From commodity plastics all the way to high-performance plastics, we have tested them all. Read into our adventures with those different materials.

TPU – The 3D-Printing Polymer With An Added Twist

Since 1937, this robust polymer has been making waves among the polymer communities. With its incredible durability, toughness and ease of processing, TPU has the advantages of rubber and plastic. This article will explain why this best-of-both worlds polymer is so useful.

What is TPU?

TPU in its granular form.

TPU, also known as Thermoplastic polyurethane, has been around even before World War II. However, its uses range from sporting goods to medical devices, from phone covers to Aerospace Surface Protection. To create this polymer in a lab, simply create a polyaddition reaction between a diisocyanate and one or more diols, well maybe not too simple, but after that a unique category of plastic emerges.

Uses of TPU

It is used in many sporting goods, including Air Jordans.

Below are some popular uses of TPU:

  • Sportswear (shoes)
  • Wire and cable coating
  • Hydraulic seals and hoses
  • Inflatable rafts
  • Phone cases
  • Medical tubing

As you can see, TPU is mainly used where flexibility plays a key role. However, it is not just flexible. Below are some other advantages of this filament.

Advantages of the Flexible Filament

TPU has many popular qualities making it great for a range of uses

You can think of TPU as a hybrid material, with a mix between hard plastic and soft silicon. When it comes to 3D-printing, usually ABS and PLA are used as the industry standard. However, if you are looking to create bending prototypes, these two fall short. TPU on the other hand is very flexible in nature. It can bend easily without affecting its design, durability and strength, with it even coming with a mild “self-healing” ability.

TPU vs Popular 3D-printing Polymers

TPU works well if you are looking for flexibility, very similar to PETG, a polymer we featured in a previous article. Lets see how it compares with PETG as well as the other popular 3D-printing materials, ABS and PLA.

Filament Special Properties Uses Strength Flexi-

bility

Dura-

bility

Print

Skills

Print

Temp.

(˚C)

Bed

Temp.

(˚C)

ABS Durable, Impact Resistant Functional Parts 2/3 2/3 3/3 2/3 210 – 250 50 – 100
PLA Easy to Print, Biodegradable Consumer Products 2/3 1/3 2/3 1/3 180 – 230 No
PETG Flexible, Durable All-Rounder 2/3 3/3 3/3 2/3 220 – 235 No
TPU Extremely Flexible, Rubber-Like Elastic Parts,

Wearables

1/3 3/3 2/3 3/3 225 – 235 No

Values courtesy of all3dp.

How Hard is TPU?

The flexible polymer also comes in different forms, most notable by the letter at the end, A or D, which refers to its hardness. This hardness is measured by different types of Shore hardness scales (for example Shore A00, Shore A and Shore D). The different Shore Hardness scales measures the resistance of a material to indentation.

  • Shore A00 Scale – measures rubbers and gels that are very soft.
  • Shore A Hardness Scale – measures the hardness rubbers that range in hardness from very soft to almost no flexibility at all, essentially the middle-ground scale.
  • Last is the Shore D Hardness Scale – measures the hardness of hard rubbers, semi-rigid plastics and hard plastics.
Image courtesy of Smooth-On.

As you can see from the chart, these scales can overlap. For example, shoe heels with a Shore Hardness of 70A can also be converted into a Shore hardness of 22D.

Our results with TPU

This polymer is great, and we really enjoy its creative uses. We were able to obtain some TPU Shore 75A, so a bit harder than the heel of a formal shoe.

TPU Shore 75A in its granular form, then extruded through the NEXT 1.0, and the resultant filament.

Doing some tests on the filament, we wanted to see how well it would extrude in our NEXT Advanced Level Filament Extruder. The results were better than we expected. As you can see in the images above, the filament extruded quite easily, resulting in a clean egg-shell white roll of filament.

A roll of filament was extruded, and a 3D-printed 3devo logo for testing.

Once the roll was complete, we decided to see how it would handle 3D printing. Going for a simple 3devo logo, we also wanted to test its flexibility. True to its hardness rating, it was still able to deform a bit, pretty neat!

In the end, this polymer serves a great purpose at providing a filament that is very easy to print with, but also durable and very flexible. If you are looking for a filament that is a combines the benefits of rubber and plastic, then TPU is for you.

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.

Year and a Half Later – Setting the standard with PEEK

Year and a Half Later – Setting the standard with PEEK
A year and a half ago, we began testing the prototype of what is today referred to as the Next 1.0 Advanced Level desktop filament extruder.
Taking forward the same commitment to quality and innovation, we focused on our next experiment – working with a semi-crystalline thermoplastic with mechanical and chemical properties ideal for sustaining high temperatures. This thermoplastic is known as PEEK (Polyether Ether Ketone).
Working with PEEK has presented interesting challenges, chief among which involved extruding it in the correct temperature range, while factoring in internal pressure, and without affecting the material’s crystallinity. It has been a good start, and our first trials turned out to be easier than expected.
But first, a bit about PEEK. And its key applications.

PEEK test result 1.75mm 3devo filament
PEEK test result 1.75mm 3devo filament – done by Apium Additive Technologies GmbH.

PEEK finds its main uses in the Aerospace, Automotive and Medical industries.

Aerospace industry: Being strong, lightweight, and durable in a wide range of temperatures, PEEK is evolving into a popular choice of material in the aerospace industry. Its low price point does not hurt either.

Aerospace part
Aerospace part
Source: www.roboze.com

Automotive industry: Besides the primary advantages of its high strength (safety), low weight, and durability in a wide range of temperatures, PEEK is also energy efficient and has the intrinsic ability to reduce vibrations. This makes it a perfect fit for the fast developing automotive industry.

Gear Pump Source: www.Apiumtec.com
Gear Pump
Source: http://apiumtec.com/en/3d-printer/

Medical industry: 3D printing has already established itself as an invaluable asset to the medical and dental industries, bringing a whole new level of freedom and accuracy to the process of printing unique parts and components. PEEK (or PEKK for dental industry) extends the scope of 3D printing, having similar properties as the human bone, and thus being one of the few materials that the body does not resist.

Implants Source: www.pkm.kit.edu
Implants
Source: www.pkm.kit.edu

Recent PEEK tests with the Next 1.0 Advanced Level desktop filament extruder
Switching from PLA to PEEK presented an unique challenge: building up the temperature inside the Advanced Level extruder to PEEK’s high melting point of 343 degrees.
We went about it in phases, using 2 cleaning compounds as transition materials. First, we slowly raised the temperature from 170 to 300 degrees with the first transition material. Once temperatures had crossed 300 degrees, we switched to the second transition material, and worked on reaching 390 degrees. This was the final stage in our trial, where we could proceed to extrude PEEK.
Because of PEEK’s steady flow and relatively quick cooling properties, extruding it to the desired thickness (2.85mm or 1.75mm) was easier than expected. Winding it on a spool was a different ballgame, though. Due to the strength of the material we had to tape the first part of the filament on the spool, so as to wind it correctly and prevent it from popping out of the spool.

3devo PEEK Filament 2.85mm
3devo PEEK Filament 2.85mm

Transition materials and PEEK
The transition material played a key role throughout our PEEK extrusion process. We first mixed the PEEK with the transition material, and then gradually lowered the temperature range while increasing the amount of transition material in the mix.

PEEK and purging compound @3devo
PEEK and purging compound @3devo

Phase 1

Image: 3devo BV - phase 1 extruding PEEK
Image: 3devo BV – phase 1 extruding PEEK

Phase 2

Image: 3devo BV - phase 2 extruding PEEK
Image: 3devo BV – phase 2 extruding PEEK

Extruding your own PEEK – The main advantages
Buying PEEK granulate will only set you back by around 100 Euros per kg, as opposed to a filament spool that will cost you to the tune of 1000 Euros per spool.
In addition to this, you can try creating custom composites with PEEK granules, by adding in different materials such as carbon fiber.

Do you have one of our Advanced Level extruders?
Contact sales@3devo.com for the profile settings to start extruding PEEK.

Extruding Polyphenylene sulfide on the Advanced Level desktop filament extruder

Braided PPS expandable sleeving has many applications across a lot of industries where wiring must be protected
Braided PPS expandable sleeves have many applications across a lot of industries where wiring must be protected.

Polyphenylene sulfide (PPS) is a high performance engineering plastic with high heat, acid, alkali, UV and abrasion resistance coupled with high dimensional and thermal stability. The plastic is also inherently flame retardant (material has been UL94 V-0 classed)  and has excellent water resistance. PPS as a material is new to Additive Manufacturing and currently little used in 3D printing. There are PPS resin grades suited for powder bed fusion technologies (Laser sintering, LS, selective laser sintering, SLS) and some FDM (Fused deposition modeling, FFF) filament is available. Outside 3D printing the compound is used for housings, electronics, electrical appliances and in the automotive industry. Solvay makes Ryton and Toray Torelina (and Toray’s Torelina resin is available as a SLS grade). There are a number of other manufacturers and also many specialized grades such as filled grades. PPS needs to be dried before processing 150 plus temperatures for 3 hours is recommended. Depending on the grade the glass transition temperature is 90, the melting point 278 and a melt temperature of between 315 and 343 when extruded. Typically for injection molding applications Polyphenylene sulfide requires 3 hours of drying at 130, a mold temperature of 130 and a cylinder temperature of 320.

PPS granulate.
PPS granulate.

We looked at and extruded PPS here at 3devo. We dried the material for 8 hours and then managed to successfully extrude filament from the material. The materials was comparatively easy to dial in and extrude as well as process.

PPS 3D Printing Filament
PPS 3D Printing Filament

We think that this is another step forward for our clients and look forward to dialing in and extruding many more materials for you.

Making PVA Filament with the NEXT 1.0 Advanced

PVA or polyvinyl alcohol is a relatively rare material in industry and is usually very difficult to process. Water acts like a plasticizer for PVA and the material is water soluble. This means that any humidity can adversely affect its performance and even eventually break it down. PVA is used in glues and also in bait bags for fishing carp for example. Bait is inserted in the bag and this is put into the water to attract fish. Once the bait bag dissolves in water, the bait spreads around the hook leading to more fish more likely to bite. The fact that PVA is water soluble and considered safe means that for a number of years it has been seen as the ideal support material for FDM 3D printing.

Fused Depositioning Modeling (FDM, also called FFF) systems use a nozzle to extrude and lay down plastic filament such as ABS or PLA. A build platform is then lowered and a new layer is applied. Industrial 3D printing systems have long used a second nozzle to extrude a sacrificial support material to support overhangs in the 3D print. This material is later removed. Sometimes supports can be a breakaway support structure or a material that has a lower head deflection temperature or strength than the build material. Stratasys, the company that invented FDM, has a wax support material for example. The company also has a PPSF support material (polyethersulfone), a polystyrene support material which is meant to be removed manually and a water soluble support material called 2-Propenoic acid, 2-methyl-, polymer with methyl 2-methyl-2-propenoate which is an acrylic and another which is a Terpolymer of Methacrylic Acid, Styrene, and Butylacrylate. Depending on the 3D printing process, the build material and the requirements of the part, many different supports are available.

Virgin PLA Granules with a much needed desiccant bag.
Virgin PVA Granules with a much needed desiccant bag.

For the desktop 3D printing community however PVA is the most researched and most coveted. PVA’s environmentally friendly characteristics coupled with the ease of use in removing the supports have lead to many companies looking into it. PVA is however notoriously difficult to keep. It must be dried before use. Even then, in a normal room PVA can quickly be adversely affected by water. In some cases a mere 12 hours in a room may degrade the material considerably. During normal 3D printing operations the material can also degrade much faster than other materials. What we discovered in our experiments with the material is that in addition to these issues care must be taken when extruding it. Any PVA remnants inside nozzles for example can wreak havoc on subsequent 3D prints and extrusions. Tricky stuff, PVA. This is also one of the reasons (along with nozzle lifting and software) while dual extrusion and support material on desktop 3D printers is so difficult to do. Many companies have researched dual extrusion and are trying to implement it. The difficulty of working with the engineering, software and material however has lead to only precious few 3D printing companies actually being able to make dual extrusion with PVA a reality. Even of those who say they can do several can not reliably do it.

A Spool of PVA filament made with the 3devo
A Spool of PVA filament made with 3devo’s filament maker

After drying out and extruding the material we were able to create good PVA filament with it in less than half a day of testing. The material was tested in prints and as a support and performed well. We will share our learnings with customers who are interested in making or developing their own PVA filaments.

Developing PA 12 FDM Filament with the 3devo Filament Extruder

A spool of PA 12 FDM filament.
A spool of PA 12 FDM filament.

At 3devo our NEXT 1.0 Advanced (Industrial) Desktop Filament extruders can be used to make all manner of grades of plastics and filaments. Many customers of ours want to use the machine to develop lots of different types of plastics. Some are interested specifically in one polymer in particular. One thermoplastic that our customer’s were specifically interested in was PA 12. We tested the material and made spools of PA 12 FDM filament for our customers.

Polyamide 12 is a widely used polymer especially in the packaging industry but it is also used in things such as concealer and medicine. The material is biocompatible, flexible and has good chemical resistance and high impact strength.

PA 12 polyamide surgical guide 3D printed
A 3D printed polyamide surgical guide made from PA 12. The guide is patient specific and made so that the surgeon knows where she can cut. By Orthaxy.

In 3D printing PA 12 is used extensively in selective laser sintering (SLS or LS) as a powder. This powder material is the most popular SLS material in the world. Surgical guides, orthotics, prototypes, short run parts and many of the 3D printed parts that you have seen have been PA 12. Materialise’s design brand .MGX was the first 3D printing design brand. Pioneering design by Jeanne Kyttannen featured the Lilly lamp which was made in both Stereolithography materials and in PA 12. As an SLS 3D printing material it has a powdery feel and is porous.

Lilly.MGX Lamp by Jeanne Kytannen and Materialise made in PA 12.
Lilly.MGX Lamp by Jeanne Kytannen and Materialise made in PA 12.

Due to high customer interest in the material we’ve decided to test and make Polyamide PA 12 FDM filament. PA 12’s versatility and high degree of use in 3D printing and beyond made it a very worthwhile material to extrude as well. We extruded the material on our 3devo Next to see if it could then be tested to see if it could confirm to customer specifications. We dialed in the material over the course of less than a day and it conformed to spec. We then 3D printed test parts on an Ultimaker 2+ to see the results as a printed part. We’re very happy with the filament and the print. Our customers are also happy that thanks to our data it will now be easier for them to dial in their specific PA 12’s. We will be adding the PA 12 Material Preset to a future software update on our machines.

A PA 12 part 3D printed on an Ultimaker. Filament made on a 3devo Next.
A PA 12 part 3D printed on an Ultimaker. Filament made on a 3devo NEXT 1.0 extruder.

ABS vs PLA Filament – What’s The Difference?

Like it or not, you simply can’t go out and start 3D printing without some prior filament knowledge. No matter how impressive your 3D printer is, choosing the wrong filament could make your next print look like it escaped from Chernobyl. Therefore in this article I’ll be giving you the very basics of printing with the two most popular filament types – ABS and PLA.