The UNI American Foundry Society (AFS) student chapter cast metal frogs as a gift for attendees of the FEF College Industry Conference. The project started in the spring semester during FEF key professor Scott Giese’s Tooling Practices class. Each student was to provide an idea designed and rigged for a final project. Many great ideas were submitted and passed on to the UNI FEF advisory board at their annual meeting. The board chose the idea from Taite Gallagher of a brass frog as a tribute to casting history.
Once the idea was chosen it came to polishing and proofing the design. After reviewing the original geometry of the frog we decided to go with a more realistic design. With limited time to freehand model a new frog we opted to laser scan an existing toy frog for a baseline. After adjusting some issues in the scanned data we were able to design a mold for the frog.
We printed four direct pour molds to proof the mold design. Originally we intended to use green sand and a 4 cavity pattern, however due to how well the four proof of concept molds turned out we opted to print molds for all of the frogs. Using printed molds with individual frogs allowed us to maximize yield, decrease time per casting, and allow for flexibility in melting and pouring. This method also proved to be time efficient as we didn’t need to make hard tooling or prepare green sand before each heat.
This manufacturing process began at U.N.I.’s Additive Manufacturing Center with the use of a S-max printer where the molds were printed using IC-80 sand. After each job the molds were excavated, cleaned, packaged, and shipped to the Metal Casting Center.
At the Metal Casting Center the molds continued their journey by being coated with a water-based graphite coating. Some molds were dried in an oven and poured the same night, but most were left to air dry. Once sufficiently dry 18 molds at a time were prepared for pouring with the application of cope rope and an iron weight.
When it came to pouring we were concerned about the toes filling completely. We tried a high pour temp around 1950°-2000°F. With the toes feeling well but having excessive flash we continuously lowered the pour temp and finally settled on 1850°F.
Cleaning the castings took the most time. We used many tools in the shop to cut the sprue and remove the flashing. From there, we used grinding stones and dremels to clean up the features of the frogs. After all the grinding, the frogs were tumbled for 12-26 hours, depending on schedule availability. After tumbling the frogs were cleaned and packaged.
To accent the frog and serve as a reminder of the CIC event, lily pads were made. The lily pads were laser cut from scrap wood from Wood Components, a local manufacturer of laminated arches. The pads were cut 12 at a time in at 18X30 laser bed.
With many changes in direction and adaptation to new obstacles this project was certainly a great learning experience for all of us involved. With many long nights and countless hours we are proud to present the 2018 Foundry Education Foundation’s College Industry Conference memento. We hope you enjoy.
We would like to extend a huge thank you to the following organizations/people:
Foundry Education Foundation (FEF), UNI Department of Technology, Scott Giese, Sairam Ravi, Clow Valve, UNI TEECA Club, UNI Graphic Technology Program, UNI Additive Manufacturing Center, UNI Metal Casting Center, Wood Components.
Landon Hinchman, Mark McAllister, Caitlyn Haller, Anders Segura, Keelan Trent, Maria Alverio, Taylor Klein, Taylor Clemons, Nate Schmidt, David Jaramillo, Travis Stanberg, Bryon Sells, Susan Alverio, Sarah Smithart, Austin Knapp.