Arrg!

Sorry, I just have to vent.

PLA I hate you! You stink you soggy ornery bastard! I'm going to rip you out of my machine and throw you onto my drive way and back over you with my monster truck because, if I threw you into the garbage disposal you would probably foul it up causing even more damage that is probably the only thing you good for, you soggy sting of grief, I'm going to torture you with a bic lighter but, your probably to damp to even catch fire! You are going to spend the rest of you life spinning around on the end of my weed whacker occasionally smacking a piece of dog squeeze.

Ahh, thanks for letting me get that off my chest.

At least it smells nice

Edited 1 time(s). Last edit at 01/20/2012 04:36PM by tbfleming.

You must have quite crap PLA? What's the main issue, other than you hate the sodding stuff.

If it makes you feel any better, I feel almost the same way about ABS

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[richrap.blogspot.com]

Well, I'm new to this so, that's problem number one.
Problem #2 computers and I are not on speaking grounds.

Na, on a serious note I purchased some PLA off ebay (name withheld) after I used up my ABS and I tried to set the machine up and run this stuff with very little success. I spent three days chasing my tail around and finial figured out the PLA is just saturated with moisture. Apparently hearing little pops from your extruder is a sign of moisture with delayed extraction and delayed termination and all kinds of other funny little things. It's like it's mocking you. You fix a problem and then it does something else. I baked about 12 feet it in the oven last night at 170f for about an hour and that seriously helped! It's still to damp to do anything with.

Have you checked the real temperature inside the hot-end or at least confirmed it's about correct to the thermistor reading?
I have used damp PLA and yes it can be a pain and let out a few pops and give a poor surface finish, but the parts should still print ok. And if you dry it at even slightly higher ambient temperature it becomes much, much better.

If you are getting a lot of pops and if the PLA is very runny then it's more likely that you just have the temperature up much too high.

If you can't easily confirm if the thermistor is calibrated -
Lower the temperature by 10 degrees C and see if that makes it any better.
If not keep on lowering until the filament drive and/or motor stall, that will give you the point at about 150 degrees C. anywhere over 160 degrees C and PLA starts to extrude. 190 is a good optimal temperature you should not need to go any higher than 200 but at a very maximum 220 when you are printing very fast (+120mm/sec) with PLA.

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[richrap.blogspot.com]

I have not checked the real temperature inside the hot-end. The PLA does not appear runny. As of now it starts to print very nice and then randomly the PLA jumps off the table and back onto the nozzle and starts to drag the loop around like a drag net, or it just creates a stutter in the bead and leaves a nice little bump that catches the nozzel on the next pass.

I'm running at 185c I'll try dropping it down.

Thanks richrap!

If yur layers are not sticking to each other then It also sounds like you may have the layer thickness too high for the nozzle you are using. When you switch from ABS to PLA you will need to re-calibrate width over thickness and also your extruder.

The extruder as PLA is harder than ABS and does not sink in so far into the hobbed bolt or drive teeth.

The WOT (Width Over Thickness) as you get less die-swell from PLA than you do with ABS, so you may need to use lower layer heights with PLA than you were doing with ABS.

What size nozzle are you using and have you measured the diameter of the extruded filament and what layer height are you using.

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[richrap.blogspot.com]