Comments on: Cooling Fan(s) for Dramatic Improvement in CupCake Print Quality

By: MakerBlock

MakerBlock — Fri, 17 Jun 2011 20:14:36 +0000

@Carboncanyon, @Keith: I was actually discussing the concept of printed part interlayer adhesion and strength with someone the other day. I think the ideal test object would be a tall thin wall. Then, try to bend/flex the part and see how far you can flex it before it will snap and it’s shape as it snaps.

Printing in PLA recently, I broke some failed prints to see how well the interlayer adhesion was – I found that my very thin (~1.5mm) parts didn’t crack along layer lines as I was expecting, but in a random-ish pattern.

By: Keith Neufeld

Keith Neufeld — Fri, 17 Jun 2011 19:58:39 +0000

Carboncanyon, that’s an interesting question! My hunch is that hot mooshy ABS sticks more strongly to hot mooshy ABS than to warm, solid ABS; so the cooling might hurt part strength. On the other hand, ABS that overlaps perfectly with the ABS below it probably sticks more strongly than ABS that’s all helter-skelter.

My heater is no longer reaching 225°C, even without the fan, and it looks like I’m going to have to take it apart and rebuild it yet again. After that I’d be happy to build a test block and break it, but I’m not quite sure how best to measure the breaking force with instruments I have available.

By: carboncanyon

carboncanyon — Tue, 14 Jun 2011 19:57:30 +0000

I wonder if there’s a way to measure part strength? I’m curious if this affects integrity at all.

By: MakerBlock

MakerBlock — Sun, 12 Jun 2011 21:56:55 +0000

@Keith: Actually, I’m not even using the fancy-schmancy ones! This is the one I’m using: http://www.thingiverse.com/thing:3091 Using more than two makes the Z platform too unstable. Since these wobble arresters don’t actually attach to the Z platform, so they can’t push or pull it out of whack. I like the engineered solution behind those springy ones, but these worked so much better for me.

By: Keith Neufeld

Keith Neufeld — Sun, 12 Jun 2011 21:50:51 +0000

MakerBlock, I think two of my Z rods are much worse than the others, and I was looking to wobble-arrest them before going full-bore to the Z rods. I’m having trouble printing the detail in the wiggle arrestor springs, though. May need to do the stepper filament drive first.

Thanks for the remarks!

By: MakerBlock

MakerBlock — Sun, 12 Jun 2011 21:40:27 +0000

There’s a slow-down option in Skeinforge that helps a lot. I think it’s enabled in the more recent ReplicatorG versions’ default profiles.

I was able to take almost all of the Z wobble out of my Cupcake by isolating the two worst Z rods and using two wobble arresters, centering the all four rods carefully within their 8mm nut sandwich, and then arranging the two worst rods so they were diagonally across from one another. Twotimes’ Z-rider is a big set of prints and gives a seriously awesome result, but you could get 90% of that quality increase by just using the same techniques I did.