Although Industry 4.0 and the Internet of Things (IoT) have been implemented in various manufacturing sectors, medium and small enterprises have limited integrations with this strategy, especially those that still rely on conventional production lines and lack the capacity for transition in near future. This paper presents a work demonstrating how conventional production lines could be upgraded for implementing an Industry 4.0 strategy, using plastic injection moulding as a case study. This transformation helps to achieve a real-time optimised value chain, considering factors such as cost, availability, and resource consumption, while the implementation cost is kept low.