How deep can i cut MDF?

[Jonathan]

It depends a lot on the size and rigidity of the machine you are using. A good machine will cut through 18mm MDF in one pass. I think the main problem is tool deflection - a small cutter (say 3mm) cutting all the way through 18mm MDF with a decent feedrate is going to bend and probably break. Some examples...

6mm cutter, 18mm DOC, 0.02mm deflection at 740mm/min, power 290W
8mm cutter, 18mm DOC, 0.02mm deflection at 3550mm/min, power 1.86kW
10mm cutter, 18mm DOC, 0.0122mm deflection at 4650mm/min, power 3.04kW
12mm cutter, 18mm DOC, 0.007mm deflection at 4950mm/min, power 3.88kW (that's max feedrate)

As you can see using a bigger cutter will reduce the deflection enabling you to use a higher feedrate, however since with a bigger cutter the rate at which you are removing material is greater you need a much more powerful spindle. You need to find a balance between all these variables. You could run a 7mm cutter at 9mm DOC and 8300mm/min using 1.64kW. However clearly a 10mm cutter will cut the parts out a bit faster than that in one pass, so it's only worth considering if the machine isn't that rigid or does not have a sufficiently powerful spindle.

Hope that helps...there are a lot of factors to consider.

[Jonathan]

Agreed about MDF should be chips not dust.

To give a real life example I have used a 16mm cutter with 9mm depth of cut at about 2400mm/min in MDF. My machine isn't very rigid though... yet.

[MrWiz73]

ok i am understanding some of all that! The website has the following info on the machine i have in mind:

Machine Working Area: X=1000 mm; Y=600 mm; Z= 110 mm
Enhanced power and precision through the use of 2 motors on the X-Axis. This arrangement provides for a constant tension and compression during milling operations.
Only high quality bearings and guideways used to provide smooth precision of operation (repeatability approx 0.02mm - 0.03mm).
X and Y guide ways are hardened and grinded, with double sets of bearings used along with precision trapezium thread lead screws.
Traverse speed of rapid feed max. 2000 mm/min
Resolution 0.00187 mm ( 1/8 Step)
Reference switches on all axes with software limit control.
Double safety emergency stop button
Energy chain for clean cabling
Milling Motor anchorage: Euroneck 43mm
Modular frame for universal application
Table size/clamping area: 1330 x 700 mm
Total dimensions incl. motors : LxWxH = appr. 1350x840x500mm
Machine comes complete with a 4-axis, 5-channel (2.1A per axis) microstepping driver. The drive consists of 4 qulaity Nanotec stepping motors (2X, Y, Z, A) with 1600 steps/rev (1/8 Step).
Control software WIN PCNC Light also provided.
2 Year Warranty.

Am i right in thinking that i will still need to do 2 passes even with 6mm MDF?