Opinel knife production

	Although knives are everyday objects, making them involves multiple techniques, which are actually very complex to apply on an industrial scale; the process involves making the handles, working and treating the steel, sharpening the blades. Blade - cutting out In a single operation in a 120 T press: the steel strap is cut out, punched with a groove and the “crowned hand” mark. Blade - quenching This operation is conducted in special controlled-atmosphere furnaces, with the temperature, which is maintained with a precision of 1°C, constantly indicated on recording tapes. The carbon steel is heated to a temperature of 900°C and quickly cooled by “quenching” in a bath of specially refrigerated oil. This transforms the internal structure of the steel. The effect of quenching is to make the steel very hard and very brittle. Quenching is "softened" by a ”tempering” operation, consisting of heating the blades up again to a temperature of around 300°C and then leaving them to cool slowly in air. The blade then takes on a lovely blue colour. The steel has become very hard and can now only be worked using an abrasive grinder, with liquid spraying. Stainless steels with a high chrome content undergo a different type of heat treatment. Among other operations, they must be heated to at least 1050°C to transform their internal structure. Obviously, the hardness of treated components is also constantly checked on-site, using devices to measure the Rockwell hardness.


	Blade - grinding At present, sharpening of each side of the knife is performed continuously, with each blade put in position, then pressed onto the grinder by a handling robot. Blade - polishing On machines fitted with fine-grained grinders. High precision removal of grease by ultrasound. Handle Made from wood squares by 9 moulding machines: cutting to length , safety catch fitting, moulding, bevelling of ends, sawing of slit, sanding, varnishing, marking. Assembly The knife is finally ready to be assembled, with the blade and the safety catch. Inspection A series of checks is performed at each of the major stages in production, generally by sampling, and each product is individually checked at the end of assembly. Some products randomly sampled after production undergo fatigue tests to measure the cutting quality, its durability and its resistance.