3D Filament

TPE and TPU – What are the differences between these two materials for 3D printing?

TPE e TPUI write this very short article only to clarify once and for all the differences, but also the similarities, between TPE and TPU.

If you are now starting to use flexible filaments with 3D printing you probably are thinking about the difference between TPE and TPU? But let’s start from the similarities.

Similarities between TPE and TPU

These two materials, despite having different properties that could differentiate them, are often confused, why? Probably because they have more points in common than differences, and I would really like to start from here.

First of all, let’s say the obvious, they are both flexible filaments. They are generally considered safe, as they do not contain toxic materials. Both have no particular difficulties to adhering to the plate, their soft nature help . They are composed of plastic molecules joined to rubber, which means that they make very long-lasting prints, both in time and wear.
It is possible to print both filaments between 230°C and 240°C, with a bed heated around 50-70°C. The densities are almost identical and are around 1.20g/cm3. Finally you can use both materials to create objects that have to bend or flex, like belts, phone covers, etc.

Differences between TPE and TPU

Short introduction TPE

TPE is a thermoplastic elastomer, which means that the materials that compose it are a mix of plastic and rubber. And this composition allows us to print this material.

“Have you ever thought about it? Why not print the rubber directly? Wouldn’t it be easier? The rubber when produced undergoes a process of cross-linking (vulcanization) that creates a grid inside the material, which gives it flexibility. This grid will disappear if it is re-fused.

It’s the principle that if you set a piece of rubber on fire, this drips and when the drops harden, they’re not gummy anymore, but they’re perfectly solid!”
By mixing the rubber with thermoplastic material, it manages to maintain its own elasticity. The TPE is really soft, with a typical hardness of only Shore: 85A.
Think that you can pull a print made of TPE up to twice its length. It was the first flexible material printed by 3D printers.

It had its peak period and is now slowly giving way to the substitute, the TPU.

 

TPE e TPUBrief introduction to TPU

TPU is thermo-plastic polyurethane. Although its invention is contemporary with that of TPE (about 1950) this material was not available for 3D printing except in very recent times (3/4 years).

However recently it is becoming very popular due to its properties. One of all is the fact of being slightly more rigid than the TPE, Shore: 94A-95A.

Thermoplastic polyurethane, going to deepen is more resistant to abrasion, oils, greases and solvents, therefore in general more suitable for industrial or pseudo-industrial applications.

 

 

So, what’s the real difference between TPE and TPU?

If you are a maker, the only difference that really makes the difference for you is the softness. We said the TPE is softer, while the TPU is stiffer.
This difference is tipping the market in favor of TPU.
Why do you wonder if it is less soft? Simply because the TPU is much easier to print. It gives much less problems as it has a behavior more similar to normal filaments in the coil.

Keep in mind that you could face many problems by printing TPE, including frequent clogging of the nozzle, the underextrusion and the winding of the filament on the pulley of the motor!

Differences in printing:

In addition to the temperature difference, which varies from producer to producer, we will have to deal with the press differently in these respects:

  • Extruder: You can print TPU with Bowden or Direct, while  you can only print TPE with direct extruder.
  • Speed: TPU supports printing speeds up to 35 or 40 mm/s. This speed becomes 15 mm/s when we print TPE.
  • Retractions: absolutely forbidden with the TPE, the most rigid TPU can bear some minimal retraction, setting the correct infiltration and preferably with direct extruder.

If you are starting and want to understand how to print: GUIDE – How to print flexible filaments

 

TPE e TPU

But why should I want to print with flexible materials? What’s the advantage?
You should consider flexible materials because you would greatly increase achievable objects and fields of application. You could print a belt, watch strap, wallet, caps.
But also Tires for radio-controlled models and other models, feet for furniture, wheels for printers, hair elastic and I could continue to the infinte!

If you want to start your experience I recommend the TPU Sunlu in different colors: easy to print and cheap!


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