MDF rough edge

[basskitcase]

When routing MDF, i seem to be getting a lot of paper left on the edge that is a pain to clean off.

What speeds/feeds do you recommend for MDF? I have been doing about 25 IPM with0.25 depth of cut with a 1/4" 4 flute carbide bit.

Also, i notice that the MDF has a tendancy to split along the laminations when doing detailed/thin pieces, like when doing thin letters on a sign. Is there any good way to avoid this? would shallower cuts help?

As a final question, it seem that the machine slows down signifiacantly when going around curve when doing offset cuts. is there any way to keep the speed around a curve consistant with normal machine feed rate? I was routing MDF this weekend and for the detail work it actually slowed down so much that the dust heated up and started burning!

[ger21]

What speeds/feeds do you recommend for MDF?

First, don't use a 4 flute bit. Get a 2 flute downcut spiral router bit. I cut MDF at 125-150ipm, at about 12,000 rpm.

The best way to avoid the splitting, is to take shallower cuts, so you're not putting as much pressure on the smaller pieces. If the parts are really small, there's not a lot you can do. MDF is just not very strong when cut into thin pieces.

is there any way to keep the speed around a curve consistent with normal machine feed rate?

What control software are you using? How tight are the curves, and how are they coded.

[Boots]

25 ipm for MDF @ 1/4 in. deep is way too slow. You didn't state your RPM. Your 4 flute tool is getting plugged up with chips and or dust. You need more chip clearence such as you get from a 2 flute. Ramping in would help also rather than plunge cutting to start. MDF will burst into flames when it reaches 451 deg. F.

[basskitcase]

Originally Posted by ger21 First, don't use a 4 flute bit. Get a 2 flute downcut spiral router bit. I cut MDF at 125-150ipm, at about 12,000 rpm. The best way to avoid the splitting, is to take shallower cuts, so you're not putting as much pressure on the smaller pieces. If the parts are really small, there's not a lot you can do. MDF is just not very strong when cut into thin pieces. What control software are you using? How tight are the curves, and how are they coded.

Mach 3. The curves i was referring to were tree leaves roughly spade shaped and maye 3/4" long. I think most of the problem was probably that i was not in constant velocity mode

As for 25 IPM being way too slow, i had i higher, but i turned it down because when cutting, i could hear my router RPM slowing down, and i didn't want to overheat it. Maybe i was being too cautious. Its a 2.25 HP Bosch.

[ger21]

Try it at the speeds and rpm I mentioned. Shouldn't be a problem, as I use a 2.25HP Porter Cable.

[louieatienza]

Definitely a 2-flute, or even 1-flute down shear or down spiral, would help. Seems to me if the flutes are clogged with MDF chips, it won't be able to push through the cut and teh router will struggle.

It would seem to me that you could raise your feed rate and take shallower passes, it mike make the MDF chips clear easier...

[robe_uk]

Am curious as why a downcut spiral is recommended, would this not force the chips into the bottom of the cut and clog it up?
I thought an upcut would eject the cut chips out of the way?
maybe am missing something?

[ger21]

A downcut will eliminate the frayed edge. Even a dull downcut will give a better top edge than all but a new upcut. And with small tools, even an upcut won't eject all the chips.

[basskitcase]

Originally Posted by ger21 Try it at the speeds and rpm I mentioned. Shouldn't be a problem, as I use a 2.25HP Porter Cable.

What depth of cut do you use?

[ger21]

1/4"

[louieatienza]

You might also want to look into compression spiral bits for MDF. They have both an up and down spiral... but they are expensive...