How LED light bulbs are made

An LED bulb needs a power supply inside the base and an aluminum back to carry away the heat.

stations: 7
things upstream: 67
raw sources: 20
steps from the ground: 9

The short version

LED bulbs are built more like electronics than lamps. Solder paste goes on an aluminum circuit board, machines place the LEDs and chips at high speed, and a reflow oven melts the solder. The boards snap apart and go to a line that glues them into bases, attaches cords and covers, and tests each bulb's light twice.

Place chips by machine

Boards are thin aluminum sheets that act as heat sinks, coated with an insulator and copper traces. After solder paste goes on, surface-mount machines place LEDs and driver chips at very high speed, working on large panels that hold many circles.

Goes in
LED Printed circuit board Aluminum Solder
Melt the solder

The panels pass through a reflow oven, a hot air furnace that melts the paste. They then snap apart like cupcakes from a tray, and power wires are soldered on by hand.
Build the driver

The small power supply goes through surface-mount machines too, then along a row of workers adding one large component at a time. Some factories buy it in from elsewhere.

Goes in
Printed circuit board
Glue into bases

Workers mark the bases and load them onto a conveyor to a gluing stage. Modules are pressed in tight so heat flows into the base.

Goes in
Adhesive Aluminum
Attach cords and cover

AC cords are fixed and automatically straightened. With the cover on, each lamp faces its first automatic lighting check.

Goes in
Polycarbonate
Rivet the cap

Lamps that light have their extra cord cut and riveted to the cap, then the cover is glued and pressed on.
Test and pack

A second lighting check removes any failures to repair. Passing lamps get a printed date, an appearance check and an automatic pack. A blower at the end sends any unpacked lamp back to the start of packing.

End of the lineLED light bulb

Worth repeating

The most efficient commercial LED lamps exceed 200 lumens per watt, while incandescent lamps manage only 10 to 17.
Lighting consumes roughly 12% of electrical energy produced by industrialized countries.