Processing Method And Sequence

5.1 Processing method

In the processing flow of the workpiece, the processing method is like a command system, drawing the entire blueprint. The processing method should take into account many aspects of the actual situation, such as the size and the nature of the blank.

5.2 Processing sequence

Whether the processing sequence is reasonable or not directly affects the quality of processing. At the same time, the processing sequence will also affect the profit return.

(1) The order of machining is the fundamental rule, following the rules of first main and second, face first and hole first, benchmark first. For some parts that require high precision and surface quality, the entire process needs to be divided into different stages, which is very helpful to ensure the quality of parts processing. At the same time, the staff can use the machine tool equipment rationally, reduce the wear of the machine tool equipment, and ensure that the heat treatment process can be carried out normally in the later stage.

(2) The heat treatment process is an indispensable step, mainly to eliminate stress and improve the performance of the material. Determine the heat treatment method according to the part materials and equipment. The heat treatment must be arranged in a suitable position in the entire process route.

(3) Auxiliary process can help efficient processing. There are many types of auxiliary processes, such as scribing, deburring, and cleaning. In the processing of steel products, demagnetization, rust prevention, and packaging are also indispensable auxiliary processes.

(4) In order to improve the processing quality of parts and increase economic benefits, it is necessary to accurately formulate the machining allowance. If the margin is too large, it will increase the loss and increase the processing cost; if the margin is too small, the errors and defects before the processing procedure will be difficult to fill. A poorly determined margin will directly affect the processing quality and produce processing waste, that is, defective products. Only by reasonably determining the machining allowance can the machining accuracy be guaranteed.

(5) The method of determining the size and tolerance of the process. The size of the process is closely related to the tolerance and the size of the process margin. The marking method of the process size and the arrangement of the intermediate process should also be determined according to the process size. The determination of the process size is the beginning of the formal processing of the process. Generally, process dimensional tolerances are determined according to economic processing accuracy, but in terms of nature and characteristics, there are two main categories: benchmark overlap. When the machining accuracy tolerance and process can be strictly determined, the calculation sequence from the front to the back, with the last machining process as the first. According to this method, the process size of each process can be calculated clearly and completely, and the tolerance value of economic processing accuracy can be marked on the corresponding process size; the benchmarks do not overlap. The positioning datum and the design datum cannot be equated directly, which may cause the problem of the datum not overlapping. The positioning datum needs to be converted many times. Although the process size calculation itself is very complicated, the principle of calculating the size chain can solve this problem well, and the accurate calculation of the process margin can determine the process size tolerance.

(6) Determine the cutting amount. In small-batch production, workers determine the amount of cutting in each process according to the existing technological level, processing method and processing purpose. There are a large part of the factors that affect the amount of cutting; because the cutting force is too large, it is easy to produce elastic deformation, machine tool vibration, tool hardness, machine power and other factors all reflect the cutting force. The common image of many factors is the size of the cutting force, the feed rate f, the amount of back tooling, and the peak cutting speed v are the key factors for the success of the technology. Secondly, it is necessary to consider and ensure that the feed rate f is maximized, and the appropriate cutting speed v is also a key factor to ensure the cutting amount. Use scientific ideas, scientific process and rigorous scientific attitude to determine the cutting amount.