Spark plugs have a lengthy and costly history of development. As research continues, manufacturers are producing spark plugs that are even more durable.
Manufacturers have tested around 2,000 electrode materials and 25,000 insulator combinations over the years to manufacture the highest-quality spark plugs.
Now, most manufacturers use silver, gold or platinum to produce electrodes with copper centres.
Each metal has different benefits. While silver offers excellent thermal conductivity, platinum is particularly resistant against corrosion.
Sillimanite and heat-resistant aluminium oxide ceramics are often used in the manufacture of insulator materials to effectively reduce flashover and electrical leakage.
Manufacturing Spark Plugs: The Components
Spark plugs vary in design but are all manufactured using the following components.
The centre electrode: a thick metal wire that slots length-ways into the plug. The electrode conducts electricity from the ignition cable to the electrode gap at the opposite end of the spark plug.
The side electrode: a short, thick nickel-alloy wire that attaches to the shell and the centre electrode, creating the spark plug gap. The gap usually measures between 0.020 – 0.080 inches.
The insulator: a ceramic casing that encompasses most of the centre electrode, while the upper and lower tips of the electrode remain exposed.
The shell: a hexagonal metal casing with threads that allows manufacturers to install spark plugs into the engine cylinder head.
Manufacturing Spark Plugs: The Process
Each major spark plug component is manufactured in a continuous line-assembly process.
Manufacturers implement quality control standards and practices throughout the process to ensure accuracy and safe manufacturing so that spark plugs can fulfil their function.
Manufacturers test incoming parts and tools – inspections and pressure testing ensure that each spark plug meets design specifications.
