This is a project I have been putting off for a couple of years & starting out with the smallest doors above the frig. My 1st cut was using 1/2" plywood. Think it was birch plywood. I used a 1/4" bullnose router bit for all the cuts with a Bosch colt router. First thing I noticed was it was ripping the plywood where the layers met. I let it finish to see what other problems might show up. My z axis dropped about 5mm or so sometime during the cutting. It has been about a year since I have used my MPCNC & should have checked the 2 screws in the Z Nutlock. I will definitely tighten them a little more before attempting another cut. My deepest cuts were supposed to be 2.7mm. Is there a better cutting bit that would be best with plywood? I really want to use plywood if I can as I plan to paint the doors. I think engraving these at 1-2mm deep would solve most of the problems & think it will look just as good if the plywood behaves. I round the edges of the doors by putting a rounding bit with bearing on the router with the router attached to the CNC & manually pushing the board thru the cutting path.
I am using the original MPCNC version & since this is the 2nd time my z axis has dropped, probably should upgrade to the latest version. That being said, what additional hardware do I need to upgrade? Looks like I at least need an 8mmx300mm lead screw & a 5/16-18 X 5" bolt. I see the link to Amazon has this bolt as threaded all the way. Do the threads need to be the full length for this bolt? Are there any other parts I need to buy other than the filament to print all the parts?
Here is a picture of my first cuts & a screen shot of how these 2 doors should more or less look.
Use the peel pocketing strategy and do some test to dial in the correct amount for a finishing pass. Tear out is something you will probably need to deal with but a sharp bit and the right amount of finish load will make it way way better.
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Bolts do not need to be threaded all the way, leadscrew does not need to be 300mm if you can find a cheaper shorter one. I believe you will also need 4x4" bolts.
Check to make sure everything is tight on all your axis. I noticed my x and y needed to be tightened on the bottom bearings, I somehow missed those. Also put a v bit in and put a ruler on your table, move the x axis say 200mm and see if it actually went 200mm. do this for your x and y.If not then you need to adjust your steps. If your z axis drops when the stepper is not under power, then you will have to start your bit on the top of the wood and hold the z coupler with a finger until you start the cutting. You may also be going too fast or too deep. Try again and slow the feed down and shorten your depth of cut so it’s not taking so much at once. You have some strange things going on with the top groove on the door. looks like it is going up and then back down? Make sure you have a sharp bit and again check your machine for tightness.
I do not see the 4x4" bolts listed in the BOM or assembly. Where are they used?
Thanks for the cutting strategy. I followed your Island procedure in the Milling basics with estlcam, but when I create the toolpaths some spots between the islands as can be seen from the attached image are missed. I selected each island with the part tool before selecting the Hole/Island & select Peel Pocketing strategy. If I leave it set to Linear pocketing strategy it looks correct. Here is a screen shot from estlcam v11.031 (Just downloaded the latest version to see if it was fixed already). Maybe I should ask Christian about this? I attached 2 screen shots showing the difference between peel & Linear.
After playing with this some more, I see where the problem is or maybe it is just a limitation. If I use an 1/8" bullnose it works, so it seems like it will not work if the space between the islands is too small. It is interesting that the gap around the border does fill in, but that measures smaller than between the islands. 6.35mm around border & 6.996mm is the shortest distance between islands. The x or y distance individually between the islands is smaller than the 1/4" bullnose. Is there something else I missed here?
Thought it might be the 2.5" lengths. I built this machine back in the summer of 2015, so it might be time to upgrade. I have upgraded some of the parts since then, but the center section is pretty much the same.
Straight flutes or a downcut will give you the better edge finish in plywood, but you’ll need to be vigilant with chip evacuation during the beginning of the cut when it’s basically slotting.
I have a few questions about finishing passes and how they work in Estlcam.
If I have a tool set to cut 5 mm deep. And I use it to pocket a 12 mm deep pocket. What will the finishing passes do? Will it cut all the rough cuts first then three finishing cuts at 5, 10, and 12 mm depths?
Same situation will the pocket finish pass cut the final width and depth or just the width?
I have tested the finishing passes with the engraving tool. It doesn’t seem to do anything at all. It doesn’t cut deeper. It just follows the same path at the slower speed. Is that intentional or a bug?
I make my finishing DOC full depth. There’s almost no load on a finishing pass. So if your finishing DOC was 5mm, then yes, it would do 5, 10, 12, but if your finishing DOC was 12mm, it would only do one more pass.
AFAIK, it doesn’t do the pocket on the finishing pass. It should only do the outer edge.
The presumption is that the first time it went around, it was flexed away from the material, and didn’t really cut to the line. Running it with a 0.0 finish pass would do the exact same path, and if there was any place that the bit flexed away from the line, the finishing pass would cut it right to the line. I can’t remember exactly how the value works, but if you make the number 0.05mm, then it will stay 0.05mm away from the line, and then cut right on it for the finishing pass. You wouldn’t be able to see the difference and you’d only barely hear it.
