The CNC machining process planning refers to the whole process, we cannot judge the nature of the process and the surface finishing. For example, some position data must be processed very precisely in the semi-machining phase or even in the rough machining phase. Sometimes a secondary post-processing of surfaces is also possible to avoid dimensional chain transformation in the final processing.
After defining the surface treatment method of the part and the machining stage, the machining of each surface in the same machining stage can be grouped into multiple stages.
1. Processing Procedures Division Process
Parts machined on CNC gears are essentially alienated into the subsequent processes rendering to the principle of processes. This will also help you better understand how cnc services work and how you can take advantage of them.
1) Divided By The Tool Used
With the same tool machining process, this splitting process is suitable for situations in which several surfaces of the work piece are to be machined. Processing centers often use this method to complete.
2) Work Piece Installations Division
A process is a technological process that can be completed by parts in a single package. This method is suitable for machining involving small parts. In order to guarantee the processing quality of the parts, all processing contents can be completed in one package.
3) Divided By Roughing And Finishing
Part of the process completed in rough machining is considered one process, while part of the completed process is considered another process. This cutting process is suitable for parts with rigidity and rigidity that require heat treatment or require high precision of the parts, require effective removal of residual stresses, and have large deformations after machining that must be divided into rough and machining steps.
4) Divided By Processing Part
The part of the process that runs the same profile as the process.
For parts with more complex machining surfaces, the sequence of CNC machining, thermal machining and secondary work should be arranged sensibly and the problem of the connection between the work steps should be solved.
2. Principle Of Process Division
Parts consist of several surfaces that have their own accuracy requirements and also have corresponding accuracy requirements between the surfaces.
In order to attain the correctness of the part building, the preparation of the machining arrangement must follow certain principles.
1) First Roughing, Later Finishing
The machining sequence of each surface is performed in a sequence of grinding, semi-machining, machining and machining to gradually improve the accuracy and surface quality of the part to be machined. If all surfaces of the part are machined with CNC machine tools, the process design is usually carried out in the order of grinding, semi-finishing and finishing, i.e. H. after the roughing, the semi-finishing and finishing takes place. Throughout the roughing machining, maximum of the machining allowance can be rapidly detached, and then each surface can be machined one after another, which can progress the manufacture efficiency and guarantee the machining correctness and surface unevenness of the parts.
This method is suitable for treated surfaces that require high positional accuracy. This does not apply absolutely, for example to the higher demands on the dimensional accuracy of the processing surface, in view of the rigidity, deformation and dimensional accuracy requirements of the parts, it can also be taken into account for the processing surface or corresponding to the rough processing, semi-processing, finishing process. For the filling. When machining exteriors with high exactness requirements, it is finest to leave the portions for a period of time amid roughening and finishing operations so as to totally dismiss the surface tension of the parts after grinding and the degree of tension and deformation. The surface area of the parts can be reduced, which is useful for improving the machining accuracy of the parts.
2) Datum Surface First Processing Principle
At the start of machining, the final surface is always machined. Since the positioning reference surface is accurate, the attachment error is small. Hence, while machining a fragment, the positioning orientation surface is always rough and semi-finished. Machining, finishing if necessary, e.g. B. Always pre-machined and pre-machined shaft parts before positioning the reference surface.
For shaft parts, for instance, the middle hole is always machined first, then the hole system and other exteriors are machined on the center hole surface and the positioning hole as an precise orientation. If there is more than one exact reference surface, the reference surface must be treated according to the reference conversion sequence and the principle of gradually improving the machining accuracy.
3) Surface Process First Then Hole Process
For box, bracket, body and other parts, the contour size of the planer is larger, and the layout of the planer is more stable and reliable, so it is necessary to process the surface of the planer first, and then the hole. Thus, not only does the post-processing have stable and reliable flatness as a positioning reference surface, but also the processing of holes on a flat surface facilitates the processing and also helps to improve the processing accuracy of the holes. In over-all, procedures can be distributed rendering to the machining sites of the parts, and simple geometric outlines are machined first, and then complex geometric shapes are machined; First, the parts are machined with less precision, while the parts with higher precision are machined first; First the plane is machined, later the hole.
4) Inner Hole First, Outer Circle Later
An accurate sleeve requires coaxiality between the outer circle and the hole. In general, the principle of the first hole and the outer circle is accepted; H. the outer circle is used as the positional reference for machining the hole, and then the higher accuracy hole is used as the positional reference for machining the outer circle. Round, which can place high demands on the coaxiality between the outer circle and the hole, and the support structure used is also very simple.
5) Minimize The Tool Changes Principle
In CNC machining manufacturer, the machining sequence should be positioned as closely as possible according to the tool that enters the machining position.