Foxconn which is Apple’s major assembler is struggling to meet the high demand of iPhone 6. The latest Apple product has been sold out during its pre-order launch, selling more than 4 million units during the first 24 hours. As the result, the customers need to wait about 4 weeks in order the device to be shipped out to their home.

All the workers in Foxconn site has been allocated to do the production of the new iPhone 6 and iPhone 6 plus.  Total of 100 assembly lines which consists more than 200,000 workers has been working around the clock in its largest production site, Zhengzhou, north central China, to meet the demand.

Foxconn was also the only assembler of the iPhone 5S and a small portion of iPhone 5C.The bigger portion of iPhone 5C was manufactured by another Taiwanese contract maker Pegatron. Later on, Foxconn stopped manufacturing the iPhone 5C to concentrate all its resources to make iPhone 5S.

Foxconn is able to produce 140,000 iPhone 6 plus and 400,000 iPhone 6 daily. This makes the iPhone 6 plus scarcer. The waiting time for iPhone 6 plus is longer, around three-to-four weeks while for iPhone 6, and the waiting time is around seven to ten business days.

The main reason of the longer waiting time is that the limited supply of 5.5-inch displays. iPhone 6 plus comes with 5.5-inch screen size. The output rate of 5.5-inch is only around 50-60% whereas for 4.7-inch is about 85%. iPhone 6 comes with 4.7-inch screen size.

The low production of display is because the display is using in-cell technology, which allows the screens to be thinner and lighter by combining touch sensors to liquid crystal display, thus a separate touch-screen layer is no longer needed.