3/4" MDF speeds and feeds to create chips

[csmg]

Good morning,
I have played with several unsuccessful settings to creat chips with MDF.  I get powder.  I have used a 1/4" downshear end mill, 18000 rpm and anywhere from 70 ipm to 150 ipm.  I have not learned the proper settings for feeds and speeds on this machine, yet.  If anyone can give me a good starting point, I would be much appreciative.
Mike

[stevem]

I don't think you will get any chips cutting MDF. It's basically a material that no mater how you cut it, it's always fine dust.
If I am not mistaken, it's made out of sawdust & resin and pressed into sheets.
So if you start with sawdust, that is all you get when you cut it!
Table saw, jig say, drill, miter saw, the result is all the same. It just makes dust.
I would try some pine or something like that. You will get wood chips cutting that sort of material.

By the way, what Axiom do you have?

[Deleted]

MDF is nasty material to machine, it always makes fine dust that goes everywhere. One thing that I found helps a slight amount is sanding and priming then optionally lightly sanding again before machining. The result is a slightly sharper edges that ends up crisper after more sanding and painting.

[Gary Campbell]

Mike...
In many cases you will not be able to generate or sustain the feedrate to generate chips on a small format machine. You can get closer than you are tho. Try these combos:

At 70 ipm use 10,000 rpm and at 150 use 13,500 rpm. those are both in the .005-.006 range. For MDF, even most profile or pocket operations you would want to be in the 10K to 13.5K range. Seldom, unless you are doing a light load 3D cut, is there a need to go over 13.5K rpm.

Using the rpm pot on the VFD, vary the rpm as you are cutting. You will hear it when you hit the sweet spot.

[Deleted]

Mar 7, 2017 13:59:13 GMT -5 Gary Campbell said:

Mike...
In many cases you will not be able to generate or sustain the feedrate to generate chips on a small format machine. You can get closer than you are tho. Try these combos:

At 70 ipm use 10,000 rpm and at 150 use 13,500 rpm. those are both in the .005-.006 range. For MDF, even most profile or pocket operations you would want to be in the 10K to 13.5K range. Seldom, unless you are doing a light load 3D cut, is there a need to go over 13.5K rpm.

Using the rpm pot on the VFD, vary the rpm as you are cutting. You will hear it when you hit the sweet spot.

When I run those numbers I get the following:

70 IPM 10K RPM with one flute is 0.007" chip load
150 IPM 13636 RPM with two flutes is 0.0055" chip load

For two flutes at 70 IPM the RPM would need to be about 6K to get in the 0.005-0.006 range.

[stevem]

The question I have is would see any chips at all trying to cut MDF.
That stuff is like cutting flour. It seems to only make dust no matter what or how you cut it.

I like Mikes feed and speed rate and would use it for actual wood and not the MDF.

[Deleted]

When I cut MDF I do get various sizes but not well formed chips. When going around edges things hang on and can be cut off in larger chunks at times, it varies but always makes a mess.

[csmg]

Mar 5, 2017 13:38:09 GMT -5 stevem said:

I don't think you will get any chips cutting MDF. It's basically a material that no mater how you cut it, it's always fine dust.
If I am not mistaken, it's made out of sawdust & resin and pressed into sheets.
So if you start with sawdust, that is all you get when you cut it!
Table saw, jig say, drill, miter saw, the result is all the same. It just makes dust.
I would try some pine or something like that. You will get wood chips cutting that sort of material.

By the way, what Axiom do you have?

Wow, its been awhile. I have the AR8.  I have since earning that MDF makes great residue called dust.

[csmg]

Mar 9, 2017 9:55:29 GMT -5 @fean said:

Mar 7, 2017 13:59:13 GMT -5 Gary Campbell said:

Mike...
In many cases you will not be able to generate or sustain the feedrate to generate chips on a small format machine. You can get closer than you are tho. Try these combos:

At 70 ipm use 10,000 rpm and at 150 use 13,500 rpm. those are both in the .005-.006 range. For MDF, even most profile or pocket operations you would want to be in the 10K to 13.5K range. Seldom, unless you are doing a light load 3D cut, is there a need to go over 13.5K rpm.

Using the rpm pot on the VFD, vary the rpm as you are cutting. You will hear it when you hit the sweet spot.

When I run those numbers I get the following:

70 IPM 10K RPM with one flute is 0.007" chip load
150 IPM 13636 RPM with two flutes is 0.0055" chip load

For two flutes at 70 IPM the RPM would need to be about 6K to get in the 0.005-0.006 range.

Gary, I was reading over some old information and found that I did not thank you for the information.  I truly appreciate you taking time to help out.  I did use your information and guidance and made a huge improvement. I will say, I am not well versed in listening to the VFD in finding the sweet spot, but I am learning.  Thank you again.
Mike

[Gary Campbell]

Mike...

You are most welcome.  I am attaching a couple slides from my basics class chipload section.  There are a few important facts in there.  

Most important would be to not sacrifice edge quality for chipload numbers.  Do this by getting a desired edge quality (with a low chipload) and then reduce RPM to see where quality drops off.  Chipload recommendations are for the bits, usually on big iron machines with high horsepower.  You will need to find a chipload that is appropriate for your machine, not the bit.

[zaxis4]

I think the last line in both of these slides is the most important one. I always say it's not a Bridgeport!! You can spend your time fussing over a few thousands or get something reasonable and enjoy your project. CNC Cookbook always gives me a reasonable place to start. I enjoy my machine for what it does. About every piece of wood is different anyway. Its not like you are milling cold rolled steel.