Techniques To Combat Chatter

Following are some of the techniques commonly used to combat chatter. Use these guidelines to establish a good foundation for optimizing your moldmaking processes. 

1.The Right Tool holder: 

 Common tool holders (side-lock, double-angle collets and standard ER collets) do not provide the accuracy or stiffness needed for high-performance machining. Better options are tool holder shanks that incorporate face and taper contact to deliver high accuracy and rigidity. This type of holder engages the precision ground face of the spindle with simultaneous contact with the taper, which provides the additional rigidity required, and also aids in damping. All tooling should be evaluated for balancing, which provides improvements in surface finish even at lower RPMs. 

2.Cutter Tooling Selection: 

Cutter tooling can greatly influence chatter. Considerations include correct substrate, geometry, coating and length-diameter ratio. Programmers often gravitate to using the largest tool that can fit, but that may not be the ideal tool size. Incorporating multiple tools with variable flute geometries is an effective way to reduce vibrations.

3.Proper Work holding:

 If the part is not properly secured, the part itself can vibrate and induce chatter. There are many excellent systems available to clamp your workpieces. Criteria to look for include high precision, high clamping force, ease of use and flexibility (allowing use across multiple CNC machine tool platforms).

4.Machine Maintenance:

If you’re trying to hold fine finishes and tight tolerances on a poorly maintained machine, you’ll need to overcome mechanical challenges well beyond the issues listed here. Keep your equipment on a regular maintenance schedule to ensure the best performance.

5.Control Solution: 

The above can correct some causes of chatter, but there are limitations to these methods. The use of new control technology—smart control systems—that navigates processes and eliminates potentials for costly surface finish problems is another method. One such technology1 is designed to eliminate chatter and take the guesswork out of the trial-and-error process typically used to find the correct spindle speed, allowing the cutting tool and machine tool to continuously operate at the highest performance. It uses a single processor intelligent numerical control2 and vibration sensors to monitor chatter noise and automatically adjust spindle speed. No longer does an operator need to babysit a cut. With this technology in place, your mold shop can be more profitable and gain a competitive advantage.