How to print non-PLA large-format objects on the gMax 1.5 XT+ (not for the faint of heart!)

[jlgtx]

Out of the box, the gMax might be able to print large-format PLA objects, but printing with production-quality materials requires nothing less than a complete overhaul of the gMax. We'll start with the overview, and add specifics in follow-up replies as time permits.

1. Replace all of the gMax's plastic parts (yes, all of them, every. single. one.) with ABS parts, printed using 100% infill.

2. Replace the electronics box cooling fan with a reliable ball-bearing fan. I recommend the Orion OD5010-12MB.

3. Add the dual-zone heated build plate, with additional bed retaining clips. Modify the ones on the sides to allow clearance for the Z-axis screws, and modify the ones on the front edge to allow clearance for the hot-end at extreme Y positions.

4. Build a heated enclosure. The enclosure must allow the electronics box fan to pull outside (cool) air into the box. Otherwise your stepper motor drivers will overheat, screw up your prints, and cause the hot-end to tear itself up. This will probably happen anyway, if you don't replace the fan (see #2). The enclosure should leave the control panel and the power supply on the outside, so they can stay cool.

5. Set up an OctoPrint server, with a relay board to control power relays for the heated enclosure and bed. Build or buy a filament sensor (two, if you have a dual extruder) and a temp/humidity sensor. Add Vitor Henrique's outstanding Enclosure Plugin to pull it all together.

6. Routinely, consistently, fastidiously check the X-axis arm level, X & Y belt tension, hot-end screw/bolt tightness, frame bolt tightness, and anything else that might work its way loose over time. Loctite may be your friend.

7. Buy Simplify3D.

8. Use a brim. I am still amazed at how effectively a brim can reduce warping -- though on a large part it's a pain to remove.

 

[Jarhead]

I didn't have to do any of that except number 3. Print with carbon fiber for just about everything.
I did add Octoprint but that isn't necessary to print, I use it because it's better.

 

[jlgtx]

If you mean carbon fiber PLA, that is really still just PLA...not an industrial-grade plastic. To print large-format parts in industrial materials like ABS, nGen, or other copolyesters, number 3 alone won't get you there. Then again, you might be talking about carbon fiber nylon, which is indeed super nice for many things. Expensive, but nice, and it doesn't handle fine detail as well as ABS or nGen. The point is that not everyone wants or needs to use CF filaments, and gCreate advertises the gMax as a multi-filament large format printer...so it's worth knowing the limitations.

 

[jlgtx]

Thanks to Joshua at gCreate for this fix!

One of the many potential side effects of a heated enclosure is that, due to the filament being warmer--thus softer--as it enters the print head, the filament between the feed mechanism and the extruder tube can get pushed out so that the filament just runs out the front side of the head instead of down into the extruder. To protect against this, replace the feed mechanism's flat-faced sealed bearing with a grooved-face version. The grooved bearings are slightly thinner than the originals, so you'll need to add a washer behind the new bearing to center it on the feed tube.

 

[jlgtx]

Large parts take awhile to print, so unless you plan to camp out next to your printer and stay awake & alert for the duration of the print, you'll also need to add a filament monitor to your printer. A simple switch-based sensor isn't really enough, because it doesn't detect failure-to-feed situations. Check out the write-ups at https://github.com/vitormhenrique/OctoPrint-Enclosure/issues/122 for some ideas.