How does Zhejiang shaft processing manufacturer determine the machining allowance of parts

Zhejiang shaft processing manufacturers often see excess materials removed from blanks or workpieces during production, and these materials are called machining allowances. Machining allowance is divided into two types: blank allowance and inter-process allowance. The blank margin refers to the error between the blank size and the design size on the part drawing, and is also called the total machining margin.



　　 In order to reasonably determine the machining allowance, Zhejiang shaft processing manufacturers must first determine the machining allowance of the parts during process design. There are three methods to determine the machining allowance:

　　1. Look-up table correction method. According to production practice and experimental research, the blank margin and process margin data of various processes have been included in the manual. When determining the machining allowance, you can obtain the required data from the manual, and then make corrections based on the actual situation of the factory. When checking the table, please note that the data in the table are nominal values. The machining allowance for symmetrical surfaces (shaft holes, etc.) is bilateral allowance, and the machining allowance for asymmetrical surfaces is unilateral. This method is currently the most widely used.

　　2, empirical estimation method, this method is to determine the machining allowance based on practical experience. In order to prevent the production of waste due to insufficient processing allowance, the estimated value is always too large, so this method is only suitable for single-piece and small-batch production.

　　3. Analytical calculation method, a method of calculating the machining allowance based on the calculation formula of the machining allowance and certain test data. The machining allowance determined by this method is more economical and reasonable, but it can only be carried out with more reliable test data and advanced calculation methods, so it is currently less used.

　　 Zhejiang shaft manufacturer reminds that when determining the machining allowance, the total machining allowance and the process machining allowance should be determined separately. The size of the total machining allowance is related to the manufacturing precision of the selected blank. It is necessary to analyze the obtained rough machining process allowance. If it is too small, increase the total machining allowance; if it is too large, appropriately reduce the total machining allowance to avoid waste.