Creating Prototypes with Sand Casting 

The process of sand casting has been the same for hundreds of years. First, a pattern is placed in sand to create the mold and a gating system of some type is incorporated for the molten metal to flow into the mold. The pattern is then removed and the cavity is filled with molten metal. After the metal has cooled, the sand is broken away and the casting is removed.

Although Hoosier Pattern started as a traditional pattern shop—machining and building these patterns while becoming an industry leader—there was more to be explored within the sand casting world. Patterns are reusable and perfect for production use, but what about low volume productions or prototypes?

Back in 2013, Hoosier Pattern bought their first 3D sand printer, expanding their capabilities to more than just hard tooling. Five years later, Hoosier Pattern now has three sand printers in house and is more equipped than ever to provide prototypes.

How It Works

The 3D sand printing process is fairly simple and works as a normal 3D printer would. A CAD file is plugged into the machine and a layer of sand goes across a large job box (70.9 x 39.37 x 27.56"). Binder is then dropped where the part is to be made—the binder joins the sand together and, after layers of this repeated process are bonded together, the mold is formed and extracted from the job box. The created mold is then cleaned and sent to the foundry to be poured within 10 days of receiving the purchase order.

Benefits to 3D Sand Printing

There are two big benefits to 3D printing prototype molds and cores—cost and time.

Traditional pattern making is expensive and it can take months to get your first casting and maybe realize it's not even what you want. Under strict timelines, this may only give engineers and designers a couple of tries to get it right. With 3D printing, a customer can have a casting in a matter of days if needed. Depending on the size of the mold or core, multiple versions of a prototype can be printed at once in the same large job box and sent to the foundry together for maximum use of time.

Hoosier Pattern's method of 3D sand printing allows a customer to print multiple versions of the same prototype at the same time because we aren't committed to tooling. Within a short amount of time, multiple designs can be printed, poured, and tested, allowing for additional alterations or decisions to be made on even a shorter timeline.

Manufacturability is another gain when it comes to 3D printing. Designers are free to castings made true to design and designs don't need to be altered or compromised by manufacturability. Complex cores that would normally need assembly can be printed as one piece. Cores can also be printed with a hollow interior, allowing gas to escape or a core to collapse if need be—this achieves high-quality internal passage systems for castings.

Additionally, 3D printing has the potential to highlight issues that—in situations of traditional tooling—may not normally come up until the molds are moved into production. Finding these issues earlier in the timeline and after fewer resources have been spent help prevent these errors from surfacing for the first time further along in the project timeline, saving time and money in the end.

Every great product started as multiple prototypes that helped shape, adapt, and perfect the final product. Prototypes are essential in detecting problems, testing to see where improvements can be made, and ultimately making the final product more useful to the end user. 3D printed sand is not directed at a certain industry or a particular customer—this technology can be used by a wide range of customers from various backgrounds and industries of all levels.

Hoosier Pattern is a boundary-breaking industry leader—we take pride in elevating ourselves and our customers to top-notch solutions, meaning higher quality castings and quicker turnaround times. Contact us today to learn more or take the first step toward working with us.