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Testing PAEK – Is It Any Good?

Here at 3Devo, we really enjoying testing a variety of different filaments. Last week we were about to test some PAEK. As you may or may not know, PAEK is a family of semi-crystalline thermoplastics with high-temperature stability and high mechanical strength. We were lucky enough to test some AvaSpire AV-621 from Solvay (provided by ALBIS PLASTIQUE France). Catchy name, but is it any good? This article will cover all you need to know about PAEK, and how it performed in our tests.
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General Information

 

Image 3devo – PAEK material provided by ALBIS Plastique France

As mentioned PAEK, or polyaryletherketone, is a family of semi-crystalline thermoplastics. In this family you will find:

  • Polyetherketone (PEK)
  • Polyetheretherketone (PEEK)
  • Polyetherketoneketone (PEKK)
  • Polyetheretherketoneketone (PEEKK)
  • Polyetherketoneetherketoneketone (PEKEKK)

Polyaryletherketone (PAEK) was first prepared in the early 1970s, but results and the overall process was somewhat limited. PEEK was the first thermoplastic to go large scale in 1977, where ICI used polyetherification reactions to create the polymer. In 1981, Victrex of Lancashire, England, introduced PEEK resins commercially. Next came PEK, introduced by BASF AG, the large German plastics company, which attempted to gain the total market share, eventually stopping all production of PEKEKK resins. This left Victrex as the only supplier of PEK resins in the world.

In the end, PEEK’s growth rates started to soar, mainly due to its high mechanical strength and chemical resistance. From vehicles, to aircrafts, to most electronics and medical applications, more and more suppliers started to enter the market. These suppliers include:

Below is a list of some of the advantages and disadvantages of using PAEK:

Advantages

  • Highly fire-resistant
  • Good chemical resistance
  • Can be used for high temperature applications
  • Excellent mechanical and dielectric properties

Disadvantages

  • Relatively high cost material
  • Anisotropic
  • High temperature molding and extrusion required

 

Tests

In our first attempt to create PAEK filament we used the AV-621 NT grade produced by AvaSpire with a melting point of 340°C, which we pre-dried at 150°C for 4 hours. The first step in the extrusion process was using PX2 cleaning purge (with a temperature range of 280-420°C) as a transition material, in order to be able to raise the temperature of all heaters to 380°C.

paek-test-1
Filling up the NEXT TEST Advanced Extruder, then running the test

The first thing we noticed while extruding with an overall temperature of 380°C, was the large amount of air bubbles in the filament. This could mean two things, either the granulate was not dry enough, or the overall temperature is too high. Lowering the overall temperature by 10°C improved the quality a lot, but now we faced nozzle lip buildup as you can see in the picture below:

paek-test-3
Nozzle lip buildup

Some polymers tend to have this problem, and it causes major surface roughness of the filament. In this case, the buildup was reduced by increasing the temperature of the front heater.

paek-test-4
A little rough around the edges

In the end we managed to create a spool of PAEK with a filament thickness of 1.75mm, but the surface of the filament was still on the rough side. This means we will keep on looking for better settings of the Next Advanced Extruder, but at least the machine has now proved its ability to create PAEK filament. This adds up in the list of successfully tested high-end polymers, along with materials such as PEEK and PEKK.

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 http://apiumtec.com/en/3d-printer/

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.

Peek Extrusion

PEEK, the superman of polymers. Currently one of the most popular high performance plastic materials on the market. In the polymer space, it would be tough to find something tougher than PEEK. It exhibits excellent mechanical and thermal properties, chemical inertness, creep resistance at high temperatures, very low flammability, hydrolysis resistance, and radiation resistance. These properties make PEEK popular in the aircraft, automotive, semiconductor, and chemical processing industries.

So naturally we wanted to extrude this bad boy. Ever since we started working on the NEXT 1.0 Filament Extruder it has been a goal to be able to extrude PEEK. Being able to successfully extrude this powerful polymer would mean our machine is a match for all polymers. Our intern Troy was put in charge of this exciting task: “it was hard to find the right temperature. Our first try was way too hot, the filament was not as sleek and smooth as it should be and it showed some heat damage.” Of course Troy wasn’t deterred that quickly and tried several times with different temperatures. “Eventually I found the right temperature that created perfect PEEK filament! Overall it was easier than expected. The bigger challenge now is finding good cleaning agent. It’s pretty powerful stuff, so getting all of the PEEK out of the machine has been an issue, but I am confident we will find a way.”

We were thrilled to have been able to produce perfect PEEK filament and are even more convinced off the sheer force the NEXT 1.0 has. Reaching this milestone has been a confirmation of our expectations and it has motivated us more than ever to finish this powerful product. Watch out polymers, we are coming for you!