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:
- Victrex (UK)
- Solvay Speciality Polymers (Belgium and US)
- Panjin Zhongrun High Performance Polymers (China)
- Jida Evonik High Performance Polymers (China)
Below is a list of some of the advantages and disadvantages of using PAEK:
- Highly fire-resistant
- Good chemical resistance
- Can be used for high temperature applications
- Excellent mechanical and dielectric properties
- Relatively high cost material
- High temperature molding and extrusion required
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.
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:
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.
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.