How To Judge The Accuracy Of CNC Machining Center?

- Jul 20, 2018-

How to judge the accuracy of CNC machining center? Regarding the accuracy of CNC machining centers, the industry has been studying ways to reduce the error. So how do you judge the accuracy of a CNC machining center? Let's talk about four aspects below.


Vertical CNC machining center test piece positioning.

The test piece shall be placed in the middle of the X stroke and placed along the Y and Z axes at appropriate locations suitable for specimen and fixture positioning and tool length. When there are special requirements for the positioning position of the test piece, it shall be specified in the agreement between the manufacturer and the user.


Fixation of the test piece.

●  The test piece should be easily installed on a special fixture to achieve maximum stability of the tool and fixture. The mounting surface of the fixture and test piece should be straight.

●  The parallelism of the test piece mounting surface to the clamp clamping surface should be checked. A suitable clamping method should be used in order to allow the tool to penetrate and CNC the entire length of the center hole. It is recommended to use a grub screw to fix the test piece to avoid interference between the tool and the screw. Other equivalent methods are also available. The total height of the test piece depends on the fixing method chosen.


The material of the test piece, the knife and the cutting parameters.

The material of the test piece and the cutting tool and cutting parameters are selected according to the agreement between the manufacturer and the user, which should be recorded. The recommended cutting parameters are as follows:

● Cutting speed: about 50m/min for cast iron parts; about 300m/min for aluminum parts.

● Feed amount: about (0.05~0.10) mm/tooth.

● Cutting depth: All milling operations should have a depth of 0.2 mm in the radial depth.


Size of the test piece.

If the specimen is cut several times, the outer dimensions are reduced, and the aperture is increased. When used for acceptance inspection, it is recommended to use the final contour processing specimen size as specified in this standard to accurately reflect the cutting accuracy of the CNC machining center. The test piece can be used repeatedly in the cutting test, and its specifications should be kept within 10% of the characteristic size given in this standard. When the test piece is used again, a thin layer cut should be performed before the new fine cut test to clean all the surfaces before testing.