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Adopting PLA as the core RepRap polymer

Posted by Adrian Bowyer 
Re: Adopting PLA as the core RepRap polymer
April 03, 2008 05:50PM
PLA Is degradable only at temperatures above 70C in high humidity.

Do you ave a sacrificial pasta machine to fill with hot-melt glue?

Vik :v)
Re: Adopting PLA as the core RepRap polymer
April 09, 2008 08:54AM
OK, now that I have spent a few days playing with PLA, PCL, ABS and weeks with HDPE, PLA gets my vote: hard, accurate and low warping. I can't see any advantages using PCL unless you need something less brittle, or not transparent. Does anybody know if PLA can be opaque?

You can make objects with PLA, HDPE and ABS with a sparse fill and they are still strong, which is good because it saves plastic, speeds up the build and seems to reduce warping. PCL is not really strong enough for that.

Stringing is a bit worse with PLA I think, ABS is best in this respect.

If you need anything high temperature or slippery then HDPE is good if you can tolerate more warping, but it stretches the extruder temperature wise.

ABS is pretty good as well, it handles higher temperatures than PLA but inter-layer adhesion is not as good. That may be beneficial for using it as its own support material though.


[www.hydraraptor.blogspot.com]
Re: Adopting PLA as the core RepRap polymer
April 09, 2008 12:10PM
I've been printing in ABS for a few days now and I haven't seen any problems with adhesion to itself. What things have you noticed Nophead? Before reading this post I was going to put in a vote for ABS as I have only been using it and HDPE and HDPE isn't that great.

Demented
Re: Adopting PLA as the core RepRap polymer
April 09, 2008 01:37PM
I have noticed in trying to make 2 corner blocks with ABS that I had the inter layer adhesion problem. I was wondering if that is why Stratus has a heated chamber and was thinking of building a box to house everything that I can heat.. I did see that the first layers will adhere best and that the higher you go the worst it gets?

Bruce
Re: Adopting PLA as the core RepRap polymer
April 09, 2008 04:11PM
Dont forget about ambient humidity. The Stratus keeps the chamber's humidity under strict controls. It would be interesting to see if any of you guys get different results and have different ambient humidities.


Jay
Re: Adopting PLA as the core RepRap polymer
April 09, 2008 04:21PM
ABS filaments sometimes behave as if they were spot welded together rather than completely fused. If you can get a start on them you can unpick them, like pulling back wool jumper. I didn't notice this when extruding 0.75 filament at 7mm/s but did with 0.25mm at 16 mm/s. It probably just needs a higher temperature when going faster. Perhaps that is why Statasys use such a high temperature, simply so they can go very fast.

PLA is much more runny and sticky, and fuses so completely I can't imaging being able to break that apart.


[www.hydraraptor.blogspot.com]
VDX
Re: Adopting PLA as the core RepRap polymer
April 10, 2008 03:46AM
Hi nophead,

i think you're right - good adhesion is a temperature vs. fluidity-theme.

When the surface of the outputted tray cools down (with smaller diameters faster then with thicker trays) or you set it down on a cold surface, the (cooled down) skin or thermal shock would prevent a proper fusing ...

Viktor
Hi!Wehere I don't know how buy or synthetise the PCL polimer. Some one can help me?
Hi!! I don't know where to buy or synthetise the PCL polimer. Some one can help me?
Re: Where can iI find or produce the PCL polymer?
May 14, 2008 09:42PM
What part of the world are you in?

Vik :v)
Re: Where can iI find or produce the PCL polymer?
May 14, 2008 10:53PM
Looks like Italy.
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