MPCNC alternative? Should we build one as a community?

Hi, I saw tom’s video today on MPCNC. Was going to build it, but no more.
I like many on that thread are disappointed, would love to start a complete community project. Maybe tom can help build and validate this. And build parts distributed, a few people lifting the load might yield best results? I also like the idea of a bounty for those who can contribute in that way. I assume not everyone has a lot of time to start from scratch and build the best cnc alone.

Please respond if you like the idea. Maybe if there are enough people

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We started on one based on 2020 extrusion. Right now looking for the right wheels for it Kinda like the ones used on some 3d printers

I have begun considering designing my own, just not ready to do so yet. I need to do a lot more research into the various ideas out there, and need to decide what exactly I want in a CNC.

Well there are some constraints for us (FRC Team 1989) to be involved
1.) It has to be completely open source
2.) It has to fit around our other projects. Right now we got to get “BumbleBot” along as far as possible before the ERRF as we want to show it there and if its not completely finished by then it got to be finished asap as we want to take it to a competition in the beginning of November to test how well a 3DP robot can compete so we kow for next season. All items for the 3DP robot are open source too as with FIRST we need to share everything otherwise nothing even close to it can ever be used by our team again.

I - Martin Pirringer - am the head mentor. I am retired - I can design a lot of parts. My restrictions/bottle neck is 3D printing it. My printers the PULSE which is currently not operational and the CHIRON are the only printers currently working for team 1989. The team has a makerbot replicator + the school was going to throw out cause it was too expensive to fix and we fixed. The school also has an airwolf but we can’t use that one cause we “print too much” and it might break. I currently have the parts that connect the 2020 for the base frame and the legs. Bumblebot is designed by the kids and sometimes I get a little ahead of them printing (they make the STLs under my guidance). The Pulse is apart cause when it ran out of warranty I decided to fix/update it. It has some “features/quirks” that annoyed the heck out of me. Like an underpowered powersupply which means if you try to run the E3D V6 at over 255 and the bed at 100 like for some ABS and definitely hobby king HIPS the 12V is 11.1 cause well the draw is too great and if you turn the fan on like for bridiging you get a thermal runaway. The Mini rambo its running therefore is running too hot and right now I got a fan strapped to it so it gets a new electronics case and wiring with fan and a 30A power Supply and an enclosure the Chiron will get one too right now the enclosure is this


A piece of plastic draped over it and the Print dry which is a converted food dehydrator next to it which ups the “chanber” temp to somewhere within the high 40C a little over 50 at the nozzle level if the bed is at a 100ish. plus it keeps the HIPS smell under wraps. Granted that smell is way less than ABS but still noticeable. Right now I am printing plates for the Rack and Pinion like this

That is about (depending on config) between 400 and 700g of filament as its pretty much solid.
Our standard print settings for Hobby King HIPS - frame brackets is (we print with a .8 nozzle) between .9 and 1.0mm outside perimeter between 1.2-1.5mm inside perimeter layer height .4mm 6-12 perimeters (the piece displayed has 9 with a 1.3mm inside perimeter 1mm outside perimeter) and 3mm floor and ceiling so its pretty much a solid piece of plastic as close as you can get 3DP to it being casted. At that print it almost never breaks along layer lines anymore. Dialing it in right is important and so are the other parameters we print a little hot so we get a little stringing but in most cases that is ok like the piece in the picture will take 12 ea 1 1/8in od bearings (We print those too)

Now to the CNC. We have a 1/2HP hand router donated that we will fit but pretty much any spindle setup will do we got to use that one as we dont have the $$ currently for another one. The Y is probably going to be like th Z on most printers with 2 steppers the X has 1 stepper and the Z will have 1 stepper. Initially we intend to run belts - maybe double belts on some . Eventually we would love to replace the belts with Rack and pinions. The 2020 extrusion we bought in 1200mm length as we need to cut pieces as big as 36x36 in mostly hardboard,. lexan and hopefully Aluminum up to .125 in thick And maybe other plastics like sheets of ABS or HIPS or PVC etc the repeatable accuracy we are looking for is +/- 0.5 mm If we get to about 0.1 tolerance we can do pc boards too. In electronics we were thinking in the direction of the Bigtree 32 bit board with TMCs to do “sensorless” homing. But right now its kinda on hold for about a month. All the parts so far and in the future are designed to be printed in HIPS. We love HIPS we print it easier than PLA on the makerbot (which is a PLA only printer) Is realy tough and we buy it at between $8 and $12/kg. Only thing we (the kids) don’t like its very limited in the range of colors it comes in Hobby King sells Black,yellow, orange, red and not all colors are in stock all the time and toner plastics sells natural (white) only. I will make a separate post on printing that HIPS. Some other minus which we don’t care about is that according to some people the Hobby King and Toner Plastic variety do not dissolve in limosene as fast as other brand name HIPS (we never tried it ) cause if we had a 2 head printer and would use a dissolveably support material we would print in HIPS and use ABS as the support material we call HIPS the better ABS smells less, is tougher, easier to print (less warp, better layer adhesion) and its the filament so far that according to our Volumetric max extrusion determination can be printed faster than any other material,

Hi,
you can build: https://www.thingiverse.com/thing:3594535
which is a 2020 version of the ANT PCB MAKER

Its a start - only for our size smooth rods with over 1 meter length carrying our 12 lb router I don’t think will cut it so the x axis will be 2 lengths of 2020 too. and there will also be some 2020 most likely or some thicker smooth rod in the Z. each 2020 extrusion on the frame will also get extra legs and supports to reduce flex and vibration and everything will be screwed down on a piece for 3/4 in plywood as a base.

Cool! There is some interest.
@mpirringer, If your design can be made flexible so most people can source and build it to have a cnc much better than mpcnc. i would be definitely help build and test it. Can even do website work, and help out team 1989.

If not possible, I think starting from scratch or using an existing design which is open source all are available options. Based on what gets the best bang for the buck in the end.

I found RS-CNC, completely open source and am considering building it:
https://www.makerfr.com/en/cnc/rs-cnc32/presentation-rs-cnc32/

Yeah its going to be a mix between that and the thingyverse one just in 2020 extrusion as we got some donated. Right now I am researching with not too much success which are the best wheels guess they are all china made cost about the same and are what are used on CR10 and CHIRON etc. So I will order some wheels and make a 3 wheel mount for them I got one for smaller ones I had lying around but this thing is going to be heavier I guess


Something like that only for whatever wheel I/we feel is better now the ones that are on the Chiron that seem to be 24 mm instead of 21 seem to be tougher and more accurate but I don’t have any of those
CNC.zip (3.0 MB)
This is what I got so far the WTEST Is what I am holding in my hand the Cornerleg - well is the corner leg the leg is what goes along the way as needed under the 2020 extrusion the templates were to get tolerances down with dimensions. All is done in inventor cause our school has and teaches in inventor so one of the rules is that if the kids are supposed to work with it it has to be inventor and well as its an educational thing I get inventor too. (for the free version you need an email associated with an educational institution and the license is that its only be used for educational purposes and not for anything commercial) One of the reasons the school felt we could not use the MPCNC as it was not open source so if we change something and pass it along it could become part of the sold one and then they felt that might be a license violation so opensource it is .

Well if anyone wants though we are at
vernonrobotics.com
and do take donations

If you are okay with Creative Commons - Attribution - Share Alike (http://creativecommons.org/licenses/by-sa/3.0/) then you could probably make use of my
extrusion holding corner bracket. I am not sure if that is what people would call open source or not. I just want a little credit. I made sure to leave it open for commercial production too.
One detail…the default parameters for my part are not for 20x20 extrusion exactly, it is for the square rail spindles from Menards and such other hardware stores. To use actual 20x20, you will want to adjust the parameters.
https://www.thingiverse.com/thing:3577992

The requirements from FIRST are that it is and can be freely shared with any other team without money changing hands - donations are ok but not to be required to share the design. So it kinda is public domain? now I am not a lawyer. When we design something to keep using it in connection with robotics we publish it with a note that reads something - hear enjoy - don’t sell it as that is against the rules and be nice and give us credit. If you really like it here is our website - you can become a sponsor.