The plastic CNC that could

Hi guys. Just wanted to share this as an appreciation for all Ryan’s hard work and all the help I have received from everyone in the forums.
I’ve got hundreds of hours on this machine without a hiccup and have paid the machine off more times than I can remember the past year. I’ve taken on more work than this machine can keep up with and am making the jump to a proper full sheet design of my own.

Anyway, I was not sure I was going to be able to make this happen. I’ve milled small 1/4" parts before with success, but did not think that this would actually work. These are the side gantry plates to my new machine. I am honestly surprised at the finish on the edges. This is a 2’x3’ cutting area. The plates are 12" x 18" x 1/2" and they will replace the MDF templates in the new cnc picture


The MPCNC will definitely not be retired, though it may shrink in size and take on a new role in my shop.

Thank you for a really fun project and the knowledge gained!

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Look at the size of that thing!!! Fun, for sure. Pretty large Z axis as well.

Shrink the MPCNC down and use it for the high precision small stuff.

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Looks like there is a space underneath the beast where a small MPCNC would fit.

Those pieces look amazing.

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Any idea what your finishing pass step over finishing pass was to get it so nice?

That is the plan! Shrink it down and shorten the z. Build the work surface out of HDPE so the machining oil doesn’t destroy it like the MDF.

Thanks again Ryan! I will be sure to post more of the aluminum parts it makes for the new machine!

I will report back tonight with feeds/speeds etc. For reference. Finishing pass was .005" full depth just to skim it to clean the edges.

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I was just thinking about making a composite base for my teeny tiny build.

What cutter are you using to chew through that metal? Aluminum I assume? The metal I’m mean…not the cutter.

6mm end mill single flute carbide. .025" step down, 13mm/s dw660 at full speed (24k rpm?) . Full depth finishing pass at the same 13mm/s .005". I use a little light oil (remington gun oil) in an aerosol can every other pass or so just because it makes me feel better lol. I don’t think i really even need it

The parts I am cutting are coming out about .015 too large, but those dimensions are not critical for most of the parts I am cutting. I need to measure the end mill to make sure it is actually 6mm. Otherwise (most likely) it may just be the machine flexing a bit. I use a v-bit to dimple the surface as a center punch to drill the holes on my drill press.

I have not had much success with 1/8" bits, as I find they do not clear the chips properly and just re-weld.

The new machine should be quite stout. The gantry will have another set of 3x3" angle irons across the back side for added rigidity. The base is a retired pallet scale, but is perfectly flat and square. It was a bear to get in place at about 550lbs. I will be sure to post a picture when it is up and running.

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Yes it is 1/2" aluminum. 6mm single flute carbide

Wow! That is a great story. Good luck with the new machine! I still haven’t done any aluminum. Can’t figure out what to do except a bottle opener!

Amazing results! Great Job!!

Don’t spend too much time on the gantry rigidity, the real weak part is almost always the Z axis on routers.

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The Z should not be much of an issue. It is 1/2 x 6" plate and there will be gussets running down the sides to create an I beam of sorts. It is running on Hiwin linear guide rail with 8 medium preload guide bearings. It is super solid now that the aluminum side plates are on. The only bit of deflection I get right now is from the gantry…and I can’t seem to leave well enough alone, so it will end up being reinforced.

The MPCNC is still milling away at all sorts of aluminum parts for it’s big brother!

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I’d enjoy seeing some aluminum video if you have it.

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