Print suddenly became longer in the Y Axis? **Solved**
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I recently had a similar problem on the Y axis of my Anet A6 that I still use sometimes.
Problem was the cheap belt included in the kit.
It had stretched... maybe because of over tightening and the heat of the heatbed above.
And I think that happened pretty suddenly within a short time span and not just over time...Well, and I had an other problem where I dripped hot glue on the pulley of the X axis and didn't notice it... it was just a tiny amount and barely visible, but was enough to increase the effective diameter (unevenly).
Like @t3p3tony, I would also suggest to test by moving the axis and to measure the actual moved distance, maybe also in e.g. 10mm steps to see if the error is conststent or not.
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Looks like my post last night didn't go through before the forum went down for a bit?
Anyway I tried another print after changing the steps per mm in the Y from 100 to 100/104 (~96) and got a perfect 100x100mm test print - I suppose that's a working solution.
@hurzhurz I did change my belts to a metal core GT2 a few weeks ago but have done maybe a dozen prints without issue and the heated bed was actually off for the print when things went wrong (since I'd never get the TPU print off of my PEI if it was on!) - but that's a good place for me to check. I did notice a bit of dirt on the belt where it engages with the pulley (it's a white belt so it's easy to spot) so who knows, maybe the teeth on the belt have slipped?!
In the office atm so i'll check again tonight.
Thanks for everyone's input so far.
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Thanks for you help guys, we have a winner!
My new tough metal core belt turns out to be not so tough and must have softened (probably from friction/heat) at some point and has actually stretched in the area over the toothed pulley.
I checked the movement as @T3P3Tony suggested and it was elongated near the centre of the bed's Y axis but not towards the edges. After @hurzhurz mentioned his issue with his Anet belts I then went and checked the belt and found this:
You can actually see where the rubber has stretched and increased distance between the belt's teeth!
Thanks again for everyone's help - turned out to not be a duet related issue at all but you guys got me looking in the right place.
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I can't find the link right now, but it clearly gave information that the minimum turn radius for steel-corded GT2 belts was larger than even 20-tooth pulleys. Consequently, the thin cords work harden and snap, allowing the rubber to stretch.
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@plasticmetal had I seen that advice before I might have been able to avoid this whole thing!
I suspect that’s what has happened, pulling the belt apart in my hands it snapped pretty easily at the point where it was engaging with the pulley while the rest of it was still pretty solid.
I had some spare rubber belts so I’ve gone back to those and all seems to work well again.
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I tried some of the white steel core belt for a while on my coreXY and that lasted for about a week. The belts felt spongy and didn't appear to be very good quality despite being more expensive. I swapped them out for normal belt again before anything went really wrong, but I could tell that something was bound to. Now I'm waiting for some genuine Gates belts.
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@hobsie Belts with an aramid fiber or equivalent in are the best (like the gates ones) as they can handle the turn radius but also do not stretch (as some of the cheaper belts do.
P.S. glad you got it working!
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@phaedrux : where did you find genuine gates belts online (at least an European source...)
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@whosrdaddy well I should say "genuine" as I haven't seen them myself yet, but they are from an eBay vendor based in Hong Kong. The only reason I bothered was that several people on the DBot Facebook group vouch for them being legit.
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Yeah saw those, don't know if they are genuine though.
The only genuine sources I found are all american.
For example this one:shipping cost from US is not cheap and minimum order is 50 feet
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You can check here. http://www.sdp-si.com/index.php
I get my belts and pulleys from this place. Not sure how the shipping would be but there isn't any minimums on belt lengths.
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@whosrdaddy Belts came today. I'm not sure if they are genuine, good fakes, or bad fakes, but they definitely look different than the usual black belts. I won't be able to actually test them out until next week unfortunately, but maybe from these pictures someone can tell me if they look legit or not.
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Thanks for that, it surely looks like the real thing.
Keep us posted how they perform
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@whosrdaddy Belts have been installed. They definitely feel different compared to the usual black belts. They are more flexible and don't spring back into shape as much. When pulling on the new belt by hand it doesn't feel like it gives as much stretch either. The tooth side has a brown color and the smooth side has a crackled appearance and texture. The fibres are all contained within the belt. I've had many cheap belts where the fibres are all coming loose out the sides of the belt. These ones have nice clean edges.
I've only done a single 6 hour print with them but so far the surface quality appears to be good.
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Can you provide a link to the supplier please
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@dougal1957 Sure. Here you go. I'm not affiliated with this seller in any way. I only heard about it through the DBot facebook group.
In my case shipping was less than 30 days and arrived via china mail air pack.
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@phaedrux Thanks for the link Phaedrux. Just ordered some myself.
Judging from the images you've posted, even if they're "fake Gates" they look pretty good quality.
Also, an fyi for everyone/anyone - i've gone and edited the reprap wiki page on choosing belts to include a wee warning about steel core polyurethane belts and small pulley diameters for others to find.
Link here: https://reprap.org/wiki/Choosing_Belts_and_Pulleys
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@hobsie so far the print quality with these belts has been phenomenal. If they are fake they are good ones. I think the biggest thing I noticed about them is that they are all cut very straight. The other belts seem to have a bit of wander. These are dead straight and they stay centered on the pulleys. They also sound quieter. I'm very pleased.
