Mistake Proofing Cam Mechanism Through Six-sigma Process: Case Study on Clothes Printing Machines


1 Mechanical Engineering Department, Faculty of Engineering (Shoubra), Benha University, Egypt

2 Production Engineering and Mechanical Design Department, Faculty of Engineering, Menofia University, Egypt


Controlling the occurrence of defects is a major challenge for manufacturing organizations that are seeking to enhance their competitive position in today’s global market. This paper considers the process of screen-printing T-shirts using hydraulic and pneumatic printing machines. Several defects in the output of this printing process have been observed, especially with multi colors printing as well as maintenance problems. The six-sigma DMADV approach has been implemented to improve the process performance. Modifications of the current printing machine design using mistake proofing principles that have been proposed to prevent or diminish the occurrence of defects. The analysis indicates that manipulation of wrong oriented products of T-shirts printing machines can be considered as the main effective problem results from machines that are driven by hydraulic or pneumatic systems. Consequently, the quality level and productivity are affected. Moreover, some stained products with leakage fluid from the hydraulic systems can appear. Relying on the DMADV process, an effective mechanical mechanism using Geneva cams was used for diminishing these problems. Geneva cams prototype is manufactured to be used in printing machines instead of the hydraulic or pneumatic systems. A prototype of the cams mechanism is used for testing and validating the presented idea.