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1 piece flat panel MDF doors8/27
We are just starting to play with cutting doors on our CNC. Think 1 piece Shaker. We are using Flakeboard Superior Plus 3/4" thick.
We are finding that the doors are cupping as soon as we mill into the face.
No need to explain why this is happening, what I need to know is how other shops are dealing with it. I have seen doors that have a pocket milled on the back side which makes sense to balance the panel.
What I am curious about though, is the shops that do not make the releif cut on the back, and how they are keeping the doors reasonably flat. Before I had my CNC, there were 3 different companies that I bought these doors from, and none machined the back face, and we never had warping issues.
Can anyone shed some light on how to machine a flat door by only machining 1 face?
What is the back of your material like? We would generally use a negative warp MDF with a melamine back for this kind of work. No problems with warping.
I have never heard of negative warp MDF. I will have to ask my supplier about this. I assumme this means it is prestressed in a warped state, so when machined it ends up flat.
Yes. That is the general idea. I think it may have something to do with the melamine back but I'm not sure
The best way I have seen so far to make a shaker MDF door is to route it in 2 pieces. You rout the frame just like a glass panel door with the face down, then I like to route a 1/2" deep x 3/8" wide dado around the inside perimeter of the panel and then from a sheet of 1/2" MDF you route the center panel and then glue and insert it into the dado so it has a 1/4" setback from the front of the face of the frame and is flush with the back of the frame.
This lets you hand sand the inside of the door frame for a better finish and you get a better finish on the panel IME.
The other advantage is you can do two tone paints, paint the frame and have a wood veneer insert etc.
Thanks, guys. I am fully aware of the different methods of making these doors. Im looking to have some light shed on how it is done with a single board, and single side machined.
I have done these for years with little issue of warping. The doors that tend to warp are either very wide (24" or so) or very tall (50" or taller). We use plum creek mdf...and I wouldn't use any other. One thing I will say is that you don't have to mill down as far as a cope and stick panel sits back from the frame. We mill ours 3/16 deep. Make two passes to get to the final depth and you will have much less sanding to do. The last pass can be just 1/32 or so...
Hope this helps.
What speeds and feeds are you using? We're using a diamond tool at 300 IPM and still getting lines.
Hi dropout--we use only carbide tooling. It's a vortex tool. Basically like a small spoil board tool that hogs the material out. I'm not at work today so I don't know what the feed speed and spindle speed are right off. I couldn't ever make the diamond cutter cost make sense when carbides mill mdf quite well and they inexpensive to change out the inserts on this type of wing cutter.
What kind of lines are you getting?
Make no mistake that a CNC milled flat panel door requires sanding...we use 100 grit and then prime them for best results. 150 doesn't seem to remove the compressed mill marks from the surface being ran over by the large diameter cutter.
we had a similar issue when we used flake board, we now exclusively use plum creek its double refined and requires less work after routing. I'm not at the office but if I remember correctly we run it at maybe 15,000 RPM and 220FPM with insert carbide tooling. we do not remove more than 1/8" per pass on the panel cutter