Sand casting has a history dating back thousands of years, and it has remained virtually unchanged during that time. However, things are changing now, thanks to 3D printing. Here are some of the outcomes of those endeavors.
Helping a Well-Established Company Stay Innovative
In today’s highly competitive marketplace, even companies established more than a century ago have to continually improve to keep customers satisfied and stop them from going elsewhere for services. D.W. Clark is a multi-alloy metal casting company that implemented 3D printing for its sand casting methods and got notable results.
The company reportedly shortened its lead time from months to weeks while eliminating traditional methods of tooling and patterns. D.W. Clark uses binder jetting technology, and vice president Jeff Burek gave an example of the potentially shortened timeframes.
“We have a customer who wanted us to finish machine an impeller within two weeks. And not having run the machine for more than a couple of builds, we were able to design the mold within a couple of days, print it, pour the casting, heat treat the casting and finish machine the casting all within two weeks.”
Another advantage of bringing 3D printing to sand casting is that it reduces the costs associated with producing complex parts. The printer works from a digital file that representatives can quickly reproduce when needed. Moreover, the printer selected by the business uses less sand than conventional casting processes. That benefit means it spends less on materials.
This case study is an example of how sand casting can help long-established companies stay relevant and continue meeting customers’ needs while achieving other benefits that help them remain resilient.
Facilitating Prototyping While Keeping Costs Down
Applying 3D printing to sand casting is also an attractive alternative when companies want to shorten prototyping time. GRATZ Engineering is a German company with several locations throughout the country and just under 250 employees. It found that using 3D printing during sand casting projects was particularly advantageous during prototyping. The company usually depends on sand casting with 3D printing, as well as direct metal laser sintering (DLMS).
Andreas Steinbronn, head of parts management, said, “Metal 3D printing like laser sintering is always too expensive if speed is not an issue. If we have two or three weeks for the prototype, we generally prefer to use a combination of classic metal casting with 3D-printed sand molds or investment casting patterns made from Poly(methyl methacrylate).”
Steibronn continued, “This cuts costs enormously, and the increased durability and stability of the components is, of course, also an advantage. The most practical aspects of this are the large building volumes and fast printing rates.”
There was also a direct comparison of 3D printing versus DMLS: “With the binder jetting printing systems, we can directly produce several variants of our prototypes, such as turbochargers, in parallel and nested on top of each other in one and the same 3D printing process, and not just in one level, as is the case with DMLS.”
Enabling Companies to Prototype Lighter and Thinner New Designs
Sand casting is a perpetually popular method of making complex metal parts. Besides the efficiency and cost-effectiveness it offers, there’s a reusability aspect. Each mold created with sand casting is a single-use item. However, after taking finished parts out of molds, people can repurpose the sand mixture for future molding projects.
Combining sand casting with 3D printing offers another kind of sustainability. It allows clients to thoroughly inspect prototypes and subject them to rigorous testing before production begins, saving substantial time and money.
A British company called Brooks Crownhill Ltd. (BCP) uses 3D sand casting when making housing for electric motors and car parts. Lee Henderson, the company’s sales director, clarified that the business is no stranger to this emerging process.
“We have been using 3D printing and casting, or printed casting, for quite some time now. The immense advantages are obvious. The process is fast, cost-effective and gives designers enormous creative freedom. This is important for rethinking established components and saving as much material as possible, for example, by optimizing the topology of the components,” Henderson said.
Henderson also discussed how using 3D printing for sand casting allowed BCP to address emerging customer needs. Clients more often demand lighter and thinner new designs. He said conventional processes, like milling or core shooting, did not accommodate the geometries of customers’ parts. However, sand casting with 3D printing does. Henderson said many people remain unaware of the benefits that 3D printing and sand casting can bring. However, results like these could help the option gain traction.
Letting Foundries Repurpose Real Estate
Before 3D printing became an option, foundries had no choice but to dedicate large sections of their facilities to housing patterned match plates. Those patterns represent copies of parts made for clients. People working in foundries depend on those plates whenever a client asks them to create a part again. The rows of those match plates often become so expansive that foundries pay warehouses to keep them.
However, since 3D printing relies on digital files, companies that use it for sand casting can minimize or even eliminate the practice of keeping physical match plates on-site. Howard Rhett works at Viridis3D, a company specializing in 3D printing for sand casting. He noted that the digitization offered by 3D printing means companies no longer need to worry about matters such as humidity control or keeping pests out of the storage facilities.
Instead, they can store the medium-to-low-use patterns on a USB drive. That’s a portable option that removes many of the inconveniences associated with traditional storage methods. If foundries free up enough space, they could use it for other purposes, such as growing their business and allowing expansion.
Plus, having clients’ files in a digital format speeds up the time between when a foundry receives a customer order and representatives start working on it. In some cases, foundry workers can pour molten metal into a large mold on the same day they receive a digital file.
Proving That the Process Brings Multiple Benefits
Ongoing research shows that people can anticipate numerous advantages if they decide to use 3D printing for sand casting. One investigation involved comparing 3D printing and conventional sand casting when making a pump bowl.
The team found that the 3D-printed approach took only 26 hours to print the sand casting mold’s parts. That’s a substantially shorter timeframe compared to the more than six weeks required for the traditional approach to reach that step. Also, the 3D-printed bowl was about 300 microns smoother than its counterpart. It was also almost 27% lighter than the traditionally cast bowl.
Another research project compared the differences between a ceramic mold made with 3D printing and sand casting and the traditional technique. The option made with 3D printing was 95% lighter and had a metallic yield optimized by 29% compared to the conventionally cast ceramic mold. Another difference was that the traditional method took nearly twice as long for fabrication. That was because the team had to make a two-part pattern and smooth its surface.
3D Printing Is a Sand Casting Game-Changer
These examples highlight why people more frequently see 3D printing as an appealing alternative to traditional sand casting. It’s not yet a mainstream practice, but that could change soon. As more companies experiment with it and get impressive results, other foundries should follow suit and make the technique more common.
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