Close



Results 1 to 10 of 10

Thread: Concerns

Hybrid View

  1. #1
    Staff Engineer
    Join Date
    Dec 2013
    Location
    Georgia
    Posts
    934
    Quote Originally Posted by Skeen View Post
    I think it's a bit of a shame, to be giving up on the self replication philosophy. And having a 3D printer motivates one, to create replacement parts on it.
    I kind of agree with this, but I think that self-replectaion has it's place, but this isn't it. I'm pretty sure NewMatter didn't come out of the RepRap community, they're showing what can be done when self replecation isn't even a consideration.

    And I'm pretty well convinced that the RepRap project has a lot of room to grow with regards to true self-replecation, and when it gets there, I'm pretty sure it will look completely different from what most people expect. (personally, I think the RepRap GUS Simpson is the most likely candidate for getting to 100% self replecation... But that's just me.)

  2. #2
    NewMatter Representative
    Join Date
    May 2014
    Posts
    60
    Regarding build table weight and skipping teeth - this is a mass independent issue. A heavier table will require more force to make it skip, but you also end up with higher acceleration forces trying to make it skip. Increasing or decreasing the table mass has no affect on the peak accelerations you can achieve. The primary factor in determining skipping is the pressure angle of the gear teeth (we use 20 deg. pressure angle pinion gears). With a 20 deg. pressure angle the maximum theoretical acceleration is well over 1G (9807 mm/s^2).

    Regarding backlash, small errors in the teeth profile will create some lost motion (not actually backlash because the teeth are always in contact). In practice, though, these errors are small compared to all of the other mechanical errors of bearing play, mechanical stiffness, motor positioning errors, etc, etc. Most discussions of accuracy often miss the major sources of errors. For instance, people talk about using 16x or 32x microstepping and think they are getting 0.01mm or 0.005mm position accuracy, where in fact steppers running at speed or under a load are still only accurate to +/- 1 full step -- the equivalent of 0.15mm accuracy. Structural deformations under acceleration loading further degrade the accuracy, but these sorts of dynamic positioning errors are very difficult to measure directly. At the end of the day, what you really have to look at is the quality of the print.

  3. #3
    NewMatter Representative
    Join Date
    May 2014
    Posts
    60
    Regarding self-replication, this is an interesting field of exploration (I come from robotics where people have been fascinated with self-assembling robots for decades). However, there's a whole world of things out there to print other than 3D printer parts for your own printer. The MOD-t is designed for people who aren't necessarily interested in 3D printers per se, or even 3D printing per se, but are more interested in having the capability of making their own customizable stuff at home.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •