This design is the result of me feeling bad about making a long post

3D Printing
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This design is the result of me feeling bad about making a long post about why threaded rods are not the way to go for a Rostock style printer. :slight_smile: Enjoy!

Originally shared by Nicholas Seward
https://www.youtube.com/watch?v=BM8me-aC3dM&feature=autoshare

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Looks interesting, what are the problems you see with using threaded rods? Except for possible speed problems it looks ok to me. But then I have not built a Rostock yet.

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@Geoff_Drake More info here: http://forums.reprap.org/read.php?178,267835

I have a theoretical max speed of 240mm/s as drawn so if I could get 1/3rd of that I will be happy. Backlash is the other possible problem but if it is a problem I have a few ways I can 3D print wear compensating nuts.

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Thanks @Nicholas_Seward , interesting reading and nice design exercise.

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Very cool, especially considering this was a penance exercise. I do agree that you probably should not use rods. You probably would not have backlash unless you accelerated fast enough to generate enough inertia to offset gravity. The wear would become an issue as you stated, bit then again, the wear doesn’t affect the pitch, only the backlash, but you accommodated for that. Very cool, nice work

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The problem with spinning threaded rod is getting it ideally straight.

If, however, you make the threaded rod only for vertical movement and use smooth guide rods (or extrusion, etc) for straight movement, then that problem is solved.

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@Nicholas_Seward But what about Simpson? Still waiting for the files there! I really want to build one, and you’re starting on new designs? You’re killing me here!
Looks cool, actually. To what extent is it an improvement over the Simpson?

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If you get right fitment for thread and nut you will have less back lash. Trick is to buy thread rolled bar. And nuts that are tapped to suit.

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@Patrick_Ryan I know. I know. Consider this a warm up to get me in the mood. (As you may or may not have noticed, there has been a dry spell of content from me due to outside forces and now I am gearing up again.) I had great plans of locking myself in a room this weekend. I am already foiled. I having to take my cat to an emergency vet clinic.

I don’t think LISA is better than GUS Simpson except for build simplicity and build volume.

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@Rob_Giseburt Yeah. This doesn’t work with just any threaded rod. You need to get rods rated for straightness.

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@Nicholas_Seward Oh, I noticed! :slight_smile:
Ok, so Lisa has better build volume - pretty much unlimited vertically, I guess - but you need high quality threaded rods, right?

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@Patrick_Ryan The high quality threaded rods only cost $60 as drawn. I wouldn’t want to push the height much more than drawn.

IMHO, the appeal of this design over GUS Simpson is that it is easier to build and maintain. However, I am working to make GUS better.