Adding an Openbuilds Openrail x axis to a Lulzbot Taz 4/5

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nopick
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Re: Adding an Openbuilds Openrail x axis to a Lulzbot Taz 4/

Post by nopick » Mon Aug 10, 2015 2:02 pm

I am really liking this. How smoothly does it roll?

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piercet
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Re: Adding an Openbuilds Openrail x axis to a Lulzbot Taz 4/

Post by piercet » Mon Aug 10, 2015 3:26 pm

Smoothly, just like butter. No carriage movement that isn't supposed to be there at all. No hesitation or catching, no harmonic drag wobble, just pure quick back and forth motion where it is supposed to be.

My only potential concern so far is if the wheel tensioners will loose up over time. If they do, it's really easy to re-tighten them. I could also use some blue loctite on the cam lobe section if necessary. So far with my very limited run time It hasn't been an issue. I'll know more after this weekend though since I plan to do a lot of printing with it. Component wear won't be an issue, and if anything does wear out, it's going to be just as easy or even easier to replace a part without dismounting the entire X carriage. Debris in the track is another unknown. It won't be an issue for the X axis, but it might be one for the Y axis. I have plans for a cover of some sort for the Y axis when I get to that point but I need to get the holes cut in the bed plate before that can go on.

nopick
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Re: Adding an Openbuilds Openrail x axis to a Lulzbot Taz 4/

Post by nopick » Mon Aug 10, 2015 3:37 pm

I would love to see a close up shot of your part sidewalls once you have some printed.

The jankiness of the IGUS bushings has long bothered me... and the flex of the rods. I have improved the tightness of my printer with hardened rails and bearings but, those seem to bring a certain texture to my prints, mostly in the Y axis... I am highly interested in something that rolls smoothly, like butter. :)

Thanks for all the hard work.

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piercet
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Re: Adding an Openbuilds Openrail x axis to a Lulzbot Taz 4/

Post by piercet » Mon Aug 10, 2015 5:51 pm

Will do. I'll use tonight to tune the system, make sure the integrated bed tensioner is working right, make sure I don't have a leadscrew pinched, etc. Once this modification is dialed in and tested, if I still need it at that point i'll bolt my Z axis mount mod up to it and see how that works. Y bed is probably going to be next week assuming I can either find a local shop to punch the 4 holes, or I get adventurous and order my own 7.2mm bits for the Bed plate. I'm going to be interested in seeing if this helped, and specifically if I have any offset in the Y direction left. My parts have always been pretty good with the Taz, and the rev 4 parts definitly helped, so any improvement over that is going to be a bonus!

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piercet
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Re: Adding an Openbuilds Openrail x axis to a Lulzbot Taz 4/

Post by piercet » Mon Aug 10, 2015 10:01 pm

nopick wrote:I would love to see a close up shot of your part sidewalls once you have some printed.

The jankiness of the IGUS bushings has long bothered me... and the flex of the rods. I have improved the tightness of my printer with hardened rails and bearings but, those seem to bring a certain texture to my prints, mostly in the Y axis... I am highly interested in something that rolls smoothly, like butter. :)

Thanks for all the hard work.

Here's a somewhat out of focus extreme closeup of the latest part under LED light at the angle that shows the absolute worst ridging. It actually looks a lot worse than it is in this shot. I still have some wobble, but its +/-0.01 in depth, which is about how much I can move my Z bearings back and forth on their rod. 'This project definitely improved and minimized it, somewhat, but where it really shines is the layering itself. I am getting the best layer faces I have ever seen. My Anti Z wobble project might clean up the rest of this, though I'm thinking I'm going to have to figure out how to mount a Z openrail section to fully mitigate it. That or find some bushings with closer tolerances on the rods.
IMG_1930.JPG
IMG_1927.JPG
IMG_1922.JPG
IMG_1920.JPG

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piercet
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Re: Adding an Openbuilds Openrail x axis to a Lulzbot Taz 4/

Post by piercet » Mon Aug 10, 2015 10:05 pm

And here are some more pictures of the modification itself:
IMG_1915.JPG
IMG_1914.JPG
IMG_1918.JPG
IMG_1912.JPG
IMG_1911.JPG

nopick
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Re: Adding an Openbuilds Openrail x axis to a Lulzbot Taz 4/

Post by nopick » Tue Aug 11, 2015 7:32 am

Nice. Thanks for the pictures. I will have to source some metal X end plates. I am currently using the printed all in one pieces.

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Re: Adding an Openbuilds Openrail x axis to a Lulzbot Taz 4/

Post by kcchen_00 » Tue Aug 11, 2015 8:48 am

Nice mod! Curious to see more testing... speed on the v-slot wheels would be particular interesting.

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Re: Adding an Openbuilds Openrail x axis to a Lulzbot Taz 4/

Post by piercet » Tue Aug 11, 2015 9:21 am

The wheels are basically roller blade wheels with a modified profile. They have 2 bearing sets in the middle. So far I've been able to print at normal speed with no issues, no heat buildup and no need for readjustment. The belt tensioner also helps somewhat. I'm going to wait on pushing the speed envelope too far until I get the Y axis mounted as well so I don't end up destroying my existing Y rod bushings.

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Re: Adding an Openbuilds Openrail x axis to a Lulzbot Taz 4/

Post by jebba » Tue Aug 11, 2015 12:13 pm

FWIW, I asked our CTO his thoughts on using these:
The short answer is yes, built correctly, rails will be better than smooth rods.

The Kauri project actually included testing of rails for making the X axis stiffer. We have sections of this v-slot rails as well as other rail systems. Rails fall into two sub-categories, adjustable and non-adjustable. With the adjustable ones, you need to individually adjust all of the roller wheels and tighten down their axle again to get the maximum performance out of it. The non-adjustable as you've guessed the just have the factory level of slop to them.
We started with the non-adjustable ones and quickly found they have the same or more slop than we have already in the TAZ design.
The issue with the adjustable ones we quickly determined is that it takes a lot of time to adjust all the rollers. There will be 3 or 4 to adjust on every rail so somewhere like 16 or so to adjust per printer. Then there is the question of how often those rollers will need to be adjusted in the future. There will certainly be a cost jump when we go to these. We haven't yet made a physical model with the V-slot rails yet. With the death of Kauri and the simplification to Lancewood the testing has been pushed to the next printer development.
-Jeff

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