[danvan]

Hi I have a problem we have started using 4" bits to attempt cutting deeper material but the longer bit makes a squealing noise when cutting and leaves blade marks on the material.

If anyone can help me that would be wonderful.
Dan

[Mountaincraft]

I would think that a longer bit like that would 'amplify' any run out in the router bearings and what not...

got picture?

What size router, what speed, feedrate, DOC?

What is the material?

[danvan]

We are using a selexx mate, 1/2" Diameter, 4" in length.

We have tested feedrates from 2000-5000.
Rpm's from 18000-10000.
MDF
What is DOC?

[Mountaincraft]

We are using a selexx mate, 1/2" Diameter, 4" in length.

We have tested feedrates from 2000-5000.
Rpm's from 18000-10000.
MDF
What is DOC?

Depth of Cut

[CarveOne]

It sounds like chatter at an rpm that causes the cutter to be in it's resonance range. If you are cutting steel or aluminum it will need to be running at a lower rpm than you state. If you are cutting wood or MDF the rpm can probably be much higher.

Try slowing down the feed rate and taking lighter cuts. Try increasing the feed rate a reasonable amount to load the cutter more. You need to find a combination that gets it out of the resonance range and provide a better cut. Look at online feed/speed charts for a ballpark number for that size cutter and material.

Are you using a router or a spindle?

How stiff your Z axis is can be a factor. Stiffer is better of course.

CarveOne

[CarveOne]

Ok, I looked up the Selexx mate CNC router machine and it has a large spindle, toolchanger, and should have no stiffness problems. Nice machine.

Is the cutter an up-cut, down-cut, or straight flute? What material does it do this squealing in? What feed rate are you using?

CarveOne

[ger21]

If I need to cut deeper than 1-1/2", I prefer to use 5/8" diameter bits, as they are much more rigid than 1/2" bits. They're expensive, though.

Is this a spiral bit, or a carbide tipped straight bit? A spiral should work better.
I also think you're feedrate is much too low for MDF. At 18,000 rpm, I'd try 10,000mm/min.

[danvan]

The bit is a two flute solid carbide downcut bit.

We did actually try 10000 at 18000 rpm and it didn't change much.

We ran the test using 3/4" mdf that we cut In one pass.

We have had no trouble running mdf with shorter bits it is just now that we are using the longer one that the problems lens have arisen.

[zool]

Hi I have a problem we have started using 4" bits to attempt cutting deeper material but the longer bit makes a squealing noise when cutting and leaves blade marks on the material.

If anyone can help me that would be wonderful.
Dan

Are the "blade marks" the same on the material on both sides of the cut?

For instance: Are the "blade marks" more pronounced on the top of the material on one side, while the "blade marks" are more pronounced on the bottom of the material on the other side?

Observing the marks and determining their relationships would indicate if the cutter was tilted and in which direction, if at all.

If all else fails, just send that ole OmniTech CNC to me and I will test it for you for a couple years and figure it out ... no charge.

[There used to be an OmniTech rep with a machine similar to yours in the industrial building my studio is in. I learned a lot of him and the technicians that set the machine up. The machines are WAY over built, and could it ever cut fast. They do need a gargantuan dust collector though, esp with MDF.]

PS. Did you call OmniTech for assistance?