Tungsten Carbide Material Bowl Production Positioning Standard Selection Criteria

       Tungsten carbide bowl production positioning standard selection criteria:

The positioning datum is divided into coarse datum and fine datum. In the initial process of processing, only the unprocessed surface on the blank can be used as a positioning base, and this surface is also called a rough reference. Use the processed surface as a positioning datum, called a fine datum.

Choice of rough benchmark

The key points to consider when choosing the rough datum are: first, how to ensure that each machined surface has sufficient machining allowance; second, to ensure the mutual positional relationship between each machined surface and the unprocessed surface. The following principles can be used for specific selection.

① When there is only one unprocessed surface on the part, in order to ensure the position requirements between the unprocessed surface and the processed surface, the unprocessed surface should be selected as the rough reference [Figure 2-7(o)]; if there are multiple unprocessed surfaces on the part For the machined surface, the surface with a higher mutual position requirement with the machined surface should be used as the rough reference, as shown in Figure 2-7 (b), the part has three unmachined surfaces. If the wall formed by surface 4 and surface 2 When the thickness uniformity is high, the surface 2 should be selected as the rough reference to process the stepped hole.

②When there is no unmachined surface on the part, when choosing the rough reference, the machining allowance of each surface should be considered reasonably, and the following two points should be paid attention to in the allocation of machining allowance.