Laser Cutting of 3M™ XYZ-Axis Electrically Conductive Adhesive Transfer Tape 9719

Introduction

3M™ XYZ-Axis Electrically Conductive Adhesive Transfer Tape (ECATT) 9719 is part of a product line of similar materials including 9703, 9705, 9706, 9709, 9709S and 9709SL. The 9719 ECATT product consists of a 100µm thick silicone adhesive layer filled with an electrically conductive scrim comprised of non-woven nickel plated carbon fibers that allow electrical continuity between substrates through the silicone adhesive layer, and additionally provide electrical continuity through the thickness (Z-axis) and in the plane of the adhesive (X-Y planes). The silicone adhesive layer itself is protected with 50µm thick PET release liners on both the top and bottom surfaces. A diagram depicting the layers of the 9719 material is shown in Figure 1.
3M XYZ-Axis Electrically Conductive Adhesive Transfer Tape 9719 Layers

Figure 1. ECATT 9719 diagram showing PET liners located on top and bottom of the silicone adhesive layer. PET layers measure 50µm thick, and the silicone adhesive layer measures 100µm thick.

3M ECATT materials are flexible adhesive tapes. The delicate tacky nature of these materials makes them difficult to process, resulting in deformation of the materials when processed with traditional mechanical methods. The non-contact nature of laser processing overcomes this difficulty, which enables the processing of applications with fine geometry and intricate detail. 3M ECATT materials are only suitable for laser cutting that produces smooth laser-processed edges and minimal heat-affected zones, without degrading the physical properties of the materials. Other laser processes are not suggested as they are not conducive to the intended use of these materials. Universal Laser Systems makes it simple to consistently and repeatedly process these materials to a high degree of dimensional accuracy because the non-contact nature of laser processing eliminates material deformation during processing.

Laser Processing Notes

3M 9719 ECATT was tested to assess laser processing compatibility and determine the best system configuration of laser peak power and wavelength. The PET liners absorb 9.3 micron energy more efficiently than other wavelengths, meaning less peak power was necessary to produce good results with minimum heat affects. The silicone adhesive layer also absorbs the 9.3 micron wavelength efficiently with clean edges free of heat effects along the processed path. Microscopy images taken at 300x magnification of the processed edge of the 9719 post-processing, with the liners in place and the liners removed, are shown in Figures 2 and 3, respectively. In these images it is shown that the PET liners contain most of the heat affects and discoloration, while the silicone adhesive layer itself is relatively free of heat effect and discoloration.
3M XYZ-Axis Electrically Conductive Adhesive Transfer Tape 9719 Figure 2

Figure 2. Microscopy image (300x) of the laser- processed edge of 3M ECATT 9719 with the PET liners in place. The heat-affected zone measures 110µm.

3M XYZ-Axis Electrically Conductive Adhesive Transfer Tape 9719 Figure 3

Figure 3. Microscopy image (300x) of the laser- processed edge of 3M ECATT 9719 with the PET liners removed from the material post-processing. The heat-affected zone measures 65µm.

Further inspection of the laser-processed material shows that the silicone adhesive layer is cleanly processed along the laser cutting path with the 30 watt 9.3µm CO2 laser source. Figures 4 and 5 depict 3D-rendered microscopy images of the processed surfaces shown in Figures 2 and 3. Figure 4 shows that the PET layer reacts to the laser energy by forming a “wave” of melted material along the top surface of the processed edge. In Figure 5 the PET liners are removed from the material, showing the smooth flat surface and laser processed edge of the silicone adhesive layer, free of adverse heat effects.
3M XYZ-Axis Electrically Conductive Adhesive Transfer Tape 9719 Figure 4

Figure 4. 3D-rendered microscopy image (300x) of the laser-processed edge of the ECATT 9719 with the PET liners in place.

3M XYZ-Axis Electrically Conductive Adhesive Transfer Tape 9719 Figure 5

Figure 5. 3D-rendered microscopy image (300x) of the laser-processed edge of the ECATT 9719 with the PET liners removed.

3M 9719 ECATT was also tested with an alternate system configuration of 10.6 micron laser energy at equivalent laser power level for comparison and determination of the effectiveness of each system configuration. The results of these tests were compared by analyzing the heat effects, quality of the processed edge, and post-processing requirements. The results of the comparison of these system configurations are listed in tabular form in Table 1 and are shown photographically in Figure 6a and 6b. Both system configurations appear viable with some reduction in quality of the results for the 10.6 micron configuration as stated in the comparison.

Table 1 System Configuration Comparison

System ConfigurationHeat-Affected ZoneProcess CharacteristicsPost-Processing Requirements
9.3 Micron (Recommended)Minimal heat-affected zone of approximately 110µm The 9.3 micron laser energy has the advantage of better absorption by the material resulting in a consistent edge along the processed path with a reduced heat-affected zone Processing of the 3M 9719 material with either the 9.3 micron or the 10.6 micron configuration did not require additional post-processing
10.6 MicronIncreased heat- affected zone compared to 9.3 micron wavelength, approximately 180µmThis configuration results in an increased heat-affected zone in the PET liner and produces a rougher edge along the processed path in the adhesive layer when compared to the 9.3 micron configuration
3M XYZ-Axis Electrically Conductive Adhesive Transfer Tape 9719 Figure 6a

Figure 6a. Comparison microscopy images (300x) of the processed edge resulting from 9.3 micron processing. The PET liner was left in place.

3M XYZ-Axis Electrically Conductive Adhesive Transfer Tape 9719 Figure 6b

Figure 6b. Comparison microscopy images (300x) of the processed edge resulting from 10.6 micron processing. The PET liner was left in place.

Processing Example

3M ECATT adhesive tape applications requiring fine geometry and intricate detail without degrading the physical properties of the material can be achieved with Universal Laser Systems technology. An example demonstrating the results of laser cutting the 3M ECATT 9719 material is shown in Figure 7.
3M XYZ-Axis Electrically Conductive Adhesive Transfer Tape 9719 Figure 7

Figure 7. Example of laser cutting 3M ECATT 9719.

Conclusion

3M 9719 ECATT is suitable for laser processing and was extensively tested to determine the most efficient processing configuration. Through this testing, it was determined that laser cutting is viable with this materia, and a 30 watt 9.3 micron CO2 laser source is the best configuration of wavelength and power for the processing of this material. The PET liners and silicone adhesive layer efficiently absorb the 9.3 micron wavelength laser energy, and, coupled with the peak power of the 30 watt laser source, produce a clean smooth processed edge that has minimal heat-affected zone and discoloration. Other materials in this ECATT product line are expected to process similarly.