The wonders of corn
Sep. 29th, 2012 04:41 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
rbandrewsOriginally, when I was going to get a printer, I was going to get a Replicator. Makerbot's (at the time) top-of-the-line, dual-extruder, build-cavity-the-size-of-a-loaf-of-bread monstrosity. I only got the Solidoodle because I saw an announcement for it, it was vastly cheaper, and seemed like a good learn-how-to-do-this machine.
Dual extruders seemed like a big deal though. Aside from the obvious "you can print in two colors" feature, you can also print water-soluble support material (called PVA, hellaciously expensive at $90/kg though). So, I was getting a little annoyed with the Solidoodle's calibration issues and I was thinking about picking up a Replicator anyway, for Christmas.
A guy on Reddit had one he wanted to sell, so I snapped it up, and it came in yesterday. I spent most of last night setting it up. There's some better and some worse parts about it, some things made me really respect the Solidoodle's design, and some things made me wonder why I put up with it for so long. But, there was one huge issue until just now: I couldn't get it to print anything.
The first layer of prints stuck fine, but after three or four more layers they'd peel up and detach, and fail. I was getting a little ticked off. It was obviously not the printer itself, which was performing beautifully, it was either a design issue or an environmental issue or both. I decided to leave it alone for a night and go play Borderlands 2.
This morning I tried taping sheets of cardboard to the sides and raising the print bed. I think part of the problem is that the Replicator has an open case, so cold air from the living room comes in and causes the print to cool too fast and warp. The cardboard shut out the air currents, raising the bed made it smear the plastic a little harder into the tape so that it would stick better. It worked okay, but it wasn't exactly ideal.
Then I tried corn. Oh man, corn is the bomb.
There are two kinds of plastic that 3d printers use. One is ABS, the most common kind of plastic in the world. You are probably touching some ABS right now. The other is PLA, Poly-Lactic Acid. It's biodegradable, made of corn. It's corn plastic. If you've ever seen a plastic cup that said it was environmentally safe, it was probably made of PLA. It melts about as well as ABS (slightly lower temp), and is about as strong (although it tends to shatter rather than bend), but it's the cooling properties that make it awesome: when ABS cools it contracts, so you have to cool it slowly and keep it nice and gooey while you print, so you have to have sticky Kapton tape and a frying-pan-hot heated print bed and a warm print cavity and all kinds of fiddly shit. PLA, on the other hand, retains its shape when it cools. You can print on to masking tape on a room-temperature bed and it comes out perfectly. And you don't have to wait an hour for the bed to heat up, and you don't have to cool the bed off afterward t remove the part!
Also it supposedly smells like waffles when it prints, although I couldn't tell. But ABS fumes always gave me headaches, maybe this will fix that.
Anyway, the Replicator is much better suited to PLA than ABS. I'll keep the Solidoodle around (I have 9 kilos of ABS to run through something, after all) but I think the Replicator is primarily going to be a PLA machine.
Dual extruders seemed like a big deal though. Aside from the obvious "you can print in two colors" feature, you can also print water-soluble support material (called PVA, hellaciously expensive at $90/kg though). So, I was getting a little annoyed with the Solidoodle's calibration issues and I was thinking about picking up a Replicator anyway, for Christmas.
A guy on Reddit had one he wanted to sell, so I snapped it up, and it came in yesterday. I spent most of last night setting it up. There's some better and some worse parts about it, some things made me really respect the Solidoodle's design, and some things made me wonder why I put up with it for so long. But, there was one huge issue until just now: I couldn't get it to print anything.
The first layer of prints stuck fine, but after three or four more layers they'd peel up and detach, and fail. I was getting a little ticked off. It was obviously not the printer itself, which was performing beautifully, it was either a design issue or an environmental issue or both. I decided to leave it alone for a night and go play Borderlands 2.
This morning I tried taping sheets of cardboard to the sides and raising the print bed. I think part of the problem is that the Replicator has an open case, so cold air from the living room comes in and causes the print to cool too fast and warp. The cardboard shut out the air currents, raising the bed made it smear the plastic a little harder into the tape so that it would stick better. It worked okay, but it wasn't exactly ideal.
Then I tried corn. Oh man, corn is the bomb.
There are two kinds of plastic that 3d printers use. One is ABS, the most common kind of plastic in the world. You are probably touching some ABS right now. The other is PLA, Poly-Lactic Acid. It's biodegradable, made of corn. It's corn plastic. If you've ever seen a plastic cup that said it was environmentally safe, it was probably made of PLA. It melts about as well as ABS (slightly lower temp), and is about as strong (although it tends to shatter rather than bend), but it's the cooling properties that make it awesome: when ABS cools it contracts, so you have to cool it slowly and keep it nice and gooey while you print, so you have to have sticky Kapton tape and a frying-pan-hot heated print bed and a warm print cavity and all kinds of fiddly shit. PLA, on the other hand, retains its shape when it cools. You can print on to masking tape on a room-temperature bed and it comes out perfectly. And you don't have to wait an hour for the bed to heat up, and you don't have to cool the bed off afterward t remove the part!
Also it supposedly smells like waffles when it prints, although I couldn't tell. But ABS fumes always gave me headaches, maybe this will fix that.
Anyway, the Replicator is much better suited to PLA than ABS. I'll keep the Solidoodle around (I have 9 kilos of ABS to run through something, after all) but I think the Replicator is primarily going to be a PLA machine.
