MAKING LARGE PRINTS
I just got done printing a 6” version of Han Solo’s smuggling ship. It may have made the Kessel run in under 12 parsecs, but it took 24.5 hours to build on my printer. I’m not complaining, I just have a few comments to share. The software I use is usually pretty good at predicting the time it will take to print a 3D model, but it missed big on this one. It missed by a factor 2 to 1. The slicing software told me it was going to take 12 hours to print. Almost exactly half what it actually took. I intended to print it during the weekend. Good thing I didn’t procrastinate (this one time) and wait until the last possible 12 hours on the last day of my weekend to print or it could have messed me up and still been printing while I went back at work.
I’m going try not to let a 24.5-hour print scare me away from making larger prints. While this print wasn’t what anyone would consider a large print, for it to take over 24 hours at that size makes me concerned with what if I had printed it at full scale? How long would that have taken? I know people print large objects all the time, but I’ve never heard about how they handle printing things that take more than a day or 2. How do they handle keeping an eye on it? There are a lot of things that could go wrong during print. By increasing the time it takes to print an item, it increases the chances something will go wrong, mostly by extending the period of time in which something can go wrong, but also by increasing the length of time that things are exposed to heat and vibration. An example of what I mean, let’s say you have a print going with area X as a footprint that can hold on to the print bed for a certain length of time, might be fine if the print only takes 7 hours to complete, but might shake loose after 8 or 9 hours of printing. This can possibly be accounted for by increasing the square inches of the base/supports of the print. But “how much to increase?” can only be answered through experience. There is no formula to how much to adjust the size of the base or increase the supports. If you over adjust, waste plastic in supports, but if you under adjust, you could waste more plastic losing the entire print.
So, how do you keep a watch on a project that takes several hours or days to print? You don’t want to or can’t sit there and babysit it the entire time. The first time I printed an object that took over night, I set up a camera with night vision (IR) and a Bluetooth connection to my phone and used my phone to take a look at it printing now and then throughout the night, from my bedroom. Whenever I’d wake up, which was often and the curse of being a light sleeper, I would turn on my phone to take a look. If something had gone wrong (knock on wood), I would have just gotten up and turned off the print, then waited until morning to figure out the cause. Of course, just turning it off would have meant a complete waste… a waste of time, material and effort. If I had a printer with a pause & continue option, I might have been able to save the print, depending on what the problem was. That is if I’d been able to catch it in time. Being able to pause a print and continue where it left off is an option that is beginning to come on more and more printers.
Another problem unique to larger prints is running out of filament before it’s done. Think about it, if it’s a large print, it’s going use a lot of filament. Most of the spools I use have about 1K grams of plastic per spool. So, right off, I know if my intended project, including supports is expected to weigh more than 1K grams (2.2 lbs.), I’m going to need more than 1 spool and that means a spool change in the middle of my print. That would be a good time for the pause & continue option, but that only works if you catch the first spool running out. An “out-of-filament” sensor is another option that is beginning to come on more and more printers. If the sensor detects a spool has run out, it can pause the print, allow for a spool change, then continue printing. A sensor that can detect an out of filament situation is an option that can be added to most printers, but unless the firmware is built to handle it and you can’t update the firmware, the best you can do is have it set off an alarm.
There is a way to handle most of the problems that come from printing large prints, even small ones as well… Octoprint. The website say’s ‘it is created and maintained by Gina HauBge.’ Octoprint is an open source program that can handle the problems I’ve mentioned and a whole more. Octoprint is an exceptional way to handle 3D printing and I would recommend it to all 3D Printers. Octoprint adds in Wi-Fi capabilities, camera operation for monitoring prints, multiple printers and lot’s more. For more information about it or to download, it’s available at octoprint.org.
Me, I’m still working my nerve and my way up to making large prints, the kind of prints that take days to print, but that will come in time, with confidence and experience. I either just have to have patience or go-for-it. I think I’ll try the patience route for now, I’m a bit too much of a chicken to try to just jump right in and see what happens. Maybe you’re less afraid then me and you’ll try the go-for-it method. Let me know how it goes.