This page contains a Flash digital edition of a book.
Visit the Product Innovations Archive at www.moderncasting.com Bio-urethane binders also were


tested on pump and impeller castings at Viking Engineered Cast Products, Cedar Falls, Iowa. Viking reported the castings poured using the bio- urethane cores exhibited less hot tear- ing and cracking than conventional ester-cured phenolic cores. The new bio-urethanes were developed by UNI to be casting facility-ready. Improved shakeout of the two binders without sacrific- ing casting quality is ideal for many applications. Cost savings are seen with decreased shakeout time, ener- gy, and damage. Trial metalcasting facilities have experienced a much


Case Study


safer mold and core room environ- ment with improved emissions on the production floor. Bio-binders decrease metalcasters’ dependence on petrochemicals by using materi- als grown or mined in the U.S. and all over the world. Funding for the CABB project has been extended, and UNI will continue developing binders and processes.


MC Visit www.mcc.uni.edu for more information.


PRODUCT INNOVATIONS


CF8M stainless steel pumps and impellers were cast using bio-urethanes at Viking Engineered Cast Products.


Custom Castings Uses Simulation to Eliminate Defects in Aluminum Part When Custom Castings, Winnipeg,


Canada, a nonferrous metalcasting facility making aluminum and zinc al- loy castings via the gravity permanent mold, semi-permanent mold and tilt pour processes, tackled a large 160-lb. semi-permanent tilt pour job, it began pushing its equipment to the edge of its capabilities. The metalcaster acquired the order for the 160-lb. casting because a vendor producing it in gravity sand delivered castings that were cracking in service (Fig. 1). Custom Castings had been using Magmasoft by Magma Foundry Solutions, Schaumburg, Ill.,


for about one year to improve its cast- ing quality and reduce sampling times, and using the software, it was able to show it could provide the casting with better mechanical properties through the permanent mold process. Custom Castings continued to use


casting process simulation during tooling development to evaluate the customer’s current casting design. By providing simulation results, it justified casting design changes that improved the castability of the part while maintaining its functionality in service. The new casting was easier to


produce, which allowed Custom Cast- ings to provide the order on time and to the specified quality level. After the design changes were approved, the metalcaster began developing an ap- propriate rigging system and process parameters that ensured unacceptable defects were not present in the casting. Having developed a robust gating


and risering system along with all the necessary process parameters, Custom Castings verified the simulation work by running a batch of samples. But it hit a glitch upon running the first batch. Large porous voids were present in the casting, which did not coincide with the simulations. Custom Castings involved Magma engineers to assist in sorting out the issue. The engineers first thought the large


Fig. 1. Parts originally produced via gravity sand casting were experiencing failure defects in service.


MODERN CASTING / June 2010


voids were due to shrinkage porosity. The simulation results were again re- viewed and evaluated to check for errors that may have caused the discrepancy in results. Variations of material tempera- ture, cycle times and mold temperatures were run to see if they would result in the observed defects. Through all the varia- tions of parameters, the casting remained nearly defect-free with nowhere near the defect severity of the first sample run. The simulations showed locations of shrinkage in the defect region, but it was minor in relation to the defect size seen in the sample run. The simulation inputs were double-


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