View Full Version : How deep can i cut MDF?
08-06-2011, 03:46 PM
I am totally new to the CNC world. I am hopefully going to purchase my first machine next month, i have my eye on the Heiz S-1000. I am looking to produce MDF shapes and letters using 4mm, 6mm, 12mm and 18mm MDF. My question is which of these thicknesses can i cut out in one pass and how many passes would i need on the thicker stuff?
Any help would be greatly appreciated, many thanks
08-06-2011, 04:11 PM
totaly depends on the CNCs ability I do 2mm steps solid carbide cutter 6mm dia and quite a fast feed rate , this way you dont need a huge power spindel , when cutting MDF you shouldent get fine powder dust should be almost like a wood shaveing cutting too slowly will cause the cutter to gum up turn black and blunt quickly .
I have cut letters in two 3 mm steps for 6mm mdf but it makes the roughter cutter howel like a dog , by the way a cutter making an unhappy noise means you are doing some thing wrong! eather feed rate or RPM . I also leave about .2 or less so you dont have to worry about holding all the letters , it cleans off dead easy with a bit of sand paper
08-06-2011, 04:19 PM
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.
08-06-2011, 04:21 PM
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.
08-06-2011, 05:24 PM
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?
09-07-2011, 07:50 AM
I show you a video link that CNC router cut 18mm MDF one pass. http://s1232.photobucket.com/albums/ff361/omnicnc/?action=view¤t=OMNI1325.mp4, and the machine specification is at this link: http://www.omni-cnc.com/products/CNC_router/cnc_router_OR1325A.html.
24-08-2011, 10:38 PM
Thinking of passes maybe of interest. A few years back I was making door cassettes for beading Primdoor hardboard pressed panel doors. We cut the top panels out by CNC to glaze the top, side issue the pressed panels sometimes did not match on both sides but in most cases was covered by the rebate of the bead. The cassettes were shaped and mitred to fit and the sheet was laid out for nesting completing the bottom bead and two side beads and roll shaped top all laid out in 1200x1200 sheet for ease of hanlding. We bought a cutter to rebate and shape on one pass with the ogee mould as well, in practice three cutters were invloved. We used two types of MDF one 25mm and one 18mm. The trick was vacumn the sheet. Due to mdf being damn porous we plunged down in one pass to bead depth required according to door thickness and glass width, but left a few MM still on. When it completed the cycle all we need do is place the sheet in the sander and when fed through the cassettes fell out and only needed some denibbling then painting.
What I am trying to say is that you do not need to go always fully through to get what you want and you can improve the finish accordingly as the bit you are machininh is never loose or weakened to break off.
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