Mechanical parts are composed of several surfaces. To study the relative relationship between the surfaces of a part, it is necessary to determine a benchmark. The benchmark is the point, line, or surface on the part that is used to determine the position of other points, lines, or surfaces. According to the different functions of the benchmark, it can be divided into two categories: design benchmark and process benchmark. According to the mechanism and characteristics of machining methods, precision machining can be divided into four categories: tool cutting, abrasive machining, special machining, and composite machining.
With the development of machining technology, many new machining mechanisms have emerged. Therefore, in precision machining, especially in micro machining, according to the forming mechanism and characteristics of parts. It can be divided into three categories: removal processing, combination processing, and deformation processing. Removal processing, also known as separation processing, is the use of force, heat, electricity, light and other processing methods to remove a portion of material from a workpiece, such as cutting, grinding, electrical machining, etc.
So how is precision machining of mechanical parts carried out?
(1) Rough machining stage. Cut off most of the machining allowance on each machining surface and create a precision benchmark, with the primary consideration being to maximize productivity.
(2) Semi precision machining stage. To prepare for the surface finishing, it is necessary to achieve a certain machining accuracy and ensure appropriate machining allowance, in order to eliminate the potential drawbacks that may arise after rough machining, and to complete the processing of the secondary surface together.
(3) Precision machining stage. At this stage, a high cutting speed, small feed rate, and cutting depth are selected to remove the machining allowance left by the previous process, so that the surface of the part meets the skill requirements of the drawing.
(4) The finishing stage. Mainly used to reduce the surface roughness value or strengthen the processed surface, primarily used for surface processing with high requirements for surface roughness (ra≤ 0.32μ m).
(5) Ultra fine machining stage. The machining accuracy is within 0; 0.0μ m. Surface roughness value ra≤ 0.00μ The processing stage of m. The primary processing methods include precision cutting, mirror grinding, precision grinding, and polishing.