Sometimes you just know from the photo that this is going to be a really cool project. When most people salvage parts from an old printer, they usually chuck the rest. In this case [Shane] made use of the entire printer to build his CNC machine.
He started with an old HP 2500C A3 printer, which he had planned to salvage for parts only. While he was taking it apart he realized the chassis would make a great frame for his actual CNC machine! With that in mind he quickly changed his game plan to making each axis inside of the printer.
He’s using regular ball bearing drawer runners for both the X and Z axes, covered with a clever design of aluminum angle to keep any possible chips from jamming them. The Y axis on the other hand makes use of the original shaft runners from the print head carriage. Each axis is driven by threaded rod using recycled stepper motors from the printer.
An Arduino UNO sits at the heart of the project with a Protoneer CNC shield to control the stepper drivers. He’s also included an emergency stop, hold, resume, and cancel buttons for manual control.
It’s a great project, and an amazing example of using what is on hand for a project. Stick around after the break to see a demonstration of it printing!
[Thanks Kruger!]
Are those steppers really out of that printer originally? They look rather substantial to have 1 of them in a printer, let alone 3.
Possible but not probable– all the printers I’ve taken apart have had steel can-type steppers, not box-type, and *none* of those, save maybe the paper driver, had mounts parallel to the drive axis, because they have individual mount points inside the case that are more practical. I’ve also never seen a printer that only had one type of stepper motor in it, and only combo printer/scanners with more than two of useful size. That said, you could drive a small electric scooter with some of the steppers I’ve seen in those, so the power isn’t in question at all.
Depends on the age of the printer. And the price I would assume.
I had an Epson inkjet about 15 years ago that had a box type stepper. The metal can design I would imagine is cheaper, so gets used in things like the near disposable inkjets. But heavy duty office type printers, older models, and the like could quite easily have “proper” stepper motors.
Old Canons also used very nice boxy steppers. These days you’re lucky to find a stepper at all, it’s more likely to be a DC motor + some nonreusable encoders to run it closed-loop.
And that’s a bad thing? Closed loop control is superior.
Why are those encoders non-reasuable? I guess you do have to mount the plastic ‘tape’ with something springy on one side as the printers do, but otherwise why not?
On the topic of big steppers: Old electric typewriter.
I found a massive 1.2A 5Ohm/winding 200steps/rot (unipolar) stepper in there once.
Superior but harder to master. I don’t know, I never tried to reuse them but it seems that they would be rather hard to use in a hobby project because the tape is tiny and the sensor and everything has to be well aligned and smoothly moving, also probably sensitive to dust. Anyway I’d like to see someone reuse one of those.
“Closed loop control is superior.”
Yes, but a regular DC motor presents a host of practical problems, like trying to move very slowly because the motor tends to stick and then jump forwards, and you have to catch the inertia and brake it down. Using a stepper motor in a closed loop is much easier because you’re just counting steps, and you can be moderately sure that telling it to step forward one step will actually achieve that.
Making large steps is easy, maintaining steady speed is easy, slowing down on a spot is somewhat easy, making small precise steps is really really hard. A plain PID controller is woefully inefficient and imprecise. To properly control it you need to make a “virtual model” of the mechanism, represented by some transfer function that predicts how the inertia and friction in the system will behave, and then use that prediction to calculate where you should “point” the thing so it would actually go where you want it.
I took apart a few newer printers recently and none of them have steppers any more. They all use extremely cheap geared DC motors with optical encoders.
This is really clever on their part because if you think about it, for the most part a printer doesnt need precise control of the print head. They just need to have a precise speed (easily achievalbe with a DC motor) and they need to know the precise location of the print head. The only bit that needs to be precisely controlled is the mechanics that feed the paper for the next line of printing, which again was done with geared motors.
Hi all,
Wow..I made “hackaday”!..so cool.
Just to clarify, the steppers are Nema17 4800gm/cm 2.5A. As pointed out, the original motors (all 7 of them) range from the small hobby 5V to the larger 12V ones for moving the print head carriage via a belt drive. They are also plain old DC motors, so not really suitable for a traditional CNC design.
The engraving test was not as good as I had hoped (certainly not as clean looking as the pen test) because of some runout in the dremel shaft. The bit seemed to climb around the edges and drag itself off to one side. I will be testing with slower feed rates and shallower cut runs to see if I can tidy it up a bit. As for shape cutting..well..that was just comical.
So it might take some re-engineering with proper smooth rod/linear bearings/CNC milling spindle to get better results..or maybe a laser conversion? :-)
Appreciate all the feedback and comments, and good to see the discussions being generated.
Cheers,
Shane.
There are all sorts of things you can do with old printers. This is an old HP inkjet thing that is a million times more useful for winding coils than it ever was for printing.
http://homepage.ntlworld.com/dknpower/winder.3gp
It is for winding Rogowski coils, took about 4 hours to make and uses Linuxcnc for control.
Neat, no, pretty, no, functional, yes. :)
If it had some description to go with it it’d be HaD-worthy.
“While he was taking it apart he realized the chassis would make a great frame for his actual CNC machine!”
What? Every inkjet i’ve ever seen shakes a good bit when the print head moves side to side.
This one was much better than all the other printers I have pulled apart. The top platform supports are really solid and required no bracing. Unless I built a Y/Z assembly that weighed several kilos, there was little risk of the moving mass generating left/right movement.
Great project, even though it’s very rarely mentioned in the comment section of this site’s articles