PTFE (Teflon) Plastic Machining

Your guide to PTFE Plastic Machining

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Excellent chemical resistance

Semi-crystalline fluropolymer thermoplastic

Widely used fluropolymer in a range of applications

PTFE (Polytetrafluoroethylene) is a semi-crystalline fluropolymer thermoplastic. It is commonly referred to as Teflon which is a brand name. There can be some challenges to machining PTFE due to its high coefficient of expansion, and its conductivity. A skilled and experienced CNC machining partner is imperative.

This guide will take you through the main attributes, common applications, notes for designers and suitable finishing and treatments, as well as UK stock sizes and property tables. Don't forget to bookmark the page so you can refer back later.

If you are interested in PTFE machined parts, please scroll to the bottom of the page for more information about our service and to request a quote.

PTFE Guide: Properties, Applications and Design Considerations

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What is PTFE plastic?

PTFE (Polytetrafluoroethylene) is a semi-crystalline fluropolymer thermoplastic. It is commonly referred to as Teflon which is a brand name.

PTFE is the most widely used fluropolymer in a range of applications. It is known for being highly resistant to chemicals and for its superior thermal stability.

Compared to other engineering grade thermoplastics it has poor mechanical properties, though glass and carbon filled grades with improved dimensional stability are available.

Because of its resistance to chemicals, PTFE plastic is commonly used in chemical, food and pharmaceutical engineering.

PTFE is favoured over PVDF for sliding applications with exposure to extreme chemical stress.

Machining of PTFE must take conductivity and expansion effects into account. When machining PTFE, we ensure we use very sharp tools and plenty of coolant to avoid any stability issues.

You may also see PTFE referred to as:

Teflon®
TECAFLON™

Main Attributes:

Excellent chemical resistance
Good electrical insulating properties
Wide working temperature from -260°C to 260°C
Poor mechanical properties – glass and carbon filled modifications available to improve dimensional stability

Low flammability
High UV and weather resistance
Suitable for food contact
Water resistant
High impact strength
Very low coefficient of friction
No moisture absorption

Note For Designers:

Due to its high coefficient of expansion, PTFE is usually machined to tolerances of around 0.13mm.

Tighter tolerances are rarely required due to the natural resiliency of the material. Where tighter tolerances are required, it is advised to use stress-relieved PTFE.

Can we meet your PTFE plastic machining needs? Contact us now

UK Stock Sizes

PTFE UK Stock Sizes

Here are the standard stock sizes/colours for PTFE in the UK. Please note we do not supply stock material, the information provided is purely for design and research purposes.

Example PTFE Stock Sizes

Stock sizes will vary depending on supplier. Please get in contact to discuss further.

PTFE is typically available in rod and plate form in lengths of 2000mm and 1200mm.

PTFE Rod

From 4 to 160mm
White (natural)

PTFE Plate

From 1x1200mm to 100mmx1200mm
White (natural)

Please note: some sizes may be non-stocked items and subject to minimum order quantities.

Technical Properties

PTFE Technical Properties

Here are the properties for TECAFLON PTFE natural which is an unfilled, unreinforced PTFE brand. Reinforced and modified grades will have different properties.

TECAFLON PTFE Properties

Mechanical Properties	Value	Parameter	Norm	Notes
Tensile Strength	22 MPa		ASTM D 4894	Tested on extruded and machined specimen
Elongation at Break	220%		ASTM D 4894	Tested on extruded and machined specimen
Compression Strength	5 MPa	1% strain	ASTM D 695
Shore Hardness	55	Shore D	ASTM D 2240

Thermal Properties	Value	Parameter	Norm	Notes
Glass Transition Temperature	-20°C		DIN EN ISO 11357	Found in public sources
Service Temperature	260°C	short term		Found in public sources. Individual testing regarding application conditions is mandatory
Service Temperature	260°C	long term
Thermal Expansion (CLTE)	13 10^-5 K^-1	23-100°C, long	ASTM D 696
Thermal Conductivity	0.20 W/(K*m)		ASTM C 177

Electrical Properties	Value	Parameter	Norm	Notes
Specific Surface Resistance	10¹⁶ Ω		ASTM D 257	Without defects
Specific Volume Resistance	10¹⁷ Ω*cm		ASTM D 257
Dielectric Strength	80 kV/mm	In air, 0.125mm thick	ASTM D 149
Dielectric Constant	2.1	50-109Hz	ASTM D 150

Other Properties	Value	Parameter	Norm	Notes
Water Absorption	<0.01%	23°C	ASTM D 570
Flammability (UL94)	V0	Corresponding to	DIN IEC 60695-11-10	Corresponding means no listing at UL (yellow card). The information might be taken from resin, stock shape or estimation. Individual testing regarding application conditions is mandatory.
Density	2.15 g/cm³