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Re: An easy magnetic ball solution.
Posted: Mon Apr 28, 2014 4:17 pm
by Flateric
They look both too fast and too hot to me eagle. I would cut the feed dramtically, this also would allow you to cut the temps also.
Just my first guess.
Re: An easy magnetic ball solution.
Posted: Mon Apr 28, 2014 5:35 pm
by Eaglezsoar
Flateric wrote:They look both too fast and too hot to me eagle. I would cut the feed dramtically, this also would allow you to cut the temps also.
Just my first guess.
Your guess was a good one. I printed another set at 30mm/sec instead of 50 and lowered the temperature down to 215c and the results were
much better. Thanks to everyone for their comments.
Re: An easy magnetic ball solution.
Posted: Tue Apr 29, 2014 8:46 pm
by bdjohns1
Eaglezsoar wrote:
Your guess was a good one. I printed another set at 30mm/sec instead of 50 and lowered the temperature down to 215c and the results were
much better. Thanks to everyone for their comments.
Did the cups print ok in the original orientation, or did you end up deciding to flip them over?
Re: An easy magnetic ball solution.
Posted: Tue Apr 29, 2014 9:38 pm
by Eaglezsoar
bdjohns1 wrote:Eaglezsoar wrote:
Your guess was a good one. I printed another set at 30mm/sec instead of 50 and lowered the temperature down to 215c and the results were
much better. Thanks to everyone for their comments.
Did the cups print ok in the original orientation, or did you end up deciding to flip them over?
I tried both directions for the cups and there was not a big difference so I just did them in the original orientation.
Re: An easy magnetic ball solution.
Posted: Wed Apr 30, 2014 10:31 pm
by bdjohns1
Ok, so I still wasn't 100% happy with the effector, so I've been playing around with it a bit more, trying to remove some of the flex between legs. What's new in v2:
1. Center hole is smaller. An e3d heatsink will still fit through with 5mm clearance to the flats (not like you even need to have it fit through!). Sorry, Kraken users!
2. Added a little more plastic to the legs - if you're a little aggressive driving the stud through, it wants to split open near the exit hole on the inside wall of the leg.
3. Filets. Glorious filets everywhere. Made the STL file a wee bit big (especially since I set Alibre to facet at 2 degrees), but hey, bits are cheap.
Renders:
[img]
http://i.imgur.com/f765541.png[/img]
Top down
[img]
http://i.imgur.com/PRBRRe1.png[/img]
Angled view
And off we go...
[img]
http://i.imgur.com/HO3iYMz.png[/img]
Re: An easy magnetic ball solution.
Posted: Wed Apr 30, 2014 11:24 pm
by Eaglezsoar
Do you think this one is sturdy enough to pass your rigid standards or do you feel that other alterations will be coming?
Don't take my question the wrong way, I would rather have 10 alterations if necessary to achieve a final product. You have
printed with the latest alteration and I was just wondering if you feel you are getting closer, have achieved what you were
attempting to achieve or still not happy.
Re: An easy magnetic ball solution.
Posted: Thu May 01, 2014 1:23 pm
by bdjohns1
I'm pretty happy with this one. I took a look this morning before leaving for work, and it feels a bit more rigid when I try to pinch two of the legs together, which was my ultimate goal of the revision. Beefing up the base and adding the filet seemed to do the job. With 33% infill, it only used 1m more filament, so the weight increase was reasonable. Worst case, I turn back the acceleration/jerk settings a little if I think the flex impacts anything.
I might give this one an acetone vapor treatment. I've only done that on a few parts before, but I felt like the rigidity improved with those parts - stiffens up the outer skin a bit.
Re: An easy magnetic ball solution.
Posted: Thu May 01, 2014 9:46 pm
by bdjohns1
[img]
http://i.imgur.com/MRi9Dq2.jpg[/img]
Progressing. I think I'll be gluing the rods up over the weekend.
Re: An easy magnetic ball solution.
Posted: Fri May 02, 2014 11:58 am
by Eaglezsoar
Thanks for the last picture of the effector with the balls mounted. Looks great!
I like the red also.
Re: An easy magnetic ball solution.
Posted: Fri May 02, 2014 12:07 pm
by bdjohns1
It hasn't been through the acetone bath yet. It actually darkens a bit in that process to a truer (to me at least) red.
One other thing I need to do is ensure I've got the balls all set right so they're sticking out the same amount. Easiest way is probably just going to be using a small setup gauge bar behind the ball to get the gap identical. I figure precision now avoids hair-pulling when I try and calibrate the new delta geometry later.

Re: An easy magnetic ball solution.
Posted: Fri May 02, 2014 12:22 pm
by Eaglezsoar
bdjohns1 wrote:It hasn't been through the acetone bath yet. It actually darkens a bit in that process to a truer (to me at least) red.
I would love to see the results of the acetone bath.
Re: An easy magnetic ball solution.
Posted: Fri May 02, 2014 4:11 pm
by Eaglezsoar
One last question, what infill percentage did you use on the effector? I was going to use 50% but I don't know if they need to be that strong.
Re: An easy magnetic ball solution.
Posted: Fri May 02, 2014 7:48 pm
by bdjohns1
I did 33% (octagonal if it matters) on KISSlicer. 1mm thick walls (4 loops).
Re: An easy magnetic ball solution.
Posted: Sat May 03, 2014 5:28 pm
by bdjohns1
Eaglezsoar wrote:
I would love to see the results of the acetone bath.
Here you go. 90 seconds exposure time in the bath, give or take (stainless pot on my heated bed, set at 90C)
[img]
http://i.imgur.com/UTi2uxpl.jpg[/img]
Re: An easy magnetic ball solution.
Posted: Sat May 03, 2014 7:38 pm
by Eaglezsoar
Now that is nice! Virtually eliminates the layer lines and adds a nice gloss. I will have to experiment with that process.
The results are worth the effort. Thanks for the pictures.
Re: An easy magnetic ball solution.
Posted: Tue May 06, 2014 5:23 pm
by lordbinky
bdjohns1 wrote:I figure precision now avoids hair-pulling when I try and calibrate the new delta geometry later.

This is true, and reminds me of a co-worker's saying about licking a dirty calf.
Re: An easy magnetic ball solution.
Posted: Wed May 07, 2014 12:13 am
by bdjohns1
Indeed.
So, since my last update, I've got everything back together and I've got the basic calibration nearly good enough (ie, after a few iterations of the calibration routine, I'm currently within 0.1mm when I come back to center). For whatever it's worth to anyone, here's roughly how much my numbers changed (and subject to change more - have to run out of town on a business trip for a few days, so no printing until after the weekend):
Z-length: -50mm (could've been less if I'd made the effector ~1.5mm thinner). Ended up having to put the groove mount adapter under the effector instead of on top. Figures the one dimension I just eyeballed was the one that didn't quite net out as planned. Still at ~310mm useable Z-height. I'll probably make a new v3 model that'll get the groovemount go on top, although I probably won't switch my own unit over - but people who want/need to be at 330mm of Z will probably appreciate that.
delta arm length: +4mm (now at 273mm)
printer_radius: -2.5mm (now at 126.5mm)
Other stuff: the holes for the end stop screw interfered a little with the belt clamps on the cheapskates. Ended up using some 1/4" standoffs to move them out. Also, if your printer is lucky and actually gets small holes to print at the right dimension, you may find that the end stop holes are a little big for a #6 screw. I think mine tapped a little too easy, so I ended up putting jam nuts on to make sure the stop doesn't wander somehow. I'll probably update the model files to shrink the holes a touch.
Re: An easy magnetic ball solution.
Posted: Tue May 13, 2014 10:19 pm
by bdjohns1
So, after a few days of work travel and a trip to STL for Mothers Day, I got back to the printer and finished the radius adjustments. Looks like I guessed right on my adjustment to delta arm length. My 25mm calibration cube came in at 24.98mm. I'll call that close enough for now.
Print quality looks good, and the magnets seem to be gripping just fine. I printed the infill with octagonal infill to get some nice quick jerky movements at 50mm/sec with no issues. Printing something with some curves now to see how those turn out.
Re: An easy magnetic ball solution.
Posted: Wed May 21, 2014 11:14 pm
by Eaglezsoar
It's been a few days now and I am just checking to see if you are happy with the parts as they are or do you plan on other alterations?
Re: An easy magnetic ball solution.
Posted: Thu May 22, 2014 10:10 pm
by bdjohns1
I've been happy with how the parts have worked so far. Only printed a few pieces, but they've all come out well. Magnet grip is strong. I haven't tried a ridiculous speed test yet, but I've done 50mm/sec perimeters and 70mm/sec infill that were fine as I was making a landscape-orientation dock for my new iPhone I got last week.
I may make an updated effector platform STL so that the groovemount parts can sit on top of the effector as opposed to below - like I noted above, that's the one whoops I had - cost me about 20mm of Z-height. It's not a high priority, because I don't really print that big right now. My max Z is 309.x mm at the moment, using 626Pilot's groovemount adapter mounted on the bottom of the effector -
http://www.thingiverse.com/thing:137140
If it's something you're dying to have, I might have a chance to fix it after the weekend. Or, if you're handy with STL files, just thin the platform - if you're really fancy, you could basically do a cutaway of the outline of 626's part. 2mm should be adequate to allow the groovemount to go on top while allowing the fan to mount underneath (I'm using cope413's fan shroud that has the little clip on top)
Re: An easy magnetic ball solution.
Posted: Thu May 22, 2014 11:31 pm
by bdjohns1
Ok, I got curious and did a speed test printing a few pieces for a geometry game for my kids that had some missing parts. I was able to get up to 100 mm/sec - at that point, my solid top layer was maybe a tad under-extruded, but I didn't do anything with my flow settings. Probably could have gone a little faster. Might try something with 60mm loops and even faster infill, just to push it.
Re: An easy magnetic ball solution.
Posted: Fri May 23, 2014 12:31 am
by Eaglezsoar
bdjohns1 wrote:Ok, I got curious and did a speed test printing a few pieces for a geometry game for my kids that had some missing parts. I was able to get up to 100 mm/sec - at that point, my solid top layer was maybe a tad under-extruded, but I didn't do anything with my flow settings. Probably could have gone a little faster. Might try something with 60mm loops and even faster infill, just to push it.
Sounds great! As far as the effector mod, that is something I will wait for you to fix, I am not a cad person at all. Someday I will learn it but right now is not a good time. When is there a good time in this fast paced, always need something done world. Fix it at your liesure, I am in no hurry for it, hell take a few days.

Re: An easy magnetic ball solution.
Posted: Sat May 31, 2014 9:58 am
by Eaglezsoar
bdjohns1 wrote:Ok, I got curious and did a speed test printing a few pieces for a geometry game for my kids that had some missing parts. I was able to get up to 100 mm/sec - at that point, my solid top layer was maybe a tad under-extruded, but I didn't do anything with my flow settings. Probably could have gone a little faster. Might try something with 60mm loops and even faster infill, just to push it.
I have printed out your rod ends, both versions and they print beautifully using slic3r but the hole for the rod comes out .40 inches instead of the .375 that I was expecting. Is this normal and is the intent to fill the gap with glue or is
much larger than it should be? Calibration objects seem to print out the correct sizes.
Re: An easy magnetic ball solution.
Posted: Sun Jun 01, 2014 9:03 pm
by bdjohns1
It may be a little oversized. I think I had the radius actually set to 5.3mm. A little loose, but I used fairly copious amounts of epoxy to secure it.
Inside holes almost always print out smaller than designed.
Re: An easy magnetic ball solution.
Posted: Sun Jun 01, 2014 9:51 pm
by Eaglezsoar
bdjohns1 wrote:It may be a little oversized. I think I had the radius actually set to 5.3mm. A little loose, but I used fairly copious amounts of epoxy to secure it.
Inside holes almost always print out smaller than designed.
Not a problem, I was going to try gorilla glue, if you spray it with a little water it expands significantly I would like to try
it on one of the arms, if it works well then I will do them all. Epoxy will be my next step if the Gorilla doesn't cooperate.