What is the Difference Between PLA and TPU

PLA and TPU are both popular filaments used in 3D printing. Understanding the difference between PLA and TPU is crucial for selecting the right material for your 3D printing projects. 

What is the difference between PLA and TPU? PLA is rigid and brittle, whereas TPU is flexible and elastic.

Key Areas Covered

1. What is PLA  
      – Definition, Features 
2. What is TPU
      – Definition, Features
3. Similarities Between PLA and TPU
      – Outline of Common Features
4. Difference Between PLA and TPU
      – Comparison of Key Differences
5. FAQ: PLA and TPU
      – Frequently Asked Questions

Key Terms

PLA, TPU, Polylactic Acid, Thermoplastic Polyurethane

What is PLA

PLA is the short form for polylactic acid. It is used in 3D printing. It is derived from renewable sources like corn starch or sugarcane, which makes it eco-friendly. PLA is user-friendly too. It melts at lower temperatures compared to other filaments, allowing printing without a heated bed. The heating bed is a special platform that keeps the printed material warm. This simplifies the printing process and makes PLA ideal for most desktop 3D printers.

PLA is odourless and it comes in a wide range of colors, allowing you to create all sorts of colorful and creative designs. Though PLA has many different uses, it also has got certain limitations like not being so strong and being brittle. The heat resistance of PLA is lower, so it cannot be used for objects that gets exposed to high temperatures.

What is TPU

TPU stands for thermoplastic polyurethane. TPU is a block copolymer. There are soft and hard segments in it. Soft segments are long, flexible polyether or polyester chains derived from reacting a diol (a molecule with two alcohol groups) with an isocyanate (a molecule with a very reactive isocyanate group). They provide elasticity and rubber-like character. Hard segments are shorter, more rigid segments formed by the reaction of a chain extender (a short diol) with the isocyanate. They contribute to strength and stability. The key chemical bond in TPU is the urethane linkage formed between the isocyanate and the diol groups. This bond is strong and durable, contributing to TPU’s overall performance.

TPU can elongate significantly without breaking, making it perfect for printing flexible parts like gaskets, phone cases, or even shoe soles. It’s also resistant to abrasions, chemicals, oils, and even low temperatures. This toughness makes it ideal for parts that need to withstand wear and tear. It comes in various shore hardness ratings, allowing you to choose between a softer, more rubbery feel or a firmer, more plastic-like feel for your printed object.

Similarities Between PLA and TPU

1. Both are thermoplastics.
2. Both PLA and TPU offer a wide range of applications in 3D printing.

Difference Between PLA and TPU

Definition

• PLA is the short form for polylactic acid, while TPU is the short form for thermoplastic polyurethane.

Rigidity vs Flexibility 

• PLA is rigid and brittle, while TPU is flexible and elastic.

Durability

• PLA is not very durable when compared to the tough TPU.

In Print

• PLA is generally easier to print than TPU.

Heat Resistance

• PLA has a lower heat resistance compared to TPU.

Conclusion

PLA, derived from renewable resources, is rigid, brittle, and user-friendly, making it ideal for colorful, creative designs on most desktop 3D printers. TPU, on the other hand, is flexible, durable, and resistant to various environmental factors, making it suitable for parts requiring elasticity and strength.

FAQ: PLA and TPU

1. What is TPU filament good for?

TPU is ideal for 3D printing medical parts such as medical device prototypes and end-use medical devices. Its flexibility, durability, and resistance to various chemicals make it suitable for creating intricate and functional medical components.

2. Is PETG stronger than TPU?

Yes, polyethylene terephthalate glycol-modified (PETG) is stronger than TPU. PETG offers superior strength and durability, which makes it a preferred choice for applications strong robust mechanical properties.

3. Which is stiffer and less flexible?

PLA is much stiffer and less flexible than TPU. Hence, PLA is usually reserved for prototypes where rigidity and ease of printing are more critical than flexibility.

4. What is the disadvantage of TPU?

Thermoplastic polyurethanes stand up well to chemicals but degrade by free radicals due to the exposure to UV and heat. This is a major disadvantage of TPU.

5. Is  TPU toxic to 3d print?

TPU is a non-toxic filament but releases harmful fumes during the printing process. Therefore, there should be good ventilation and a good air filtration system in order to prevent getting long term,  harmful health conditions.

Reference:

1. “Polylactic Acid.” Wikipedia. Wikipedia Foundation.
2. “Thermoplastic Polyurethane.” Wikipedia. Wikipedia Foundation.

Image Courtesy:

1. “TPU texture” By Luigi Chiesa – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Polylactid sceletal” By Polimerek – Own work (Public Domain) via Commons Wikimedia