CoreXY print distortion?
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Over the past couple of weeks I have discovered my coreXY has a pretty large offset between the motor axis. In fact when I print a 145mm test square to isolate the motors (45 degrees), the difference left to right is pretty much exactly 10mm. I just measured the installed length of the two belts at full tension and they are under half a mm difference. As far as I can see my geometry is correct and things are parallel or perpendicular. In fact the only change I made lately is Duet firmware version and some adjustments in settings to max print area. Is there someplace there could be a setting that I'm missing that could cause this? Has anything changed in Duet "corexy mode" that could be a problem in the just released firmware? When I pulled the belts my XY mechanism moves like a dream. My entire printer runs on linear rails. I have never seen this distortion in past prints. Although I have mostly printed smaller models.
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Are you by any chance using steel-cored belts?
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Yes, since they were called out in the BOM. But I have been on the hunt for genuine Gates since the E3D guy swears by them for their coreXY dream build. So far no luck finding them.
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These are genuine gates power grip 2gt betls I have them on my kossel XL. https://www.ebay.co.uk/itm/2M-GATES-6mm-2GT-GT2-RF-Fiber-Glass-Reinforced-Rubber-Timing-Belt-for-3D-Printer/141938661911?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055119.m1438.l2649
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Hong Kong
I saw those. I'll place an order. Meanwhile I put two brand new steel core belts on and I'm about to test.Thanks
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Looks like it was the belts. That's pretty shocking, but I have read plenty of stories so it should be no surprise.
Thanks
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@3dmntbighker I just got some Gates belts as well and the difference was subtle but noticeable compared to run of the mill belts. Steel core belts on small radius bends are a ticking time bomb.
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So far I can't find any Gates belt longer than 2 meters, and that is not quite long enough. I need 7ft to have a margin . A 5 meter belt would give me two.
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E3d sell the gates belts on there website now they aren't advertised as gates they are just advertised as upgrade gt2 belts. I recently contacted gates about there polychain gt2 belts and they advised me that they have been replaced by polychain carbon gt2 that use carbon fibres in the core.
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I've used these. Might be able to get the length you need.
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@monster-delta Damn, I want those, but looking at the catalog they start at 8mm so that a means a total re-work of my drive system.
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@3dmntbighker I've been trying to get some but its pretty hard to find somwhere that stocks them at the moment, i was planning to run the 8mm and just change out the pulleys
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@3dmntbighker Ask them if you order more 2m if it will be one pice. As far I know it should be.
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@djdemond are the deffinately genuine?
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Well this is what they look like up close:
They look nice and they feel nice although I'd echo what Mark Rehorst (Digital_Dentist) on reprap says they don't seem to make much difference to print quality. I am running 3 lengths on my delta at around 2 meters per belt, so it's a distance over which stretch/elasticity should be apparent in substandard belts, but they seem to work about as well as chinese no-name fibre reinforced belts. I was able to discern a difference with steel-cored belts until they progressively failed resulting in weird, hard to diagnose skew.
I doubt this helps...
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They look just like mine.
I found that my cheap Chinese belts had a bit of a curve to the edges and would ride up and down the pulleys a bit. The gates belts are dead flat and don't travel at all. They seem more flexible and don't feel like they have as much give.
I might have just had really crappy belts.
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Anyone already found Gates Belts longer than 2m? Would really like to give them a try but I'd need at least 2,4m each...
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@kuhnikuehnast just order 4 of them and they'll send you an 8m length
