parts with high precision; First process the plane and then the hole.

(4) The principle of "inside before outside"

For precision sleeve, the coaxiality of outer circle and hole is required to be high. Generally, the principle of first hole and then outer circle is adopted, that is, the outer circle is used as the positioning benchmark to process the hole, and then the outer circle is processed with the high-precision hole as the positioning benchmark to ensure that the coaxiality requirements between the outer circle and the hole are high, and the fixture structure is also very simple.

(5) Principle of reducing the number of tool changes

In CNC machining, the machining sequence should be arranged according to the sequence of cutting tools entering the machining position as far as possible

As a modern precision machinery parts manufacturing producers, mastars with CNC machining as the core technology, have entity factory, testing equipment, and the integration of rapid prototyping, mold, processing and other supporting manufacturing resources, to provide quick proofing, medium and small batch production and fitting, easier then the truly one-stop services.

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