I  want a camera mount for my Prusas that enables me to have a camera ride on the Y-axis. The problem, is two-fold. The first, is thermal. The heated bed is in direct contact with where I want to attach the mount (my plan is to have the mount swap in place of one or two of the little metal spacers under the Prusa's heat bed.) The second is that the Y is already a fair bit of mass to sling around, any mass addition at all could cause severely negative impacts to the machine's dynamics.
 
So I'm going to try leveraging a generative design tool to get myself an optimal balance of stiffness and weight.
 
 
 

Design Notes

2024/02/14 - Initial stab at it

To start, I'm going to see what I'd get if I design for a GoPro, but I don't really intend to go with anything larger than a Raspberry Pi HQ camera. So we'll see how it looks with a GoPro mass as a conservative first pass.
 
According to the GoPro site, the GoPro 12, with battery, weighs in at 153g.
 
For the model, I started with just defining the contacts  for under the bed. The right one is slotted to allow the bracket to be used on either the right or left side. And, frustratingly, these are not symmetric for some reason. So it is slotted to allow for either the 105mm (left) or 110mm (right) position.
 
pcm_model1_242ea.jpeg
 
I added in the disk for the camera mount. It's basically just a bit 1/4-20 washer. I offset it 75mm from the centerline of the stage fasteners and with its bottom surface 15mm above the bottom of the bed spacers. This should put the plane of the camera mount 10mm above the print surface. This seems like a reasonable spot for a nice wide angle timelapse.
 
pcm_model2_2a069.jpeg
 
I then added in a first swing at a keep out zone. I think I covered everywhere needed, but I'm sure I'll be wrong :)
 
pcm_model3_c3668.jpeg
 
I set one face of each space as fixed.
 
pcm_model4_d4812.jpeg
 
I approximated the load of the camera mass at 2N. 
 
To get a rough number to use for the side loading due to acceleration, I got an accel rate of 1000mm/s^2 from a quick perusing of forums. So I put that with the 153g GoPro mass and got 0.153N....to be fair, I put it in MathCAD before I knew the number would be as easy as 1000...
 
pcm_math1_50ecc.jpeg
 
Again, to be conservative, I'm going to round this up to 0.5N. And I will apply two load cases, one in each direction of Y movement.
 
I'm ultimately hoping to send this to PCBWay to take advantage of their metal AM, and have this printed in Al. So I set the only Al option in Fusion's additive materials library and started the solver runnin!...now I wait...
 
 First batch of solutions are done! Overall, they look pretty good, other than I forgot to include keep outs inside of the bores. I'm also a little worried about that spindly little link to the left mount.
pcm_result1_2db87.jpeg
 
 I added some material to the keep out for the holes. I also  changed the constraint for the left side mount to be only constrained in Z. My hope is that this will force a little bit of cross-bracing.
 
I also updated the 'design objectives' to include a maximum deflection criteria. I set it at 0.01mm globally, which may be a bit too optimistic. So once I see what comes out I can adjust if needed.
 
 Well I didn't get the cross brace that I was hoping for, but this definitely looks  abit more substantial:
pcm_result2_4cc37.jpeg
 
I'm going to  call it there for today, but I exported two of the results from that last series to see how a quote looks.

No comments

Leave your comment

In reply to Some User