The Correctional Services Department has recently transformed the existing mask factory at Shek Kong Correctional Institution into the first "3D Printing Material Workshop," aiming to integrate green and technological elements into the inmate rehabilitation process. From October 2025, the workshop will adopt a "one-stop" production model, covering raw material handling, printing material manufacturing, product design, final printing, and packaging components. The department has partnered with City University of Hong Kong, utilizing patented technology to convert waste materials into 3D printing substrates, using coffee grounds provided free of charge by chain coffee shops and correctional training facilities for food recycling. Inmate industrial production thus becomes part of the waste-to-resource initiative, giving second lives to waste products. Correctional Services Deputy Director (Industrial Group II), Kenny Pun, stressed the importance of equipping the workshop with the latest 3D design software and printing technology to enhance inmates' creative work. Together with correctional staff, inmates are encouraged to use professional software for modeling and leverage artificial intelligence to refine their designs, producing more innovative products. Additionally, design faculty mentors from the City University of Hong Kong provide training in design and sketching skills, further enhancing inmates' professional knowledge. A prototype of the prison's 3D printed coffee grounds channel cover is showcased.