Ultra-high molecular weight polyethylene has been micro-scratched with 90° cube corner tips. The scratch mode was flat-on, uni-directional and single pass. The micro-scratches and cross-sectional scratch profiles were characterised with atomic force microscopy. No detached debris is produced. Cross-sectional scratch profiles have been analysed using Zum Gahr’s formalism giving an fab ratio slightly above zero. This is consistent with expectation for ductile polymers where none or little detached debris is produced. However, the observation contrasts with that for other polymers, such as PMMA, PEP and PC, for which inconclusive results suggest an excess pile-up implying an inconceivable change of mass density or material gain.