Stroke represents a major cause of disabilities worldwide, with over 17 million individuals affected globally. Robotic hand rehabilitation devices offer a promising solution for therapy due to the reduced number of rehabilitation specialists. This research presents the development of an innovative hand rehabilitation device that embeds rigid materials into a soft body using PolyJet 3D printing technology. A comprehensive analysis of index finger and thumb biomechanics was performed using the OptiTrack motion capture system. Based on the captured data and anthropomorphic dimensions, a parametric customizable finger module was developed. A dual-cable actuation system mimics the natural pathways of the tendons, with palmar cables for flexion and dorsal cables for extension. The device was tested using various objects with different shapes and sizes and successfully performed all the grasps while maintaining user comfort. This work contributes to soft rehabilitation robotics by developing a modular, customizable, cost-effective rehabilitation design that can improve the practical implementation of this kind of device and enable personalized rehabilitation tailored to each individual's requirements and rehabilitation goals.