Additive Manufacturing Pages 21 to 26 Applying Ultrasonic AM to Moldmaking By Mark Norfolk Ultrasonic AM is a hybrid additive and subtrac-tive system which adds a welding or printing head to its CNC milling platform. A unique process, the print head is able to print metal at room temperature . This process is also called solid-state welding because it happens in the solid form. No melting is occurring. This true welding process is based on ultra-sonic welding developed in the s for elec-tronic circuits. The wire-bonding process essen-tially uses ultrasound at room temperature to weld metal. Printing at room temperature is essential because when you heat a metal, you change its properties. When you heat a metal to its Half of an injection mold with embedded sensors. melting point and then resolidify the metal, you really change its properties. Many printing processes that melt metal have metallurgical concerns because they are heating and cooling, making miles Another example is embedding temperature and pressure of weld. Ultrasonic AM does not melt, so the material com-sensors in molds using a strain sensor or a strain gauge to ing in is the same as the material going out, albeit a different back out pressures. However, once you embed the sensor, it shape. This process does not heat up, so it is not changing is there for the tool’s life, as it is embedded in solid metal. any properties of the metal. Another application for ultrasonic AM is welding dissimilar Not melting or perform-metals, where one layer is aluminum, another is copper and ing this process at a low still, another is stainless steel. Most welding processes can-Ultrasonic AM does not temperature offers the abil-not bond dissimilar metals. If using a fusion or arc-welding melt, so the material ity to embed components . process to melt and solidify, those metals will mix and make With ultrasonic AM, you coming in is the same as something unusable. can lay down an electronic Ultrasonic AM can layer different metals together to the material going out, circuit, print metal directly improve mold performance because it is not a melting pro-albeit a different shape. over it and because the cess. You can print copper in the center of a core to wick metal is not getting hot, it away heat and keep the outside of the mold stainless steel, won’t get damaged. This for example. process is used to embed sensors and electronics, which You also don’t have to print an entire part. Start with a translates into molds. large chunk of material and then only print the features that You can use ultrasonic AM to embed temperature sensors will beneit from additive—for example, printing a copper anywhere in a metal part that you are printing and receive core over the top of the die face. continuous data from that sensor while it’s in operation. If you don’t have to print it, don’t. Use the appropriate Many shops conduct engineering studies using this technol-tools in your arsenal. ogy to determine how a mold is performing. FOR MORE INFORMATION For example, ultrasonic AM has been used for over a decade to embed sensors into parts that are on airplanes, sat-Fabrisonic LLC / 614-688-5223 mnorfolk@fabrisonic.com / fabrisonic.com ellites and nuclear reactors. It is the same concept as it would Mark Norfolk, PE, President be with a mold: you want to get a sensor in a speciic location and measure data during that product’s life. 26 MoldMaking Technology — — JULY 2021 Image courtesy of Fabrisonic.