Knife Sharpening Robot: ABB Arms and the Whetstone

A knife sharpening robot may sound like a gadget nobody needs, but a sharp edge comes down to angle, pressure and repetition, and a robot arm is good at all three. This post follows sharpening from whetstones of the early Middle Ages to the grinding cells in knife factories. It then looks at where ABB robots such as the IRB 1200 and the GoFa could fit, and whether a machine will ever hold your chef's knife against a stone in your own kitchen. Where ABB has no project, the post says so.

An early medieval whetstone fragment with a hanging hole, dated 900 to 1100. Photo: North Lincolnshire Museum / Wikimedia Commons (CC BY 2.0)

How whetstones and street grinders kept edges keen

People have sharpened blades on stone for a very long time. A whetstone fragment in the North Lincolnshire Museum collection is dated to between 900 and 1100, and it has a hole for hanging it from a belt. Different regions became known for their stones. Arkansas stones are cut from novaculite, a hard quartz rock quarried in the Ouachita Mountains. Belgian coticules from the Ardennes were valued for sharp edges as far back as Roman times, and Japanese craftsmen preferred natural water stones from around Kyoto.

An 1853 engraving of a knife grinder working at a foot-driven wheel on a cart. Photo: Engraving after P. Weenix / Wikimedia Commons (public domain)

Most households did not own a good stone or know how to use one, so the work went to specialists. Knife grinding was a trade, and an engraving dated 1853 shows a grinder at work with a foot-driven wheel mounted on a cart. Around 1899 to 1900 the photographer Eugene Atget photographed a rémouleur, a knife and scissor grinder, with his wheeled grinding stand in Paris. The grinder pushed the cart from street to street and sharpened whatever the neighbourhood brought out, one edge at a time.

A rémouleur, a knife and scissor grinder, with his wheeled stand in Paris, 1899 to 1900. Photo: Eugène Atget / Wikimedia Commons (public domain)

Mechanizing the skill began with guides, because the hard part is holding a constant angle by hand. Western kitchen knives are usually sharpened to about 20 to 22 degrees per side, and East Asian kitchen knives to about 15 to 18. Clamp sharpeners with preset angle holes, pull-through sharpeners and electric models with a fixed angle all take the angle out of the user's hands. The fixed angle has a cost, since it may not suit every blade, such as a Santoku. Some systems use a magnetic support that holds either 15 or 20 degrees.

A clamp-style knife sharpener that holds the blade at a set angle. Photo: Wtshymanski / Wikimedia Commons (CC BY-SA 4.0)

Knife makers, robot grinders and this month's sharpener tests

Factories solved the angle problem with robots long before homes did. Taiwanese maker Liow-Shye, which produces Atlantic Chef kitchen knives, bought its first KUKA robot in 1999, and the company says it still runs. A robot grips the blade and presses it against a grinding machine at an angle set for the edge, making repeated passes with controlled pressure. The company reports lower defect rates and less wasted material, though packaging is still manual. Published patent filings describe similar systems, with a six-axis arm and a camera that profiles each blade before grinding and polishing.

An ABB IRB 6700 grinding a steel part in Teqram's EasyGrinder cell at Ancofer. Photo: ABB

Shoppers are still buying the manual versions. On 4 October 2026 Which? published its guide to the best knife sharpeners of 2026, comparing rolling, electric and manual options, and on 15 October Food & Wine ran a tested list of the five best. Neither list covers robots. Every product on them still leaves the user holding the knife at some angle, so the home market is active but nobody sells a machine that holds the angle for you, and a robot arm that did would be a new kind of kitchen product.

A pull-through knife sharpener of the kind sold for home kitchens. Photo: Paul Martin / Wikimedia Commons (CC BY 2.0)

ABB has not announced a knife sharpening product, so what follows is a possibility. The ingredients exist. An ABB IRB 6700 grinding steel parts in a Teqram EasyGrinder cell at the Ancofer steel plant shows ABB arms doing grinding on a production line. The compact IRB 1200, launched in a new generation in 2025, handles small parts, which suits blades. A GoFa CRB 15000 can be taught by hand guiding, so a sharpener could show it a good stroke, and RobotStudio can simulate a stone path before any steel is touched. For related work, see ABB grinding and deburring and cutlery manufacturing.

The new generation ABB IRB 1200, launched in 2025, a compact arm for small parts. Photo: ABB

What a home sharpening robot would still have to solve

A home unit would face a drawer of different knives: a thin Japanese gyuto, a heavy German cleaver, a serrated bread knife, a pair of scissors. Each has its own bevel and its own safe angle. The robot would have to identify the blade, measure its profile with a camera and choose the right stone, which is what the patent filings describe for factory systems. Making that work on a stranger's worn and chipped knife, at a price a household would pay, is the open problem for the next few years.

Sharpening a Japanese knife on a whetstone in a wooden holder. Photo: Didriks / Wikimedia Commons (CC BY 2.0)

Safety is the second problem. A spinning abrasive and a blade in a gripper would sit in a kitchen with children and pets. ABB's SafeMove software limits speed and workspace for robots that share space with people, and cobots such as the GoFa stop when they sense contact, but a sharpener would still need an enclosure around the grinding zone and a way to contain sparks and metal dust. Many cooks also enjoy sharpening by hand on a stone, so a robot would have to offer a consistent result in a few minutes.

Moving an ABB GoFa arm by hand to teach it a path. Photo: ABB

The likelier first customers are businesses. Butchers, restaurants and knife shops that sharpen hundreds of blades a week can justify a cell, and a mail-in sharpening service could run one. In factories, the near term is more flexible cells that grind several knife shapes with one arm and a quick program change. At home, expect better guided sharpeners first. Programs for cells like these are usually built and tested first in RobotStudio before any blade touches a wheel.

A street knife grinder at work with his pedal-powered cart. Photo: FLLL / Wikimedia Commons (CC BY-SA 3.0)

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