White PLA turns dark and nasty.

I don't know what could be going on. I've tried:
changing the temp: 190-200 degrees C.
changing speed: from 30mm/s to 120mm/s

I would change filament but I don't have any other. Is this a common issue with PLA?

Sorry for the horrible picture, my phone camera sucks..

[imgur.com]

I normally print at 170 for PLA, it does depend on your pla and what hot end you have, but 200 for pla seem really high to me.

Is your hotend leaking?

Quote
Dust
I normally print at 170 for PLA, it does depend on your pla and what hot end you have, but 200 for pla seem really high to me.

200 PLA is not unheard of. Im currently printing at 210.

It could be dirt/dust that is getting burnt up in your hotend. Try taping a cloth or sponge around your filament as it enters your extruder.

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I've printed with white PLA several times over, was my first color I printed in. I can definitely tell you that lower temps are better, my blue has almost the same sensitivity. I print my PLA at 162 on my Solidoodle. Sometimes 158.

@gmh39 I do have a dust cleaner attached.

@Ralph.Hilton That could be it. I'll have to give it a good cleaning and see.

Here's a better photo. As you can see, the darker, discolored output doesn't last for more than a few cm. It is also more shiny than the regular output.

[imgur.com]

Edited 1 time(s). Last edit at 04/03/2014 01:43PM by dudesom.

Depending on your hot end design, there could be plastic stuck in pockets that occasionally mix in with the new color.
Clean your hot end, and what hot end do you have.

Edited 1 time(s). Last edit at 04/04/2014 12:53AM by A2.

It may also be possible that the temperature reading you are getting is too low and the actual temperature of the hot end is higher than what you set. Try reducing the temperature by steps and see when it becomes too low to print.

dudesom, Ralph.Hilton is more on target I believe. If you look at this image, you can see the same thing in my filament duck, you can see the same stringing. This was caused by filament leaking out of the top of my heat block and dripping back down into the feed to be deposited within the print. I have also found that if the bottom of the heat block gets any filament on it, from a part not sticking for example, it can produce the same effect. From your image, however, I don't think the underside of the heat block is the culprit but a leak is not out of the question.

Edited 1 time(s). Last edit at 04/08/2014 01:45PM by lukan.

For our PLA filament, the print temperature from 180-220 degree is normal,because temperature differs with different printers.For our filament on Makerbot,Ulimaker,Makerpi, it is ok to print at 190,but
for another China brand, it needs 230.

Which color do you print before the white one? There maybe some remains inside the extruder. Black is not easy to flow completely.

Another possibility is that the filament is dirty,so try taping a cloth or sponge around your filament as it enters your extruder,this may solve the problem.

The last is that the white filament is not very white itself.

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I had this happen once, but just a bit, while printing white PLA..im pretty sure it was a small build up inside that had burnt due to sitting, then started mixing in with the fresh stuff and extruded out...I would say its due to temps being a bit high, possibly causing some build up, burn, then extrusion..play around with a wide range of temps and see what works best