I’ve been dialing in better prints – or at least trying too. One of the bigger things I printed today after work was a Raspberry Pi case (~2.5” x 3.5”). This is supposed to be flat, but instead, this happened:
If you can’t tell, the lower layers shrunk as the print started to cool; it warped. Since the print is stuck to the tape, it pulled the tape up off of the print bed. That’s a problem, obviously because it distorts the print. However, that also caused a secondary problem:
Since the “last layer” was higher than it was supposed to be (because it warped-up), the print head smushed the top-layer of printing plastic, distorting the print farther, and leaving clumps on the corners. Or in the case above, the print head came in from the side and hit a high-spot, and left clobs of plastic!
The solution, as I understand it – and what the internet tells me, is to get a heated bed. New, that’s $99 for my particular printer – but there are used ones – and universal ones on eBay for example. So, I need to research this and then make a purchase.
Other things of note…
Even though I saw this print was going to fail after the first :15 minutes, I let it continue. It took about 1.5 hours to print the 2 sides of this case, by the way. Anyhow, the good news is, I printed at 195 degrees Celsius and I got a noticeably smoother/better finish. It’s still not great, but it’s far better than my first prints. I clearly had the extruder temperature too high, before. With each print, I want to try going as low as I can.
That seems to be the “magic number”. You want the extruder just hot enough to melt the plastic, but no more. ANY amount hotter will make your print sloppier and messier! Again, it’s imperfect, but the consistency is much better than my first prints:
Unless or until I hear something different, I’m going to research heated beds. As of right now, I know nothing about them, how they hook up, etc. So, I’ll research that, pick one up, then try some more test prints!