Crooked Y axis help needed
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D-bot with crooked Y axis , I can't understand where is the problem . Any idea?
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the extrusion cuts might not be a perfect 90 degree.
as long as the gantry moves without binding this should be ok. -
I would say that's actually normal when the belts are loose. When everything is tensioned up it should pull it all into alignment.
When I installed my Y axis I strapped the Y axis to the rear of the frame so that it was pushed evenly against it and then attached the belts and tensioned them up. I also loosened the wheels on the sides and then re-tightened them to let them settle into place.
Everything is nice and straight after being tensioned.
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Thank you guys for the feed back. I am rebuilding my printer almost from scratch in the hope of improve print quality and I am becoming little paranoic trying to assemble it it in the best way.
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@claustro It looks like you have a single bolt holding the 2020 x rails onto the carriages. So try this. Slacken those bolts, and see if you can push the two carriages back against the rear rail. If so, do that then tighten the bolts with the carriages still pressed against the rear rail.
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Maybe change it to CoreXY?
On CoreXY you can compensate crooked y axis by adjusting the belt tension -
a d-bot is corexy
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@veti ok, I had think it is a h-bot.
Then just adjust the belt tension and the crooked should get away. -
It's generally best to get the axis aligned properly first because it is also best to have the belt tensions even. Starting with crooked geometry then relying on uneven belt tension to correct that error, is just plain wrong (IMO).
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see the build guide from the blv cube.
https://www.thingiverse.com/thing:3382718Tools
MUST have: 90 Degree Corner Clamps if you want a good printing results.
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How does it behave at the other end of the Y axis? If it is the same, the frame isn't square and that needs to be fixed. Like @deckingman says, you should make it work right without the belts first, then tension the belts and make sure it's square again.
You can check for squareness by measuring the diagonals of the top of the frame (and all the other planes, too). If the frame is square, the diagonals will measure the same in each plane.
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I made a try loosening the frame screw and tight them again without luck.
Tomorrow I'll try to check the squareness of all the frame using a 90 degree clamp.
I almost disassembled al the printer so this is the best time to check that everything is fine.
I'll keep U posted. Thank you very much for all your help.
Andrea -
@claustro Measure the diagonals rather than using a 90 degree clamp which might not be accurate. If the diagonals are the same length, then the frame is square. So then you can set the carriage parallel with the rear frame member as per my post of 2nd June.
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@deckingman ok tomorrow I'll check diagonals.
this is what I used for squaring the frame.
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@claustro How big is the frame? Just as an example, if that square is out by 0.5 degrees, so either 90.5 or 89.5 then over a length of 500mm, that could lead to an error of about 4mm.
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@claustro That is a square recommended for carpenters. It is not abnormal to have some small deviation from 90° (like 89.5° or 90.5°). For precise alignment you need a prop[er machinist square (https://en.wikipedia.org/wiki/Machinist_square). These come in various accuracy grades, with least accurate grade being significantly more accurate than the carpenter squares (about 10 times more accurate for the same price range) and the most accurate having very low tolerances (60-70 times more accurate for 3-4 times the price).
For a little bit more money you can get something like this - https://www.pecktool.com/product/300mm-12-precision-machinist-square-wide-base/. This makes CNC alignment must easier as it can be hold precisely on a flat surface.
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This post is deleted! -
@catalin_ro bought this one
thx
@deckingman
the frame is 460x413x520 -
@claustro For info, I used a calibrated cross line laser to set my (600 x 600 x1000 mm) frame square. The emphasis being on calibrated. (Actually you can't calibrate a laser level but you can measure the error and apply the correct compensation). I got ridiculed on the RepRap forum for suggesting this (mostly by people who have no idea how to calibrate and use a cross line laser) so I won't go into details. But trust me you know it's square when the "arms" on the square are bigger than the frame.
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@deckingman said in Crooked Y axis help needed:
cross line laser
I have a cross line laser I am going to search reprap forum
