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Re: New printer design with new 'twist' for XY on Z March 06, 2018 02:39AM |
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o_lampe
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If the ballnut's OD is 40mm, I could solve this with just using a 42mm ID bushing, correct?
Not really, how would you deal with the belt tension?
Magic?
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Re: New printer design with new 'twist' for XY on Z March 06, 2018 01:23PM |
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MKSA
The way you use the ball screws, they are part of the structure, the frame. Can be seen in the rendering and you wrote it initially.
If you "attach" them to a frame as advised, then we are back to a more classic approach, still with plenty of issues some described above.
The printer needs an enclosure regardless, so it will have top and side plates. I think the print should be stationary like a delta and the reason for this design being created. Having the XY on a Mic-6 plate will guarantee they are on the same plane; just need to make sure the Z movement doesn't screw up anything.
Would love to solve these issues aesthetically
Edited 1 time(s). Last edit at 03/06/2018 01:24PM by klcjr89.
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Re: New printer design with new 'twist' for XY on Z March 06, 2018 03:48PM |
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klcjr89
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MKSA
The way you use the ball screws, they are part of the structure, the frame. Can be seen in the rendering and you wrote it initially.
If you "attach" them to a frame as advised, then we are back to a more classic approach, still with plenty of issues some described above.
The printer needs an enclosure regardless, so it will have top and side plates. I think the print should be stationary like a delta and the reason for this design being created. Having the XY on a Mic-6 plate will guarantee they are on the same plane; just need to make sure the Z movement doesn't screw up anything.
Would love to solve these issues aesthetically
To move the bed versus moving the whole XY gantry plus print head etc has already been discussed on this forum. Same plane guarantee ? Why ? So, document and justify why you think so.
Note the comparison with the Delta is irrelevant.
Same for aesthetic. See above, DD comments about youtube etc.... Functionality must prevail.
"A comical prototype doesn't mean a dumb idea is possible" (Thunderf00t)
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Re: New printer design with new 'twist' for XY on Z March 06, 2018 05:24PM |
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MKSA
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klcjr89
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MKSA
The way you use the ball screws, they are part of the structure, the frame. Can be seen in the rendering and you wrote it initially.
If you "attach" them to a frame as advised, then we are back to a more classic approach, still with plenty of issues some described above.
The printer needs an enclosure regardless, so it will have top and side plates. I think the print should be stationary like a delta and the reason for this design being created. Having the XY on a Mic-6 plate will guarantee they are on the same plane; just need to make sure the Z movement doesn't screw up anything.
Would love to solve these issues aesthetically
To move the bed versus moving the whole XY gantry plus print head etc has already been discussed on this forum. Same plane guarantee ? Why ? So, document and justify why you think so.
Note the comparison with the Delta is irrelevant.
Same for aesthetic. See above, DD comments about youtube etc.... Functionality must prevail.
Having the XY on a mic-6 plate is much better than using V slot which isn’t great when you do the measurements on a surface plate.
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Re: New printer design with new 'twist' for XY on Z March 07, 2018 11:36PM |
As far as I understand the cut aluminium plate as X/Y frame is mainly to keep YY symmetrical and angled, as that's the direction of the plates rigidity. The thickness to surface ratio I've seen till now look like they would twist in the Z direction. Now, a cut stone slab, that should assure a flat plane (I'm only half kidding, a granite frame printer would be something)
(I'm only half kidding, a granite frame printer would be something)
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Re: New printer design with new 'twist' for XY on Z March 08, 2018 03:31AM |
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orea
Now, a cut stone slab, that should assure a flat plane
This is not kidding at all.
I have suggested that and plan it for the bed (1cm thick 25by25). Easy to find in graveyard(just use the side without the lettering
For the printer base, I looked to use a 40cm concrete slab but settled for a 4cm kitchen top, good enough, a bit lighter and better looking.
Edited 1 time(s). Last edit at 03/08/2018 03:32AM by MKSA.
"A comical prototype doesn't mean a dumb idea is possible" (Thunderf00t)
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Re: New printer design with new 'twist' for XY on Z March 08, 2018 08:12AM |
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klcjr89
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691175002
I edited my post with a few more details. The side-loads on a 3d printer might be small, but you are still looking at maybe 200-400g of acceleration depending on the speed and extruder being used.
If you put that load on the very end of a 500mm rod that is only being held by a tiny section on one end it will still bend quite a bit. For example here is an extremely rough FEA where I modeled the whole assembly as a solid block of steel and it moves 0.05mm when 200g of force is applied. Its not awful, but the simulation is probably 2-4 times more rigid than your actual build will be and that kind of deflection will be visible.
The bigger problem IMO is that if you leave the rods unsupported and someone bumps into them you are essentially applying half a meter of leverage to a very small hole in a piece of cast aluminum. I'd guess 2Kg at the top of the rod could permanently damage the alignment of the printer.
Again, not awful, but not really something I'd want to risk.
Your post and edited post are helpful! When you mentioned the 22mm diameter leadscrew as 'doing almost nothing', do you mean that it's just oversized for no purpose other than visually matching the size of the linear shafts?
Would it be possible to lift the XY plate with only one ballscrew and not using my diagonal approach?
In the wood planer I mentioned, it actually uses 4 leadscrews as the posts and uses a closed loop chain to wrap around all four leadnuts:
Ohhh... you are using large leadscrews. Those should be more than enough to ensure the stability of the printer. Remember, when copying the design you need to copy all of it.
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Re: New printer design with new 'twist' for XY on Z March 08, 2018 11:24AM |
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MatthewHall
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klcjr89
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691175002
I edited my post with a few more details. The side-loads on a 3d printer might be small, but you are still looking at maybe 200-400g of acceleration depending on the speed and extruder being used.
If you put that load on the very end of a 500mm rod that is only being held by a tiny section on one end it will still bend quite a bit. For example here is an extremely rough FEA where I modeled the whole assembly as a solid block of steel and it moves 0.05mm when 200g of force is applied. Its not awful, but the simulation is probably 2-4 times more rigid than your actual build will be and that kind of deflection will be visible.
The bigger problem IMO is that if you leave the rods unsupported and someone bumps into them you are essentially applying half a meter of leverage to a very small hole in a piece of cast aluminum. I'd guess 2Kg at the top of the rod could permanently damage the alignment of the printer.
Again, not awful, but not really something I'd want to risk.
Your post and edited post are helpful! When you mentioned the 22mm diameter leadscrew as 'doing almost nothing', do you mean that it's just oversized for no purpose other than visually matching the size of the linear shafts?
Would it be possible to lift the XY plate with only one ballscrew and not using my diagonal approach?
In the wood planer I mentioned, it actually uses 4 leadscrews as the posts and uses a closed loop chain to wrap around all four leadnuts:
Ohhh... you are using large leadscrews. Those should be more than enough to ensure the stability of the printer. Remember, when copying the design you need to copy all of it.
The large leadscrews were mentioned in my original post (22mm thick) and in my design pic, but sometimes it's hard to tell proportions from a picture. I don't think it's worth copying the small Z height of the planer.
Edited 1 time(s). Last edit at 03/08/2018 11:26AM by klcjr89.
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Re: New printer design with new 'twist' for XY on Z March 16, 2018 05:49PM |
The planer only cuts the tiny amount that the blades stick out.
on some planners this is adjustable
--- many fixed at 1/8 " or tuned to the power of the motor and drive system
Leadscrews allow you to plop head down on wood and take the 1/8" cut that blade sticks out
and keep the feeder rollers (if it has them) in contact with wood
NOT a good example for 3D printing
on some planners this is adjustable
--- many fixed at 1/8 " or tuned to the power of the motor and drive system
Leadscrews allow you to plop head down on wood and take the 1/8" cut that blade sticks out
and keep the feeder rollers (if it has them) in contact with wood
NOT a good example for 3D printing
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