Laser Processing of Isovolta ISONOM® NMN 0881 Flexible Film

Introduction

ISONOM® NMN 0881 flexible film is part of a product line of paper and film laminates produced by Isovolta. ISONOM NMN 0881 is a three-ply laminate film comprised of a PET film layer laminated between two layers of DuPont Nomex Type 464, a light-weight insulating calendared paper. Each of the three layers are 50µm thick totaling 150µm in thickness. A diagram depicting ISONOM NMN 0881 is shown in Figure 1.
Isovolta ISONOM NMN 0881 Flexible Film Layers

Figure 1. ISONOM NMN 0881 diagram illustrating the Nomex layers (50µm each)
on top and bottom and the PET layer (50µm) in the middle.

ISONOM NMN 0881 is mainly utilized in battery production as slot liners, slot closures, and phase insulation for low-voltage motor production, and is frequently used as an interlayer insulation in transformers and other electrical machines and appliances. The Nomex component of ISONOM NMN 0881 provides physical toughness, and PET contributes to the exceptional electrical performance of polyester, enabling ISONOM NMN 0881 to perform in demanding electrical applications. ISONOM NMN 0881 can be used in electrical environments with temperature ratings up to 311°F/155ºC. This material combines mechanical properties such as high tensile strength and edge tear resistance with high electrical insulation performance.

ISONOM NMN 0881 is suitable for laser cutting; however other laser processes are not suggested as they are not conducive to the intended uses of this material. Universal Laser Systems makes it simple to consistently and repeatedly process this material to a high degree of dimensional accuracy as the non-contact nature of laser processing eliminates material deformation during processing.

Laser Processing Notes

ISONOM NMN 0881 was tested to assess laser cutting compatibility and to determine the best configuration of peak laser power and wavelength. The film laminate ISONOM NMN 0881 appears to absorb both the 9.3µm and 10.6µm CO2 laser wavelengths efficiently with slight differences in processing results. A microscopy image taken at 300x magnification of the edge of ISONOM NMN 0881 is shown in Figure 2. The 3D image in Figure 3 depicts how the film responds to laser cutting with the recommended system configuration of a single 75 watt 9.3µm CO2 laser source.
Isovolta ISONOM NMN 0881 Flexible Film Figure 2

Figure 2. Microscopy image (300x) of the edge of ISONOM NMN 0881. The heat-affected zone measures 60µm.

Isovolta ISONOM NMN 0881 Flexible Film Figure 3

Figure 3. 3D-rendered microscopy image (300x) of the ledge of ISONOM NMN 0881.

ISONOM NMN 0881 film was tested with both 9.3µm and 10.6µm CO2 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 4. 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 ConfigurationHeat-Affected ZoneProcess CharacteristicsPost-Processing Requirements
9.3µm (Recommended)Minimal heat-affected zone of approximately 60µm This configuration results in a smooth edge that exhibits minimal heat effects and discoloration No post-processing is required
10.6µmMinimal heat-affected zone of approximately 50µmThis configuration results in increased discoloration and rougher surface texture along the edge
Isovolta ISONOM NMN 0881 Flexible Film Figure 4

Figure 4. Microscopy images (300x) of the edge resulting from the 9.3µm wavelength (left) and 10.6µm wavelength (right).

Processing Example

ISONOM NMN 0881 applications requiring fine geometry and intricate detail with no degradation of the physical properties of the material can be achieved with ULS technology. An example demonstrating the results of laser cutting ISONOM NMN 0881 using the recommended system configuration is shown in Figure 5.
Isovolta ISONOM NMN 0881 Flexible Film Figure 5

Figure 5. Example of the geometry possible when laser cutting ISONOM NMN 0881.

Conclusion

ISONOM NMN 0881 flexible film is suitable for laser processing 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. ISONOM NMN 0881 efficiently absorbs the 9.3µm laser wavelength to produce an edge that has a minimal heat-affected zone and nominal discoloration.