What should be considered in the preparation of the shaft parts processing technology of precision mechanical parts? This is a problem that will be encountered when processing shaft parts, and it should be considered before the official start of processing. Only by making adequate preparations in advance , in order to carry out correct CNC machining or machining of shaft parts, so as to avoid errors in processing and improve processing efficiency.
The process analysis of CNC machining should be carried out on the part drawing, and the specific contents are as follows:
(1) Whether the dimensioning method in the part drawing is suitable for the characteristics of CNC machining;
(2) Whether the geometric elements constituting the outline in the part drawing are sufficient;
(3) Whether the reliability of the positioning datum is good;
(4) Whether the machining accuracy and dimensional tolerances required by the parts can be guaranteed.
For the part blank, the process analysis is also carried out, specifically:
(1) Analyze the adaptability of the blank in terms of installation and positioning, as well as the size and uniformity of the allowance;
(5) Whether the machining allowance of the blank is sufficient, and whether the allowance is stable during mass production.
1. Selection of machine tools
Different parts should be processed on different CNC machine tools, so CNC machine tools should be selected according to the design requirements of the parts.
2. Selection of tool setting point and tool change point
Tool setting point: It is the starting point of the movement of the tool relative to the workpiece in the index control machining.
Tool change point: It is set for the programming of multi-tool processing machine tools such as machining centers and CNC lathes.
When programming, the workpiece is regarded as stationary, and the tool is moving. The tool setting point is usually called the program origin. The main points of selection are: easy alignment, convenient programming, small tool setting error, convenient and reliable inspection during processing, and the tool setting point should be coincident with the tool position point during tool setting.
3. Selection of processing method and determination of processing plan
The selection principle of the machining method is to ensure the machining accuracy and surface roughness requirements of the machined surface, but in the actual selection, it should be considered in combination with the shape, size and heat treatment requirements of the parts.
When the processing plan is determined, the processing method required to meet these requirements should be preliminarily determined according to the accuracy and roughness requirements of the main surface.
4. Selection of machining allowance
Machining allowance: The amount generally refers to the difference between the solid size of the blank and the size of the part.
There are two principles for the selection of machining allowance, one is the principle of minimum machining allowance, and the other is that there should be sufficient machining allowance, especially for the last process.
5. Determination of cutting amount
Cutting parameters include depth of cut, spindle speed and feed. The cutting depth is determined according to the rigidity of the machine tool, fixture, tool and workpiece, the spindle speed is determined according to the allowable cutting speed, and the feed rate is determined according to the machining accuracy and surface roughness requirements of the part and the material properties of the workpiece.
