The focus of the pure fundamental level consideration is how to reduce the error and improve the accuracy, so the basic principles of selecting the essential surface are
First: the principle of datum overlap. Should choose as much as possible the design reference as the positioning reference. Especially in the final completion, to ensure accuracy, more attention should be paid to this principle. This can avoid causing position error benchmark deviation;
Second: the principle of unity of the benchmark. Should choose a unified positioning datum surface of various surface treatment, as far as possible to ensure the position accuracy between the surfaces; sometimes also follow the principle of common datum, repeated processing;
Third: the principle of self-referencing. Some small machining allowance and unified finishing process, to ensure the quality of processing and productivity, with precision machining surface itself as a base level.
The role of precision machining process
First, is the main technical documents to guide the production
Mechanical machining workshop production planning, scheduling, workers' operations, parts processing quality inspection, processing cost accounting, are based on the process procedures. To deal with production problems, but also often to process procedures as a common basis. Such as dealing with quality accidents, should be in accordance with the process procedures to determine the responsibility of the relevant units, personnel.
Second, is the main basis for the production of preparatory work
Workshop to produce new parts, first of all, to develop the parts of the machining process procedures, and then according to the process procedures for production preparation. Such as: the new parts processing process in the analysis of key processes; preparation of the required tools, clamps, gauges; raw materials and blank procurement or manufacturing; the purchase of new equipment or old equipment modifications, etc., must be based on the process to carry out.
Third, is the basic technical documents of the new machinery manufacturing plant
When the new batch or high-volume machining workshop, should be based on the process regulations to determine the type and number of machine tools required and the layout in the workshop, and then from there to determine the size of the workshop area, power and lifting equipment configuration and the type of workers required, technical grade, quantity, etc.