High precision parts processing
The machine vision measurement of high-precision product parts belongs to non-contact measurement, which can not only avoid the damage to the measured object, but also adapt to the non-contact situation of the measured object, such as high temperature, high pressure, fluid, dangerous environment and so on.
High precision machining shoulders the important mission of supporting the progress of new science and technology, and the need of national defense strategic development and the attraction of high profit market of ultra precision products promote the rapid development of new ultra precision machining technology. Ultra precision machining technology is a processing method to reduce the surface roughness of the workpiece, remove the damage layer, and obtain high precision and surface integrity. At present, ultra precision machining, which does not change the physical characteristics of the workpiece material, needs to make the shape precision and surface roughness of the workpiece reach submicron and nanometer level respectively, and even pursue high surface integrity.
Complex surfaces are generally composed of multi curvature surfaces, which can achieve the high precision of some mathematical characteristics and pursue the appearance of function and aesthetic effect, including aspheric surface, free-form surface and irregular surface.
Complex surface has become an important working face of many industrial products and parts in aerospace, astronomy, navigation, auto parts, mold and biomedical implant fields. For example, aspheric optical parts can correct various aberrations and improve the identification ability of the instrument; The complex curved mirror can effectively reduce the reflection times and power loss, and improve the accuracy and stability; The engine cylinder with complex curved surface can improve the working efficiency; At the same time, some mold cavity, auto parts more and more application of complex surface shape, to meet the functional requirements and aesthetics. With the increasing demand of complex surface parts and the continuous improvement of performance requirements, the traditional processing methods have been difficult to meet the practical application requirements, and it is urgent to further improve the processing level of complex surface parts in order to achieve ultra precision machining. Due to the variability of curvature of complex surfaces, it is very important to study the material removal mechanism, subsurface damage and other characteristics to improve the machining accuracy and efficiency, and the pollution of machining residues has been widely concerned.
In this paper, the research progress of ultra precision machining of complex surfaces is reviewed. The development of ultra precision machining of complex surfaces is reviewed. The principles and influencing factors of ultra precision forming and ultra precision polishing of complex surfaces are described. The factors such as the degree of fit between machining tool and workpiece surface, precision, surface damage and efficiency in ultra precision machining of complex surfaces are compared, In the end, the scientific prediction and Prospect of the ultra precision machining method of complex surface are given.
Parts processing is a process that directly changes the appearance of raw materials and makes them into semi-finished parts or finished products. This process is called process flow, which is also the processing process benchmark of parts. The process flow of precision machinery parts processing is more complex.
According to different processes, the processing process benchmark of precision mechanical parts can be divided into casting, forging, stamping, welding, heat treatment, machining, assembly and so on. It refers to the general term of the whole process of CNC machining and machine assembly, while other processes such as cleaning, inspection, equipment maintenance, oil seal and so on are only auxiliary processes. Turning methods change the surface properties of raw materials or semi-finished products, and the numerical control machining process is the main process in the industry.
The process datum of precision mechanical parts processing includes positioning datum, positioning datum used by lathe or fixture when processing in CNC lathe; Measurement datum, which usually refers to the standard of size or position to be observed during inspection; Assembly datum, which we usually refer to the position standard of parts during assembly process.
Precision machinery parts processing needs to produce stable products, in order to achieve this goal, the staff must have rich machining experience and excellent technology. As we all know, machining is the same fine work, we must have excellent technology to do well.
Secondly, whether the processing process of precision mechanical parts is standardized also determines whether the product is good. Production and management are bound to need a set of process, the process is for the production of products and services. Thirdly, we must pay attention to the communication in the production process, whether it is the node time or when there is a problem, we must strengthen the communication. The communication between the processing plant and the equipment manufacturer is an important condition for the processing of automatic equipment parts.
