Ok, version 1 of my z-stage is ready for prototyping.
I will make a prototype with 2mm acrylic. Won't be usable, but should look pretty cool
There is an error I just noticed after putting all the stuff together for Pic 2: The front is a bit too far recessed. I will move it further to the front a bit (making the "nose" where the front center hole for the platform sits) shorter. I experimented with multiple hole positions.
The hotend usually doesn't sit in the center between the x-y axes, but is somewhat offset. On the Original hotend, the nozzle is offset about 10mm to the right and 10mm to the front.
Anyways, I figured it's not necessary to put 9 holes there so you can correct offsets in all possible directions, but instead I went with 2 holes (center + 1 correction). Now, you just have to turn your hotend the right way so that the offset fits.
I made the arm as triangular as reasonably possible. As discussed, making it triangular downwards doesn't work.
On the assembled picture, I added some quick dummies for the bearings (top only). As you can see, they protrude about 4mm, and that is their short side. They can be mounted upside down so that they protrude 16mm. That works for the top, as well as the bottom bearings.
This is why I lowered my "cage" height again.
If you go with the bearings upside down, then the arm can be made "thicker" by up to 16mm. This will make it stronger if necessary (if no steel is used).
So, on wednesday I'll see if I can lasercut the parts @ the Zurich FabLab. If they fit together and the construction seems sturdy enough, I'll have them lasercut in steel within the next weeks.
/edit:
Just in case you wonder:
My offset correction goes to the front and left, instead of the right. That's because I'll be using Nick Foley's E3D integrated printhead which goes to the front and left. The UM original printhead can easily be assembled in the same way.
/edit2:
Just had a minor epitaph on the toilet! (should spend more time there...)
The bottom part is completely left-right symmetric. So I will just optimize the design for my "front left" offset and leave the centered hole away (this one is useless anyways). By just flipping the part, you can convert it to "front right" offset
Recommended Posts
Top Posters In This Topic
85
22
21
13
Popular Days
Jan 16
21
Jan 17
12
Jan 21
11
May 7
10
Top Posters In This Topic
jonnybischof 85 posts
Dim3nsioneer 22 posts
aviphysics 21 posts
zumfab 13 posts
Popular Days
Jan 16 2014
21 posts
Jan 17 2014
12 posts
Jan 21 2014
11 posts
May 7 2014
10 posts
jonnybischof 60
Dang.. Got a problem with the triangular shape:
If I want to raise the lever attack point, it means that I have to raise the bottom plate with the arms. But that also raises the bearings -> no effect.
If I really want to do that, I need to separate the rear part of the bottom plate from the front part, meaning pretty much a complete reconstruction. But.. A good part of the stiffness of this construction comes from the fact that the same piece that holds the bearings also holds the platform. I don't want to lose that benefit..
So, I guess that I'll make my prototype with a more or less L-shaped arm. I can "fake" the T shape by mounting the bearings upside down and can then decide whether that is necessary or not. If it is, then I'll redesign the thing again and make a solid, triangular construction with a solid rear frame and a well attached arm. But the simplicity of the current design just calls to be tried out
Link to post
Share on other sites