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Portable machine tool insight: How carbide inserts are made


Video courtesy of Sandvik Coromant. © Sandvik Coromant. Mirage Machines is not responsible for any of the adverts that may appear while you are watching any videos on this website and blog.

You might have decades of field machining experience and an impressive inventory of in-situ machining equipment, but if the carbide inserts you are using are damaged or simply not fit for purpose, your end results will suffer.

Carbide inserts are the unsung heroes of the in-situ machining world, they are designed to withstand extreme heat and force and are made from some of the hardest materials in the world.

So how exactly are they made?  Find out by watching the video created by Sandvik Coromant, or read the summary below.

A typical insert is made of 80% carbide and 20% metal matrix that binds the carbide grains together. This metal matrix includes materials such as titanium and cobalt, with the latter being the most common. As you might expect, the manufacturing process is precise and tightly controlled and takes around 2 days from start to finish. A summary of the process shown in the video is detailed below;

Batches of the raw materials are tested for consistencyThe main ingredients are dispatched automatically at different stops on the production line.The ingredients are then milled to the required particle size, together with ethanol, water and an organic binder. This process takes between 8 and 55 hours, depending upon the exact recipe.

  • The slurry is pumped into a spray dryer, where hot nitrogen is sprayed to help evaporate the water and ethanol.
  • When the remaining powder is dry, it consists of identically sized spherical granules. A sample is then taken for quality checking.
  • Barrels containing 100kg of ready to press powder arrive at the automated pressing machine, where up to 12 tons of pressure is applied.
  • Each insert is weighed and at certain intervals and inspected visually by an operator.
  • At this early stage, the pressed inserts are still very fragile and need to be hardened in a sintering oven. The sintering process turns them into an extremely hard cemented carbide product which is almost as hard as diamond. The organic binder is incinerated and the insert shrinks to 50% of its original size. This takes around 13 hours at a temperature of 1500 degrees Celsius.
  • (At Sandvik Coromant), the excess heat is recycled and used to heat the premises in winter.
  • Each insert is ground in different grinding machines to achieve the exact size, geometry and tolerances.
  • As the carbide insert is now extremely hard, a disc with 150million small industrial diamonds is used to grind it.
  • The excess carbide is recycled, along with the oil used as cutting fluid.
  • The majority of inserts are coated through either chemical vapour deposition (CVD) or physical vapour deposition (PVD).
  • PVD- inserts put in fixtures and put into oven. The thin layer of coating makes the inserts harder and tougher. This process sis also where the insert gets its specific colour.
  • Finally, the inserts are manually inspected again before laser marked and packed.
  • When inserts are worn out they can be returned for recycling and the process of making a new insert begins.

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