The digital twin technology offers a tight coupling between the simulated process and the actual world events. In the field of tool wear monitoring (TWM), such system characteristic is essential to maintain the accuracy of the wear prediction by taking into account the actual condition data during the machining process. This paper presents the implementation of the digital twin technology where the micro-milling machining process is simulated by using the spindle controller, spindle motor, and cutting torque model. The wear monitoring was performed by comparing the spindle motor’s simulated and real-time electric current. A virtual environment was developed using FreeCAD - an open-source CAD system, to represent the processes and objects involved in the machining. The digital twin framework ensures that the simulation and real-time data were synchronized in the virtual environment. This paper focuses on the building blocks and technical implementation in realizing a digital twin application in the domain of micro-tool wear monitoring.