New Whitepaper on Duplex Coating Solutions for High-Pressure Die Casting
Duplex coating solutions for high-pressure die casting
High-pressure die casting is becoming increasingly popular for high-volume mass production of complex-shaped parts. It’s is a high-stress process for the dies, often involving short cycle times, high temperatures, and abrasive materials. Especially when Al alloys are used, dies experience wear and die damage. This leads to increased scrap rates and machine downtime for maintenance, and in some cases even the scrapping of the die itself. Physical vapor deposition (PVD) coatings can protect dies against wear, increase productivity and machine availability, and reduce scrap rate and machine maintenance.
Figure 1: Duplex Ionbond™ 35-coated die for high-pressure aluminum die casting
Wear and failure modes in Al high-pressure die casting
The high die wear rates for Al alloys result from a combination of corrosive attack by molten Al, high melt temperatures and a higher concentration of abrasive alloying elements. Silicon (Si) is added to Al alloys to improve fluidity and die-filling capacity of the melt. These Si particles are extremely hard and thus highly abrasive to the die surfaces. The die-casting process has short cycle times, causing rapid thermal cycling. This increases the demands on the die.
Common wear types in high-pressure die casting are:
- Adhesive wear
- Erosion or “washout”
- Soldering or “sticking”
- Heat checking
All of these wear mechanisms affect the quality of the products and the manufacturing productivity. Heat checking, in addition, is the main cause for die failure.
Improving wear performance and productivity
Machine downtime, frequent die replacement and high scrap rates all reduce profitability. PVD and CVD coatings excellent resistance to soldering and erosion. If eliminating heat checking is the most important goal, because the die failure frequency is too high, a supportive plasma nitriding treatment is needed in addition to a PVD coating. This is known as a duplex coating.
Ionbond developed the Ionbond™ 22 (AlCrTiN) and Ionbond™ 35 (CrWN) coatings based on our fundamental understanding of the high-pressure die casting process. Field tests at our customers demonstrate the superior performance of Ionbond™ 22 and Ionbond™ 35, outperforming TiAlN- and AlCrN-based coatings. Both coatings combine a high mechanical and thermal stability with a high resistance to erosion and soldering. This provides Ionbond’s customers with two promising coating solutions to prevent two of the main failure mechanisms in high-pressure die casting: product quality (and a high scrap rate) and machine downtime due to die maintenance. With an additional plasma nitriding treatment, both coatings are also available as duplex coatings.
Would you like to know more about Ionbond coatings for high-pressure die casting?
Are you interested in learning more about our single and duplex coatings for high-pressure die casting? Download our whitepaper. It provides more technical detail, test results and case studies, and goes into more depth about the benefits and options.
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