The basic requirements for CMM fixtures
In fact, cnc milling - do not require very chaotic CMM fixture, only requires a large positioning, clamping mechanism on it. Its plan principle and general milling machine CMM fixture similar to the joint cnc milling characteristics, here only to start a few fundamental requirements:
1) To keep the placement of the parts from the machine coordinate system and the direction of the coordinate system, the CMM fixture should be able to carry out the orientation placement on the machine tool, CMM Holding Fixture for Stamping Parts and also to ensure that the coordinates of the harmonious part positioning plane and the machine The
2) In order to keep the workpiece in the process of all the necessary to complete the surface to be processed enrichment, CMM fixture to do it is probably open, so the clamping mechanism components and processing surface should be retained between the stability of the partition, Tight mechanism components can be low to low, to prepare for CMM fixture and milling machine spindle sleeve or knife sets, cutting tools in the process of collision.
3) CMM fixture rigidity and stability is better. If you do not take the process of changing the clamping point in the process of processing, when the process must be replaced in the clamping point can not be time, be particularly careful not to change the clamping point due to damage CMM fixture or workpiece positioning accuracy.
(2) commonly used CMM fixture type
Milling Commonly used CMM fixtures are probably the following:
1) Almighty with CMM fixture; CMM Holding Fixture for Stamping Parts used in a small amount of production or development of small and medium parts in the cnc milling machine on the milling.
2) special milling CMM fixture; is specifically for a certain project or similar to the workpiece manufacturing CMM fixture, usually in the mass production or development must be taken when.
3) multi-position CMM fixture; can simultaneously clamp multiple parts, can reduce the number of tool changes, but also easy to wall processing, a wall loading and unloading parts, CMM Holding Fixture for Stamping Parts is conducive to shrink the preparation time, improve productivity, more suitable for mass production.
4) pneumatic or hydraulic CMM fixture; practical for the production of large quantities, to take other CMM fixture and particularly laborious, laborious parts. Can reduce the labor intensity and improve productivity, but the CMM fixture layout more chaotic, the cost is often higher, and the manufacturing cycle is longer.
5) vacuum CMM fixture; practical for a larger positioning plane or a larger sealable area of the workpiece. Some cnc milling machines (such as wall milling machines) own a universal vacuum platform, in the placement of the workpiece, the shape of the rectangle rough, can be directly with a special rubber (with a certain size requirements of the hollow or solid circular section) embedded Into the CMM fixture seal tank, and then put the blank, start the vacuum pump, you can clamp the blank. On the shape of the rough, with rubber strips are not appropriate, to be in its surrounding putty (commonly used rubber mud) seal, so do not only very difficult, and take a long time, CMM Holding Fixture for Stamping Parts the effect is low. In order to conquer this difficulty, a special transition vacuum platform can be used to superimpose it on a universal vacuum platform.
In addition to the above-mentioned several CMM fixtures, cnc milling is usually used to take vise, dividing head and three-jaw chuck and other common CMM fixture.
(3) cnc milling CMM fixture selection principle
In the selection of CMM fixture, it is usually necessary to think about the production of the product batch, production effects, quality assurance and economy, etc., can be selected with the following principles:
1) in the production of small or developed, should be widely adopted with all-round CMM fixture, only with the CMM fixture can not handle the workpiece when the folder can be abandoned;
2) small or batch production can be considered when taking a special CMM fixture, but should be even if the general;
3) in the production of large quantities can be considered when the multi-station CMM fixture mild moving; hydraulic CMM fixture.