PTFE laser material processing

Gasket made out of PTFE

PTFE is a synthetic polymer used in many fields. The acronym stands for Polytetrafluoroethylene, but it is better known under trade names such as Teflon or Algoflon. It appears as a plastic material, usually white in color though it can be colored black with additives. It can be used alone or in combination with other polymers.

PTFE belongs to Perfluorocarbons, a class of polymers composed mainly of fluorine and carbon chains.

Their chemical composition offers a wide range of properties which include:

  • Non-stickiness
  • Waterproof
  • Resistant to chemicals
  • Resistant to fire and high temperatures
  • High insulating power
  • Smooth

The applications are numerous. It is most commonly known for its use as a anti-coating material for kitchenware. But PTFE is also used to create gaskets, insulating tapes and in any other place where a component that reduces friction and resists corrosive agents is needed.

The fact that it is mainly composed of carbon makes it perfectly compatible with the CO2 laser wavelength. Laser cutting, perforation, marking and engraving on PTFE is easy and gives excellent results.

The interaction between PTFE and CO2 laser

The results obtained with the interaction between CO2 laser and PTFE are affected most by its high insulating power.

In general, when the laser beam reaches the surface of a material, it concentrates a very high energy in a single point. According to the characteristics of the material used, different chemical or physical transformations occur.

In the case of PTFE, the energy generated by the laser breaks the molecular bonds of the fluorine and carbon chains causing the chemical transformation of the material (laser marking) or its removal (laser cutting and engraving processes).

As previously mentioned, PTFE is a material with excellent insulating properties. It therefore absorbs heat at the point of contact with the laser without dispersing it in the surrounding area. It also has a high melting point. Both of these characteristics highly influence the laser’s behavior. The poor thermal conductivity combined with the high melting point mean that the HAZ (Heat-Affected Zone) is very reduced. It is limited to the point of contact between the laser beam and the material.

As a result, laser processing on PTFE is very precise and clean. The chances of accidentally damaging the material or creating blackened or burned areas are very low. The fact that PTFE absorbs CO2 laser energy very well also makes processing very efficient in terms of speed.

PTFE Laser cutting

In laser cutting, the beam is used to remove material along a predefined cutting path. The removal of the material occurs by sublimation: the energy generated by the laser is concentrated in a very small area, and it is precisely the high energy density that causes the instantaneous passage of the material from the solid state to the gaseous state.

Laser cutting is used in many activities such as creating openings in a material, cutting out shapes from a sheet of material, making pieces from a matrix.

The peculiarity of the cut on PTFE is that the cutting edges are clean and perfectly finished and the obtained piece therefore does not require any further work. Laser cutting makes it possible to follow highly complex cutting paths.

PTFE Laser drilling

Laser drilling is a variant of laser cutting.

In this process the laser is used to create a hole in a sheet of material, just like a mechanical drill would do. Laser perforation doesn’t suffer from the same limitation of traditional mechanical processing.

Microscopic holes can be created with laser technology. They can range in size from a fraction of a millimeter to the maximum area the machine’s design characteristics allow.

In addition, with laser technology, all the processing parameters (the inclination of the walls of the hole, the taper, the depth and density of the holes on the surface) can be controlled with great precision. It is possible to create pieces with all the characteristics best suited to the function they must perform. In the case of a filter, for example, holes can be created with precise dimensions, shape and arrangement.

PTFE Laser marking and engraving

PTFE also lends itself well to laser marking and engraving processes. These two processes are typically used to emboss logos, alphanumeric codes, barcodes or QR codes and various types of information on a particular material.

Marking and laser engraving, on the other hand, are similar processes even if the processing mechanism is different.

Both processes are based on the interaction between the laser beam and the surface of the material, but in laser marking, a chemical transformation of the material takes place, while for laser engraving, just like in laser cutting, the material is removed. Marking takes place on the surface: the material is transformed to create a contrast with the area that surrounds it. In engraving, on the other hand, the laser creates a groove in the material, the mark is carved into its surface.

The choice of one process over another depends on the type of application or material being used.

On white PTFE, for example, laser marking gives poor results because the mark does not have enough contrast to create a sufficiently visible mark. As mentioned, PTFE has a high melting point, so it is difficult to create burn marks.

Oppositely, on black PTFE, marking is more successful. At high temperatures PTFE expands and a white mark appears in contrast with the surrounding black.

Laser engraving, on the other hand, can be performed on any type of PTFE with optimal results. As we have said, PTFE is an excellent absorber of the CO2 laser wavelength, but also a bad conductor of heat. This ensures that the area affected by heat is limited to the point of interaction between the laser and the material, resulting in a very precise and clean engraving.

Write to us to know more about how to process PTFE with CO2 laser.

Each laser application has its own particularities. There is no rule that applies to all circumstances and all materials. To find a solution that suits your needs, contact us, and we will be happy to find the best solution for you.