Making 3D prints that don't look like shit?
June 19, 2017 9:34 AM   Subscribe

I've had a 3D printer for a few months. The print quality has been massively variable, ranging from “hey, that looks pretty smooth” to hairy, warty misshapen lumps with huge voids and random Z-skips. I know not to expect injection moulded quality, but I'm not even getting consistency with the same gcode file and material. How did you get to consistent output?

The printer's a basic kit-built Reach 3D Bowden-fed machine. It's driven from a pretty vanilla RAMPS/Marlin controller. I've upgraded it with a heated bed and an E3D clone extruder ('cos I accidentally melted out the stock one). I'm printing with eSUN PLA+, a tougher PLA that needs a few more degrees than regular PLA. I had problems with regular PLA snapping in the extruder tube. Typically I run at 215 °C hot end / 50 °C bed. I have not-very-directable, always-on layer cooling. I'm now fairly careful about bed levelling, as the Reach's inductive sensor is easily knocked off calibration.

I have managed pretty good results with a commercial PrintrBot before, but I just can't get much worth a damn out of this machine.
posted by scruss to Sports, Hobbies, & Recreation (6 answers total) 5 users marked this as a favorite
Alas you have to slowly and methodically narrow down the problems one by one - you probably have more than one!

My favourite test pattern is a thin walled cube (in vase mode), you get to see if everything is moving in straight lines and how well layers stick together, and it only takes a few minutes to print. If you can't do a pretty cube then anything complicated has no chance.
posted by samj at 10:34 AM on June 19, 2017 [1 favorite]

You said it yourself, "I'm not even getting consistency with the same gcode file and material." That can only mean your machine is changing/moving over time in ways that it shouldn't. I'm not very familiar with this particular machine or cartesians in general, but check and tighten every joint in the frame, look for any play at all in the z-screw rod or whatever you call it and any gears. If there are belts, get them as tight as you can, etc.

Welcome to a world of frustration with occasional moderately whelming success!
posted by cmoj at 11:51 AM on June 19, 2017 [2 favorites]

You can always print upgrade parts for your printer (for instance, a better fan shroud, or mounts to increase rigidity). Also, check to see if there's a facebook group for your particular model - that's helped me a lot with mine. Also, is it possible that your filament is absorbing moisture?
posted by destructive cactus at 1:07 PM on June 19, 2017

My partner suggests checking to see if the nozzle is clogged, as that was causing him problems for a while on our 3D printer.
posted by Stacey at 1:23 PM on June 19, 2017

With kit built machines like that one, an intermittent electrical short or bad connection can happen. What does it sound like?
posted by poe at 8:53 PM on June 19, 2017

Lack of consistency with a 3D printer rarely has to do with the electronics, per se, but about the physicality of the machine. Step one for me would be to double check every mechanical connection: tighten belts, make sure set screws on the motors are tight, etc. Every single screw/bolt.

Then, as samj said above: print a simple hollow box. Observe: are the layers peeling? Check the Z. Do you see "drift" in one direction or the other? Check the X or Y as appropriate.

My experience with that filament on a Lulzbot Taz is that it prints fine at 205 or so...215 had me getting lots of strings and lumps due to over-extrusion.

Good luck!
posted by griffey at 6:59 AM on June 20, 2017 [2 favorites]

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