Clamping of parts
1. Selection of positioning datum
When machining in the machining center, the positioning of parts should still follow the six point positioning principle. At the same time, special attention should be paid to the following points:
(1) When multi station machining is carried out, the selection of positioning datum should consider the positioning mode that can complete as many machining contents as possible, even if all surfaces can be machined. For example, for box parts, the combined positioning method of one side and two pins should be adopted as far as possible.
(2) When the positioning datum and design datum of a part are difficult to coincide, the assembly drawing should be carefully analyzed to clarify the design function of the design datum of the part. Through the calculation of the dimension chain, the dimensional position accuracy requirements between the positioning datum and design datum should be strictly stipulated to ensure the machining accuracy.
(3) The programming origin and the part positioning datum may not coincide, but there must be a definite geometric relationship between them. The selection of programming origin mainly considers the convenience of programming and measurement.
2. Selection of fixtures
On the machining center, the task of the fixture is not only to clamp the parts, but also to determine the machining origin of the parts with the positioning datum as the reference datum. Therefore, the positioning datum should be accurate and reliable.
3. Clamping of parts
When considering the clamping scheme, it is necessary to ensure reliable clamping and minimize clamping deformation.
Tool selection
Tools play a vital role in NC machining, so when selecting tools for machining centers, the following basic requirements should be followed:
1. Good cutting performance: it can withstand high-speed cutting and strong cutting and has stable performance.
2. High accuracy: the accuracy of the tool refers to the shape accuracy of the tool and the position accuracy of the tool and the clamping device;
3. Equipped with perfect tool system: meet the requirements of Multi Tool continuous processing.
The tool head part of the tool used in the machining center is basically the same as that used in the NC milling machine. The tool handle part of the tool used in the machining center is different from that used in the general NC milling machine. The tool handle used in the machining center is equipped with a clamping groove for the manipulator to clamp. Therefore, when selecting tools, we must follow the product processing requirements of the machining center.
