We know that in the machining industry, the positioning datum of the machining center is important, so what are there?
1. When the station machining including the design datum cannot be completed on the machining center at the same time, the positioning datum and the design datum should be overlapped as much as possible. At the same time, it must be considered that after positioning with this reference, all key precision parts can be machined in one clamping. Generally, the processes completed on the machining center are arranged at the end.
2. When machining both the datum and the processing of each station on the machining center, the selection of the positioning datum needs to consider completing as much processing content as possible. For this reason, it is necessary to consider a positioning method that facilitates all surfaces to be processed. For example, for a box, it is best to use a positioning method of two pins on one side to facilitate the processing of other surfaces by the tool.
3. The origin of the workpiece coordinate system, that is, the “programming zero point”, does not necessarily have to coincide with the part positioning datum, but there must be a definite geometric relationship between the two. The main consideration for the selection of the origin of the workpiece coordinate system is to facilitate programming and measurement.
For parts with high dimensional accuracy requirements, when determining the positioning reference, it should be considered whether the coordinate origin can be accurately measured by the positioning reference, and the measurement method should be taken into consideration.
4. Try to choose the design datum on the part as the positioning datum. That is, each positioning datum used on the machining center should be processed in the previous ordinary machine tool or machining center process, so that it is easy to ensure the precision relationship between the machining surfaces of each station, and when some surfaces need to be clamped multiple times Or when other machine tools are completed, choosing the same datum positioning as the design datum can not only avoid positioning errors caused by datums not overlapping, ensure machining accuracy, and simplify programming.