Another problem reportedly rests with flaws in the production output. The percentage of successful iPhone 6 Plus units assembled is only around 50 percent to 60 percent, a person at a display component supplier told the Journal. That means Foxconn has to throw out the units that don't meet quality standards. The iPhone 6 fares better with a successful production rate of more than 85 percent.
"We have been churning out 140,000 iPhone 6 Plus and 400,000 iPhone 6 every day, the highest daily output ever, but the volume is still not enough to meet the preorders," a person familiar with the matter told the Journal. "For iPhone 6 Plus, we are still ramping up the production line. Another reason for the limited supply is the shortage of 5.5-inch displays."