Poor 3D sensor yield rates are expected to impact iPhone X’s launch supply as Rosenblatt analyst Jun Zhang pegs current production volume at just 400,000 units per week.

In an interview with StreetInsider.com, the analyst said that the figure is actually a substantial increase from the previous estimate of 100,00 units per week.

Despite the increase, Jun maintained his production estimates of 20 million and 50 million iPhone X units for the December and March quarters, respectively. In other words, Apple may be unable to meet demand for iPhone X until 2018 at the earliest.

He does not see further order push outs for the OLED phone in October.

Japanese publication Nikkei said today that the sophisticated 3D sensor in Apple’s TrueDepth camera, which enables Face ID and other features, remains the biggest production bottleneck.

Citing a tech executive familiar with iPhone X production, Nikkei says manufacturers are still struggling to perfect 3D sensors and dot projectors in the TrueDepth camera.

The person could not pinpoint the exact manufacturing problem.

In September 2017, analyst Jeff Pu also identified the dot projector, supplied by Lumentum, as the troublesome component holding back mass production of iPhone X. A report this morning stated that Himax has now started shipments of TrueDepth’s wafer-level optics to Apple.

While this is good news, each and every part that goes into the handset must be manufactured in volume and on time for Apple to meet its self-imposed targets.

The delay is already hurting companies that have been contracted to assemble the phone. Semiconductor foundry TSMC and contract manufacturer Foxconn, for instance, both reported a drop in revenue in September due to the iPhone X manufacturing delay.

The anticipated OLED device goes for preorder on October 27 ahead of November 3 launch.