Add powder injection molding (PIM) to the list of candidate processes for making smart phone covers stronger and less expensive.
Machine builder Arburg and chemicals’ giant BASF formed a joint venture to develop a material and process to produce housing components for smartphones. The concept was first demonstrated at the World PM2016 Congress and Exhibition, held in Hamburg, Germany last October, and more recently at Arburg’s in-house technology fair in Lossburg, Germany, last month.
“The booming international smartphone market offers huge potential for powder injection molding because this process enables the use of materials such as stainless steel, titanium and zirconium oxide, requires much lower material volumes and is significantly more cost-effective than machining,” says Hartmut Walcher, PIM expert at Arburg,
A hydraulic Allrounder 470 S with a clamping force of 10 tons produced the components from a flow-optimized Catamold 17-4 PH Plus from BASF in Hamburg. A lightly larger press was used in Lossburg. A changeable hot runner mold featuring liquid temperature control was designed to produce a closed or four-part frame. Cycle time is about 55 seconds.
The mold temperature is dynamically controlled to help ensure a constant green density throughout the entire part. The polishable surface finish is described as very good. One goal is to minimize part distortion at a wall thickness of only around 1 mm. Part length is 136 mm.
Arburg has manufactured more than 1,000 PIM machines in the past 50 years.
Powder injection molding is a method to mass produce net shape metal or ceramic parts. Powders are mixed with a polymer binder so the material will flow into an injection mold. Parts are first injection molded (called green), and then the binder is removed and parts are “baked” in a sintering oven to remove pores created by the binder.