compact carrier for Kossel Deltas
Posted by o_lampe
|
Re: compact carrier for Kossel Deltas November 22, 2017 12:09PM |
Flexural modulus of ABS is about 2.25 GPa. Aluminium has it at 68 GPa.
The ability to resist deflection grows with the third power of thickness.
If there is enough space so that you can make your ABS part about 3.3 times thicker (compared to the aluminum original) then it will have the same ability to resist bending. Maybe make it about 4.1 times thicker since 3D printed ABS will we weaker than injection molded ABS.
Flexural modulus of PLA is about 4 GPa. If you print in PLA it should be enough to make it 2.6 - 3.3 times thicker than the aluminum original.
Just some rough numbers
The ability to resist deflection grows with the third power of thickness.
If there is enough space so that you can make your ABS part about 3.3 times thicker (compared to the aluminum original) then it will have the same ability to resist bending. Maybe make it about 4.1 times thicker since 3D printed ABS will we weaker than injection molded ABS.
Flexural modulus of PLA is about 4 GPa. If you print in PLA it should be enough to make it 2.6 - 3.3 times thicker than the aluminum original.
Just some rough numbers
|
Re: compact carrier for Kossel Deltas November 23, 2017 02:43AM |
Thanks for sharing the belt attachment for the smart effector. I might copy it on my "deluxe" Delta.
I played around with dc42's tip to turn around the belt on the idler side and I came up with a simple ( but maybe too weak ?) solution:
I cut the belt in two pieces and CA-glued them teeth-to-teeth. Now I have a part with a smooth part for the idler side and a driver side, with teeth inside.
I tried to rip it apart, but the CA glue does a really good job here.
This slim design even fits in the 2020 slot ( which was my major concern ). Just have to make sure the glued pieces don't have to run over the idler.
If I ever replace the belts on my CoreXY, I try to do it there too. There are way more idlers to deal with.
I played around with dc42's tip to turn around the belt on the idler side and I came up with a simple ( but maybe too weak ?) solution:
I cut the belt in two pieces and CA-glued them teeth-to-teeth. Now I have a part with a smooth part for the idler side and a driver side, with teeth inside.
I tried to rip it apart, but the CA glue does a really good job here.
This slim design even fits in the 2020 slot ( which was my major concern ). Just have to make sure the glued pieces don't have to run over the idler.
If I ever replace the belts on my CoreXY, I try to do it there too. There are way more idlers to deal with.
|
Re: compact carrier for Kossel Deltas November 23, 2017 02:49AM |
Quote
hercek
Flexural modulus of ABS is about 2.25 GPa. Aluminium has it at 68 GPa.
The ability to resist deflection grows with the third power of thickness.
If there is enough space so that you can make your ABS part about 3.3 times thicker (compared to the aluminum original) then it will have the same ability to resist bending. Maybe make it about 4.1 times thicker since 3D printed ABS will we weaker than injection molded ABS.
Flexural modulus of PLA is about 4 GPa. If you print in PLA it should be enough to make it 2.6 - 3.3 times thicker than the aluminum original.
Just some rough numbers
If I read your explanation correctly, I could make the aluminum clamp much thinner than the PETG version. ( given that the PETG version is already strong enough)
But then I thought, it might be the rubber belt teeth which can only withstand so much belt tension and I have to use the same size aluminum clamp to get enough teeth "involved"?
Edited 1 time(s). Last edit at 11/23/2017 02:50AM by o_lampe.
|
Re: compact carrier for Kossel Deltas November 23, 2017 02:10PM |
Eight teeth would be good, because I have 2x5 teeth involved now. The cutouts are now placed where the beefy part of the clamp is.
I also added two M3 screwholes. That way the rods are separated from the slider clamp and I could use them as belt tensioners, too. ( in case 5 teeth are strong enough )
I also added two M3 screwholes. That way the rods are separated from the slider clamp and I could use them as belt tensioners, too. ( in case 5 teeth are strong enough )
|
Re: compact carrier for Kossel Deltas November 27, 2017 03:42AM |
Was shopping for NEMA17 dual shaft steppers with 0.9°, but couldn't find any. 
Has anyone seen one? (1.5-2A will do )
Has anyone seen one? (1.5-2A will do )
|
Re: compact carrier for Kossel Deltas November 27, 2017 07:23AM |
Just a quick sketch.
You can see the outer XL frame, the steppers with dual shaft and the inner frame driven by the rear pulleys.
The outer carriers/rods are smart effector/magarms, easy to remove.
The bed ( in my case ) is at the top. In other cases, it has to be replaced by the smaller bed.
I call it the Matrioska-Delta
How long did it take to get the dual shaft,0.9° steppers? Waiting for parts can be soo annoying, especially because I have plenty of spare time until Jan. 2018.
Downgrading to 1.8° would make both Deltas less accurate, don't you agree?
Edited 2 time(s). Last edit at 11/27/2017 07:38AM by o_lampe.
You can see the outer XL frame, the steppers with dual shaft and the inner frame driven by the rear pulleys.
The outer carriers/rods are smart effector/magarms, easy to remove.
The bed ( in my case ) is at the top. In other cases, it has to be replaced by the smaller bed.
I call it the Matrioska-Delta
How long did it take to get the dual shaft,0.9° steppers? Waiting for parts can be soo annoying, especially because I have plenty of spare time until Jan. 2018.
Downgrading to 1.8° would make both Deltas less accurate, don't you agree?
Edited 2 time(s). Last edit at 11/27/2017 07:38AM by o_lampe.
|
Re: compact carrier for Kossel Deltas December 13, 2017 03:39AM |
I finally got the frame assembled and running. There is a little squeaking noise from one off the carriers. The belt clamp is rubbing inside the T-slot ( can be fixed ). The belt can now be tightened by two screws on the carrier.
The rods I had laying around are a bit to long for the frame. I only have ~130mm Z-height, also the rods bind quite early. That's partly due to being almost vertical, but also because the upper rod ends are in line with the Delrin mushroom sliders. If I'd move them a few mm to the inside, they could move freely. But that would add a lever to any wiggle in the slider.
Video link
The rods I had laying around are a bit to long for the frame. I only have ~130mm Z-height, also the rods bind quite early. That's partly due to being almost vertical, but also because the upper rod ends are in line with the Delrin mushroom sliders. If I'd move them a few mm to the inside, they could move freely. But that would add a lever to any wiggle in the slider.
Video link
|
Re: compact carrier for Kossel Deltas December 29, 2017 10:42AM |
I shortened the rods and repaired the cracked ends. Mag arms will take a while to arrive.
Although the effector is too loose for my liking, I still had pretty good mesh bed results.
The rest of the setup is very basic too, but the twisted vase came out pretty well.
A few gaps in the wall, I blame the dangling extruder for it.
I also made a short video of it, only worth looking if you are curious about the dangling part
Video Link
Although the effector is too loose for my liking, I still had pretty good mesh bed results.
The rest of the setup is very basic too, but the twisted vase came out pretty well.
A few gaps in the wall, I blame the dangling extruder for it.
I also made a short video of it, only worth looking if you are curious about the dangling part
Video Link
|
Re: compact carrier for Kossel Deltas January 02, 2018 04:00AM |
I redesigned the beltclamp, because the rods were binding to early. The target printable radius is at least 100mm, but I was stuck at 60-70mm.
The rod ends are still very close to the belt- and slider axis, so any play won't have a huge lever to spoil the output.
I have to replace them and see what I get. The print quality is pretty good already...
The rod ends are still very close to the belt- and slider axis, so any play won't have a huge lever to spoil the output.
I have to replace them and see what I get. The print quality is pretty good already...
|
Re: compact carrier for Kossel Deltas January 22, 2018 03:43AM |
When I posted this picture, I didn't get much response ( not even from the trolls
)Here's another teaser to tickle your brains: the doubledecker_delta.
It can stay permanently assembled and also uses the same controller and dual shaft steppers.
The big Delta would run a Volcano hotend with a big nozzle, while the upper Delta suits a small nozzle or a laser engraver or.....?
Edited 3 time(s). Last edit at 01/22/2018 03:46AM by o_lampe.
|
Re: compact carrier for Kossel Deltas January 22, 2018 04:36AM |
If you happen to have a Delta with single shaft steppers at the bottom, you don't have to turn it upside down like I did. Just extend the shaft of the idler in the upper corner and fit a second idler to run the small doubledecker_delta. When you use the big delta, you only have to loosen the grubscrews of the upper delta idlers. Or build both Deltas with the same height, so the upper carriers don't block the lower ones.
No more excuses now
No more excuses now
Sorry, only registered users may post in this forum.