Cheap CNC router to use with 3D printer toolchain
03 Feb 2015 04:05 #55598
by ProfHankD
Cheap CNC router to use with 3D printer toolchain was created by ProfHankD
I learned to use a Bridgeport Series 1 CNC mill back in the late 1970s, and have done a lot with such mills, but I don't have one now. I do own a MakerGear M2 3D printer, which has been a joy to work with, but now I'm looking for a small and cheap CNC router/mill/engraver that I can use to make mostly wooden parts to integrate with 3D printed stuff made on the M2. The M2 build area is 200x200x250mm, so I'm looking for at least a 200x200mm bed workspace and the ability to machine hardwood at least 3/4" thick. Most of my designs are done with OpenSCAD, and I would like to be able to render select components using a CNC without having to tweak the design files by hand; I'm willing to write code that would extract slices from OpenSCAD files and render G codes if no existing tools can do that. Alternatively, OpenSCAD can generate STL files, which I'd want to generate G code from.
So, the question is how feasible would it be to do this using LinuxCNC to drive a cheap CNC mill like, for example, the 3020 router/engraver? Suggestions?
I'd really like to keep cost under $800, and the 3020 seems to be as low as $500 or so....
Thanks.
So, the question is how feasible would it be to do this using LinuxCNC to drive a cheap CNC mill like, for example, the 3020 router/engraver? Suggestions?
I'd really like to keep cost under $800, and the 3020 seems to be as low as $500 or so....
Thanks.
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03 Feb 2015 07:57 #55614
by Todd Zuercher
Replied by Todd Zuercher on topic Cheap CNC router to use with 3D printer toolchain
That is the sort of thing Linuxcnc is probably used for the most.
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03 Feb 2015 08:06 #55615
by andypugh
LinuxCNC can't do this part of the chain, just to be clear. LinuxCNC is a machine controller, and should be easily capable of running any of the small machines in your price range (but avoid anything with onboard "smarts" and a USB connection. You need to be able to send simple step and direction commands on discrete pins.
CAM software for Linux is still limited. You could try PyCAM to see if that works with your models. FreeCAD has some work on a CAM module, but it hasn't appeared yet.
I am currently using the trial version of CamBam on a windows VM. However there is also a Linux version. As I have a (legit) license for Autodek Inventor and that has a CAM module I haven't explored that widely.
Replied by andypugh on topic Cheap CNC router to use with 3D printer toolchain
I'm willing to write code that would extract slices from OpenSCAD files and render G codes if no existing tools can do that. Alternatively, OpenSCAD can generate STL files, which I'd want to generate G code from..
LinuxCNC can't do this part of the chain, just to be clear. LinuxCNC is a machine controller, and should be easily capable of running any of the small machines in your price range (but avoid anything with onboard "smarts" and a USB connection. You need to be able to send simple step and direction commands on discrete pins.
CAM software for Linux is still limited. You could try PyCAM to see if that works with your models. FreeCAD has some work on a CAM module, but it hasn't appeared yet.
I am currently using the trial version of CamBam on a windows VM. However there is also a Linux version. As I have a (legit) license for Autodek Inventor and that has a CAM module I haven't explored that widely.
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03 Feb 2015 09:08 #55616
by ProfHankD
Replied by ProfHankD on topic Cheap CNC router to use with 3D printer toolchain
I didn't think LinuxCNC could take OpenSCAD or STL files into G code, but that is definitely part of the toolchain I want, so I was hoping to hear some "I use this for that" type comments.... PyCAM looks interesting; I'm downloading the .deb now. I'll play with that and anything else open source, but I suspect I'll end-up writing my own G code toolpath generator and make it freely available. I built my first 3D-model-to-CNC-toolpath compiler back in 1977-1979 to run on a NorthStar Horizon generating code for a Bridgeport Series 1, so if I could make it work under those constraints, I doubt I'll have too much trouble making one work now. ![;-) ;-)](/media/kunena/emoticons/wink.png)
My primary concern is actually the lack of limit switches, etc., on the 3020 in particular. Is this asking for trouble? How reliable is LinuxCNC with an open-loop system like the 3020? I assume I'd be setting home position by jogging to the desired spot?
Is there a different comparably cheap system I should check into?
BTW, I'm also guessing that for 3/4" wood and the tiny tools being used, I can probably get away with having a sacrificial 1/8"-1/4" board fixed to the bed and simply use 3M double-sided tape to secure most parts for machining (a trick that used to work for many wood & plastic parts even on real CNCs). I'm thinking I might also 3D-print some custom dogs for the 3020 bed. Any other clamping issues I should know about?
Thanks again.
![;-) ;-)](/media/kunena/emoticons/wink.png)
My primary concern is actually the lack of limit switches, etc., on the 3020 in particular. Is this asking for trouble? How reliable is LinuxCNC with an open-loop system like the 3020? I assume I'd be setting home position by jogging to the desired spot?
Is there a different comparably cheap system I should check into?
BTW, I'm also guessing that for 3/4" wood and the tiny tools being used, I can probably get away with having a sacrificial 1/8"-1/4" board fixed to the bed and simply use 3M double-sided tape to secure most parts for machining (a trick that used to work for many wood & plastic parts even on real CNCs). I'm thinking I might also 3D-print some custom dogs for the 3020 bed. Any other clamping issues I should know about?
Thanks again.
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03 Feb 2015 18:06 #55626
by andypugh
One way is to push the carriage up against the hard-stops before turning the machine on, then configuring it to home immediately without motion.
Adding limit switches shouldn't be difficult.
Looking on eBay things like www.ebay.co.uk/itm/4-Axis-CNC3020-ROUTER...-Chuck-/390390623824 seem to include a lot more "cleverness" in the controller than necessary, and I haven't found proper manuals to see what it is really doing.
Replied by andypugh on topic Cheap CNC router to use with 3D printer toolchain
My primary concern is actually the lack of limit switches, etc., on the 3020 in particular. Is this asking for trouble? How reliable is LinuxCNC with an open-loop system like the 3020? I assume I'd be setting home position by jogging to the desired spot?
One way is to push the carriage up against the hard-stops before turning the machine on, then configuring it to home immediately without motion.
Adding limit switches shouldn't be difficult.
Looking on eBay things like www.ebay.co.uk/itm/4-Axis-CNC3020-ROUTER...-Chuck-/390390623824 seem to include a lot more "cleverness" in the controller than necessary, and I haven't found proper manuals to see what it is really doing.
I have heard of the "Sable" www.ebay.co.uk/itm/Sable-2015-CNC-ROUTER...e-kits-/201270959233 but it isn't a class of machine I know much about. I think if I wanted one I would build from scratch.Is there a different comparably cheap system I should check into?
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03 Feb 2015 19:45 - 03 Feb 2015 19:52 #55633
by ProfHankD
Replied by ProfHankD on topic Cheap CNC router to use with 3D printer toolchain
The 3020 I'm looking at is more like
this model
, which seems pretty basic, but I'm really looking at this as a suppliment to my MakerGear M2 3D printer and hence trying to keep cost down -- and under $500 including shipping sounds great. I have tons of old PCs with parallel ports that I could dedicate as controllers for the CNC. Honestly, the M2 is and will continue to be the real workhorse for me; I've been directly printing things like camera parts with complicated internal structures and even M42 (42mm dia., 1mm pitch thread) threads without any problems. I mostly use PLA, which has really great material properties (reminiscent of aluminum in many ways) and prints beautifully on the M2's heated borosilicate bed with no clamping and no environmental issues (e.g., fumes, dust, etc.). There are just two catches:
- Overall part dimensions are usually good to about 0.1mm, but large flat pieces coming near the heated bed edges will often contract and slightly lift the corners as the print lower layers cool, resulting in up to 1mm or more warp in the bottom flatness of the part. Incidentally, because this warp happens during printing, dimensions near the top of the part are rarely affected by the warp -- the hot plastic gets forced to the right spot despite having a warp under it.
- PLA (and other easily extrudable plastic) starts to soften at relatively low temperatures, so parts that have to hold shape while being subjected to heat (e.g., bearing surfaces subject to frictional heating) are problematic.
My idea is to use a small CNC mainly to make the larger mostly flat pieces out of stable wood/composite materials and then bond them to the much more complex PLA parts via simple joinery and glue. (Plastic wood filler works well for filling any minor gaps and smoothing the "thready" PLA surface so a painted assembly would look like one piece.) I would also use the CNC for making some simple bearing surfaces that would perhaps be best described as custom-sized/shaped washers, at worst including machining an occassional bayonet lens mount flange out of a material like brass or aluminum (although I regularly 3D print such parts and they work well provided there's no major heat exposure). I've also done woodworking as a hobby, and I'd probably also use the CNC for making things like wooden music box parts and simple engraving.
A good example of the kinds of things I'm making is the 3D-printed multi-camera in the above image. I printed this as just 3 parts: rear, front, and lens focus mount. The lens mount and front component camera mounts work best 3D printed, but I think the basic box for the rear of the multi-camera really would make more sense fab'd subtractively, and putting the pieces together would necessitate some joinery (e.g., relatively deep dados) that a laser cutter wouldn't have fun with.
So, is that 3020 with an old PC running LinuxCNC a viable CNC for this type of machining? Anybody using one of these 3020 with a PC running LinuxCNC? Thanks.
Last edit: 03 Feb 2015 19:52 by ProfHankD.
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03 Feb 2015 21:02 #55638
by andypugh
I would imagine so. I suspect that you might be looking for a spindle motor upgrade eventually, but perhaps not. They advertise "EMC2" compatibility, they even have our old logo on the advert.
Replied by andypugh on topic Cheap CNC router to use with 3D printer toolchain
So, is that 3020 with an old PC running LinuxCNC a viable CNC for this type of machining?
I would imagine so. I suspect that you might be looking for a spindle motor upgrade eventually, but perhaps not. They advertise "EMC2" compatibility, they even have our old logo on the advert.
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03 Feb 2015 21:32 #55644
by Todd Zuercher
Replied by Todd Zuercher on topic Cheap CNC router to use with 3D printer toolchain
I'd highly recommend a vacuum table for milling wood and other soft items.
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04 Feb 2015 00:38 #55653
by ProfHankD
Replied by ProfHankD on topic Cheap CNC router to use with 3D printer toolchain
Are you talking about a vacuum clamping system or vacuum dust removal?
I'm very serious about hoping the 3M double-sided tape will suffice for clamping many pieces. Hey, it worked for smallish wood/plastic parts on an old Bridgeport Series 1... and that was using huge tools compared to what the bits for this CNC will nibble away.![;-) ;-)](/media/kunena/emoticons/wink.png)
I'm definitely thinking in terms of making an enclosure of some kind and having some dust removal mechanism, but haven't really thought it out yet. If I ever cut metal, I'm assuming I'll want coolant too, so I'm thinking maybe add a removable coolant collection tray and manually filter and reuse the coolant. It shouldn't be hard to design and 3D-print add-on parts to attach a shop vacuum or a bottle rigged for dripping coolant (for that matter, what coolant does one normally use with this class of machine?).
I'm very serious about hoping the 3M double-sided tape will suffice for clamping many pieces. Hey, it worked for smallish wood/plastic parts on an old Bridgeport Series 1... and that was using huge tools compared to what the bits for this CNC will nibble away.
![;-) ;-)](/media/kunena/emoticons/wink.png)
I'm definitely thinking in terms of making an enclosure of some kind and having some dust removal mechanism, but haven't really thought it out yet. If I ever cut metal, I'm assuming I'll want coolant too, so I'm thinking maybe add a removable coolant collection tray and manually filter and reuse the coolant. It shouldn't be hard to design and 3D-print add-on parts to attach a shop vacuum or a bottle rigged for dripping coolant (for that matter, what coolant does one normally use with this class of machine?).
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04 Feb 2015 17:27 - 04 Feb 2015 17:36 #55674
by ArcEye
You really have to shop around on Ebay, dozens of people are selling the same Chinese stuff at hugely varying prices, some with huge P&P costs to bump the price up
In the UK, Portsmouth seems to be the centre of Chinese imports by Chinese living over here.
There are similar centres in US (CA) and Australia as well
They usually sell without P&P
For instance this 3040, which is cheaper than your 3020, but exactly the same build and even the picture is almost identical.
www.ebay.co.uk/itm/PROFESSIONAL-CNC-3040...&hash=item4d0a0601f1
If general 'rip-off Britain' criterea apply, I would be surprised if you could not get a 3040 for the same dollar price as the £ price here and have a bit more flexibility in terms of what you can machine
regards
Replied by ArcEye on topic Cheap CNC router to use with 3D printer toolchain
The 3020 I'm looking at is more like this model,
You really have to shop around on Ebay, dozens of people are selling the same Chinese stuff at hugely varying prices, some with huge P&P costs to bump the price up
In the UK, Portsmouth seems to be the centre of Chinese imports by Chinese living over here.
There are similar centres in US (CA) and Australia as well
They usually sell without P&P
For instance this 3040, which is cheaper than your 3020, but exactly the same build and even the picture is almost identical.
www.ebay.co.uk/itm/PROFESSIONAL-CNC-3040...&hash=item4d0a0601f1
If general 'rip-off Britain' criterea apply, I would be surprised if you could not get a 3040 for the same dollar price as the £ price here and have a bit more flexibility in terms of what you can machine
regards
Last edit: 04 Feb 2015 17:36 by ArcEye.
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