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PEI – Extruding The High-Performance Polymer

PEI, Polyetherimide, is one of the more rare polymers we have tested here at 3devo. That, however, does not mean it is any less useful. This high performance engineering thermoplastic, usually with an amber to transparent colour, makes a great name for itself in various high-demanding applications. It can often replace metal or other strong substances thanks to its impressive chemical and mechanical properties, but how well does it extrude? In this article we will make a brief overview of PEI as well as our extrusion tests for this strong polymer.

Filament Summary

PEI’s characteristics include extreme rigidity, high strength (even at elevated temperatures), long term heat resistance, dimensional stability and good electrical properties. It is easy to spot due to its light amber colour (unfilled) and is usually semi-transparent. Like other amorphous, high temperature resins, PEI has outstanding dimensional stability and is inherently flame retardant.

PEI does resist chemicals, such as hydrocarbons, alcohols and halogenated solvents. Creep resistance over the long term allows PEI to replace metal and other materials in many structural applications. It is also widely used in electronics because of its good arc resistance and dielectric constant. Furhermore, PEI is UFDA/USDA and USP class VI compliant.

Applications

PEI used in vape mouthpieces (left) to plastic manifolds (right) via Carville Plastics
  • Reusable machined components
  • Aircraft/Automotive instrumentation
  • Plastic Manifolds
  • Electrical insulators
  • Electrical component housings

Advantages

  • Great thermal stability (continuous use temperature of 365F/180° C)
  • High strength
  • Continuous rigidity and strength to 340F (170°C)
  • Dimensionally stable
  • Excellent flame and heat resistance (UL 94 V-0 rated)
  • Consistent dielectric properties over a range of frequencies
  • Good acid resistance
  • High resistance to autoclave sanitizing
  • Low moisture absorption
  • Can withstand steam autoclaving
  • Inherently flame retardant
  • Certified Grades for food-contact and bio-compatibility applications

Disadvantages

  • Can be expensive
  • Not a lot of colour choices (amber or sometimes transparent)

Extruding PEI (ULTEM 1010 Resin)

Here at 3devo we were able to acquire some PEI for extrusion tests (Ultem 1010 Resin was used). Because of its high strength factors we were interested to see what the results would be. Below is an overview of the whole process, however, for a more detailed report please contact us via the sales contact page.

Preparation

PEI resin (left) and adding it into the hopper (right)

First cleaning of the NEXT extruder had to take place.  Using ASACLEAN™ GL2 followed by ASACLEAN™ PX2, we were able to clean the device to prevent any impurities impacting the results. Once both materials had run through the device in order to properly clean it, the heaters were all set to the same temperature (160 °C). 

Observation Indicators

There are three important things to look out for when extruding new filament for the first time:

  • How does the filament look? Are there any signs of bubbles/holes, die lines, weld
    lines, melt fracture or warpage?
  • Is the flow similar to that of standard PLA (when using the same rpm)?
  • Is it possible to pull the material without any trouble (the material does not stick to
    the puller wheel and does not break as a result of the force of the puller)?

Extrusion Summary

Extruding PEI (left) and the results (right)

After multiple tests, we concluded that PEI is able to be successfully extruded with the NEXT. The tests we ran determined that PEI should be extruded below 370 °C (but not too low) in order to prevent bubbles and holes from forming, and that proper cleaning methods should be used in order to determine the best results.

Conclusion

In the end, PEI was a very interesting polymer to test out compared to other ones we have tested in the past. Its high strength, rigidity and thermal stability meant that a lot of care had to be taken when running the tests. PEI though is a great filament and very useful, especially in aerospace and automotive applications.

Is PETG the best filament in the 3D Printing Industry?

When it comes to 3D printing, information about filaments such as PLA and ABS is plentiful. However there is another filament out there –  PETG. With its strong, durable and ease of use characteristics, are making it more and more popular by the day. 3devo delves into what PETG is, how it compares to the aforementioned polymers in terms of printing and extrusion.

What is PETG?

 

 

Source: Pixabay

 

PETG first started as simply PET, or polyethylene terephthalate. PET had and still has many great uses, with its fibers being used everywhere from food packaging to plastic bottles, as well as other common plastic items. There are many variations of PET, such as ETE, PETP, PET-P, etc., however, the G in PETG stands for glycol. Glycol prevents crystallization in the thermoforming process (i.e. preventing it from turning hazy).

Thanks to the glycol, it means the classic PET is modified for extra durability. PETG has recently become very popular as 3D-printing filament due to this durability, so let’s take a closer look at what makes it so great.

Why did we choose to test PETG?

Source: 3devo testing area – PETG (Genius 80M) in its granular form.

 

PETG has quite a few beneficial properties, especially when it comes to applications such as 3D printing. It comes in a whole range of translucent colours, but here are some of its most common attributes:

 

Durable – regular PET becomes very hard and brittle when it starts overheating. PETG is also more flexible than ABS and PLA, too. The inclusion of glycol really helps here, making items such as a plastic bottle more comfortable to hold in the hand as well.

 

Temperature resistant – both minimal shrinkage and warping make it great for printing large objects.

 

Sticky – PETG is a bit sticky, this means that it would not be good to use it as a support structure for 3D printing models, but its layer adhesion is usually fantastic.

 

Good chemical resistance – great chemical resistance, with good water, acidic and alkalic resistance.

 

Tough – PETG is very strong. It’s not brittle, however, it can be easily scratched (more easily than ABS). It also has a high impact resistance, similar to that of polycarbonate.

 

Amorphous – excellent transparency and high gloss surface (great for artistic print items).

 

Environmentally friendly – recyclable and food safe. In medical applications, it also stands up to radiation and chemical sterilization techniques without changing color.
In short it combines the benefits of PLA (easy to print with) with the benefits of ABS (strong, durable and temperature resistant).

 

Common applications of PETG

Source: 3devo printed parts with in house made PETG filament (Genius 80M)

 

PETG is used in a variety of signage, packaging, industrial and medical applications:

 

  • Medical equipment such as braces and pharmaceutical packages
  • Protective guards/coatings
  • Bottles and food packaging
  • Guards and covers for electronic equipment
  • Point-of-purchase and graphic displays

Why PETG instead of PLA or ABS?

Source: 3devo 2.85mm spool PETG Genius 80M, made on the NEXT 1.0 Advanced Level Extruder

 

When it comes to printing with PETG, the above characteristics all help making it a great choice. As shown above extruding a roll is simple (you can visit our store if you’re in the market for an extruder), and printing is not too bad either (some users have made this their top choice of filament). We would not recommend printing everything with it as you might not always want your item to be so flexible, but below is a brief summary of how it compares with PLA and ABS.

 

PETG PLA ABS
Hardness Very flexible Not very flexible R105 to R110 (Harder)
Durability Very flexible Not very flexible More flexible
Food safe Food safe Food safe Not food safe
Heat bed Heated bed is not a must but it can be an advantage Doesn’t need a heated bed for 3D printing Needs a heated bed for 3D printing
Price Slightly more expensive than PLA (+/- 10%) Average price range Cheapest of the three
Recommended 3D printing temperature 220 to 250 °C for the hotend 190-220°C 230-250°C
Recommended print-bed temperature 50-60°C 50-70°C 80-120°C

Most makers out there say PETG isn’t the easiest to initially print with, as you first have to find that “sweet” spot if you want to create some quality prints.
We at 3devo really enjoy this practical polymer. PETG is very practical and easy of use when it comes to printing, and its combination of rigidity and mechanical properties makes it a great all rounder, perfect for your next 3D-printing idea. Don’t forget to check out our blog for more interesting articles.

What is a Filament Extruder?

What are we building?

3devo is developing a filament extruder. This is a machine that processes plastic pellets into a plastic wire. This plastic wire (filament) is mainly used as printing material for 3D printers, in a manner similar to an ink cartridge being used by a regular printer.

Overall, filament is extruded on an industrial scale. We developed a product that makes the quality of industrial extrusion setups within everyone’s reach. Taking the systems and knowledge of industrial machinery and reducing the size to fit a consumer desktop model in such a way that each user can have his own professional filament extruder. This means scaling down, simplifying, automating and making the extrusion process more consumer-friendly.

For more information check our product page!

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