Spark Plug Manufacturing: ABB Robots and Ceramics

A spark plug looks simple: a threaded steel shell, a centre electrode and a white ceramic insulator between them. Making millions of them that fire reliably is another matter, and spark plug manufacturing mixes ceramics, metal forming, assembly and inspection on one line. This post traces the plug from Lenoir's engine to Bosch's 1902 magneto system, looks at the Denso and Niterra news from October 2026, and asks where ABB robots could fit. ABB has not published a spark plug project, so the fit described here is a possibility.

A used spark plug held in a hand, showing the steel shell, electrode and white insulator. Photo: ProjectManhattan / Wikimedia Commons (CC BY-SA 3.0)

From Lenoir's sparks to the porcelain plug

Étienne Lenoir built one of the first internal combustion engines in 1858 and patented an electric ignition for it in 1860, which is why many historians credit him with the first spark plug. Edmond Berger is said to have made an experimental plug in 1839, though he never patented it. These early igniters served slow gas engines, and a plug that could be made by the thousand had to wait for the next generation of engines.

A gas engine from Lenoir's era, shown at the Musée des Arts et Métiers in Paris. Photo: Lomita / Wikimedia Commons (CC BY-SA 4.0)

The turning point came at Bosch. In the summer of 1901 Robert Bosch asked his engineer Gottlob Honold for a magneto ignition without the unreliable break-spark mechanism. Honold delivered a high-voltage system, the patent was applied for in January 1902, and on 24 September 1902 Bosch delivered the first high-voltage magnetos to Daimler Motorenwerke. The plug that went with it is generally treated as the first commercially viable one. A threaded metal shell held a central electrode, separated from the shell by a porcelain insulator, and that layout survives today.

A vintage Bosch spark plug with its porcelain insulator, shown in the Landesmuseum Stuttgart. Photo: RudolfSimon / Wikimedia Commons (CC BY-SA 3.0)

The insulator became the hard part, since it has to hold off high voltage inside a hot cylinder. Later improvements are credited to Albert Champion and to the Lodge brothers, sons of the physicist Sir Oliver Lodge. Modern insulators start as alumina powder mixed with a binder and water, granulated, packed around a pin in a rubber mould and pressed from all sides under hydraulic pressure. One patent describes then baking the pressed body at 1450 to 1700 degrees Celsius. A 1944 British photo series shows workers making plugs for Flying Fortress bombers on machine lines.

Workers in a British spark plug works in 1944, part of a series on plugs for Flying Fortress bombers. Photo: UK Ministry of Information via Wikimedia Commons (public domain)

Denso, Niterra and the plug line in 2026

On 2 October 2026 Denso announced it would discontinue the planned transfer of its spark plug and exhaust gas sensor business to Niterra, according to its newsroom and reports in Nikkei Asia and Just Auto. The agreement had been signed on 1 September 2025. Denso said electrification is still advancing but demand for varied powertrains has lasted longer than expected, so keeping the business suits its CORE 2030 plan. For plug factories, the news means the line keeps running at Denso rather than changing hands.

A modern white ceramic spark plug beside a dark, worn plug body. Photo: Industry shill / Wikimedia Commons (public domain)

Production today mixes pressing, firing, glazing, assembly and testing. Inspection suits a robot and a 3D scanner, since a plug has a ceramic that can chip, an electrode gap that must be right and a thread that must be clean. ABB sells a 3D Quality Inspection cell, 3DQI, in which a robot scans a part and checks it against the design. Nothing in the sources says ABB runs it on spark plugs. The principle carries over, because a robot can present each part to the sensor in the same way, thousands of times a shift.

ABB's 3D Quality Inspection cell scanning a metal part. Photo: ABB

For the assembly side, the best fit is ABB's small arms. The IRB 1300 is a compact industrial robot for small parts and tight cells, and the IRB 1200 is built for fast machine tending and handling. A cell could load shells into a crimping press, seat insulators and move finished plugs into gauges. The IRB 360 FlexPicker could then pack them. Teams normally build and test a cell like this first in RobotStudio, checking cycle times and reach before any hardware arrives. The ABB robot use cases page shows how similar cells are used elsewhere.

An ABB IRB 1300 small industrial robot with an operator holding the FlexPendant. Photo: ABB

Spark plugs after the peak of the petrol engine

Electric cars have no spark plugs, so the long-term market is debated, and Denso's own statement points to hybrids and other mixed powertrains lasting longer than first expected. Plugs also sit in generators, motorcycles, mowers and boats, and in the engines homeowners service themselves. For these buyers a plug is a cheap, replaceable part. Car demand will probably fall over the long run, but the speed of that fall is uncertain, so factories plan for more than one outcome.

Spark plugs of two designs on a table, the cheap replaceable part at the center of the plug business. Photo: Wikimedia Commons contributor (CC BY-SA 4.0)

The open problems are cost and flexibility. A plug sells for a few dollars, so a robot cell must pay back on tiny margins, and many plants run old lines that were built for single products. A flexible cell that can switch between plug types in minutes helps when demand shifts. Skills are another gap. Staff must understand ceramics, vision and robot programming at once. ABB's YuMi can handle very small parts, but it suits light assembly steps only, so engineers have to match each task to the right robot.

ABB's YuMi assembling small parts beside a lab worker. Photo: ABB

Over the next few years, the likeliest change is more inspection and more flexible handling. Cobots and small arms can take over the repetitive loading, gauging and packing that workers do now, while people move to setup, maintenance and quality work, where judgement still matters. Operators also gain from simpler programming, since ABB's Wizard easy programming lets someone without code experience build a basic routine. In the home, the effect will be invisible: the plug in a mower or a motorcycle will come from a line with fewer defects. A plant that already runs small-parts cells with RobotStudio and OmniCore controllers can reuse the same tools when a plug line needs to change.

ABB IRB 360 FlexPicker delta robots picking items on a moving line. Photo: ABB

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