Tips for Soft PLA?

[eric-lester 1]

I recently got a pretty good deal on some soft PLA. I bought it because I thought it would be a good material for printing phone cases. Shown here are the first two layers of a print I did with it recently.

I've never used soft PLA before, and you can see that there are TONS of little holes in it from some pretty inconsistent but severe underxtrusion...while I did manipulate the parameters a little (eg I increased the flow rate and turned up the temperature to around 230), the entire first layer and most of the second layer where printed very slowly (bottom was at 30% and top was at 65%) with constant parameters, yet you can still tell where some sections worked flawlessly and others just look horrible. The plate is fine and so is the model; I recently printed this gcode in ABS, and it came out beautifully. Any help on temps, speed, flowrate, fan speed, etc. for soft PLA?

 

[donmilne 2]

What printer do you have? (editing your profile to say so might be a good idea).

If UM2, are you still using the stock feeder?

 

[fabiodl 0]

reduce the speed to 50% or less (tune menu while you are printing)

[tommyph1208 55]

try adding a little bit of oil in the bowden tube, it will reduce friction and probably help alot with the extrusion

 

[eric-lester 1]

try adding a little bit of oil in the bowden tube, it will reduce friction and probably help alot with the extrusion

 

 

I ran some Teflon through it, and it does seem to be helping.

 

reduce the speed to 50% or less (tune menu while you are printing)

 

Yeah, this was a common tip I saw, but it seemed to have varying success. I tried another print of that same case at full speed, and it was no better or worse than a slow one...

 

What printer do you have? (editing your profile to say so might be a good idea).

If UM2, are you still using the stock feeder?

 

I do have a UM2 (and have amended my profile to reflect so....thought I did when I made it...whoopsies ), and I am still regrettably using the stock feeder. I think that this may be the issue, as I recently cranked the tension up because ABS kept slipping. When I pulled out some of the soft PLA, it was deformed horribly. There wasn't a lot of scrunching up (as I would associate with a lot of friction, so the Teflon probably did help), but the dimensions had almost uniformly changed to around 2.35mm +/- 0.04mm by 2.90mm +/- 0.05mm. That last one bothers me, as there is a lot f variance, and it's entirely possible that some sections had a width of above 3mm.

I'm in the process of printing a new feeder right now, because tensioning the stock one is a pain, and when I do, I'll try really decreasing the tension. The quilt on the stepper digs into the soft PLA very well anyway, so I shouldn't need a lot.

 

[jameshs 42]

soft filament needs really really slow speeds and slightly more heat than normal to get good extrusion and to get layer adhesion - really slow (did I say that )

 

[DidierKlein 729]

+1 for slow speed.

And keep the most constant speed possible and disable retractions if possible.

I try to keep an constant speed of 30mm/s with flex pla from Ultimaker it works pretty good

 

[eric-lester 1]

I understand the slow speeds, but that doesn't explain why at a constant slow speed it goes from extruding perfectly well to suddenly barely extruding at all...

 

[drunkun_munky 0]

Does the feed slip backwards on the first few layers? If it does you will need to reset the bed height. If that doesn't work try a bit of glue on the bed.

 

[eric-lester 1]

It isn't an issue of adhesion; what does actually extrude sticks fine. And I did check the bed height--but the issue persists to higher layers as well. I haven't gotten a chance to really look into it properly yet as school is killing me, and I have lots of other things to print with ABS.