Commit 5bb6ac2d authored by Ruben Castro's avatar Ruben Castro
parents 4ade7460 6dca9a09
......@@ -304,3 +304,10 @@ The vertical side face needs to attach to the horizontal side face at some point
There is a general design for how this will work:
<picture of the general sketch
# torsion on x axis
![torsion_img](media/test_x_current.png)
As we can see from the picture above, the initial design suffers too much under torsion. I tried three different changes and submitted them through a FEA test, and the last one proved much better, improving performance by about 85% by adding a third bar at 45 degree angle to horizontal. As we can see from the stress test, the stress is much more evenly distributed this way as opposed to being concentrated on where the carriage is. Now I must redesign x axis to incorporate this somehow.
It's nice, I think I can reuse most components and only swap out the middle angled brackets and run the bar between them. Let's test it out.
......@@ -90,7 +90,8 @@ Also... Spring on Z axis?
Gettin better.
#### New bearing design.
With the 45 degree bearings, tightening was easy because contact was only at a point. There is no need to maintain alignment. With the full contact bearing, there is now extra bolts needed to tighten it up. This adds up to more space which is fine and attainable for the y axis carriage attachments. But I wonder if there is a neat solution for the x axis to take up less space. Maybe one is enough and let flexture and the pressure from the material makeup the difference?
With the 45 degree bearings, tightening was e
asy because contact was only at a point. There is no need to maintain alignment. With the full contact bearing, there is now extra bolts needed to tighten it up. This adds up to more space which is fine and attainable for the y axis carriage attachments. But I wonder if there is a neat solution for the x axis to take up less space. Maybe one is enough and let flexture and the pressure from the material makeup the difference?
##### Mounting stuff to bottom
......
# RCAT 0040
The RCAT 0030 is very solid when it comes to the base. The base is quite rigid in all degrees of freedom, however, it is easy to see its weak point in restrospect: the attachment from the x carraige to the bed. There is a diving board effect that happens at the edges and it could lead to major deflections. Thus the search for a more rigid structure is here.
###### Measure of static forces that machine will encounter
- 400 g at 1G
simple F=m*A. F = 0.4kg*9.81m/s^2 -> F= 3.92 N. This is a tiny load my friends. I have been working with 200N loads. lol.
total Force = 3.92*1/0.3(efficiency) = 13.067 N
- belt tension = 20 N
# Side face attachments
The vertical side face needs to attach to the horizontal side face at some point. There is a desire to maintain the base as close to the 0030 as possible. So for the 0040, the edge rail webs will be swapped out to fit a more boxy way to attach rails for the bearings.
There is a general design for how this will work:
<picture of the general sketch>
There is a desire to make the previous way the bed works to keep being the bed. The bed is just so nice. The isogrid-type bed is surprisingly rigid and way better than a simple 1/4" sheet, which makes sense from an inertial point of view.
## basic structural loop
![cat0040_draft1_image](Notes_media/CAT0040_structural_draft1.png)
Here is the basic structural base of the machine. It is interesting to note that while this version shall have a axis without intertwined actuators, it could easily be Core-XYed
![side_structure](Notes_media/CAT0040_structural_side_draft1.png)
A few things to note: The boxy structure at the end. Lateral forces are transmitted through the base of the x-carriage onto the vertical side rail. Traditionally, these loads are handled poorly with bending-type loads, however, here the unsupported beam is only a short distance from the 3d printed joint up to where the bearings run through (~2cm), and after that is supported by a joint through the diagonal triangle support and into the base, and attached at a second point down at the actual junction with the bed itself. This should be rigid enough. The vertical loads are handled lower down with those loads carried through the side webs, whose inertia is maximized on that axis, leading to lower bending since all loads carried through are purely in the Z direction. There is a worry I have of the X direction forces handled from the motors into the rail.
## To-do before laser cut
- check al displacement from bearing to plates are 1mm
- Add kurf compensation to diagonal pieces
- Add pulley situation
- Finish X carriage situation with classic room for kinematic mount
- Carriage let it go all the way in
-
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