What Is Chatter?
A Chatter in the machine tool industry refers to abnormal vibrations during cutting and grinding, leading to chatter marks on the machined surface and potential damage to tools and machinery.
Types of Chatter
There are two main types of chatter vibrations:
- Self-Excited Chatter: Also known as regenerative chatter, it arises from periodic fluctuations on the newly machined surface or multiple vibration modes. This type often leads to a progressive increase in machining irregularities and periodic vibrations.
- Forced Chatter: Caused by internal or external vibrations impacting the machined surface, leading to significant machining irregularities.
Principles and Control of Chatter
The control methods for chatter depend on its cause:
- Self-Excited Chatter: Control strategies focus on system vibration response, influenced by cutting conditions, tool geometry, and machine dynamics. Solutions include modifying cutting speed, depth of cut, spindle speed, tool design, and enhancing machine rigidity. Tool improvements might involve using spring tooling or dampers.
- Forced Chatter: For internal vibrations, solutions include isolating vibration sources, using flexible couplings, and adjusting rotational speeds. External vibrations can be mitigated through anti-vibration foundations or rubber mounts. Fluctuations in cutting force can be managed by altering tool shape, cutter blade count, or using unequal pitch cutters.