Hacklab Reprap Coolness 2

So what’s happened since my last post on the Hacklab RepRap? Quite a lot.

First of all, I went on a bit of a printing spree:

8 Vertices and more than 30 bar clamps. It turns out that you can easily print 3 vertices in one run:

The Makerbot finishes printing 3 Prusa Vertices in one run.

Rob redesigned y-* to work with the new vertices:

Rob's new y-end-motor design compared to the Prusa design.

UPDATE:  Josef just pointed out that the latest version of the Prusa is very different. Check out the latest version here. So the preceding and next points are obsolete. Unfortunately, I don’t have one like that sitting around to do a side by side picture with. Rob would like me to mention that his work was inspired by Vik’s work.

And the idler just gets replaced by a bearing or two! That’s part drop one of this post. One gets away with this by putting the rails for the platform up instead of down, which also has the advantage of increasing the y build area (with the designs in the works for the new platform mount, it may almost double it).

It’s actually pretty awesome to see this budding hacklab-mini inside a regular Prusa:

OK. So that’s what Rob’s Been up to. But what about me?

Most of my work has been related to z-motor-mount.

Firstly, I killed tight_grip. What was tight_grip? The idea was based off an observation I made. If you make wholes for the threaded rod a little bit to small, they’ll self-tap when you put the rod in and act like nuts. It seemed like a great way to bring down the vitamin count. The only problem is that it made things hellish to assemble since the rods wouldn’t slide, especially when combined with the new vertices. So I got rid of the feature which actually wasn’t much of one.

But there was a good idea in there. So I made 3d printed nuts:

They actually work quite well (see video), though they’re a little tedious to get on the first time. I’m thinking of making a design for the vertices on the same principle, to get rid of the interior nut.

But the main thing I did was go through several iterations of designs for z-motor-mount. The first thing I tried was using a single top rod for z-motor-mount:

But that has big problems in that the natural way to carry it is by the top rod which, with this design, runs a substantial risk of breaking.

Then I tried moving diagonal rods to the side to reduces x length.

Then I tried cutting off the back half and moving the z smooth rod to the front.

The best part of this design is that, by putting the smooth rod at the front, we make a rod and two parts unnecessary.

Consider the old way to mount the smooth rod to the bottom:

This becomes something like:

It’s also an experiment in rounded parts. Actually, the following code may be of interest to some people:

module roundedCylinder(h,r,r2){
 //By Christopher Olah. BSD.
 cylinder(r=r-r2,h=h);
 translate([0,0,r2]){
 cylinder(r=r,h=h-r2*2);
 for (z=[0,2]) translate([0,0,z*(h/2-r2)])
 rotate_extrude() translate([r-r2,0,0]) circle(r2);
 }
}

(I BSD’ed it so it would be compatible with roundedBox.)

Though, honestly, I don’t think it was worth it. It massively increased compile time and wasn’t really visible in the print.

In any case, I finally decided to design it from the ground up.

This design takes advantage of the motor for its structural integrity. It also has smooth rod at the front, and gets the same advantages. Furthermore, by decreasing the distance between the smooth and threaded rod it is possible to shrink the size of x-end-*. Also, it prints in ~30 min. The original took about an hour and 20 min. Just saying.

(Since these designs break everything, I’ve put them in the crazy-colah branch, in case you want to check them out…)

On a related note, last post I mentioned threaded rod instead of belts for x-end-*. Here’s a pic:

Though I’m not actively working on those at the minute.

Finally, I should announce that we now have a mailing list for hacklab-reprap. If you want to participate in the development process, please join!

Tags: 3d printing, openscad, reprap