Well, following up from our survey results – you said you wanted more case studies so we thought we catch something very topical in the news this week. The injection moulded iPhone 5C polycarbonate case.
Below we talk through the manufacturing steps and have inserted images for illustration. We have missed two assembly steps of the steel rear plate and antenna that have been bonded in. Apple describes these steps as enhancing the in-hand feel of the polymer as it adds density, rigidity and perceived quality to the feeling the hand. I also remember my original polycarbonate iPhone casing had a cheap feel and did eventually crack so they have done a good thing there and automated some steps. Also with the new smaller lightning connector they have a much more mechanical stronger aperture rather than the open sided design.
It is clear and contrary to press speculation the 5C is not a cheap product and they have taken a number steps to increase in-hand perceived quality.
Injection moulding
The tool shown is likely a development tool having only 2 impressions and a cold sprue. This 2 impression tool running at 30 seconds for 120 hours per week would produce 28,800 cases and 1.38 million PA, I am sure Apple are forecasting much greater sales than that?
CNC machining of button apertures
Like Apple, where you need very accurate dimensions, a post moulding operation controlled by CNC is the solution. Kavia has customers that require machined diameters for accuracy of concentricity and small tolerances.
Split-line polishing
The nature of the design creates split-line on the return radius, this is likely to be only 0.1mm but important to Apple to automate the polishing off as this is high contact point in the hand and directly linked to user product quality perception.
Kavia does not have a customer that requires split-line polishing but it is an important stage of design for manufacture evaluation we offer our customers.
Lacquer spray coating
Apple says the coating offers a high gloss and durable finish. Kavia does add coatings to mouldings mainly for aesthetic reasons but some products are sprayed internally for EMC Shielding, both these services along with chrome plating are contracted out to specialist.
