nFEP – PFA or FEP film

Which one in better?

New to fep-film.com is a range of PFA film to complement our successful FEP film options and based on many requests from specialized 3D print companies. PFA films can be supplied in a range of thicknesses:

• 50 micron
• 100 micron
• 125 micron
• 150 micron

It can be pre-cut to customer requirements to suit your 3D printer profile or supplied as an un-cut roll with a width of 1220 mm and a length of your choosing.

Why fep-film.com?

To give a bit of background, fep-film.com is part of Holscot Europe with over 50 years of experience in the manufacture, manipulation, and application of materials like FEP and PFA. Our knowledge of fluoropolymers combined with our advance manufacturing processes and innovative customer solutions make us a leading expert in this field. In this blog we dive deeper in comparing Nfep and PFA and we try to answer questions such as:

• What are the benefits and properties of n-FEP and PFA?
• What materials are better?
• Is nFEP the same as PFA?

Introduction           

PFA film’s origin heralds from the fluoropolymer group of materials. DuPont developed fluoropolymer high-performance melt processable materials such as FEP and PFA in the 1950s as derivatives of the original fluoropolymer Teflon™ (PTFE).  PTFE itself is very difficult to manipulate. It cannot be extruded, is extremely difficult to weld and cannot be thermoformed so FEP and PFA were created as materials which could be more easily processed. PFA is part of this family of materials and more closely resembles Teflon™ (PTFE) in terms of its properties. They have significantly improved chemical and physical properties compared to other traditional commodity polymers (e.g., polypropylene).

Advantages:

PFA film (Perfluoroalkoxyalkanes)

 PFA (film) is a transparent copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether. Its properties closely resemble polytetrafluoroethylene (PTFE) more commonly known as Teflon™, and include, high chemical resistance, exceptional UV transmittance (96%), excellent flexibility, resistance to elevated temperature (up to 260 °C) and impressive slip and release characteristics resulting from its low coefficient of friction.

Unlike PTFE it is melt processable so can be extruded as tube and sheet and also blow moulded and injection moulded. It is also thermoformable so can be welded and vacuum formed, Due to its inertness and non-stick properties, PFA film is widely used in the chemical and semiconductor industries as well as food processing and general advanced processing applications. Taking advantage of the elevated temperature resistance, higher flex life (10 times that of FEP), stiffer mechanical properties and low coefficient of friction compared to FEP, these are reasons PFA is used in the 3D printer industry as a release film.

FEP film (Fluorinated ethylene propylene)

 A transparent copolymer of hexafluoropropylene and tetrafluoroethylene, it also was developed by DuPont as a melt processable form of PTFE (Table 1). It is chemical resistant with excellent UV transmission (96%), has good flexibility and is resistant to elevated temperature up to 205 °C which is below that of PFA and nFEP. Representing the family of fluoropolymers, it too has excellent non-stick capabilities. FEP is used extensively as a wire coating to take advantage of its electrical resistance.  It’s non-stick properties and heat resistance makes FEP film the material of choice for release film in composite construction. The versatility of FEP means that it is called for in a wide diversity of applications and industries, including heat shrinkable sleeves for the Paper and Packaging Industries, tubing and sheet for chemical industry applications, vacuum formed components for Aerospace applications and UV resistant protection of lamps. In the market of fluoropolymers, FEP is more economically priced compared to other fluoropolymer materials (e.g., PFA).

Non-FEP Film (nFEP)

Reports suggest non-FEP (nFEP) is a specially treated FEP film that is transparent and has an exceptionally smooth texture (Phrozen, 2022). A further report suggests nFEP and PFA returned a similar trace when overlaid and analysed using Fourier-Transform Infrared spectroscopy (FTIR) (Figure 1), so it is possible PFA has been rebranded nFEP for the 3D printer release film market (Engineering 360, 2016). The texture is reported to be smoother than FEP and has an improved air permeability compared to FEP. In the 3D printer industry, nFEP appears to also encourage reduced printer failures resulting in a superior quality final model compared to FEP (Epax, 2022). nFEP has a light transmittance of 95% and can endure a continuous temperature of 260 °C. This temperature value is comparable to PFA and PTFE but much higher than FEP (205 °C). It should be noted that to obtain more reliable material property information, further customer trials and analysis would be required as this is currently not available from the manufacturer.

Figure 1 FTIR trace – Epax nFEP overlaid with PFA.

So, what material is better?

This depends a bit on your needs and expectations. If price is the most important and you only print infrequently, we feel the well proven option of FEP will suit your needs. In general, for 3D printing these thicknesses are commonly used:

• FEP film in 50 micron thick – for one-off printing such as dental applications
• FEP film in 100 micron thick
• FEP film in 127 micron thick

If a higher temperature or stiffer mechanical properties are desirable probably a PFA film will be more suitable as we do not have sufficient data on the nFEP material as you can see in Table 1 below.

• PFA film in 50 micron thick – for one-off printing such as dental applications
• PFA film in 100 micron thick
• PFA film in 127 micron thick

Table 1 Targeted material comparison summary.

Is nFEP the same as PFA?

As previously mentioned in the nFEP section, it is possible PFA has been rebranded as nFEP. However, more technical data is available for PFA compared to nFEP as the Japanese manufacturer of nFEP is reluctant to release more data. We believe customers are more likely to purchase PFA 3D printer release film from a reliable source where material test data is readily available. However, as full data has not been released, it is hard to say whether nFEP and PFA are the same. We do however see from our findings and open-source research that the properties are remarkably similar and PFA is slightly cheaper than nFEP.