Furrying mdf- knightmare!!!!

[1albobs]

I have an ongoing problem and wondered if you could give me any tips? I'm suffering with bad furring edges when cutting and engraving mdf. This is even happening with brand new end mills. I use 1/13" 2mm 2 Flute Carbide Ball Nose End Mills Hi Quality CNC bits 8mm CEL.
I'm guessing it's a spindle speed/feed rate issue I have? I've read a fair bit on various sites and I've had a play around with the machine, adjusting both but still got the problem. It's taking a lot of sanding to get our products perfect and slowing production right down. I'm using Mach3 btw. I am a novice and I've no formal training/background in cnc etc and learning as I go along really.


My machine was bought secondhand and is homebuilt but works totally fine. It is a fixed gantry CNC machine(info below)
Overall dimensions
Wide 800mm, deep 900mm, height 1450mm
Cuts approx 500mm x 400mm
Components are:-
Nema23 keling motors on all axis
Controller gecko G540
Running Mach3 program
My router is a Kress 1050


I do use standard mdf from the likes of Jacksons, Travis Perkins(both local to me) and also Wickes. It is stored horizontally on racking in the garage(not on an outside wall though). I have tried to experiment with coating some mdf with pva to see if this aided me with cutting but it hasn't made much difference to be honest.
Waste material is hoovered away as the machine makes its passes. I've found the thicker mdf and other types of wood-based materials cuts a lot better.
Cutting depth is 1.5mm with a 2 mm 2 flute ball nose mill,
x axis is velocity 1000mm per min acceleration 850mm per sec and y axis is the same.
I have tried the drill at 12000 & 17000 speed but not much difference in cut quality.
Regards,
Al

[Clive S]

Those types of mdf are not of the best quality mdf is made in various grades Caber, Medite or Scandia etc. do a google search. Try here http://www.lathamtimber.co.uk/ProductDetail.331.html ..Clive

[mitchejc]

I've never tried such small dia cutters so I cannot comment on what to expect. There's probably good reason why you use those small cutters but have you tried something like the 1/4inch or 6mm budget straight 2 flute cutters just to see what sort of cut quality you get? Is it possible to post a close up photo of the finish as that might help to diagnose the problem.

[alboy]

I have an ongoing problem and wondered if you could give me any tips? I'm suffering with bad furring edges when cutting and engraving mdf.


I do use standard mdf from the likes of Jacksons, Travis Perkins(both local to me) and also Wickes.
Al

That will be the problem, the standard MDF will always fur as the core of the material is not dense enough for routing to a good finish, you will need something like medite MR or MRND teh MR (moisture resistant) is dyed green, ok if you are painting over it, the MRND is the usual MDF colour throughout. Both of these have a very dense core structure and you get a much better finsh.

Hope this helps

Al