What is the HARMONIZER?

HARMONIZER is a machining vibration monitoring program that can detect differences between stable and unstable machining. When unstable cutting conditions occur HARMONIZER suggests alternative spindle speeds and/or reduction in depth of cut to eliminate the chatter. For more complete details on this process see the section entitled Technical Principals.

Background of the HARMONIZER

The HARMONIZER utilizes well developed signal processing strategies and machining vibration technology developed over 50 years including patented and patentable technology.

What makes the HARMONIZER work

The following information explains the general spindle speed selection technique for avoiding chatter. This selection technique is the basis of the HARMONIZER.

Fundamental Concepts: Several fundamental concepts that exist in combating chatter using spindle speed selection are the following:

· Axial and radial depth-of-cut have a direct and proportional affect on the stability of machining.

· Spindle speed has a large deterministic affect on stability.

· Chatter frequency is related to the dominant natural frequency and spindle speed.

· Chip loads above a small minimal level do not strongly affect stability, only tool displacement.

No Resonant Vibration: The most common misconception is that this technique drives the system into resonance. This is not the case because machining is not a "classic" forced vibration problem where the periodic force is applied regardless of system displacement. The cutting force being applied to the tool is a function of chip thickness. The chip-thickness is dependent upon cutter displacement, which is dependent upon cutting force. Therefore, this is very similar to a feedback-type system in which stability dictates rather than resonates vibration. Figure 10 illustrates the effect of the force. By synchronizing (aligning the phase of) the tool vibration so that it coincides with a tooth frequency (or multiple), the chip thickness, which is proportional to cutting force, is made constant. As a result, the force variation is minimized. The spindle speed, as long as it is in phase, only affects the number of vibration cycles between tooth passes.