Thursday, July 05, 2018
The trash can solution
My previous 3D printer used spools of filament of 600 grams. The new one can use spools of 800 grams from the company that made the printer, but it can also use 1 kg spools from other brands. So the spool I am currently using is 1 kg of a relatively cheap brand; it cost me 22 Euro for 1 kg, instead of 34 Euro for 800 g. As a typical 28-mm scale figurine of a medium size monster or hero is just about 5 grams, one prints a very long time with one single 1 kg spool. But I am starting to wonder whether getting half-price ABS for my 3D printer was a good deal.
One minor problem with cheaper ABS is that I need to find the best printer settings myself, while the software has presets for the Zortrax materials. Usually that takes me one or two prints of a small benchmark model to get the settings right. But with the current spool I'm just not getting there! First I had problems with layer-to-layer adhesion, the printed models breaking easily along the Z-axis. I was able to fix that by increasing the print temperature to 290°C. But at this higher temperature the molten plastic is very fluid, and flows out of the nozzle even when it shouldn't. That leaves strings and "outgrowths" on the surface of my prints. Normally you can fix that by increasing the retraction setting, which pulls the material back into the nozzle. But I already pushed that one up by a factor of 4 with no effect. The molten plastic in the nozzle is too fluid to be pulled back.
I am starting to think that this particular material simply isn't suited for my printer. At 290°C it is too fluid, but at lower temperature it isn't sticky enough to hold onto the previous layer. In addition to that this is the mauve roll where the prints come out in pink, which isn't my favorite color for figurines anyway. The good news is that I bought only one spool of this particular ABS, and I still have other spools of more expensive materials. I think I might save myself the trouble of failed prints or prints that require a lot of post-print work to fix the surface and just chuck that spool into the trash can. Lesson learned: The time and effort needed to print something is more valuable than the material used, so it isn't worth saving money on cheap ABS. I'll do some more testing with better ABS, but in the long run I might actually go back to printing miniatures in PLA, which appears to be better suited for that particular purpose.
One minor problem with cheaper ABS is that I need to find the best printer settings myself, while the software has presets for the Zortrax materials. Usually that takes me one or two prints of a small benchmark model to get the settings right. But with the current spool I'm just not getting there! First I had problems with layer-to-layer adhesion, the printed models breaking easily along the Z-axis. I was able to fix that by increasing the print temperature to 290°C. But at this higher temperature the molten plastic is very fluid, and flows out of the nozzle even when it shouldn't. That leaves strings and "outgrowths" on the surface of my prints. Normally you can fix that by increasing the retraction setting, which pulls the material back into the nozzle. But I already pushed that one up by a factor of 4 with no effect. The molten plastic in the nozzle is too fluid to be pulled back.
I am starting to think that this particular material simply isn't suited for my printer. At 290°C it is too fluid, but at lower temperature it isn't sticky enough to hold onto the previous layer. In addition to that this is the mauve roll where the prints come out in pink, which isn't my favorite color for figurines anyway. The good news is that I bought only one spool of this particular ABS, and I still have other spools of more expensive materials. I think I might save myself the trouble of failed prints or prints that require a lot of post-print work to fix the surface and just chuck that spool into the trash can. Lesson learned: The time and effort needed to print something is more valuable than the material used, so it isn't worth saving money on cheap ABS. I'll do some more testing with better ABS, but in the long run I might actually go back to printing miniatures in PLA, which appears to be better suited for that particular purpose.
Labels: 3D Printing