The structure and shape of machine parts are composed of some basic geometric surfaces, and the machining process of machine parts is the process of obtaining these geometric surfaces. A variety of machining methods can be Selection of Surface Machining Methods for Part Machining, but the machining quality, processing time and cost that can be obtained by each machining method are different.
The task of the engineering and technical personnel is to select the appropriate machining method according to the specific micromachining conditions to ensure that the machine parts that meet the requirements of the drawings are processed.
When selecting a machining method, generally first select its process machining method according to the technical requirements of the main surface of the part and the specific conditions of the factory, and then select the CNC Turn-Mill Machining method of each related previous process on the surface one by one.
The processing surface of the parts has machining requirements, generally it is impossible to meet the requirements through one processing, but can gradually meet the requirements through multiple processing (ie, multiple processes).
The steps to determine the machining method can be summarized as follows, based on the analysis and study of the part drawing:
- ①First of all, according to the technical requirements of each swiss machined surface, determine the machining method and machining plan.
- ② When determining the machining method, the properties of the material to be processed should be considered.
- ③ To determine the machining method, the production type should be considered, that is, the productivity and economy should be considered. Special equipment can be used for large quantities, and general equipment and process equipment are usually used for single-piece small batch production.
- ④ To determine the machining method, the existing equipment and technical conditions of the factory (this workshop) should be considered, and the existing equipment should be fully utilized to tap the potential of the enterprise.
Division of machining stages
When the machining quality requirements of parts are relatively high, they generally have to go through different processing stages to gradually meet the machining requirements, which is the so-called “gradual refinement” principle. Generally, it has to go through three stages of roughing, semi-finishing and finishing. If the machining accuracy of the plastic part is particularly high and the surface roughness is particularly small, it must go through the finishing stage.
The main tasks of the various machining stages are outlined below:
- ①Roughing stage: remove most of the allowance on the machined surface, so that the blank is close to the finished part in shape and size.
- ②Semi-finishing stage: remove the error left after rough machining, make the workpiece to be machined to the accuracy, prepare for the finishing work, and complete the machining of some minor surfaces.
- ③ Finishing stage: ensure that each main surface meets the machining quality requirements specified in the part drawing.
- ④ Finishing stage The main task is to reduce the surface roughness or further improve the dimensional accuracy and shape accuracy, but generally can not correct the position error between the surfaces.
The main purposes of dividing the machining stages are:
- ① Guarantee the quality of parts processing: After dividing the stages, the machining errors caused by the roughing stage can be gradually corrected through the semi-finishing and finishing stages, and the machining quality of the parts can be easily guaranteed.
- ②It is conducive to early detection of blank defects and timely treatment.
- ③ Conducive to the rational use of machine tools and equipment.
- ④In order to insert the heat treatment process in the machining process, and at the same time make the heat treatment exert a sufficient effect, the machining process is naturally divided into several stages, and each stage has its own characteristics and the purpose it should achieve.
In addition, dividing the workpiece machining into several stages is also beneficial to protect the finished surface from damage such as bumps and chip slips.
Dividing the process into several stages is for the entire metal and plastic machining process, and cannot be limited to the processing of a certain surface.