Dexmet PolyGrid 8PTFE10-125ST Expanded PTFE

Laser Processing of Dexmet PolyGrid® 8PTFE10-125ST Expanded PTFE

Introduction

Dexmet PolyGrid® 8PTFE10-125ST, a flexible, thin gauge, expanded PTFE mesh sheet is part of a product line of precision-expanded plastics. The PolyGrid 8PTFE10-125ST selected for testing is comprised of a 300µm thick PTFE mesh sheet. A diagram depicting PolyGrid 8PTFE10-125ST is shown in Figure 1.

Dexmet PolyGrid 8PTFE10-125ST Expanded PTFE Layers

Figure 1. PolyGrid 8PTFE10-125ST diagram illustrating the PTFE sheet (300µm thick).

Dexmet PolyGrid 8PTFE10-125ST is used in applications ranging from battery manufacturing and aerospace engineering, to the automotive industry. It is used in electrolyzers, fuel cells, battery electrodes, EMI shielding, medical devices, as a filter media, and in chemical processing applications requiring membrane support. PolyGrid 8PTFE10-125ST is only suitable for laser cutting, which produces consistent ledges and minimal heat-affected zones. The non-contact nature of laser processing enables PolyGrid 8PTFE10-125ST applications with small features and fine geometry to be cleanly cut, which may be difficult to achieve with traditional mechanical methods. Other laser processes are not recommended as they are not conducive to the intended use of this material. Technology available from Universal Laser Systems (ULS) makes it possible to consistently and repeatedly process this material to a high degree of dimensional accuracy with virtually no material deformation during processing.

Laser Processing Notes

Dexmet PolyGrid 8PTFE10-125ST was tested to assess laser processing compatibility and to determine the best configuration of peak laser power and wavelength. PolyGrid 8PTFE10-125ST appears to absorb both the 9.3µm and 10.6µm CO₂ laser wavelengths efficiently but with observable differences in processing results. Based on testing, it was determined that the 9.3 wavelength produced better results. A microscopy image taken at 300x magnification of PolyGrid 8PTFE10-125ST after laser cutting with a 75 watt 9.3µm CO₂ laser source is shown in Figure 2.

Dexmet PolyGrid 8PTFE10-125ST Expanded PTFE Figure 2

Figure 2. Microscopy image (300x) of the edge after laser cutting PolyGrid 8PTFE10-125ST. The heat-affected zone measures 25µm.

PolyGrid 8PTFE10-125ST mesh was tested with both 9.3µm and 10.6µm laser wavelengths. The results of these tests were compared by analyzing the heat effects, edge quality, and post-processing requirements. The comparison of these two system configurations is listed in tabular form in Table 1 and shown photographically in Figure 3. The 9.3µm configuration produces a noticeably better edge when laser cutting this material and is the recommended configuration.

Table 1. System Configuration Comparison

System Configuration	Heat-Affected Zone	Process Characteristics	Post-Processing Requirements
9.3µm (Recommended)	Minimal heat-affected zone of approximately 25µm	This configuration results in a smooth edge that exhibits minimal heat effects and no discoloration	No post-processing is required
10.6µm	Minimal heat-affected zone of approximately 40µm	This configuration results in an edge that exhibits increased heat effect and roughness	No post-processing is required

Dexmet PolyGrid 8PTFE10-125ST Expanded PTFE Figure 3

Figure 3. Microscopy images (300x) of the edge resulting from the 9.3µm laser wavelength (left) and 10.6µm laser wavelength (right).

Processing Example

PolyGrid 8PTFE10-125ST applications requiring fine geometry and intricate detail without degrading the physical properties of the material can be achieved with ULS technology. An example demonstrating the results of laser cutting PolyGrid 8PTFE10-125ST using the recommended system configuration is shown in Figure 4.

Dexmet PolyGrid 8PTFE10-125ST Expanded PTFE Figure 4

Figure 4. Example of the geometry possible when laser cutting PolyGrid 8PTFE10-125ST.

Conclusion

Dexmet PolyGrid 8PTFE10-125ST is suitable for laser cutting and was extensively tested to determine the optimal processing configuration. Through this testing it was determined that laser cutting is viable with this material and that a 75 watt 9.3µm CO2 laser source is the recommended configuration. PolyGrid 8PTFE10-125ST efficiently absorbs the 9.3µm laser wavelength to produce an edge that has a minimal heat-affected zone and nominal discoloration.