In recent years, there has been an increment on micro-components for medical purposes, diseases treatment and surgical equipment, requiring biocompatible materials such as some engineering polymers. Nonetheless, the micro size of these parts impose challenges for fabrication using high production processes, like polymer injection moulding submitted to high cooling rates and variability of the process, in addition to the complex design of precise mould micro-cavities. This paper presents the development of a complete mould for a polymer locking ligation system fabrication, a medical device selected as a case study for micro-injection moulding tooling. This development includes the prediction of appropriate injection parameters and process conditions using computer simulations and a comparison with real values of pressure and temperature during the process, due to data acquisition with piezoelectric sensors. The results show a moderate error between experimental and simulated results, in terms of pressure (0.05% prediction error) and average cycle temperature at the sensor location (13% prediction error), which proves that the proposed approach can be used for precision micro-injection moulding applications