Friction plays an important role in forming processes of thermoplastic laminates. A model is currently developed to predict the frictional properties of these materials and validation experiments are being conducted. The development of a friction measurement rig for thermoplastic composites is not straightforward. Controlling the transverse pressure profile on the laminate is essential for accurate measurements. Mould deflections and the setup type used (pull-out versus pull-through) have a significant effect on homogeneity of the profile. This is validated by measurements of the pressure profile and analyses of the experimental setup. In turn, the inhomogeneity of the pressure profile can make the experimentally obtained friction properties unsuitable for model validation.