Despite record output, Foxconn unable to keep up with massive iPhone 6 demand

According to sources familiar with the supplier's operations, Foxconn has 100 dedicated assembly lines in Zhengzhou working around the clock in an attempt to meet preorders and launch day allotments for Apple's iPhone 6 handsets, reports The Wall Street Journal.

"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," the unnamed source said. "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."

One insider said 5.5-inch display yields are somewhere between 50 to 60 percent, meaning nearly half of all produced panels are scrapped as they do not meet Apple's strict standards. Retina HD displays bound for the 4.7-inch iPhone 6 are faring better with an output rate of about 85 percent.

Sources said Foxconn is responsible for manufacturing all iPhone 6 Plus models, as well as a "majority" of iPhone 6 versions. The report contrasts rumors from August that claimed Pegatron had won 50 percent of iPhone 6 orders, which at the time was said to be some 50 million units.

Reports from as late as July claimed Apple's larger 5.5-inch iPhone would not be ready in time to launch with the 4.7-inch iPhone 6, though Apple has put those rumors to bed and will debut both smartphones this Friday. Supplies for the "phablet" device appear to be constrained, however, as the larger phone was first to see delivery dates slip when preorders went live last Friday.

The stage is set for a record-breaking launch this week, as Apple on Monday announced combined iPhone 6 and 6 Plus preorders exceeded four million units within their first 24 hours of availability.