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19 Mai 2022

Performance boost in aluminum forming: enabling cost-effective trimming of aluminum with Tetrabond™ (ta-C)

For companies in sheet metal forming, the generation of burrs and slivers is an ongoing challenge, especially when it comes to forming aluminum alloys. Burrs and slivers can reduce the final product quality and are costly to remove, which drives the search for solutions that prevent them from forming. Ionbond’s solution for this challenge is our Tetrabond™ tetrahedral amorphous carbon (ta-C) coating – a thin, extremely hard coating with a smooth surface and low sticking.
 trimming dies for sheet aluminum forming

High-quality parts need calibrated machining processes

Shearing is one of the most frequently used processes in sheet metal manufacturing and forming operations. This process of stamping parts from sheet metal includes blanking, trimming and piercing, and is widely applied in different industries such as primary metal, automotive or household appliances. The overall quality of the stamped part is defined by the height of the burrs on the sheared surface, the dimensional accuracy of the part and the absence of splitting. To meet quality standards and customer expectations, stamped parts frequently need a manual metal-finish operation for deburring. This is time consuming and adds costs to the stamped part.

These days, aluminum alloys are popular because they help reduce the weight of automotive body panels. That means the quality of shearing operations has increasingly come into the spotlight. Aluminum alloys are replacing low carbon steel because they can improve fuel economy while maintaining strength for passenger safety purposes. However, many manufacturing processes were originally designed for low carbon steel, and now need to be adapted for use with aluminum alloys. This is especially true of trimming, as both materials demonstrate different forming behavior due to differences in mechanical and chemical properties and mass density.

Tetrabond deposited on trimming dies for sheet aluminum forming

Ionbond Tetrabond drastically reduces the scrap rate

Ionbond has developed the Tetrabond coating as part of our forming and molding tool coating portfolio. It is an economical solution that ensures excellent product quality of stamped parts and increases the productivity of highly automated stamping processes by drastically reducing the scrap rate. Tetrabond is a non-hydrogenated tetrahedral amorphous carbon (ta-C) coating that belongs to the class of diamond-like carbon coatings. It was tailored to the specific need of forming tools with a sp3 ratio (sp3/(sp3+sp2+)) between 60 % and 70 % and a hardness above 3,000 HV0.02.

Abrasive wear resistance of TiN and Tetrabond™


  • Is a thin and extremely hard coating designed to maintain maximum forming tolerance and edge sharpness
  • Has an abrasion resistance comparable to nanocrystalline diamond coatings deposited by chemical vapor deposition (CVD)
  • Has an extremely smooth surface
  • Has a minimum adhesion tendency (anti-sticking) towards non-ferrous metals
  • And has a very low coefficient of friction.

That makes it the perfect match for trimming aluminum alloys.

Compared to conventional hydrogenated DLC coatings (a-C:H), Tetrabond™ has an enhanced temperature stability up to 500 °C, which extends the range of forming applications and choice of workpiece materials. Tetrabond™ can be deposited on complex tool geometries and on a broad range of tooling materials, including cold-work, hot-work and high-speed steels, stainless steels and cast iron. A proprietary decoating process allows refurbishment of production tools after regrinding, making the best use of expensive forming tools.

Comparison of abrasive wear resistance of TiN and Tetrabond™

Post written by
 trimming dies for sheet aluminum forming
Dr. Ing. Tobias Brögelmann
Global Segment Manager Forming & Molding Tools
 trimming dies for sheet aluminum forming
Would you like to know more?
If you are interested in the technical data of our Tetrabond™ coating, download our factsheet here