By Doug Smock
Valve mold components featuring conformal cooling channels made with the AgieCharmilles AM S 290 Tooling system were on display at the EOS GmbH Electro Optical Systems exhibit at the K show.
EOS, Krailling, Germany, and GF Machining Solutions Management SA, Lausanne, Switzerland, teamed up to develop the tooling system.
The machine made the parts from EOS MaragingSteel MS1, a steel powder optimized for direct-metal-laser sintering that is also heat treatable and easily machined. Parts can be post-hardened to more than 50 on the Rockwell Hardness C scale by age-hardening at 914 degrees Fahrenheit for six hours.
The additive manufacturing (AM) process for the insert required 75 hours on the EOS M 290 metal-laser-sintering system, which deposited and fused metal powder in 40-micron layers. A 400-watt ytterbium fiber laser fused layers of steel stock.
When the AM build was complete, it took five more hours to separate the insert from a supporting plate using the wire-electrical-discharge machining process, also known as wire-cut EDM. Then the insert had to be surface-finished with milling and die sinking EDM. That took another 25 hours.
Doḡan Basic, product marketing manager for AM at GF Machining Solutions, said it is difficult to estimate the specific time savings from using the AgieCharmilles AM S 290 Tooling system.
The payoff for conformal cooling is greatest for large molded parts, such as the pipe valve made with the AM components. Not only are cycle times reduced, but there are also fewer stress points in the part. The size of the production run must be large enough to amortize the cost of the components made via AM.
Some American moldmakers that were early buyers of selective laser-sintering equipment have struggled to find customers willing to pay the additional costs involved, despite the benefits. Part of the problem is a tendency of OEM purchasing departments to buy tooling based on initial capital cost rather than on a total cost concept that includes piece-part cost for the life of the tool.
Though the specifics still aren't clear, the AgieCharmilles AM S 290 Tooling system holds promise to reduce initial overall cost.
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