Thursday, August 21, 2008
Going Round In Circles
I took apart a swivel chair the other day and noticed an interesting ball bearing race in the bottom of it. So I made a RepRap'd version to fit under the Z axis drive rods, which currently sit on a couple of washers and some grease. Suz an I will hopefully fit them to Phoenix today, if we manage to get any time to ourselves.On my machine it needs some tidy-up with a 5mm drill because I've not got the smooth-moving Arduino board installed on the Darwin yet. But once reamed out, the holes in the bearing race hold eight 4.5mm (.177) BB's normally used in an air pistol to plink at tin cans with in the garden.
It's sort of a compromise between running on bare plastic and using skate bearings - which cost me NZ$6 a piece. BB's cost me less than a cent each and are also available from the same sporting goods stores as the skate bearings.
If they work well enough, I'll add them to the next run of the lasercut design. Ponoko's website tells me that the current one is 60% complete, so hopefully I'll see it early next week.
Vik :v)
Sunday, March 04, 2007
CAPA vs. ABS bodies extruders
I've hit a temporary snag with the PC software, so I'm going for the firmware while fixes happen by magic. Well, sweat & swears - er - tears from Simon and Adrian, I suspect, but let me carry on in ignorant bliss...
I've noticed that my half-washer bearings slip a bit (crappy job of smoothing the lands on the screw, I suspect), so I've packed a little bit of CAPA on top of them. This prevents exposed sharp edges engaging with the filament from dragging things around. In short, it stops your half-washers from popping out. I hope. Here's an old ABS one compared to the freshly-minted CAPA part. The CAPA part is the one on the left. The slightly fuzzy appearance of the bearing is due to Vaseline.
I've taken advantage of the squishy properties of CAPA a bit, I know, but it seems to work. Now we just hope the bearings don't heat up enough to melt the CAPA when you run them fast.
Keep on reading for our shameless fund-raising plug...
Vik :v)
I've noticed that my half-washer bearings slip a bit (crappy job of smoothing the lands on the screw, I suspect), so I've packed a little bit of CAPA on top of them. This prevents exposed sharp edges engaging with the filament from dragging things around. In short, it stops your half-washers from popping out. I hope. Here's an old ABS one compared to the freshly-minted CAPA part. The CAPA part is the one on the left. The slightly fuzzy appearance of the bearing is due to Vaseline.
I've taken advantage of the squishy properties of CAPA a bit, I know, but it seems to work. Now we just hope the bearings don't heat up enough to melt the CAPA when you run them fast.
Keep on reading for our shameless fund-raising plug...
Vik :v)
Labels: bearing, capa, darwin, extruder, polymorph, reprap, washer
