Ultrasonic injection moulding or ultrasonic micromoulding has emerged as a novel replication technique of microparts and micro-features for polymeric materials in the recent years. In this new approach of micromoulding, the melting of the polymeric feedstock is completed in the fractions of a second whereas conventional micromoulding techniques involve barrel heaters and residence times of molten material. Hence, the degredation problems of the temperature sensitive materials could be avoided by controlling the heating or melting process carefully. This would give the technique a significant advantage in manufacturing of micro parts, pharmaceutical devices, and functional surfaces. In this work, replication capabilities of ultrasonic moulding is investigated using a nanosecond laser machined mould insert that have different features on micron scale. Thermal imaging techniques were used for the flow visualisation in the mould cavity and temperature distributions are correlated with the replication quality of the final parts. The quality of the parts were also compared with conventional state-of-the art micromoulding machines.