A closer look at New Matter’s MOD-t 3d printer

So last week the SupplyFrame office Prusa i3 finally gave up the ghost — the z-axis threaded rods unwound themselves from their couplers and the whole thing fell apart. So we needed to get some better couplers as our tubing wasn’t going to cut the mustard anymore. Thankfully Pasadena is full of 3d printer people! Within a few blocks of our office we have New Matter, DeezMaker, and a soon to be announced 3d printer from ToyBuilderLabs.

The one everyone is talking about right now is New Matter who recently announced an already successful fundraising campaign for the first run of their $250 3d printer, the MOD-t. This has been making the rounds recently due to its low price and stated aim of bringing 3d printing into the home of the masses (a tale as old as time, right?). It’s a lovely goal for sure, but they will definitely have their work cut out for them, but perhaps this is the team to make it happen? We decided to head over to their lab since it’s just around the corner from our office and see if we could get them to print some new couplers and maybe take a look at their printer while we were at it, videos and pictures after the break!

The mechanics

They have been working with frog to design a 3d printer that people will be comfortable to have in their homes, and we think they’ve done a pretty good job on that front. It certainly looks pretty, but we’re hackers so we wanted to see under the hood. While they don’t have a working version of the final model yet, we did get to see one of their prototypes up close and personal. We honestly haven’t seen a 3d printer built with fewer components than this, they’ve really managed to boil it down to the bare essentials, while still keeping it functional. Take a look at the pictures…

Their key mechanical design breakthrough is their rack and pinion driven XY bed, they’ve managed to do away with all the bearings, smooth rods, and threaded rod screws and replaced them with a simple mechanism of two pinions that the bed sits upon. The bed itself is a simple block of plastic with the racks attached underneath, this sits on the pinions and is then driven around the XY axes as they turn. This really is quite ingenious, but we had to wonder if this would have any negative issues, for instance could dirt and other crud get stuck in the gear system? Was there any backlash in the gears? Does the build plate bounce around at high speeds?

We asked [Steve Schell], New Matter’s CTO about this:

Any small debris that finds its way onto the pinion rods tends to get swept out of the way as the table slides along the length of the rod (remember the rack & pinion interface both meshes and slides). Large debris could cause an issue, but we just haven’t seen any real source for this type of debris in our testing to date.

We also took a close look at the gear system as it was moving around and there is very little backlash (if any) in the system at all, [Steve] says they were very careful to select the right rack and pinions and ensure their assembly process works to tight tolerances and it seems to have done the job. Finally the build plate is apparently heavy enough to keep it down on the pins even at higher speeds. They get 80mm/s print and 200mm/s maximum slew speed out of the printer which is fairly respectable given the design and they say that they haven’t had any issues with the bed at this speed. Check the video out below for a closer look at the bed during printing.

The removable bed really is a great benefit of the rack and pinion design, no more struggling with the printer to remove a part, just pop the bed off, set it aside to cool and pop another bed in to get started printing again straight away. We asked [Steve] if they planned on selling replacement beds, but they weren’t yet sure on the price or when they would be available.

We do plan to sell spare / replacement beds, but haven’t set a price. It’s not a very expensive component, but we’ll need to factor in packaging, handling, shipping, etc. in order to determine a retail price.

We were also very concerned that we saw no mechanism to level the bed, here’s what Steve had to say:

Since the bed is moving in both of the horizontal axes relative to a stationary extruder, there’s absolutely no need for bed leveling. Our testing confirms this, as we’ve done nothing in the construction or calibration of our prototypes to correct for any sort of bed leveling. All that is required for good consistent adhesion of the first layer is (a) straight pinion rods, which we control with the vendor and our manufacturing process and (b) tight tolerances on the build plate and its molded-in gear racks, which we also control in our manufacturing process.

This brings us round to their manufacturing process. We all prefer open source designs here, and sadly the MOD-t is not open source. But it appears this is largely to due with the manufacturing processes they will be using to produce the machine. While they could open source it, who is realistically going to spin up a fab house with custom boards, injection molded parts, and machined assemblies to reproduce the design? They have also been working hard to find the right suppliers that will allow them to hit their $250 price point and not go broke doing it. For instance, they’re using optical encoders with their DC motors for accurate positioning, this is usually quite expensive on small runs but since they are planning for tens of thousands they can start getting to scales that make it cost efficient over stepper motors.

The software

The software side of things is still in heavy development, they plan ultimately to have a single ‘push button print’ approach from their store in the browser. This really is a necessity for the device to reach the mass market as we really don’t think you can get a wider consumer market to use Slic3r or Skeinforge! So they are keeping the store very tightly controlled, everything on the store should print perfectly out of the box, no calibration, no messing with settings etc. As such the store is essentially DRM controlled, more out of necessity than anything else.

That’s not to say that the machine itself is though, we’ve been assured it takes standard GCode and standard PLA 1.75mm filament. Any controlling software you would usually use on your reprap or similar device will work. Of course, you’ll then be stuck tweaking settings as you are with all 3d printers, but that’s the trade off.

The prints!

New Matter were kind enough to print us 2 new sets of Whosawhatsis’ Buko Z coupler v2 for our printer, these came out fairly nice and were not too difficult to install in-place on our machine without disassembling everything. Of course we screwed up and these couplers don’t fit with our X axis parts meaning we need to raise the bed and spend yet more time fiddling with the printer rather than actually — you know — printing stuff.

Catch the video below for some up close action shots of the MOD-t prototype and let us know what you think of the mechanical design in the comments!

Comments

  1. repkid says:

    I thought it was a hoax due to lack of info but it seems they’re legit. Nice piece of kit!

  2. slavoj says:

    The store approach seems like an interesting way to sell printers at a loss and still make a profit (kind of like desktop printers sometimes are with ink). It doesn’t really jive well with the open source spirit that got 3d-printering off its feet but I wouldn’t be surprised to see this software+DRM based profit model catch on.

    • kendall14 says:

      ” Can I print 3D files that I got somewhere else?
      Yes. We’ll include desktop software for slicing STL files.

      Can I use software other than New Matter’s to print with?
      Yes, the MOD-t will support standard G-code so more advanced users can use existing 3D printing software such as Slic3r.

      What is the material this printer uses?
      The New Matter MOD-t prints in polylactic acid (PLA) . PLA is a benign, environmentally friendly and biodegradable thermoplastic, typically made from renewable sources such as corn or tapioca. PLA is used in a variety of applications from compostable packaging material to medical implants. ”

      Just what they put on the website.

  3. jdarling says:

    Really interesting and nice design on the XY table control. Could easily be adapted for use in CNC allowing multiple tables for quick change.

    • Torque says:

      Although then you’d either need a vacuum system or live with the constant fear of jamming/”derailment” of the bed.
      Though with how ABS plastic emits funky fumes when melted, a vacuum system to outside filter & container might be a good idea anyway.

      • Ben Delarre says:

        Well the printer is PLA only due to the lack of heated bed. I had wondered if a wireless power transfer system under the bed area might work. Could you put a giant coil under the XY axis, and wirelessly transmit enough power to run a heater coil embedded in the bed? Losses would be huge I guess…

        • Anathae says:

          I don’t see a reason why a power pigtail couldn’t be run to the bed. With the correct plug, it could be unplugged from the bed during removal, and there are existing cable management solutions for running a cable from a stationary spot to a device that moves about in a constrained space.

          • Hans Peter says:

            Or isolate the pinion rods from the casing and use them as contact points for the heated bed connector. Maybe not feasible with ~10A running in there, but hey – it’s just an idea.. oh, and no temperature reference.. but open-loop control is possible

        • Angry Midget says:

          That kind of beats the point being cheap.

          I don’t see why a flexible cable slab as seen on a regular printer wouldn’t work.
          As long as it isn’t stiff enough to pull the bed off its gears

          • Ben Delarre says:

            Oh of course, I doubt they could do it for production…I was just toying with the idea of hacking it up myself! I’m somewhat fascinated by wireless power transfer. I really want a way to send significant power to devices hanging on walls without lots of unsightly cables.

            You’re right though, a suitable flexible cable (maybe some of that silicone coated stuff) would probably work fine.

          • Torque says:

            As long as the wires are secured properly so the solder joints don’t get stressed by the movement of the bed, then I don’t see any problems

  4. ianmcmill says:

    What’s the technical term for the geared x and y axes ?

  5. a_do_z says:

    I like the way it moves. Fun to watch.

    It looks like the plate rests on top of the two pinions with no sort of upstop. There are two racks for each of the x,y dimensions. So, there are 4 contact points making for a pretty stable arrangement.

    But, when the pinions are both driven to the extreme ends of their respective racks, two of the four support points are very close together (stacked almost on top of one another). In that, uhm, “corner case”, does the opposite corner of the plate want to sag?

    • Jeff Kerr (New Matter consultant) says:

      The corners of the build platform actually have little feet that normally glide just a couple of thousandths above the bottom of the tray. If you print a large part with an off-center CG, then these feet will actually touch down in the extreme X-Y positions. The motion is tiny, though and and isn’t noticeable in the print.

  6. Moser Labs says:

    Clever design and execution. I especially like the hotend – so darn simple! I’m in the process of getting my slacker Mendel up and running to print parts for an i3 I wanna make

  7. tjb1 says:

    The equipment used does not determine whether or not it should be opensource…

  8. phlt says:

    Great, little, affordable printer.

    Some people could now compare “Poor Man’s 3D Printer” to that one (quite close price gap, specially early bird – although different league. )

  9. untrustworthy says:

    Closed source, closed design, and drm? That’s a lot of evil shit. Hope these guys fail.

    • Tony says:

      So buy a MakerBot then, that’ll show-em.

      Typically fool who’ll never buy or build anything, but can recite pointless rhetoric with the best of them.

      DRM? So what, pull the electronics and replace them.
      Closed source? Closed design? Are you blind? Lost your screwdriver? Can’t figure out how a few mechanical parts work?

      You should join LoserADay, hacking is obviously beyond you.

  10. Dougal says:

    Nice! $250 is a price point that could finally get me a 3D printer. And while I probably *could* build one myself on the cheap, with most of the parts coming from old equipment in my garage, or purchased at GoodWill and such, I just don’t have the time. So a pre-fab solution is almost a must, for me.

    And while having it as Open Source would be good for warm fuzzies, it doesn’t bother me much. There are plenty of existing OSH printers, and I’m sure nothing will stop people from hacking these on their own, if they feel the need.

    • +1, especially since it will work with Gcode and isn’t software crippled.

      I’d much rather have something like this as a tool, rather than another project/maintenance hassle, and this price is pretty reasonable for something if I knew I’d use it a lot.

  11. occam49 says:

    The key to this design is making the pinons long so the x rack slides along the x pinion when the y pinion is driven and vice versa. I’m sure this has been done before, but not for a 3D printer. That sliding action is what helps keep gunk out of the gears. I see the potential for chatter in the sliding action should sticky deposits build upon the pinions or they become corroded or worn. What are the pinons made of ? Are they coated with teflon or some other low friction coating?

    • Jeff Kerr (New Matter consultant) says:

      On our prototypes, we’ve been using acetal racks on uncoated 12L14 steel pinion rods. We have not seen any chatter or stick-slip problems. For production, we will still be using acetal for the molded racks, but we will be looking into various coatings for corrosion resistance.

  12. RunnerPack says:

    I love the Iraqi peanut drive system, and the fact that it uses servos instead of steppers. It looks like it uses a Bowden cable system for the filament, but I can’t see where said filament is hiding in their publicity shots. They also don’t mention/show how easy/hard it is to load.

    I don’t think the huge bread-box you have to take off (and find a place for while off) is going to be very popular, though. I hope they’re ready for the lawyer-storm when “little Timmy” leaves it off and then burns himself, gets caught in the gears, gets asthma from the fumes, etc.

    I would probably order one right now, but I just got a 7×12 lathe (for the same price =D ) that I hope will facilitate making my own printer (and pretty much any other imaginable machine part) in the near future.

  13. valley_nomad says:

    They have a lot to do for DC servo. I haven’t seen one successful 3D printer using DC servo yet. They may end up using stepper in production.

  14. Open-Electronics.org says:

    This is nothing new to move the XY axes. Our 3D printer 3Drag [http://www.open-electronics.org/3drag-3d-printer/] works on this principle. This allows (if the mechanism is robust) to transform the 3D printer in a CNC.

    • Sheldon says:

      The novelty isn’t in the fact that they do move the bed (like yours and, as you point out, like standard [CNC] mills), it’s how.
      Take one axis movement and it could be viewed as largely the same but it’s how two are factored in at the same time such that the bed becomes very simple with two sets of “teeth” (racks) at the two heights corresponding to the two axis; when one axis is driven, the teeth of the other axis just slides along and vice-versa.

      I’d be intrigued to know what decisions were made in terms of the bed weight as I’d be worried that it could skip because there’s nothing (other than gravity) holding the rack & pinion system down.

      • Open-Electronics.org says:

        Yes you are right. It ‘s definitely a great product and very cheap.
        Some time ago has been released an interview that he was referring specifically to the movement of the plate. Here an extract:
        “The combined X-Y axis motion system in the MOD-t is patent-pending, and we believe one of the real differentiators in our product,” explained New Matter’s Co-Founder & President Steve Schell.

      • Jeff Kerr (New Matter consultant) says:

        It turns out how fast you can accelerate without the bed skipping teeth is independent of the mass. A table that weights more will be held down with greater force, but it also takes more force to accelerate it laterally. The maximum theoretical acceleration is mostly determined by the pitch angle of the gear teeth,(20 deg.) which works out to well over 1g (~10000mm/sec).

        • Sheldon says:

          Ah. I can see the sense in that.
          Thanks for the detailed reply.

          I guess what I was thinking of was more where the “business end” was perhaps more akin to a mill bit where there are reactive forces on the bed rather than an extruder which has practically nil. As it also applies no force, this could also make an excellent bed for keeping a laser cutter cost down and it’d keep the whole optics arrangement simple (no moving mirrors and focussing is easily done with the single Z travel).

          With the corner supports, if they’re relatively low friction, beyond balancing the acceleration when moving the bed, I wonder where the practical limit is to the table size as it makes it incredibly cheap to make as there are no expensive linear rails.
          Hmm, may have to look for some supplies and have a play :-)

    • Nathan says:

      Yours doesn’t use rack and pinion and is about $650.

  15. alright guys i just bought one, it’ll be a year till i get it (mega bummer) but when it comes, ill do a full write up on it on my website and put this printer through its paces, im super excited this will be the first printer ill actually own

  16. surfingtheether says:

    Year lead time? F that just buy a printer that is ready to ship now. Not like they cost much anymore and only being able to print PLA is all but useless other then for making toys.

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