SoliForum - 3D Printing Community — PLA woes

Re: PLA woes

2015-05-18T07:27:26Z

yes temp and speed are great suggestions. I only tried PLA once on my SD2 and that near full roll is up for adoption or trade for an ABS roll. ;^) I wont risk my printer over PLA which has very little better ability over ABS other that maple syrup smell (means nothing about hazards you cant smell). too easy to ruin the stock hot end and ABS extrudes much better results.

Re: PLA woes

2015-05-17T22:45:40Z

The dry extrusion in the first picture looks like the extruder is running too hot for PLA - I'd take it down 10C and see what effect that has.

Re: PLA woes

2015-05-04T02:57:57Z

I have switched back and forth between PLA and ABS several times with no major issues. I heat up to the ABS temp or just a little under, put in the PLA and manually extrude until I get a clean color change - at least 100mm, usually more like 200mm just to be sure. After that I turn the temp down asap and after it drops down, extrude another 50mm to clear any that may be overheated.

You dont say what kind of printer or hotend you are using, but on my SD4 with the stock hotend I was printing with PLA around 163-165 pretty successfully (keeping in mind solidoodle thermistors are not placed the best), bed at 60, top open and one side off (I have one side set up to easily remove/replace using magnets) - PLA doesn't like to be too warm.

I would try doing a temp calibration (20x20 or 25x25mm single wall cube, fairly tall) to find the ideal temp for your machine - figure out what temp it starts to ooze at and start about 5 or 10 degrees above that, increase by 5 degrees every 20-25 layers or so

Re: PLA woes

2015-05-03T21:32:32Z

Hey does someone mind sending me their slic3r setting for nice circles like these, I can't seem to stop my extruder completing a circle and then quickly jumping to the other side and back for no reason at all and leaving a nasty trail of gunk behind.

Re: PLA woes

2013-11-27T20:14:26Z

I printed a clear PLA vase once, and the leftover orange ABS appeared in random places on it. It didn't effect the quality of the print as far as I could see.

Re: PLA woes

2013-11-27T17:34:26Z

Temps below 170C I didn't try -- perhaps I should, with nozzle fan off, because when the nozzle fan comes on I get something like this:

And this is after PID autotune (at that target temp, with fan on during autotune, five cycles). Perhaps the erratic temp behavior (I get a dip with ABS as well, but not *that* bad, and I don't get any overshoots either) is also evidence of other material in the nozzle?

I don't think PLA filament quality is the issue (newly unpackaged, from reputable sources, two times.. unlikely?).

Re: PLA woes

2013-11-27T16:50:21Z

Your ABS print looks great.

I've only printed in PLA, so I can't comment on switching, but your squirrel print looks too hot, and probably too fast. You are probably better off without the enclosure (I've never used one), and the fan would help there too. Also you might up your retraction.

The only thing I can add about the inconsistent flow is that it looks to me like inconsistent filament (maybe diameter variation or it has some moisture?).

PLA woes

2013-11-27T16:32:05Z

All posts I've seen seem to suggest that printing in PLA basically involves just printing at a lower temperature. Unfortunately that has not been the case for me.

I've tried everything I can think of. My current (weak?) theory is that that there is leftover ABS(?) in the nozzle, and that's affecting the PLA. So:

- Has anyone printed PLA with the stock (MG) hotend?
- If so, were you printing ABS before and, if yes, how did you make the switch?

Tried cleaning with guitar string, didn't find anything (string just came out from top). Plus, if there is a partial clog, why don't I have any issues at all with ABS? Perhaps ABS is not as soft, so the extruder can still push it through? The only evidence of a partial clog is that, when I switch back to ABS, the nozzle occasionally squirts sideways for the first 600mm or so (extruding in air to, hopefully, flush nozzle).

[Scratching head...]

Generally, I've had all possible issues with PLA (nozzle temperature inconsistency, flow inconsistencies, partial clogs, jamming from the top, stripped filament, warping on overhangs, dry extrusion, blobbing, stringing, etc etc), and I think I've tried pretty much everything (temps from 170 to 190 -- with Matterhackers PLA, recommended 195 to 215 --, PID autotune each time, measured filament diameter with micrometer, did extrusion multiplier calibration, double-checked E-step calibration, bed leveling, tried various bed offsets, tried with nozzle fan and without, with enclosure and without, with heated bed and without, etc etc). I'm pretty much running out of ideas. The *only* thing that hasn't been a problem at all is getting PLA prints to stick to the bed, but everything else has mostly been a disaster. With ABS I have no issues whatsoever (and much less warp than with PLA, which goes counter to what I read). I've tried two different brands of PLA (Matterhackers and Makergeeks, both of which seem to be well-regarded), with the same results.

Here is a summary picture (full size):

If I remember correctly, the unenclosed PLA print was at 174C (182C first layer) and the enclosed ones were at 172C (again 182C first layer). ABS is at 197C. Note that gaps in extrusion are always after retractions (I tried lengths 2.5 - 3.2 mm and speeds 70, 75 and 80mm, but the gaps don't appear to follow a regular pattern?) -- except for the gaps due to clogging (filament softened too much inside the enclosure in that one).

Also, despite calibrating flow (all cylinder walls are 0.41-0.43mm, with target width of 0.42), I get inconsistent gaps in solid layers (full size):

[Pulling hair...]

I'm shelving PLA until I get my E3D, but if these images remind anyone of something they've seen before, please chime in.