LFV - Low Frequency Vibration

**machining 4 all** · Mar 20, 2021, 04:20 PM

**nova_robotics** · Mar 22, 2021, 06:13 PM

Is this for breaking chips?

**machining 4 all** · Mar 22, 2021, 06:23 PM

Exactly! It is an unconventional machining process used to break chips in ductile materials (low carbon steels, for example). It also shows good results in the machining of polymers, pure aluminum and some alloys used in the naval, aeronautical and aerospace industries. Depending on the specific model of the equipment, different types of vibration are obtained (see image).

**nova_robotics** · Mar 22, 2021, 06:45 PM

That's interesting. I have ****ty tools and use them poorly so they chatter all over the place. Basically the same thing. I'm a trend setter.

**hemmjo** · Mar 22, 2021, 06:48 PM

It seems to me that a similar thing happens on a regular old lathe. The natural vibrations of the tool and work piece create differences in cut depth. Especially in roughing cuts, then when a finish cut is made, the vibrations would be different, resulting in a nicer finish.

The cut off tool is especially prone to vibrations, and failure do to excessive vibration.

**machining 4 all** · Mar 22, 2021, 06:53 PM

That's it, there are materials that don't break chip easily, even if you change the machining parameters or use chip breaking tools. The fun is trying to control the shape of the chip, when possible, so as not to end up with a bird's nest on top of the machine!

**machining 4 all** · Mar 22, 2021, 06:58 PM

Yes hemmjo, there is also a relationship between the depth of machining, the tool nose radius and the rigidity of the equipment. When the cutting edge of the tool is worn or broken, the tendency to cut is vibrating and noisy, which is very irritating. If the machine has excessive play, then the tool makes small bumps and may even break. The secret of the process is to know how to choose and sharpen the tool correctly!

**hemmjo** · Mar 22, 2021, 07:10 PM

So are these Low Frequency Vibrations something that are created on purpose? Or is the animation a demonstration of how the unwanted but often naturally occurring vibrations affect the machining process?

**machining 4 all** · Mar 22, 2021, 07:40 PM

Yes, they are vibrations controlled by the machine! They are usually 1.5 times greater than the frequency of the part.

**Frank S** · Mar 22, 2021, 08:03 PM

Originally Posted by hemmjo

So are these Low Frequency Vibrations something that are created on purpose? Or is the animation a demonstration of how the unwanted but often naturally occurring vibrations affect the machining process?

yes they are purposely created. in the case of the deep bore in the video it would be next to impossible to plunge straight in without reversing out due to chip fouling