What are the main positioning options for gantry machining centers?

The datum selected by the gantry machining center should ensure accurate positioning of the workpiece, convenient and reliable loading and unloading, and the size calculation of the selected datum and each processing part is simple to ensure the processing accuracy. When selecting the positioning datum, try to choose the design datum as the positioning datum; when the positioning datum and the design datum cannot be the same, the positioning deviation should be strictly controlled to ensure the processing accuracy, and the workpiece needs to be clamped and processed more than twice.

The selected datum can realize the processing of key precision parts in one clamping and positioning. The selected datum should ensure that as many processing contents as possible can be realized. During batch processing, the part positioning datum should be as close as possible to the tool datum for establishing the workpiece coordinate system. When multiple clamping is required, the datum should be consistent before and after.

The basic requirements of the gantry machining center for the fixture are that the clamping mechanism shall not affect the feed, the processing part shall be open, the fixture can be directional installed on the machine tool, and the rigidity and solidity of the fixture shall be good.

General fixtures such as vises, dividing heads, chucks, etc., combined fixtures are composed of a set of general components with standardized structures and standardized sizes. They are specially designed and manufactured for one or several similar processing. Multi-station fixtures can clamp multiple workpieces at the same time. Group fixtures are specially used for clamping workpieces with similar shapes and sizes and the same or similar positioning, clamping, and processing methods. The selection principle of the gantry machining center fixture is to give priority to general fixtures under the premise of ensuring processing accuracy and production efficiency.