Hoping to put a lid on some perceived controversy around bent 2018 iPad Pros, Apple published a support site late Friday night describing the device's manufacturing process. The site is called "iPad Pro unibody enclosure design" and starts by saying that Apple's latest tablet is "strong, light and durable." The company continues to notice that the new design has flat edges "instead of the curved edges found on previous-generation iPad models." (Some believe these straight edges make small turns more noticeable and easier to see with the naked eye, and Apple later mentions this point.)
Apple focuses the article on Wi-Fi + Cellular iPad Pro, which has seen most reports of a slight bend ̵
To provide optimal cellular performance, small vertical bands or "splitter" on the sides of the iPad, parts of the cabinet can act as mobile antennas. For the first time on the iPad, these bands are produced using a process called co-molding. In this high temperature process, plastic is injected into accurately milled channels in the aluminum housing where it binds to micropores in the aluminum surface. After the plastic has cooled, the entire cabinet is finished with a precise CNC machining, providing a seamless integration of plastic and aluminum into a single, strong enclosure.
These precision manufacturing techniques and a rigorous inspection process ensure that these New iPad Pro models meet an even tighter specification for smoothness than previous generations. This flatness specification does not allow more than 400 microns deviation over the length of some pages – less than the thickness of four sheets of paper. The new straight edges and the presence of the antenna slots can make the subtle aberrations in the flatness more visible only from certain angles of vision that are imperceptible during normal use. These small deviations do not affect the strength of the cabinet or the product's function and will not change over time through normal use.
As you can see, Apple repeats it like the previous one The Verge last month: some weak bends are a result of the iPad Pro's production and cooling process, and the company seems to suggest that as long as anyone " Subtle deviations in the flatness "are not visible under normal scenarios – which means when you face the iPad head on and actually use it – they should not be a concern for the customers. The 400 micron flatness specification first revealed by hardware VP Dan Riccio also gets another mention (this time with the added context that it applies over the length of any page).
If 300-400 microns are noticeably bent, I think this is a problem. The images of bent iPads people share, looks like they are bent much more than 0.4mm.
– John Gruber (@gruber) December 21, 2018
But Apple does not provide a visual example of what an iPad with a 400 micron deviation looks like. What is this in the layman's terms? Is an iPad Pro lifting off a flat surface beyond the specification? There are several images of the bent iPad Pros on the web that are apparently distorted beyond this measurement, but should people have stacked sheets to find out the nearby calls?
But I read a bit about the antenna line and flat edges that make the discrepancies more visible to mean yes, even bends falling into this Spec can be noticeable if you know where to look. When a device becomes as thin as 5.9 millimeters, your eye will have an easier time finding small errors. I have seen relatively few complaints about bending with the Wi-Fi-only model, as it has metal that runs around the entire outer edge with no antenna split.
Again, as it first told The Verge last month, Apple asserts that a bend within the specification will not compromise the unit's structural strength, power output, or deteriorate over time. The company does not go into how it is so confident in that statement, but probably the iPad Pro has been through a variety of testing. The support page mentions the inspection process, but does not address the sustainability check.
Apple encourages anyone who believes their iPad Pro cabinet to twist or bend over 400 microns to contact the company's support channels, and also reminds customers of a 14-day return policy. The statement stops short of issuing a formal replacement program for devices outside that return window, but the point of customer support tells me that representatives are probably well aware of the situation.