delta tilt movements

Hi reprap.

I built a delta printer based on kossel v250. Dimensions are very similar, i only have more height (print height about 500mm and total height 1mtr exactly).

we are printing good calibration cubes, 25x25mm with 0.05 variation.

The problem comes when i try to print something with large surface. I can see that large movements (>40mm) on +x and -y raise go down, and on -x and +y raise up, maybe 3mm about, but this makes that the hot end jamming on top.

I check and recheck endstops, and i measured if on differents heights the rollers are perfectly positioned from the base.

Theres no describe typical convex or concave surface. This is solved.

what is the problem? all topics that I saw is about flatness, not about this.

Thanks.

Probably the frame is flexing because it is not rigid enough. You can add cross-braces to try to make it stronger.

Eventually you may come to the conclusion that you don't need to print any object taller than 250mm more than once a year or once every two years. You can then reduce the height of your printer to a more reasonable 750mm and you'll notice that all other things remaining the same, it will become more rigid.

Hi andrew, we add double frame on top to prevent this on v2:



apparently on v1 with single frame on top there is no problem with this.

My guess is that one or more of your towers is tilted slightly, i.e. not perpendicular to the bed. To a first approximation, this is equivalent to the tower positions being displaced from the ideal positions, which is possible to correct by calibration. So either measure your tower angles and correct them, or use whatever mechanism your firmware provides for compensating for misplaced towers.

I had this problem on my Mini Kossel, and I didn't manage to sort it until I implemented my least squares calibration algorithm in the firmware, which I describe elsewhere.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Thanks dc42. I will check the perpendiculars towers.

Where can i read your calibration algorithm? im looking for.

P.S.: Sorry foy my poor english.

The autocalibration algorithm I use is in the firmware source for Duet electronics at [github.com]. If you are not using Duet electronics, there are some other possibilities:

- Rich Cattel's fork of Marlin includes an autocalibration feature, although it sometimes takes many iterations of probing to converge, unlike mine which takes just one iteration.

- You can do the Z probing or take readings manually, then feed them into this wxMaxima script [github.com], which does a least-squares fit and tells you what adjustments you need to make.

Edited 1 time(s). Last edit at 04/22/2015 12:37PM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

@jukillo,
I can see two 1m tall printers, V2 in the foreground and V1 in the background, and then a giant printer in the back, is that V0? In any case, they all look very impressive, very beautiful and well made, and very tall.

Personally, I don't think print heights beyond 30cm are of any practical use, and the taller the printer, the more flex the frame will have, this is dictated by laws of physics and is inevitable. For 1m tall printers, I would suggest cross-braces are a necessity, and not an option.

Quote
dc42
The autocalibration algorithm I use is in the firmware source for Duet electronics at [github.com]. If you are not using Duet electronics, there are some other possibilities:

- Rich Cattel's fork of Marlin includes an autocalibration feature, although it sometimes takes many iterations of probing to converge, unlike mine which takes just one iteration.

- You can do the Z probing or take readings manually, then feed them into this wxMaxima script [github.com], which does a least-squares fit and tells you what adjustments you need to make.

Yep, im using mega+ramps hardware.

Quote
AndrewBCN
@jukillo,
I can see two 1m tall printers, V2 in the foreground and V1 in the background, and then a giant printer in the back, is that V0? In any case, they all look very impressive, very beautiful and well made, and very tall.

Personally, I don't think print heights beyond 30cm are of any practical use, and the taller the printer, the more flex the frame will have, this is dictated by laws of physics and is inevitable. For 1m tall printers, I would suggest cross-braces are a necessity, and not an option.

No, is not a printer, maybe you see the hidden rack behind of the screens, .

Problem persists. All seems to be perfect. I dont know what may happens here.

I try to adjust endstop offsets on eemprom, but when i adjust y tower, x tower starts to fail again. On x tower and z tower positions at z0.0 nozzle raise up 0.3mm but on y tower, nozzle reach the glass when z1.6.

What is your segments per minute setting?
GT2 6mm belts?
How did you calibrate your bed exactly?
Our delta is 800mm of build volume. And we have some wierd behavioring.

Edited 1 time(s). Last edit at 05/15/2015 03:59PM by karabas.