How refrigerators are made
Nitrogen runs through a fridge's tubing before any refrigerant does, and a machine sniffs for leaks at the very end.
- stations
- 11
- things upstream
- 88
- raw sources
- 27
- steps from the ground
- 10
The short version
Nitrogen goes through a refrigerator's tubing before any refrigerant does, because it exposes bad joints safely. Earlier on the line, sheet metal is welded or clinched into a shell, a vacuum-formed plastic liner snaps inside, and polyurethane foam swells to fill the gap. Copper coils and a compressor are attached, the sealed circuit gets its charge, and each unit runs with sensors inside.
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Weld the outer shell
Steel or aluminum sheet comes off a coil and its pieces are welded or clinched. Clinching crimps two sheets together under pressure with no added fastener. Seams that will show get welded and ground down until they read as one piece.
Goes in -
Paint the bare metal
Sheet bought precoated skips this step. Other parts are sprayed, or dipped in a paint and solvent bath and then heated so the coat bakes on.
Goes in -
Vacuum form the liners
A thick plastic sheet, a little oversize, is clamped at its edges and heated. Suction pulls it into a mold, where it cools, and the excess is trimmed off. Inner doors are nearly always made this way.
Goes in -
Nest liner inside shell
The inner cabinet snaps into the outer one. Some tubes and wires are threaded through the gap between the walls while it is still empty.
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Foam the wall gap
A robot or a long manual gun shoots foam between the walls, and an oven makes it expand into a stiff, insulating core. One patent describes mixing liquid polyol and isocyanate into polyurethane, with vent holes to let trapped air escape ahead of the foam. Doors get the same treatment.
Goes in -
Attach the cooling circuit
Copper tube is cut, bent and soldered into condenser and evaporator coils, which arrive at the cabinet as a unit. Screws and clips hold the other cooling parts, the joints are soldered, and a protective coating is sprayed over them. Fins of aluminum or alloy add surface area on some designs. The compressor, a sealed motor and pump, is mounted at the base.
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Hang the doors
Gaskets loaded with magnets are screwed onto each door to make the seal. Handles and hinges go on next, and the hinges are screwed to the cabinet with some room for adjustment.
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Pressure test with nitrogen
Tubing subassemblies, and then the whole unit, are filled with nitrogen to reveal flaws in the tube or the solder. Nitrogen is a safe gas to use for this.
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Charge the sealed loop
Units that pass receive their refrigerant. The main type now used in Europe is isobutane, labeled R-600a, a replacement for gases that harmed the ozone layer.
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Run and sniff for leaks
Sensors inside the running unit track its temperature over time to confirm it reaches design levels, including during defrost. A machine that detects refrigerant then gives it a final sniff. If a charged unit is rejected, special equipment drains the gas for reuse.
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Tape in shelves and pack
Shelves, crispers and ice trays go in and are taped down for the trip. The unit gets a last look before it is packaged for shipping.
Goes in
Worth repeating
- Clinching joins two metal sheets much the way a stapler does, except that no staple is involved.
- To work out where foam should go, engineers once filled complete fridge cabinets by trial and error, then ripped them apart to see the result.
- Governments banned the refrigerant R-12 in new refrigerators in 1994 because it damaged the ozone layer.
Back to the ground
Follow every input upstream and refrigerator starts as these 27 raw sources.
Everything it is made of See it on the map
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Keep walking
Sources
- Refrigerator, How Products Are Made
- US5740074A, Method for filling a compartment cavity with foam
- Refrigerator
Cite this page: "How refrigerators are made." Assembly Line, 2026-11-03. https://assemblyline.org/make/refrigerator