TrickLaser Ball-Cup Arms

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UltiBots
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TrickLaser Ball-Cup Arms

Post by UltiBots » Mon Jul 31, 2017 9:21 am

Hi All - I recently added experimental carriages and effector STLs for TrickLaser Ball-Cup Arms to our GitHub. The carriages include a belt tension mechanism and use 6mm eccentric spacers. You can use your existing MagBall ends. They were printed in Carbon PETG for strength. Initial tests used Atomic's CARBON FIBER EXTREME BLACK PETG. 360mm and 375mm arms are being tested. You will also need 6mm eccentric spacers (x3), 3mm alum spacers (x3), M3x22 screws (x3).

Initial testing has gone well so we decided to offer a Carriages and Effector Set printed in CARBON FIBER Extreme Black PETG.

Discussion of carriage assembly is here viewtopic.php?f=21&t=121.
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IMG_7370.jpg
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Brad - UltiBots LLC

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mhackney
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Re: TrickLaser Ball-Cup Arms

Post by mhackney » Mon Jul 31, 2017 9:34 am

Great, I did the measurements to compare ball cup arm length to mag ball and I've asked TrickLaser to make mine 375mm - that should closely reproduce the actual length of the existing mag balls.

Edit: i meant 375mm. I fixed above.
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Alexander Mundy
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Re: TrickLaser Ball-Cup Arms

Post by Alexander Mundy » Mon Jul 31, 2017 1:15 pm

Nifty

Ken.S
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Re: TrickLaser Ball-Cup Arms

Post by Ken.S » Mon Jul 31, 2017 10:32 pm

Neat! I actually had a set of rod ends shipped out today to reverse engineer them as $35 per set is reasonable for an injection molded set but I can print those on an SLA minus the heat deflection of injection ABS for about $3 per 12 or so. So they wouldn't work in an enclosure as it starts to get weird at about 120F and the injection parts would outperform there.

Brad or Michael: what's the diameter of the rods and the distance between them? I can print a custom flexible rubber band to keep them from shifting as backup to a spring. They aren't meant to stretch as much flex (stretching causes it to rip) but the dimensional accuracy is phenomenal and they are very solid

Not sure if that's actually beneficial or if the springs don't really ever fail

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UltiBots
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Re: TrickLaser Ball-Cup Arms

Post by UltiBots » Tue Aug 01, 2017 10:42 am

Ken.S wrote:
Mon Jul 31, 2017 10:32 pm
Brad or Michael: what's the diameter of the rods and the distance between them? I can print a custom flexible rubber band to keep them from shifting as backup to a spring. They aren't meant to stretch as much flex (stretching causes it to rip) but the dimensional accuracy is phenomenal and they are very solid
Carbon fiber archery tube used is ultra-light and stiff, 7.3 mm O.D., wall thickness is only .54 mm
Brad - UltiBots LLC

Ken.S
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Re: TrickLaser Ball-Cup Arms

Post by Ken.S » Tue Aug 01, 2017 9:42 pm

I printed a set of experimental carriages in tough resin, I think the newer one piece design lends itself to to SLA prints more since they come out so solid
IMG_6757.JPG

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Alexander Mundy
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Re: TrickLaser Ball-Cup Arms

Post by Alexander Mundy » Tue Aug 08, 2017 6:42 am

Question in regards to length. I noticed Michael mentioned about 15mm was the additional length need between mag ball and cup rods to be the same effective length. I have the old K250 that I have upgraded to metal corners. That put the towers slightly closer together, however I would still like a little longer than the effective length of the 288mm mag ball arms = 303mm cup arms? So is there a downside to going to say 315 or 320mm cup arms besides Z height?

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UltiBots
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Re: TrickLaser Ball-Cup Arms

Post by UltiBots » Tue Aug 08, 2017 8:15 am

We have yet to test the BCA (ball cup arms) on the K250. Adding 15mm to arm length accounts for the removal of the angled ball ends on their mounts. So. 288 + 15 = 303 would essentially match the stock K250.

History... We got the 288mm figure from another open source delta. I always wanted a little more reach for the K250. I tested the 304 arms and they gave the reach but also lost some Z. The length is up to you but 315 seems like a nice number.
Brad - UltiBots LLC

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Alexander Mundy
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Re: TrickLaser Ball-Cup Arms

Post by Alexander Mundy » Tue Aug 08, 2017 8:10 pm

Thanks

bvandiepenbos
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Re: TrickLaser Ball-Cup Arms

Post by bvandiepenbos » Wed Aug 09, 2017 12:26 pm

Hey All,
I printed Brad's prototype bc carriages and the wheels are way to close together to fit on my towers.
Even with eccentric at widest setting wheels are 1.3mm closer than the stock mag-ball carriages currently on my machine.
Axle centers of mb carriages when installed and at proper tension on machine measure 40.62 mm
I just measured model, axle centers are drawn at 38.5 mm...
no wonder it won't fit.

What are others experiencing for fit/eccentric adjustment??

If any of you could measure axle center distance when installed on towers it would be really helpful.
(stock mb carriages or new bc, either would help)

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