The principle of workpiece positioning

Positioning: During processing, the workpiece must first occupy the correct position.

Clamping: After the workpiece is positioned, it is always kept in the correct position so that the workpiece will not be affected by external forces during processing.

Installation: The whole process of the workpiece from positioning to clamping.

1. Six-point positioning principle Any rigid body has six degrees of freedom in the space Cartesian coordinate system. To obtain an accurate position of the workpiece in the fixture, its corresponding degrees of freedom must be restricted. 2. Several situations in positioning

(1) Complete positioning Positioning where all six degrees of freedom of the workpiece are restricted.

(2) Incomplete positioning According to the processing requirements of the workpiece, it is not necessary to limit the positioning of all degrees of freedom of the workpiece.

(3) Over-positioning Two or more positioning elements repeatedly restrict the positioning of the same degree of freedom of the workpiece.

(4) Under-positioning According to the processing requirements of the workpiece, the degrees of freedom that should be limited are not fully limited.