The alleged problems were revealed this week by Chinese-language newspaper 21st Century Business Herald, which said that the manufacturing issues come from a factory in China known as Lens Technology. A worker with the company's quality control department said that the company is still trying to work out the right balance of paint thickness and opacity, in order to ensure the panel allows enough space for the digitizer overlay, but also gives the level of white that Apple expects the product to have.
Industry sources also indicated that each machine owned by Lens Technology can only cut three iPhone 4 glass covers per hour. The report said that the company's current production capacity can only meet half of Apple's demand for the iPhone 4.
Demand for the iPhone 4 has been unprecedented, selling 1.7 million units -- available in black only -- in the first three days. It was the most successful product launch in Apple's history. Last week, the company announced it had sold more than 3 million in its first three weeks.
The process of developing the glass itself is also lengthy and tedious. As noted by Engadget, the manufacturing involves "developing the tooling, cutting the raw material (mainly sourced from Germany, Switzerland and Japan), fine-milling using CNC (computed numerically controlled) machines, sanding the edges, polishing, strengthening, cleaning, coating, screen printing, baking, anti-shatter treatment, assembling, and packaging."
Apple Chief Executive Steve Jobs said on Friday that the white iPhone 4 remains on track to ship by the end of July. He said quantities of the model will be limited at first, but will ramp up over time.
In June, Apple said in a press release that the white iPhone 4 has "proven more challenging to manufacture than expected." The white model has not been available since the iPhone 4 launched on June 24.