1. Part clamping in CNC machining
The basic principles of positioning and installation are mainly reasonable selection of positioning datum and clamping plan. The specific principles to be followed are:
(1) The design, craftsmanship and programming of the three should strive to unify the benchmarks;
(2) The number of clamping installations should be reduced as much as possible, and the machining surface can be processed as far as possible after one clamping positioning.
2. The basic principles of choosing fixtures in CNC machining
(1) The coordinate direction of the fixture and the machine tool should be relatively fixed, and the size of the part and the machine tool coordinate system should be coordinated as much as possible.
(2) If the processing volume is not large, modular fixtures, adjustable fixtures or other universal fixtures should be used as much as possible to shorten production time and reduce production costs.
(3) If it is mass production, then special fixtures can be considered, but the fixture structure should be as simple as possible.
(4) The loading and unloading of parts should be fast, convenient and reliable, and the parts on the fixture should not hinder the processing of the various surfaces of the parts.
3. Machining errors in CNC machining
The machining errors in CNC machining mainly include programming errors, machine tool errors, positioning errors and tool setting errors.
Programming error: It is the error generated in the programming process, which is composed of approximation error and rounding error.
Machine tool error: mainly includes CNC system error, feed system error, etc.
Positioning error: it is the error produced by the workpiece or fixture during the positioning process.
Tool setting error: refers to the error generated when determining the relative position of the tool and the workpiece.