When reports of the 2018 iPad Pro bending started getting media attention, Apple was quick to dismiss the matter saying that certain units can ship with a slight bend. It said that a bend of up to 400 microns is fine, with the design tolerances for the tablet being tighter than for previous iPads.

Apple has now provided more details in a support document on the new manufacturing method it is using on the iPad Pro which can be blamed for the bend. The Cupertino company is using a new “co-molding” manufacturing method for the new iPad Pro in which plastic is injected into milled channels in the aluminum enclosure. After the plastic cools down, the enclosure is finished with a precision CNC machining operation.

iPad Pro cellular models now feature Gigabit-class LTE, with support for more cellular bands than any other tablet. To provide optimal cellular performance, small vertical bands or “splits” in the sides of the iPad allow parts of the enclosure to function as cellular antennas. For the first time ever on an iPad, these bands are manufactured using a process called co-molding. In this high-temperature process, plastic is injected into precisely milled channels in the aluminum enclosure where it bonds to micro-pores in the aluminum surface. After the plastic cools, the entire enclosure is finished with a precision CNC machining operation, yielding a seamless integration of plastic and aluminum into a single, strong enclosure.

The new design of the iPad Pro and the manufacturing method might make any bend in the frame more visible to the naked eye from certain angles. This bend, however, will not have any negative effect on the strength of the enclosure. Apple has a tight tolerance 400 microns — less than four sheets of paper — for its 2018 iPad Pro and any device with a higher degree of bend will be eligible for replacement under warranty.