Fixing Pulley Innacuracy

[jonnybischof 60]

Well, definitely get rid of the original pulleys if you want to improve your printing accuracy.

If you want to switch to GT2, you also have to remember that you need new belts - in contrary to the good MXL pulleys by foehnsturm.

I settled with the GT2 pulleys from Robotdigg.com. They are very cheap, but actually the quality is surprisingly good. Nice machining, 2 setscrews instead of just 1, and no visible roundness-error. Also, they are very small which is necessary when using them in an Ultimaker. I didn't use the included setscrews as they are probably not hard enough to tighten them as much as is needed. But I didn't actually try them (already had good setscrews around...).

I will buy these again since Misumi's industrial quality pulleys are simply too expensive (about 10x more than the robotdigg ones).

 

[anon4321 16]

Just be aware that the GT2 pulleys are slightly different in diameter and pitch. This prevents you from getting the exact right length of belts for the long belt. Thus you may run into tensioning issues.

 

[Dim3nsioneer 557]

The tension of the 606-GT2 belts is just perfect (but you need different x-y-blocks, e.g. Chopmeisters twister blocks). And the steps per mm is exactly 80. Then the dimensions are perfect. Enough reasons for a change?

 

[anon4321 16]

Exactly, you need different blocks. I tried the 303 tooth GT2 with the twister blocks and had a HORRIBLE time. The blocks are designed for the stock belts and the shorter center-to-center distance if the 303 GT2 belts means that the built in tensioner is too much.

Did you use the twister blocks as designed or with a different clamp part?

 

[Dim3nsioneer 557]

It's a different clamp part for the gt2 belts. It is designed by Chopmeister but not yet released on Youmagine I think.

 

[jonnybischof 60]

By the way, there is a slight difference in length (only 0.5mm) between the x and y shafts. I've found the 606 teeth belts to fit very well to the shorter part, but the 0.5mm more on the other side made them very tense and hard to rotate. Maybe that's because the belts were very new and could be stretched a little bit in time, but that shouldn't be necessary...

For the original Ultimaker, I would rather use "long enough" belts and tension them.

 

[antiklesys 3]

So to recap:

-either get new machined pulleys for the stock UM belts

OR:

-Get GT2 pulleys from: robotdigg.com

-Get 606 GT2 belts (any source for this? also 606 or 303??)

-Use Chopmeister Twister Blocks with different belt clamp (anyone has it?)

-Upload custom firmware with 80 steps / mm

 

[jonnybischof 60]

You can of course get your GT2 pulleys somewhere else, too. But Robotdigg gets my recommendation

Belts: 303 teeth, 606 mm length (GT2 = 2mm per tooth). Thanks for pointing that out

Most manufacturers specify belt length (so, it's a "606 belt"), not number of teeth. But you have to be careful about that.

Or you can just buy a few meters and cut the belts to size. You can easily join the belts in the belt clamp of the slider block.

This is generally recommendable because you don't have to worry about getting the correct belt length.

I got 606mm belts from Misumi, they offer pretty much any belt length which is cool.

Haven't looked into the firmware yet, but yes, you'll need to adjust the values. No need to re-flash the firmware, you can change the values with the Ulticontroller (if you have one...).

 

[anon4321 16]

You can also set the steps/mm via gcode so no ulticontroller or custom firmware required.

Other (US) sources of belts and pulleys would be:

http://www.sdp-si.com/

Long https://sdp-si.com/eStore/Catalog/PartNumber/A%206R51M303060

(oddly the pitch length doesn't match the number of teeth (612 vs 303) hopefully it is an oversight).

Short https://sdp-si.com/eStore/Catalog/PartNumber/A%206R51M100060

Adafruit

Pulleys

http://www.adafruit.com/products/1251

http://www.adafruit.com/products/1252

These are 3-4x the cost of robotdigg. Hopefully that translate to quality.

 

[antiklesys 3]

Has anyone got a link to a modified version of the previously mentioned belt clamp for GT2 Belts for the Chopmeister's Twister Blocks?

That'd be handy to have. Couldn't find it on thingiverse nor youmagine.

 

[Dim3nsioneer 557]

Chopmeister cleared his Thingiverse account after the 'Takerbot' events. His designs can be found on Youmagine including the twister blocks.

I got the GT2 clamps from him directly in order to test them. They worked quite well. However, I think it should be him distributing the design. I'll let him know that there is a demand for the GT2 clamps...

 

[antiklesys 3]

Much appreciated Dim3nsioneer

 

[chopmeister 0]

Hey guys! Thanks for the nice emails, I was away from the forums and 3d printing for a long while due to some personal issues but I hope I'll be back on track soon.

I don't like publishing untested stuff so I sent the GT2 clamps to DIm3nsioneer to test since I had no practical way of doing that, but since he says they actually work, I'll add them to YM ASAP. Thanks for the interest and I hope your TwisterBlocks serve you a long time.

 

[scherdin 0]

Hi, I found this thread when looking into upgrade my newly bought UM. I like the idea of high precision pulleys and possibility to keep my existing belts. Foehnsturm, is it still possible then I would like to buy a set of 12.

[zumfab 3]

What is the status of the pulleys fohnsturm was supplying? I am rebuilding an Ultimaker and I think this would be the ideal solution for the situation.

 

[foehnsturm 969]

Hi,

I'm very sorry but there are there are not enough inquiries for are reasonable production lot (which has to be some 100 pulleys).

 

[zumfab 3]

Hi,

I'm very sorry but there are there are not enough inquiries for are reasonable production lot (which has to be some 100 pulleys).

 

I felt that was a good reason to kick this thread again, to see where the interest stands today I can imagine there being more people interested, since the last batch shipped quite a while ago.

 

[jonnybischof 60]

Most people (including me) are going for GT2 pulleys & belts. They're usually well made, and easier to integrate into a custom made project due to their metric measurements.

 

[zumfab 3]

Most people (including me) are going for GT2 pulleys & belts. They're usually well made, and easier to integrate into a custom made project due to their metric measurements.

 

Both the fact that it is hard to judge what you will get and that new belts are needed I do not really like. Though maybe I just need to look into GT2 hardware properly sometimes, rather than look for something that might never happen.

 

[Dim3nsioneer 557]

Both the fact that it is hard to judge what you will get and that new belts are needed I do not really like.

:?:

This is what you will get: a 3D printer with minimum backlash; an even number for the steps per mm (80); pulleys without excentricity unlike those of UM; no need for a tensioner on the long belts.

I was actually surprised that UM didn't introduce the GT2 belts for the UMO+ as the UM2 runs on GT2 belts.

 

[macua85 52]

I'm in for some new pulleys if you run another batch. Guess we need around 10 people? Can we start the interest here (committed interest)

1. Macua85 - full set

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[gizmo999 11]

2.gizmo999-full set

 

[anon4321 16]

You guys should just consider switching to GT2 belts and pulleys. Another member had good luck with pulleys from robotdigg.com. The pulleys are about $2 USD each or about $24USD for a full set.

http://www.robotdigg.com/product/23/GT2-Pulley-20-Teeth-8mm-Bore

http://www.robotdigg.com/product/9/GT2-Pulley-20-Teeth-5mm-Bore

http://www.robotdigg.com/product/38/Closed-loop-GT2-Belt,-101-Teeth-202mm

http://www.robotdigg.com/product/10/Open-Ended-6mm-Width-GT2-Belt

NOTE, you would need new XY blocks for the open loop such as

http://chopmeister.blogspot.com/2013/12/twisterblocks.html

ALSO NOTE: you need to print the GT2 form of the clamp.

ALSO NOTE: THe commonly available closed loop GT2 belts won't work with the standard XY blocks as they tend to be slightly shorter.

I got my pulleys from adafruit and belts from SDP/SI at 4x the price.

My understanding is that the GT2 profile is better for bidirectional motion and have less backlash.

 

[zumfab 3]

:???::

This is what you will get: a 3D printer with minimum backlash; an even number for the steps per mm (80); pulleys without excentricity unlike those of UM; no need for a tensioner on the long belts.

 

I understand the confusion, but I was referring to the quality of whatever pulleys you buy, not the benefits of good pulleys in general I find it hard to judge quality.

 

[macua85 52]

I'm in for some new pulleys if you run another batch. Guess we need around 10 people? Can we start the interest here (committed interest)

1. Macua85 - full set

2.gizmo999-full set

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