Apple has posted a new support article that gives some insight into how the 2018 iPad Pro is manufactured, clearly as a follow up to the reports of customers receiving bent iPad units in the runup to Christmas.

It says slight bends may be more visible to the eye due to the new straight edge design, and reiterates that Apple specifies 400 micron flatness tolerances — and anything outside of that range should qualify for warranty repair/replacement.

The document says that for the first time ever, Apple is using a new manufacturing method called ‘co-molding’.

Specifically, on cellular iPad Pros, the plastic antenna bands in the sides of the iPad are bonded with the metal by injecting the plastic into milled channels in the enclosure.

Apple says that the new squared-off design and antenna splits on the cellular version may make some slight bending easier to see with the naked eye, from certain angles. In normal use, a 400 micron variation in flatness should be imperceptible.

However, it reiterates that its tolerances are even tighter on the 2018 models compared to previous iPads.

Apple invites anyone who believes their iPad Pro is bending beyond the 400 micron tolerance level to contact Apple Support. It confirms that its warranty will cover damage ‘due to a defect in materials or workmanship’.