Assessing the influence of four cutting methods on the thermal contact resistance of open-cell aluminum foam

The application of open-cell aluminum foam often involves a cutting operation to the desired shape and dimensions. Depending on the applied cutting method, this operation can result in a significantly different contact surface area between the foam and a substrate, and a substantial plastic deformation of the struts near the cutting plane. Both are characterised for four cutting methods: circular saw, band saw, sawing wire and electron discharge machining. The first two methods result in a significant local compression. No compression is observed with the other two methods. However, the eroding nature of electron discharge machining results in blunt strut-ends which minimise the contact surface area. The highest contact surface area is obtained with a sawing wire cut.The thermal contact resistance is deduced from experimental data obtained from a press-fit bonding with 0.5 MPa pressure between foam and substrate. Data analysis is done via a conventional zeroth-order thermal resistance model. The highest thermal contact resistance is found for a sample cut with a circular saw. Cutting with band saw reduces this with 25%, electron discharge machining yields a reduction of 36% and sawing wire results in 64% reduction of the press-fit thermal contact resistance.