Headlamp Assembly: From Acetylene to ABB Robots

Headlamp assembly used to mean a worker fitting a bulb, a reflector and a glass front into a brass or steel shell. Today's headlamp is a sealed plastic module full of LED boards, cooling parts and electronics, sometimes with a matrix of individually switched light sources, and it has to stay watertight for the life of the car. This post traces how lamps went from acetylene to halogen, xenon, LED and matrix units. After that come the robots that now glue, seal and test them, the latest news from the lighting industry, and the places where ABB robots fit in a headlamp plant.

The LED Matrix headlamp of a 2015 Audi A4 in red, with its light strip and projector modules. Photo: Kickaffe (Mario von Berg) / Wikimedia Commons (CC BY-SA 4.0)

How car lamps went from acetylene to sealed beams

The first car lamps burned oil or gas. Acetylene lamps became popular in the 1900s, and by 1904 some makers supplied acetylene generator cylinders as standard equipment. Electric headlamps were offered as an option on the Columbia Electric Car in 1898. Peerless made them standard in 1908, and in 1912 Cadillac combined its Delco ignition and lighting into one electrical system. A lamp of that era was a small piece of hardware, with a polished reflector, a bulb holder and a glass lens clamped into a metal body, and people put it together and adjusted it by hand.

The brass headlamp of a 1913 Ford Model T Speedster, a reflector and glass front in a metal shell. Photo: BrokenSphere / Wikimedia Commons (CC BY-SA 3.0)

In 1924 the Bilux bulb put low and high beams into a single bulb, and in 1940 United States law made the 7 inch round sealed beam the standard. A sealed beam was one glass unit with the filament, reflector and lens fused together, so the car plant had nothing to assemble except the lamp itself. The H1 of 1962 was the first tungsten halogen light source, and the H4 of 1971 was the first twin filament halogen bulb, giving both low and high beam from one bulb.

City employees watch a car approach for a headlight alignment check at an auto emission inspection station, August 1975. Photo: Lyntha Scott Eiler, NARA via Wikimedia Commons (public domain)

Plastics changed how lamps were built. In 1983 the United States allowed replaceable bulb headlamps and hard coated polycarbonate lenses, and today most reflectors are compression or injection moulded plastic. The headlamp became a moulded housing and a clear lens joined by adhesive, which is the kind of repetitive bonding job robots handle well. Xenon HID lamps followed on the BMW 7 Series in the early 1990s, and Hella and Bosch made the first production low beam units from 1992. Every new light source brought more parts, more wiring and more aiming steps to the assembly line.

A BMW 330Ci coupe with its xenon headlights switched on. Photo: Dr.jameshughes / Wikimedia Commons (public domain)

Gluing, sealing and testing LED and matrix modules

LED headlamps arrived in 2006, when the Lexus LS 600h got the first series production LED low beams. The 2007 Audi R8 was the first car whose headlamps did every function with LEDs, and in 2013 the Audi A8 introduced digitally controlled, glare free Matrix LED headlamps. On a typical modern line, the housing and lens are moulded first and the LED boards and optics are mounted. The lens is then bonded into a groove in the housing with a polyurethane hot melt or a similar adhesive, and the sealed unit is leak tested before aiming and light checks.

The Matrix LED headlamp of an Audi TT, showing the low beam and daytime running light. Photo: Kickaffe (Mario von Berg) / Wikimedia Commons (CC BY-SA 3.0)

Robots already do much of that work. A Ford patent family on agile robotic headlamp assembly describes a welding robot that sonically stakes the lens to its frame and an adhesive robot that injects adhesive to seal the housing. The companies making lamps are changing hands and building plants. On 30 September 2026, OPmobility signed an agreement to buy 100% of Hyundai Mobis' lighting business for an enterprise value of 600 billion won. In October 2026 the Chinese headlamp maker Xingyu picked Landis, North Carolina, for its first United States plant, a $50 million first phase making moulded parts for headlights and taillights with at least 300 jobs.

ABB robots in the body shop at BAIC's electric car plant in Qingdao, China. Photo: ABB

A recall from the same weeks shows why the process has to be tightly controlled. In late September 2026, Ford recalled 41,748 Expedition and Super Duty vehicles because a contaminated LED chip in the headlight assembly could make the lamps fail. ABB robots fit several steps of a lamp line. An IRB 1200 or IRB 1300 can place LED boards and optics, a larger arm such as the IRB 2600 can carry a dispensing gun around a housing groove, and a GoFa cobot can load a leak tester next to an operator. Bead paths are usually planned in RobotStudio, and our post on robotic gluing and sealing goes further into dispensing.

An ABB IRB 2600 industrial robot at work in a production cell, the size of arm that can carry a dispensing gun. Photo: ABB

Where headlamp lines go next

Headlamps are becoming electronic products. Matrix units with many separately switched segments, projection functions and housings shared with sensors all add circuit boards, connectors and calibration steps. That work suits small, accurate robots with vision, since a misplaced LED board or a thin adhesive bead may only show up as a recall years later. Lines will also have to record each lamp's history, including which camera checked it and which leak test it passed, so a plant can trace a fault like the Ford chip problem back to a batch.

LED headlights on a Lexus hybrid, the car line that introduced series production LED low beams. Photo: Flickr user 8363028@N08 via Wikimedia Commons (CC BY 2.0)

Owners rarely see any of this, though they feel it when a lamp fails. A headlamp's aim and seal decide whether the car passes inspection, and inspection stations have checked headlight alignment for decades. Plants that make replacement lamps will face the same quality rules as the original suppliers. Lines that build lamps for several car models at once favour flexible cells, where a robot switches programs and grippers between variants, over a dedicated machine for each lamp.

Employees testing headlights at an auto emission inspection station in downtown Cincinnati, Ohio, September 1975. Photo: Lyntha Scott Eiler, NARA via Wikimedia Commons (public domain)

Cost is the first open problem, because suppliers are squeezed by carmakers and by new competitors such as Xingyu arriving in the United States. Skills are another. Programming dispensing paths, tuning vision and running leak tests all take trained people, and tools like ABB's no code programming are meant to lower that barrier. Hot melt adhesive also brings safety concerns, so those cells need fences or careful guarding. Cobots will probably work beside conventional arms on these lines, each taking the steps that suit it.

ABB robots working on a car body in final assembly, where headlamps are fitted to the car. Photo: ABB

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