Sunday, August 1, 2010

I need design advice? And who better to ask than a community of Developers?

I have a choice, and I can't really figure out which direction to go.  If I keep the build plate 6 inch, and continue to use 608 skate bearings, & place the extruder on the X trolley, Brutis will only have +- 50mm travel in the Z axis.  I could very easily end up with only 40 mm in the Z axis by the time I give myself some margin.  This is enough travel to be able to print all the Mendel parts, which is the main design goal, but it would give a build area of 150mmx150mmx40mm which looks really sad...

I see a few directions I could go here, any advice?

a. Since the top vertexes are already different than the bottom axises, I could make those vertex much bigger (same size as the Mendel, but with only 6mm/ 1/4 rod), and turn the gear motor sideways and design a whole new extruder that can fit between the upper threaded rods.

b. Forget having the extruder on the trolley and just go back to assuming bowden extruder (which adds cost, reduces print quality, and makes this harder to calibrate).

c. Make the build area bigger, therefore adding 5mm in the Z for every 10mm I add in build area.  I have to be careful here because the point here is to keep the print time below 20 hours.

d.  Since 40mm is enough for Mendel say the hell with it and just let it be.

e.  Something that I am missing that you would be kind enough to share?

I know I need to alter the placement of the Y motor (needs to go lower), to allow more room for the smooth rod supports.  Also I need to move the cross beams that support the Z axis down below the side bars to again allow more room for that y stage.  But she is looking good in my opinion.  But I am at a point where either I have a lot more work to do, or I get to start making printed prototypes on Monday.  What do you say?


  1. What if you were to change the angle in the upper and lower frame vertices, so that the frame becomes an isosolese triangle rather than an equilateral triangle by decreasing the angle in the lower vertices, and increasing it in the upper? This would probobly give you the ability to make the print area as tall or short as you like, just by changing the angle in those 6 parts. It wouldn't require any more print time either.

  2. I am keeping it a delta. Going square would really up the RP mass. And then I end the point of this project.

  3. "The RepRap Breeder project has in mind to branch off a Replicating Rapid Prototyper with only one focus, reproduction."

    I vote (d), go with 40-50mm height. Most people are probably going to print a mendel anyway.

  4. That sounded a bit rude, sorry.
    What I ment was, most people are probably going to use your printer to print themselves a mendel at some point. So I would gladly sacrifice some build height if it makes the design easier to construct.

    Note to self, use the preview button.

  5. Keep at it Neil! :)