Thin-wall technology: A case study of notebook computer mold design

The computer notebook industry is continually focusing on making notebook computers more lightweight. Part of the weight reduction comes from thinning the notebook housing wall thickness which is slowly approaching 1mm. At this time the industry is presently molding notebook cover housings at 1.5mm with one gate. However, as wall thickness decreases, more gates are required to fill. the parts. Multiple direct gating through a hot runner system and valve gated drops are required. The gating should be on the backside of the part which will require reverse gating and "a" side ejection. This type of gating can also produce undesirable weld lines and gate witness marks which both contribute to poor surface aesthetics. GE plastics developed a thinwall PC notebook test mold to understand thinwall processing in high now length to wall thickness applications. This paper is a case study of how we progressed through the development of the notebook tool and some of the pitfalls encountered.