Cherry Pi III Is Available
Posted by AndyCart
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Re: Cherry Pi III Is Available September 16, 2014 07:28PM |
Why doesn't that pile of parts look like a printer yet????? 
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Re: Cherry Pi III Is Available September 18, 2014 12:43AM |
That's very possible. They were designed for the Bosch/Rexroth compatible extrusion that I use from KJN in the UK.
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Re: Cherry Pi III Is Available September 19, 2014 01:04AM |
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maso
I used OpenBuild V-slot too, and for me it was more than a few mm. I was using 10-32 hardware, so that might affect things a bit. But I couldn't even fit the nut and washer in the slot, much less the plastic part too.
I wound up redesigning the t-nuts to fit some small-profile 10-32 nuts. Not the best design, but I superglued each one in and they are pretty sturdy.
Edit: Here's the nuts I designed. In case it proves helpful for anyone.
Hey maso... Did you also encounter the issue that OpenBuilds V Slot is not compatible with the carriage design? I'm finding that there's a fair bit of a gap between the mini V wheels and the extrusion. Along the lines of 3-4mm total (probably about 2mm each side?). Obviously this means there's a lot of play.
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Re: Cherry Pi III Is Available September 19, 2014 02:28AM |
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maso
I did find that I had to tighten those carriages down quite a bit. Come to think of it, I had to shave some plastic out of the slot in one of them so that I could get it tight enough.
But it really wasn't too bad. And the printer is working swell now. Maybe one of us should try to make a carriage that has the wheels closer together sometime.
Honestly, mine are far enough apart that I will have to design another wheel section of the carriage. I've just dry attached the wheels and it's enough that if I put the two wheels on the same side into the V slot, the bottom of the wheel on the other side is flush with the outer surface of the extrusion.
Hmm, now I need to find a local printer who'll produce it for me.
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Re: Cherry Pi III Is Available September 19, 2014 07:05PM |
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pugzor
Hey maso... Did you also encounter the issue that OpenBuilds V Slot is not compatible with the carriage design? I'm finding that there's a fair bit of a gap between the mini V wheels and the extrusion. Along the lines of 3-4mm total (probably about 2mm each side?). Obviously this means there's a lot of play.
I noticed the same thing on the set that I printed. Too loose on V-slot, and too tight on Misumi 2020 T-slot. If you are making a true V-slot carriage, please share the files because I for one need them.....
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Re: Cherry Pi III Is Available September 20, 2014 04:45AM |
Hi Guys
I managed to get hold of a piece of V slot to compare it to the extrusion that I use, Bosch/Rexroth from KJN in the UK
You can clearly see the difference in the 'V' between the two types, hence the poor fit on V slot with it's much deeper V.
I've modified the carriage .stl and attached it above. You will also need to use the modified Rod Carrier, also attached.
Regards
Andy
I managed to get hold of a piece of V slot to compare it to the extrusion that I use, Bosch/Rexroth from KJN in the UK
You can clearly see the difference in the 'V' between the two types, hence the poor fit on V slot with it's much deeper V.
I've modified the carriage .stl and attached it above. You will also need to use the modified Rod Carrier, also attached.
Regards
Andy
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Re: Cherry Pi III Is Available September 21, 2014 09:43PM |
Hey Andy, pretty confident the carriages you sent me were the old design; it'd definitely explain the poor fit for me! I also compared to the sketchup you just posted.
In the file, A is ~5.2mm but the piece I've got is ~4.0mm. In the file, B is ~2.4mm but the piece I've got is ~3.3mm.
That's all the issue is, I think!
In the file, A is ~5.2mm but the piece I've got is ~4.0mm. In the file, B is ~2.4mm but the piece I've got is ~3.3mm.
That's all the issue is, I think!
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Re: Cherry Pi III Is Available September 22, 2014 02:52AM |
Hi Guys
For clarity the current production version of the Mini V Wheel Carriage for use on KJN Bosch/Rexroth extrusion (as per the Cherry Pi III BOM) is this :-
The modified version that should be OK on V Slot is this :-
Regards
Andy
For clarity the current production version of the Mini V Wheel Carriage for use on KJN Bosch/Rexroth extrusion (as per the Cherry Pi III BOM) is this :-
The modified version that should be OK on V Slot is this :-
Regards
Andy
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Re: Cherry Pi III Is Available September 22, 2014 05:40PM |
Stray from the BoM, pay the consequences! Haha. Lesson learnt. 
Out of interest Andy, what settings do you use to generate your carriages? As in, what % fill etc so that you got a good amount of flex for adjustment?
Additional question edited in: Did anyone secure the micro switches in with a touch of CA? Yes, I'm clearly a novice at this, just want to stuff as little up as possible. Screwing things up is inevitable, minimizing the screw ups is a choice!
Also Andy, I know you've stressed that the arms need to be exactly the same length... but what's the tolerance you'd think is acceptable? I think I've got less than 1mm difference between the longest and shortest of my arms with the ball ends on... is that close enough? Or should I be shaving them until I can't distinguish a shortest and longest arm?
Another edit; now with pics of aforementioned arms!
Edited 2 time(s). Last edit at 09/22/2014 06:36PM by pugzor.
Out of interest Andy, what settings do you use to generate your carriages? As in, what % fill etc so that you got a good amount of flex for adjustment?
Additional question edited in: Did anyone secure the micro switches in with a touch of CA? Yes, I'm clearly a novice at this, just want to stuff as little up as possible. Screwing things up is inevitable, minimizing the screw ups is a choice!
Also Andy, I know you've stressed that the arms need to be exactly the same length... but what's the tolerance you'd think is acceptable? I think I've got less than 1mm difference between the longest and shortest of my arms with the ball ends on... is that close enough? Or should I be shaving them until I can't distinguish a shortest and longest arm?
Another edit; now with pics of aforementioned arms!
Edited 2 time(s). Last edit at 09/22/2014 06:36PM by pugzor.
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Re: Cherry Pi III Is Available September 29, 2014 06:34PM |
Woo hoo, I picked up my replacement carriages yesterday. That couple of mm makes soooo much difference; they fit perfect on the V slot. 
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Re: Cherry Pi III Is Available October 03, 2014 01:35AM |
@andy
I found this ball joint on the firedelta google group . I think it will be useful for the next iteration of cherry pi
google group
Edited 1 time(s). Last edit at 10/03/2014 01:36AM by ekaggrat.
I found this ball joint on the firedelta google group . I think it will be useful for the next iteration of cherry pi
google group
Edited 1 time(s). Last edit at 10/03/2014 01:36AM by ekaggrat.
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