PLA

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1 Introduction

PLA (here) stands for Polylactic acid or polylactide. It is a kind of plastic. This article describes its use as 3D printer filament

See also:

2 PLA in 3D printing

“PLA is a biodegradable, thermoplastic, aliphatic polyester derived from renewable resources, such as corn starch (in the U.S.) or sugarcanes (rest of world). Although PLA has been known for more than a century, it has only been of commercial interest in recent years, in light of its biodegradability. [...] PLA is slightly more brittle than ABS once it's extruded, but that is more than made up for by it's almost complete lack of warping, the ease of part removal, and the lack of any bad smells. It gives off a faint odor of Candyfloss (cotton candy) when it's printing.

Due to PLA's relatively low glass transition temperature, manufatured parts can not be used in situations where temperatures are higher than about 70-80 degrees C... PLA cups cannot hold hot liquids ” (BFB Wiki, retrieved June 2012)

PLA comes in variants.

Proportions + color pigments added will modify melting temperature and other behavior ! This implies that recommendations for your 3D printer only apply to the kind of PLA that was sold by the company (official recommendations) or that was bought by users (blogs, forums, wikis).

Typically, older PLA filament printed around between 205 and 210 degrees. More recent 4043D prints at lower temperatures, i.e. around 190 +/- 10.

The raft is usually printed colder than the rest that so that it can be more easily removed. Also, if you don't have a cooling fan, you must go as low a possible since warm PLA bends easily.

Recommendations from the RepRap Wiki

  • 4032D requires higher temperatures and may need to be set as high as 230°C
  • 4042D should extrude at 190°C (4032D technical data sheet from NatureWorksLLC)
  • 4043D extrudes between 160-220°C. Starting around 180 is a good start. (4043D technical data sheet from NatureWorksLLC)
Health risk

I don't know if inhaling PLA fumes is healthy, but Polylactic acid (PLa) is naturally biodegradable in the human body and it forms lactic acid. It definitely seems to be much healthier than ABS.

That being said, PLA contains paint and some of that may not be healthy. I am somewhat suspicious of some of the newer "brillant" plastics.

3 Links

Introductions
Printing with PLA
List of suppliers
"Local" Suppliers (there are many more, see above !)