“Mobile phones went from plastic to metal, which allowed us to produce small, thin phones with big displays. Phones need to be technologically advanced, but it’s also important that their finishes meet fashion”, said Jason Wojack of Motorola, speaking at the keynote luncheon at PIM 2007. “We used aluminium on our first metal phone in order to keep the weight of the phone low. We found that in order to meet all of the specification demands [such as an effective flip function, stable hinge parts, for example], the use of MIM was the best, and in many ways, only solution”.

So why the reluctance to use MIM in the first place? “Mobile phone life cycles are very short, approximately one year. Fashions change quickly and we need to remain competitive in the market. MIM production cycles are perceived to be long and not very cost effective. MIM processes from vendor to vendor tend to be different making over-head managing of MIM parts more difficult to meet shorter development cycles” said Wojack. “But MIM was the only process that would successfully produce the part”.

MIM is used in the production of several different parts of a mobile phone. Tungsten is used for the vibrator counter weights, high strength steel is used for hinge parts, chromed steel adopted for the lanyards and side buttons and ceramics are needed for the housings. The most vital use of MIM in phones is the slider, barrel and hinge – due to its strength, only MIM was proven to survive at the cross-section.

The advancements and continuing improvements of MIM combined with mobile phone trends will result in substantial opportunities in the mobile electronic industry for MIM, said Wojack. “There is a definite lack of understanding concerning MIM, and this ignorance results in reluctance to use it”.

MIM is only used in complicated phones that slide, flip or twist. “There would be no advantage in using MIM on standard block phones, due to time and financial constraints” said Wojack.