STERLING HEIGHTS, MI – Chrysler is betting several production processes created for the new ’15 200 sedan production will result in more satisfied customers.

Bringing the new 4-door to life at this suburban Detroit plant is a combination of high-tech automation mixed with old-fashioned visual inspection and detective work.

Chrysler, now part of Fiat Chrysler Automobiles, invested $1 billion in the Sterling Heights assembly plant, pulling it back from the brink of closure in 2010.

That money went toward a variety of improvements, including an advanced Kuka laser-braze system in the new $165 million body shop here that gives the 200 a trim-free roof.

“Our laser braze on our roof will be the first in this market segment,” Tyree Minner, Sterling Heights plant manager, tells media during a tour.

Chrysler began using the technique, which joins the roof and body sides of car seamlessly without the need for added trim, with the ’08 Chrysler 300 and Dodge Charger large cars. The current Dodge Dart compact car and new Jeep Cherokee CUV also user laser braze.

Before brazing takes places, two spot welds each are performed at the front and rear of the 200’s roof to maintain a stable geometry. Then the panels go into the laser booth, where even pressure is applied, pushing the roof into the body sides to ensure the panels are no further apart than 0.01 in. (0.3 mm).

A silicone-bronze wire is fed through a frictionless feeder and a laser liquefies the wire, creating a mechanical bond between the roof and body-side sheet metals. The joint then is ground smooth for a “Class-A appearance,” says Dan Koessler, body-in-white process engineer at the Chrysler Technology Center, who describes the laser-braze process as being similar to “a very high-tech caulk gun.”

Other new automation in the body shop includes an auto-panel line and an open-gate framer.

The auto-panel line robotically fastens the doors, fenders, decklid and hood to the car via 51 stations and 68 robots, aided by 24 vision systems that make sure the robots are in alignment before screwing components down.

“By far, quality is better with this line (because of) the tolerances we can hold with robots, plus the ability to make virtual shims is essential,” says Brian Kelly, launch manager-APL & Closures at the plant.

Tolerances for closures, flushes and gaps are plus-minus 0.04 in. (0.9 mm), and 74 “critical points” are monitored for flush-and-gaps, he says.