Introduction

Henkel Bergquist™ Hi-Flow® 105 is part of a product line of hi-flow phase change materials (PCMs) that includes 225F-AC, 225UT, 225U, 625, 300P, 300G, 565U, 565UT, and 650P. The Henkel Bergquist Hi-Flow 105 sheet product selected for testing consists of three layers totaling 139µm thick. The center layer is a 137µm thick aluminum reinforcement carrier. On each side of the reinforcement carrier there is a PCM layer measuring approximately 2µm thick. A diagram depicting Henkel Bergquist Hi-Flow 105 is shown in Figure 1.Henkel Bergquist Hi-Flow 105 PCM has a phase change temperature of 65ºC and is designed to replace grease as a thermal interface when electrical isolation is not necessary. The non-contact nature of laser processing enables applications with small features and fine geometry to be processed, which may be difficult to achieve with traditional mechanical methods. Bergquist Hi-Flow 105 is only suitable for laser cutting that produces smooth, laser processed edges and minimal heat-affected zones without degrading the physical properties of the material. Other laser processes are not suggested as they are not conducive to the intended use 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

Henkel Bergquist Hi-Flow 105 PCM was tested to assess laser processing compatibility and to determine the best configuration of peak laser power and wavelength. Bergquist Hi-Flow 105 PCM absorbs 9.3µm energy more efficiently than other wavelengths available from Universal Laser Systems, meaning less peak power was necessary to produce good results with minimal heat effects. The aluminum reinforcement carrier absorbs the 1.06µm wavelength more efficiently than other wavelengths. The combination of 9.3µm and 1.06µm laser wavelengths in the MultiWave Hybrid™ system configuration, which combines the two wavelengths into one simultaneous beam, produces a smooth processed edge with minimal heat effects. The 1.06µm laser is able to effectively process the aluminum, while the 9.3µm laser clears away the Hi-Flow 105 material. A 300x magnification microscopy image of the processed edge of Bergquist Hi-Flow 105 PCM is shown in Figure 2. The 3D image in Figure 3 depicts how the PCM reacts to the laser energy by forming a small “wave” of melted material along the top surface of the processed edge (red area).Bergquist Hi-Flow 105 was tested with three alternate system configurations, a 1.06µm laser combined with a 9.3µm laser, a 10.6µm laser combined with a 1.06µm laser and a 1.06µm laser alone. The results of these tests were compared by analyzing the heat affects, the processed edge quality, and post-processing requirements. The results of the comparison of these system configurations are listed in tabular form in Table 1 and shown photographically in Figure 4. As stated in the comparison, all three of the configurations appear to be viable, but the MultiWave Hybrid system configurations produce better results with the 1.06µm and 9.3µm configuration. The MultiWave Hybrid 1.06µm and 10.6µm configuration results in some reduction in quality, as stated in the comparison.Processing Example

Bergquist Hi-Flow 105 applications requiring fine geometry and intricate detail without degrading the physical properties of the material can be accomplished with Universal Laser Systems MultiWave Hybrid technology. An example demonstrating the results of laser processing Bergquist Hi-Flow 105 PCM using the recommended system configuration is shown in Figure 5.Conclusion

Bergquist Hi-Flow 105 is suitable for laser processing and was extensively tested to determine the optimal processing configuration. Through this testing it was determined that laser processing is viable with this material, and a 75 watt 9.3µm CO₂ laser source, combined with the 50 watt 1.06µm fiber laser source using MuliWave Hybrid technology, is the best system configuration for the processing of this material. The Hi-Flow 105 PCM efficiently absorbs the 9.3µm wavelength laser energy while the aluminum reinforced carrier absorbs the 1.06µm laser energy to produce a clean edge with minimal heat-affected zone and discoloration.