Diamond-Like-Carbon Coated Dies for Electromagnetic Embossing

Area of Science:

• Manufacturing Engineering
• Materials Science

Background:

• Electromagnetic forming (EMF) is a high-speed, contactless process ideal for microstructuring thin sheet metals.
• Die design is critical in EMF, with adhesion being a significant challenge across various die materials like aluminum, copper, and steel.

Purpose of the Study:

• To investigate methods for preventing die adhesion during electromagnetic forming.
• To evaluate the effectiveness of amorphous hydrogenated carbon-Physical Vapor Deposition (a-C:H-PVD) coatings on steel dies.
• To analyze the influence of die surface structuring and initial sheet properties on embossing quality.

Main Methods:

• Testing various die materials (Al, Cu, steel) for adhesion during EMF.
• Applying a-C:H-PVD coatings to X153CrMoV12 steel dies.
• Structuring coated dies with micro hard milling to create tribology-effective patterns.
• Embossing Al99.5 sheets using coated and structured dies.
• Topographical analysis of embossed microstructures and assessment of sheet surface influence.

Main Results:

• Adhesion phenomena were observed for all tested conventional die materials.
• The a-C:H-PVD coating effectively prevented adhesion on steel dies.
• Tribology-effective patterns on the die surface influenced embossing quality.
• Thicker sheets and specific initial surface topographies of the sheets resulted in better embossing outcomes.

Conclusions:

• a-C:H-PVD coatings are a viable solution to mitigate die adhesion in electromagnetic forming.
• Die surface engineering, including patterning and material selection, is crucial for successful microstructure embossing.
• Initial sheet properties significantly impact the quality and feasibility of EMF microstructuring.