Skills of using spring collet
December 12, 2022
During the use of the spring chuck, if it is used with high accuracy, it will generally bore a tool first, so the accuracy of the chuck is the spindle accuracy. For the spring collet after front end quenching, as long as the use is reasonable, the life factor is not considered at all. Jade
The precision of the meter tooth type and special-shaped spring collet is determined by the manufacturing precision of the collet.
The spring chuck is a simple technological device, but there are many main factors that affect the clamping force. Understanding the basic principles can help the workpiece (or tool) to be clamped correctly and find faults quickly. Here are some main factors affecting the clamping force and summarized experience:
(1) Axial force. The pull rod applies an axial tension to the spring collet. In the use of the spring collet, the axial force and tension can vary from
But the principle is basically the same. Therefore, a large axial tension will produce a large clamping force, and vice versa. General pull
The axial tension of the rod can be adjusted on the CNC machine tool.
(2) In the use of spring collets, the locking angle of collets will determine the radial clamping force provided by spring collets under the same axial tension, which is usually determined by machine tool manufacturers and spring collet manufacturers. The locking angle should be selected from the perspective of economy
In terms of reliability, it is determined according to different machine tool types, operating conditions (dynamic and static) and uses (workpiece and tool)
Yes.
(3) The friction between the workpiece (or tool) and the spring collet will directly affect the firmness of the clamping (but will not affect the clamping force
Size). The greater the friction, the more firmly the workpiece is clamped, and vice versa. To overcome the interference between the spring collet and the workpiece (or tool)
With relative rotation or axial movement, various measures can be taken during the manufacturing process of spring collet to improve the friction force, such as deliberately making serrations in the inner hole of spring collet or dipping cemented carbide microcrystals on the clamping surface.
(4) Friction between the spindle cone and the spring collet at the locking angle. The friction force also directly affects the clamping force of the spring chuck on the workpiece. When the friction force is too small, the clamping force is not enough, which will cause the relative rotation of the workpiece; Too much clamping force will speed up the spring clamp
The head is worn.
(5) In actual use, the spring collet should always be loosened to replace the workpiece, for example, when it is used on the turning machining center
A layer of lubricant is sprayed on the surface of the inner hole of the spring collet. If possible, it is better to use coolant for lubrication, so as to wash the debris on the spring collet
It can also provide good lubrication effect. Regular application of lubricating grease at the locking angle of the spring collet can reduce long-term wear
Increase clamping force. Other better lubricating materials can also be used, including high-quality grease or wax based materials with EP (extreme pressure) characteristics.
(6) The reasonable selection of the clamping diameter of the spring collet can ensure that the spring collet produces the maximum clamping force on the workpiece and achieves the best clamping state, thus ensuring the high quality and precision of machining. If the diameter of the inner hole of the spring collet is too large
When the head is closed, the workpiece is only clamped by the hole of the spring collet, which is likely to cause the geometry between the outer circle of the workpiece and the inner hole of the spring collet
The shape does not match, so the clamping force is reduced. If the diameter of the inner hole of the spring collet is too small, the collet will only be closed in the collet
The inner part of the hole is in contact with the workpiece, so although the clamping force is increased, it will result in different axes between the chuck and the workpiece. A spring collet with a specification size can only clamp and position workpieces with a corresponding diameter size.
