part of a casting. Tese inserts, often made of sand, prevent the molten metal from filling the entire mold, so interior cavities can be included in the casting design. In recent years, the growth
of 3-D printing capabilities has become a topic of interest for every manufacturing industry. In met- alcasting, the process offers the po- tential of producing complex molds and cores with desirable mechanical and physical properties. Printed cores and molds allow for immedi- ate evaluation of design iterations without the additional costs and lead time associated with tooling, which speed the development of cast components for end users. While many sand casting sup-
Fig. 3. The matchplate for the castings included vent lines.
pliers are experienced with printed cores and molds, little research has been done into the performance of long, thin cores. Larger cores gen- erally are able to handle the forces exerted during the flow of metal during the casting process, but less robust designs are relatively untested. In the research paper, “Per-
formance of Long, Tin Printed Cores in Aluminum Castings,” two researchers evaluated the perfor- mance of printed cores that covered a range of diameters and lengths. Te primary aims of the study were to see whether cores were strong enough to hold up during pouring and whether gases could be vented from the mold through internal pas- sages in the core. If longer and/or thinner printed
cores can be integrated into castings, engineers will have more freedom in designing interior cavities in cast- ings. Te potential increased com- plexity offered by these 3-D printed cores could lead to reduced costs and lead times for casting customers.
Testing the Tubes
For the A356 aluminum castings, tubes with wall thicknesses of 0.06- in. were created with internal diam- eters ranging from 0.25 to 0.875 in. and lengths ranging from 2 to 12 in. Printed cores were used to form
28 | METAL CASTING DESIGN & PURCHASING | Nov/Dec 2015
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