Polylactic acid, also known as PLA, is a thermoplastic material commonly used in additive manufacturing. It is one of the most commonly used materials in 3D printing and can be used to create a wide range of parts, packaging and prototypes for the medical, food, cosmetics and textile industries, among others.

How is PLA made?

PLA is made by fermenting the sugars in plant-based materials such as corn starch or sugar cane to produce lactic acid, which is then condensed into a lactide and polymerised. From there, PLA can be sold as raw plastic pellets for use in manufacturing processes such as injection moulding and casting. Alternatively, PLA can be converted into a filament, wound and sold for use in additive manufacturing.

What is PLA used for now?

PLA is used in a wide range of industries for a variety of applications. Among them:

• Food & Beverage. Derived from natural sources, PLA is non-toxic and food safe. It can be used to package items for human consumption.
• Medical. PLA’s non-toxicity means it can be used to make parts or components such as fixation screws or other implantable devices.
• Textiles. PLA is breathable and lightweight, making it an excellent choice for creating textiles.
• Cosmetics. Relatively affordable and environmentally friendly, PLA is an increasingly popular choice for creating cosmetic packaging – both for cost and environmental reasons.
• Prototyping. Especially when 3D printed, PLA is a solid candidate for prototyping where speed, cost and ease of use are paramount.

What are the types of Polylactic?

There are three main types of PLA – PDLA, PLLA and PDLLA. Learn about the properties of each.

• PDLA (poly-D-lactic acid). PDLA biodegrades more slowly than other types of PLA.
• PLLA (poly-L-lactic acid). PLLA is most commonly used for 3D printing and injection moulding. PLA+, a type of 3D printing material that is stronger than regular Polylactic, is also typically made from PLLA, but with strength-enhancing additives.
• PDLA (poly-D-lactic acid). PDLA degrades faster than other types of PLA, making it a good choice for pharmaceutical applications that will be ingested by humans or animals.

In addition, Polylactic is available in many colours and finishes such as matte, gloss and silk. It can also be purchased in hybrid form – containing a blend of Polylactic and materials such as wood, or with additives to enhance properties such as strength or flexibility.

How does pricing for Polylactic 3D printing filament work?

Prices of Polylactic 3D printing filament will vary, depending on factors including color and characteristics. For example, hybrid filaments that combine the properties of Polylactic and materials such as wood – or increase properties such as strength or flexibility – will be more expensive than regular Polylactic filament. Typically, however, prices of Polylactic 3D printing filament will fall between €20-70 per kilogram.

Is Polylactic a sustainable material?

PLA is derived from natural materials, which means it is much more environmentally friendly than other plastics. It is biodegradable, compostable, and recyclable.

What are the main properties of Polylactic?

PLA has a number of interesting properties. Among them are

• High stiffness. Polylactic is a very stiff and brittle material, which means it also has low flexibility.
• Good strength. Polylactic is a relatively strong material, with a flexural strength of 103 MPa.
• Low melting point. With a melting point of around 145°C, Polylactic is well suited to 3D printing.
• Good aesthetic properties. Due to its low melting point, Polylactic material can be used to create parts with smooth surfaces and fine detail.
• Low UV and temperature resistance. Polylactic deforms quickly under high temperatures and UV light.
• Chemical resistance. Polylactic is resistant to chemicals and is not soluble in solvents such as acetone or isopropyl alcohol, although certain chemicals can cause it to release lactic acid, which can be harmful in large quantities.
• Dimensional stability. Polylactic does not warp, which means it can be used to print large parts that are very close to the dimensions of a 3D model.

What post-processing techniques do you use for Polylactic 3D printing material?

Here are a few ways that PLA 3D printing filament can be post-processed.

• Remove support. Polylactic 3D printing filament is often printed with PVA (polyvinyl alcohol) as a support material for overhangs or other tricky areas. When creating a part using Polylactic and PVA, the finished part is submerged in water to dissolve the support material (as PVA is a water-soluble polymer).
• Sanding. Polylactic is capable of producing smooth surfaces, but certain areas may need to be sanded to make them smoother.
• Polishing. Parts made from Polylactic can also be polished with a buffer to achieve the smoothest possible surfaces.
• Painting. PLA filament is available in a wide range of colours, but you may still want or need to paint PLA printed parts, depending on the application.

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