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Do I understand this correctly? (CNC mill / 3D printer combo)

Posted by Erik 
Do I understand this correctly? (CNC mill / 3D printer combo)
April 19, 2012 02:47PM

I've started planning my first 3D printer, and I plan to use Gen7 electronics and a Wade's extruder. It occurred to me today that it may be nice to have my own CNC mill as well. So, I'd like to be able to build a single machine that can function as both a 3D printer and a CNC mill. I've done some searching for DIY CNC projects, but I can't find much information about the electronics. The "Teacup" entry on the List of Firmware page suggests that it can handle milling. So, my question boils down to this:

Do I understand correctly that I can use Gen7 electronics with Teacup firmware to do both 3D printing and CNC milling, potentially all in one machine, just by swapping the mill head for the extruder and by using different software on my PC?


Re: Do I understand this correctly? (CNC mill / 3D printer combo)
April 20, 2012 07:19AM
Yes, this is correct.

That said, the problem of combo machines isn't electronics or firmware, but the different work loads these machines have to comply with. Printers have a lot of "mileage" at very low forces; mills run slower, but with substantially higher forces.

Generation 7 Electronics Teacup Firmware RepRap DIY
Re: Do I understand this correctly? (CNC mill / 3D printer combo)
April 24, 2012 01:23PM
Have a look at Easymaker, an upcoming CNC/printer hybrid.


Sumpod.com (light milling, not open-source)



Re: Do I understand this correctly? (CNC mill / 3D printer combo)
April 27, 2012 05:16PM
Now that I own both a CNC mill and a 3D printer, I feel I'm qualified to say: If you want a CNC mill and a 3D printer, get a CNC mill and a 3D printer.

The taskloads are so vastly different that a combined machine just does not make sense. 3D printers are all about going as fast as possible against no other resistance than inertia, but any serious mill has to be (comparatively) stiff as heck and much slower.

Only situation where the combination makes sense is when you already have a CNC mill and mount an extruder on it to print the parts for your 3D printer.
I own both a 3d printer and a mill. I'm also the designer working on EasyMaker. My disappointment in the two machines is why I made EasyMaker.

3d printers need speed -- this is partly true. With high speed, your print will finish sooner, and this makes it more practical to do things like low layer heights or large prints. Slow printers can do the same job, but it isn't as practical.

The problem with many 3d printers is that they're weak, and hence, need a lot of care in construction and well selected parts. Slightly bent rods have made many a printer crappy, from Prusa's to MakerBots. CNC mill class parts make building 3d printers easy, as the linear strength of parts corrects for construction/materials errors, and hold up better in shipping -- thus are likely to arrive true and straight. But CNC class parts are heavy, and most printers made with these parts are slow. This is the core problem in a hybrid.

To solve this problem, I gave EasyMaker a fixed-gantry, low inertia mode. In this mode, inertial mass is about equal to a Prusa, but linear strength is a lot better. In this mode, it can go as fast as a Prusa, and probably a lot faster. I haven't yet tried a max speed test, but I've confirmed it can match my Prusa. I've got video to prove it.

One of the more interesting things I learned in the design of EasyMaker is that the fixed gantry, high-speed mode may not be needed. Good-enough speed may be achievable in moving gantry mode. ( Moving gantry mode is much higher inertia -- it's a mode meant for milling ). The only part that can't handle high-speed in moving gantry mode is the Y axis belt. There's a lot of lash in direction changes, as there's a lot of inertia to overcome. However, I'm not sure it's the belt itself -- I think it's the acrylic motor mount.

As for milling -- it mills better than my existing mill. I just achieved first-run of milling yesterday, using hand-written GCode. I was able to mill at speeds and end-mill sizes I could not achieve with my existing mill. Though, I did go beyond the limits of the stepper drivers. I'm now working on getting the electronics figured out to handle the current/torque I want to achieve.

As a hybrid, I can print parts that make the mill more useful -- things like workpiece holders, adapters, motor-mounts( example -- I printed the mounts for my spindle )etc... At the same time, I can do neat new things, like mill something and then print onto it, since the dimensions remain the same( aka X0, Y0 are the same physical point. If two machines, X0, Y0 are different physical points. )

I too believed that mills and printers should be separate bots for a while. But the duplication of parts -- motors, electronics -- and my poor results with either my printer or my mill kept pissing me off. After I discovered T-Slot aluminum, I realized the two could be hybridized. I expected the hybrid to be about the same as either machine, maybe with some compromises that I could live with. It turns out that hybridizing the machine improves both. The hybrid works better as a printer, and works better as a mill -- Something I didn't expect. I hate to use the word, "synergy", as Dilbert has ruined it for me. But, synergy is the correct word here. The linear strength of CNC class parts makes building, error correction, and precision easy to achieve, creating a great printer. The usefulness of the printer enhances the mill, making a great mill.

At the same time, the hybrid is cheaper than two machines -- a printer and a mill. And I suspect that the machine can add even more abilities in the future -- for example, lathe abilities, or 4-axis features, etc... I don't know for sure -- this is just an Alpha, and it's just coming together right now.

Anyway -- thanks for reading, and as Red Green would say, "If the women don't find you handsome, they should at least find you handy."
Re: Do I understand this correctly? (CNC mill / 3D printer combo)
May 15, 2012 11:04AM
Sounds like an interesting project.

Can you mill metals with it? I would put aluminium milling as a minimum requirement for a mill. Being limited to plastics and wood limits the usefulness of a mill quite a lot, especially when you also have the capability to print plastics.

Also, I still don't get how it would be any better than a Prusa at printing plastic. Even if you had problems with a Prusa, it doesn't mean that an owner of a well tuned Prusa would get any benefit from mill-style design, and there are already several designs replacing the threaded rod frame with sturdier elements. A well built Prusa is already accurate and fast enough that the movement isn't a quality bottleneck.
It's early in the morning, and I have little time to shower and go in to work, so I'm going to write like a caveman, Faster.

Dunno. Haven't tried metal. I Think the Design can, but the Proxxon I use is way too weak for metal. More powerful router needed to test, new mounts, need to design for router. Much work to do for case I no interested in.

Don't care about metal personally. HDPE + foam PVC + Wood = fast & fun! ( Like big parts done in 15-30 minutes ) Foam + PhlatBoyz vacuformer = Awesome. Dunno why people think metal important -- old biases from word, "mill' seems cause. When use different word, people no ask/care about metal. When use word router, people ask about size -- think furniture. When use word mill, people ask about metal. When use word subtractive, people ask, "huh?". Old biases wrong, Machine this size, weight, capable -- amazing.

Like SmartPhone revolution. Everyone still thinking in terms of ordinary cell phones when BlackBerry come. Everyone still thinking, "RepRap" or "Router" or "Mil". This very different. Canot explain how different. Imagine first smart-phone user explaining, "It like phone, it like computer. It hybrid!" to friend with phone and computer. Friend no understand why so awesome. Can't see mixing two -- too biased from existing things. Friend would say, "Can I write word documents on this? I'm not interested in a computer I can't write word documents on!( Really happened. Not made up example -- memory instead )" See point? New word invented -- "Smartphone". People no call it "Computer/Cell phone hybrid." Reason why. First smartphones clunky. Remember Windows CE Phone in 1999? See iPhone today. This somewhere in that spectrum. Too new to fully understand, both by user, and by creator.

New word needed. But what? Will start thought thread in mind.

Quality difference between best-quality printer ( Stratasys, maybe Ultimaker ) and worst quality mill -- mill wins. Not even close. Smooth edges! Glossy surfaces. Way more precise, Much faster.

Read this:
[lcamtuf.coredump.cx] -- mill extremist view, too far for normal person. Good ideas.

Not even close to well built prusa, or Makerbot. Used all at HackerSpace. Blow them away. Like Porsche vs Yugo, or more like iPhone vs phone from 1999. RepRap, MakerBot, etc... Outdated.

Still Prototype. Already more capable. And more fun. Still learning cool things about it -- and I'm the designer. Example -- didn't know what stall characteristics were. Just learned that 2 days ago. Realizing design inherently safe -- didn't know this 2 days ago! Great for beginning makers. Something that won't kill/maim an 8 year old, or a drunk 20 year old artist. Will hurt -- but not seriously. Even eye safe -- can probably irritate your eyes in case of accident, but not blind you or leave things embedded in there. Something safe to learn on, teach your kids, etc...

Metalwork means more power -- that destroy inherent safety. Can kill/maim if I make change. Good trade? Dunno. May have to make this trade if market demands. I no want. I think it bad trade. Maybe some compromise possible? Or maybe learn something new about robot that make it possible and work like I want? Don't know -- still experimenting.

Also -- got straight A's in technical writing, exposition, etc... My essays used by college English professors for future classes. Weird to be asked at end of term, "Can I give this to next class as example of how to write best essay?" No write like caveman normal days. Low sleep. Low time. Also, surprisingly fun! Self amused! Caveman style closer to pure thought -- big ideas, weak connections, no context switches. Very different. Learn more about self. Wonder if all humans think like this? Possibly very hard to read. No context switches mean people no understand word choices. Confusing. Oh well -- no time.
Sweet applied Science!!! Where speed and precision is a goal where can Lasers fit in? Measure, Confirm and Control. Contour and polish a rough piece of ugly Carbon to a Mirror Finish and Diamond Clarity. I was pondering and had been thinking if X and Y and Z are the same and then I read your Blog. I have started with a simple concept. Build an OctoCopter with parts I manufacture using off the shelf and affordable technologies. Chemical or Carbon based, parts are parts and it takes 2 or more of anything to make something of substance. I believe your on the correct path and can't wait to see it.
Re: Do I understand this correctly? (CNC mill / 3D printer combo)
November 27, 2012 02:32AM
... normally I'm not advertising my company here, but this is an interesting bit of tech, that should find it's way into the DIY-szene as soon as possible - lasersintering+milling

It's some more in development regarding 'intelligent' support structures, but here I have to respect NDA's eye rolling smiley

I'm working on DIY-lasersintering long befor I've entered Delcam, so there are some other 'free' bits of info and tools though ... e.g. high power IR-diodelasers with 9Watts CW for cutting/sintering applications below 100€ winking smiley

Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]
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