Workpiece Clamping Skills of CNC Machine Tool

After the workpiece is positioned, a clamping force is generated through a certain structure, and the workpiece is pressed against the positioning element to maintain an accurate positioning position, and the position will not be generated due to the cutting force, workpiece gravity, centrifugal force or inertial force of the CNC lathe, etc. Changes and vibrations to ensure machining accuracy and safe operation. This mechanism for generating clamping force is called clamping device.

1.The basic requirements that the clamping device should have

(1) The clamping process is reliable and does not change the correct position occupied by the workpiece after positioning.

(2) The clamping force is appropriate. It is necessary to ensure that the position of the workpiece is stable and the vibration is small during the processing, and it is also necessary to prevent the workpiece from excessive clamping deformation.

2.Selection of clamping force direction and action point

(1) The clamping force should be directed towards the main positioning datum.

(2) The action point of the clamping force should fall within the support range of the positioning element and be close to the geometric center of the support element. The clamping force acts outside the support surface, causing the workpiece to tilt and shift, and destroy the positioning of the workpiece.

(3) The direction of the clamping force should be conducive to reducing the magnitude of the clamping force.

(4) The direction and action point of the clamping force should be applied to the direction and position with better rigidity of the CNC machine tool parts.

(5) The clamping force action point should be as close as possible to the workpiece processing surface. In order to improve the rigidity of the workpiece processing part and prevent or reduce the vibration of the workpiece, the action point of the clamping force should be as close as possible to the processing surface. When the shift fork is clamped, the main clamping force: acts vertically on the main positioning base surface, and an auxiliary support is set near the processing surface. Appropriate auxiliary clamping force can be applied to improve the installation rigidity of the workpiece.

3.Estimation of the clamping force. The size of the clamping force has a lot to do with the reliability of the workpiece installation, the deformation of the workpiece and fixture, and the complexity of the clamping mechanism. During the processing, the workpiece is affected by cutting force, centrifugal force, inertial force and the gravity of the workpiece itself. When processing heavy and large workpieces, consider the effect of workpiece gravity. When the workpiece is processed under the condition of high-speed movement, the influence of centrifugal force or inertial force on the clamping effect cannot be ignored.