Fluffy mdf

[richie00boy]

You might find you have to slow the CNC down to a snails pace. The MDF from B&Q and the likes is the lowest grade. Go to Wickes or Jewson and get the moisture resistant type. This is about the best you can get easily. If you have a good wood merchant they should be able to get you deep router grade which makes B&Q MDF look like toilet paper. It will be double the price though, but the reduction in messing about with sorting the edges can make it good value.

[Steven W]

Cheers Ritchie. Just went and bought a sheet of Medite MR. It's a much denser board and not that much more expensive £26 per 8x4 sheet. Thinking about the speed I pass the piece with manual router it's an awful lot slower than the cnc. So with denser mdf and slower feed speed I will hopefully get the result I am looking for. Will let you know how I get on. Steven

[JAZZCNC]

You might find you have to slow the CNC down to a snails pace.

No quite the opposite.!! . . .Chances are your not cutting fast enough or deep enough.

What speed & feeds are you using and what DOC.

Also what machine is it.? If it's the 6030-40 type machine then chances are you'll never be able to cut MDF without flufff has it's not upto the job.?

[Steven W]

Jazz - just tried Medite MR mdf at a feed speed of 20mm/sec and this has stopped the fluffy core. Not sure what the spindle speed as its reading a frequency number (3000) not rpm. DOC was 3mm through an 18mm board. Its a beautiful finish even better than the manual router finish which I was pleased with. The issue now is it takes a nation to route so next trial will be to step the feed speed up a bit and maybe try and increase DOC. Not sure how much life I will get from the cutter
Thanks for everyones input on this one as I was giving up hope. Hopefully this will be of use to anyone else with the same problem.

[birchy]

3000 won't be the frequency as it's far too high. It's probably the RPM!

[JAZZCNC]

Unless the MDF is damp you shouldn't get fluff no matter the manufacturer. If you getting fluff then your cutting wrong for the density of that material, the Medite MR will just be a different grade or density and you've got lucky on Feeds etc.

20mm/s is far to slow for MDF not matter what size cutter or DOC and even if you were cutting at 3000 Rpm which again is ridiculously slow for MDF or wood it's all wrong.

Every machine needs feeds & speeds tweaking to suit it's build but even allowing for that these feeds are way off. I think you'll find the cutters will wear very quickly.

Give some details of cutter and an idea of the strength of machine, also spindle your using IE: picture and will suggest some feeds to try.

[Mad Professor]

Just to give an idea.
With my DIY cnc router, I can do 18mm MDF cutting at around 3-4m/min, full doc @ 24k rpm, with a 10mm twin straight flute TCT cutter.
I am left with clean cuts, no fur's etc.

[JAZZCNC]

Just to give an idea.
With my DIY cnc router, I can do 18mm MDF cutting at around 3-4m/min, full doc @ 24k rpm, with a 10mm twin straight flute TCT cutter.
I am left with clean cuts, no fur's etc.

Ye but that's only because of them brackets I cut for ya . . .

Now that's more like the speeds and with a decent sized cutter, thou I would suggest doing faster in 2 passes for increased tool life.
I always work on 50% cutter Dia has max DOC thou in soft stuff like this I'd do 100%.