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CASTING INNOVATIONS Creating Rapid Molds With 3D Printing

3D printing offers a quick means to produce sand cores and molds, without tooling, for small quantities of cast metal testing and prototype assemblies and components. In contrast to conventional mold making, in which the production of pattern plates or core boxes alone can take sev- eral weeks, 3D printing makes it possible to “print” smaller sand molds in as little as a few hours. Te molds are cre- ated in an automated process based on CAD data using the layer building method, which consists of the repeated application of 300 micrometer-thick quartz sand layers selectively glued together with a binder. After printing, the mold is unpacked and cleaned of excess sand. 3D print technology places

of several hundred parts.” Te VX4000 machine can

produce 13.1 x 6.6 x 3.3-ft. sand molds with a volume of 282.5 cu. ft., which provides sufficient room for the rapid production of large individual molds (Fig. 1). Or, it can be used for the efficient produc- tion of smaller parts. Te machine operates at

Fig. 1. Voxeljet’s 3D printer VX4000 can produce large sand molds up to 282.5 cu. ft. in volume.

sand molds and cores for metalcasting in accordance with customer specifica- tions. Te company’s U.S. partner is 3D Systems Corp., Rock Hill, S.C. “Never before have we printed such a

fewer restrictions on the designer’s freedom of scope. Designs can be made true to their structure without having to watch for draft angles or undercuts. Even molds that have been modified during the testing phase can be printed immediately in accordance with the new CAD data, without requiring tool modifications. Current 3D printing systems from

Voxeljet Technology GmbH, Fried- burg, Germany, create high-quality

broad spectrum of molds and assisted so many customers from different industries,” said Dr. Ingo Ederer, CEO of Voxeljet. Due to the lack of tool costs up to

a certain batch size, 3D printing can be significantly less expensive than conventional methods. “Te smaller the batch size, the

greater the cost advantage offered by our Voxeljet technology,” Ederer said. “And depending on the complexity and size of the molds, 3D printing can still be the preferred choice for batch sizes

more than three times the build speed of the company’s standard printers, but with the same resolution and precision. Tis is possible because of its wide print

head, which results in time and cost savings for users. Building platforms are alternately inserted into the process station to allow for continuous building in three-shift operations. (Fig. 2). Tis 3D print technology recently was used to produce the Batoidea chair, created by Belgian designer Peter Donders (Fig. 3). Its design conjures up the image of an elegantly gliding sting- ray. Te chair, made of cast aluminum, was deemed too expensive to make without the use of 3D print technology. Donders was able to turn his uncon- ventional ideas into reality using the Rhino3D modeling program. Te CAD data set required for 3D printing was automatically available on the computer following completion of the work. Five sand molds were needed to

produce the large chair, with the largest individual mold measuring 0.04 x 28 x 15 in. Te final design consisted of a thin- walled aluminum cast structure, which underwent further processing until the

application of the finishing varnish. Visit for more information.

Fig. 2. Building platforms are alternately inserted into the process station to allow for continuous building in three-shift operations.

Fig. 3. This cast aluminum designer chair was produced with Voxeljet 3D printing technology.

December 2012 MODERN CASTING | 47

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