Simple Solutions That Work! Issue 9

BACK-2-BASICS Contact: ALYSSA M. CORRAL [email protected] The first pour using the 3D printed sand printed piece was a success. No defects or cracks were found on the prototype. 20 additional castings were needed and all of them were poured flawlessly using the 3D printed cores. Not only were there zero defects, but all the prototypes were made in a few days rather than a few weeks like traditional metal tooling would have required. Hoosier Pattern works very closely with all customers enabling our designers to make changes on the fly to keep all projects moving forward to meet the customer’s needs and deadlines and ideal and more practical for quick turnaround times. CASE STUDY — DALTON FOUNDRY Dalton Foundry of Warsaw, Indiana had a case to solve for a customer and time was running out. The part in question was a section of 443 pound gray iron gear case and the corners or ribs in several points that was cracking during the casting process. The gear case cover housing is used in industrial air compressors used at work sites to generate air and power. This was a porotype casting and it was scheduled to go into production. Dalton attempted several processes and gating related changes but the crack kept appearing on the final casting. Because of where the crack was appearing and the nature of the crack, Dalton employees thought that the cracking might be the result of stress during the solidification process. Repeated simulations were ran that referenced the original design that led to the conclusion that the defects were related to the customer’s design. It was realized that the stress in the casting was the result of the original design because the base was so large that it took much longer to solidify than the other areas of the casting. A plan was then put in place to cut the metal tooling again, but the redesign of the part took much longer than was expected and now time was becoming critical to the project. It was at this point that Dalton turned to Hoosier Pattern and opted to make the cores using our 3D sand printer. With this specific case, Dalton saw that the 3D printer could print directly from the CAD file without the upfront tooling cost. This was groundbreaking, especially with a prototype piece that had a history of cracking. Design changes could be made quickly and a new core could be printed and pour ready within days. 31