Tag Archives: Darwin

New affordable 3D printer – the Ultimaker

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Ultimaker

Ultimaker

Update 3/28/2011:  The Ultimaker is available for pre-order!

Erik de Bruijn along with a newly formed Dutch RepRap group have put together this new design for a low cost RepRap alternative.  The stated goal of their blog is “designing/developing an easy to build low cost 3D printer with a small form factor but large build envelope.”  Erik has invited everyone to comment on this beta design.  It’s interesting to see their progression of prototypes in their second blog post.

The interesting thing about this model is that it combines some of the best parts of Darwin and MakerBot and what appears to be a Bowden extruder.

The very nature of FDM1 means that the robot will only move the Z axis a little bit every once in a while.  One of the design drawbacks to the Darwin was that the heavy extruder head (motors, gears, heating elements) were so heavy that the entire robot would rock or vibrate with the lateral XY movements.  MakerBot got around the heavy extruder head problem by moving the platform in the XY and moving the extruder head only up and down.  This design decision isn’t without it’s tradeoffs, however.  One downside is that their build area is much smaller than a Darwin.  Another downside of the MakeBot design is that once the object being built reaches a sufficiently large volume or height, moving the object around quickly on the XY platform causes it to vibrate, shake, and become somewhat unstable.

One of the main improvements inherent in the Bowden extruder is that it allows you to take the heaviest parts of the extruder head, separate them from the rest of the extruder head, and move those heavy pieces to a different location.  Using a Bowden extruder makes a Darwin style robot much more feasible – the small moveable print head won’t have the mass to cause the robot to become unstable.

It seems that combining either of the X or Y movements with the Z probably won’t matter all that much, since the Z axis will only move about 0.33mm or so per layer and the Z axis typically doesn’t operate at the same time as either the X or Y axis.  Combining the as the new RepRap version II, Mendel, design shows us that combining the Z axis along with either the X or Y axis, but not both, can lead to a very stable configuration.

What I like about the Ultimaker design is that it would appear to incorporate some of the best parts of the MakerBot and Darwin designs. It appears to have a bolt/nut/T-slot MakerBot style assembly structure using thin lasercut wood pieces for the body.  I found these parts to bolt together very quickly.  Contrast this to the Darwin/Mendel structure using lots of nuts and threaded rod and printed plastic parts to hold it together.  At the same time, by making use of a Bowden extruder and the Darwin body shape, it appears to be able to use most of the interior volume for printing.

I suspect it probably uses fewer parts than a typical Darwin, but I can’t be sure.  I also have to wonder about the cost of lasercut wood versus the cost of nuts and threaded rod.

Nice find RepRap Log Phase!

  1. Fused deposition modeling – basically creating a layer and then fusing a new layer on top of that layer in succession to build up an object. [↩]

RepRap – The Movie

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I can just see the movie trailer now…  Picture a team of scientists in full body biohazard suits commenting on the development of the Mendel after the Darwin.

  • Dr. Buxom: “But, professor…  it’s mutated.  I’ve never seen anything like it.”
  • Professor McSternly: <grimly >”I have.”
  • Dr. Buxom: <now breathless> “Professor!  This is amazing!  Where?!”
  • Professor McSternly: “And you have too.” <stabs at a minority report style globe/map of the world>
  • Dr. Buxom: <puzzled> “I don’t understand…  North Africa?”
  • Professor McSternly: “Not just North Africa…”  <looks into camera>  “Egypt.” <cue music BUM BUM BUM!  Takes off glasses.>  “The pyramids.”  <BUM BUM BUM!!!!!!!!!!!!!!!!>

Oh jeez…  Did I just write the first RepRap fanfic?

Enney Meaney

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It occurred to me today that a lot of people are using their RepStraps to build Mendel parts.  Then I wondered, “How many Mendels are in operation now, anyhow?”

I would guess a dozen or so – with far more on the way.  What I find interesting is the seemingly large proliferation of Mendels (or, at the very least, blogs about Mendel parts and construction) versus the dissemination of Darwins within the prior year.

If this is the case (and I really have no evidence of this, just my impressions), is it something about the RepRap project that has suddenly taken hold?  Something about the Mendel over the Darwin?  Is it the increased RepRap documentation, more YouTube/Vimeo videos?  Is it the availability of parts on eBay, plastic/resin parts from molds, or something else?  Is it MakerBot?  Thingiverse?  Facebook, Twitter, MakerFaires, or MakerTweetBook?  More mainstream coverage in the media?  Was is health care reform, killer bees, or the loss of the Mars rover?  Is it subliminal messages embedded in the MakerBot website?  Have we been plugged into the Matrix?!?!

I know someone is going to say “a combination of these things” – but really, if you had to pick one thing, what would you say it is? 1

  1. P.S. I’m voting for the killer bees. [↩]

Help with a RepStrap alternative list

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I’m trying to put together a list of all of the RepRap/RepStrap alternatives out there. 1  Later I’ll put up the list with links to their instructions and where to get parts.  Here’s what I have so far:

  1. RepRap – Mendel, Mini-Mendel, Darwin, McWire
  2. MakerBot
  3. RepMan
  4. ShaperCube
  5. Profound Devices
  6. Tommilese

Am I leaving any out?  If so, please leave a comment.

  1. Mind, this is just a list of those open source 3d plastic FDM printers, where the plans and instructions are available.  It’s not meant to include those machines people are building on their own or converting existing 3axis CNC’s into a RepStrap. [↩]

RepRap interim challenge obstacles

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The RepRap challenge has a number of obstacles for the interim award.  There are two in particular that seem insurmountable.

  1. Maintain a total materials and parts cost under $200 and that 90% of the volume of the printer parts be printed.
  2. The ability to print autonomously without a PC attached.

I have to imagine something large enough to accomplish all of the other goals would cost well over $200.00.  If an entire Darwin or Mendel were trasmorgrified King Midas1 style into pure plastic, I would think the plastic alone would eat up 90% of the budget.  Even the best deals around the internet for RepRap parts just the electronics are roughly $215.

I say it seems insurmountable – but if someone had told me two years ago I could one day buy a full kit for building a robot that would make me any plastic thing I could imagine for $1,000.00  I would have laughed at them.

  1. or Calvin and Hobbes [↩]

MakerBot, Mendel, Mendel-Mini Build Areas

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Owning a MakerBot, I’m not even sure why someone would need something to print pieces much larger than the MakerBot build area.  Printing something as large as just the maximum build volume of a MakerBot would take ages.

While the official longest print logged on the Makerbot website is Zach’s Disney head, clocking in at 2 hours and 45 minutes, I’ve read about people printing for up to 8 continuous hours.  If the build volume for a Mendel is 4.3 times that of a Makerbot, it would take more than 34 hours to fill that build area.

When you’re printing a door hook in 15 minutes, it doesn’t pay to drive to the hardware store.  When it takes 34 hours to print a big plastic brick, you’re better off driving to the gas station, filling up your tank, driving to McDonald’s, filling out an application, working an hour, quitting and demanding your paycheck, driving to the hardware store, buying a single brick, and then driving back home.  I figure that kind of silliness would only take half a day or so.  Heck, with 34 hours, you could do this at least six times over.