Foundry Uses HPI's 3D Sand Printer To Make Deadline

Dalton Foundry of Warsaw, Indiana had a case to solve for a customer—and time was running out.

Client: Dalton Foundry

Product: Gear Case Housing

Batch Size: Prototype (20)

Product Size: 29" x 26" x 12"

Material Cast: Class 30 Gray Iron

Traditional Method Cost & Timeframe: 8 Weeks at $13,000.00

HPI's 3D Sand Printing Method Cost & Timeframe: 1 Week at $1,165.00

Product Overview

The problem part in question was a section of 443-pound gray iron gear case. The corners—or ribs—in several points were cracking during the casting process. The gear case cover housing is used in industrial air compressors found at work sites to generate air and power. This was a prototype casting that was scheduled to go into production but couldn't be moved forward in the process if the end result was cracked.

Client Challenges

Dalton attempted several different processes and gating-related modifications, but a crack kept appearing. Because of the location and nature of the crack, Dalton employees thought the cracking may be a result of stress during the solidification process. Repeated simulations were run referencing the original design, which led to the conclusion that the defects were related to the design itself. The stress in the casting was the result of the original design’s base being so large that it took much longer to solidify than the other areas of the casting.

Our Solution

A plan was put in place to cut the metal tooling again, but the redesign of the part took much longer than expected. Now time was becoming critical to the project. It was at this point that Dalton turned to Hoosier Pattern and opted to make the cores using our 3D sand printer. In this specific case, Dalton saw the 3D printer could print directly from the CAD file without the upfront tooling cost—this was groundbreaking, especially with a prototype piece that had a history of cracking. With our 3D sand printing capabilities, design changes could be made quickly and a new core could be printed and pour-ready within days.

Results & Conclusion

The first pour using the 3D printed sand core was a success—no defects or cracks were found on the prototype. Twenty additional castings were needed and all of them were poured flawlessly using the 3D printed cores. Not only were there zero defects, but all the prototypes were made in a few days rather an in the few weeks a traditional tooling method would have required.

Our Competitive Advantage

Hoosier Pattern works very closely with all of our customers, enabling our designers to make changes on the fly to keep projects moving forward and meet customers’ needs and deadlines. Hoosier Pattern's 3D sand printer operation is effective and more practical for quick turnaround times.

"Our customer was up against the wall needing parts. We were aware of 3D printing and that a printed core would be turned in less than a week. The success of the part required two leaps of technological faith: stress simulation and using printed cores. Both worked out great" - Rob Burita, Tooling Engineer, Dalton Foundry

Calculating the Cost of 3D Sand Printing

In traditional tooling, there are three big points of cost that can make or break a project budget—machining and maintenance, materials, and labor. Each retooling change can add tens of thousands of dollars to overall cost, be it a large design alteration or a small adjustment. Having to wait to find faults in a mold or core after pouring the part in a foundry not only adds to costs, but also adds time you might not have to the frame of the project. A new mold or core will need creating based on an updated design and the process will need repeating until a successful part is produced.

The solution? 3D sand printed molds and cores.

3D printing cuts costs and can help shorten the production process dramatically from what you would expect from traditional tooling methods. Because just one CAD data file is needed to construct a 3D sand printed mold or core, entire steps that would normally be necessary in a traditional process can be factored out. Because of this, economical production is possible with 3D printing, enabling volume to range from individual pieces to small batches of parts.

In 3D sand printed molds and cores, the possibilities in complexity are near limitless—with that complexity also comes an added benefit of cores and molds having potential to be printed in one piece, taking out the entire step of assembly in the overall process and any costs associated with the step.

Our Cost Calculator 

When determining the cost for a core or mold, we typically take the L x W x H dimensions of the to-be-printed piece’s bounding box in cubic inches and multiply them by $0.13. If we don't have to clean the core or mold and can ship it exactly how it comes out of the box, we multiply the amount by $0.11 per cubic inch. Our minimum printing charge is $450.00.

Hoosier Pattern is an industry leading innovator and manufacturer. We pride ourselves in elevating our work and our customers with quality, cost-effective solutions, meaning great castings and quick turnaround times. Contact us today to get started.

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.

The Benefits of 3D Sand Printing 

Hoosier Pattern opened its doors in 1997 as a traditional pattern shop. Over 20 years later, HPI has become an industry leader as a premier pattern shop and—as of 2013—an additive manufacturer as well. Hoosier Pattern is one of the only shops in the United States that has both rapid prototyping and hard tooling capabilities. Many customers come to HPI and ask how they can determine whether to 3D print something versus having a tool built for their project.

The difference in benefits between 3D printed sand and hard tooling boil down to two factors—time and money. Hoosier Pattern's 3D printed sand molds take around ten days to craft and cost $0.13 per cubic inch. Hard tooling can take anywhere from a few weeks to several months to complete and costs can climb to thousands of dollars.

On the surface, 3D printing looks like the way to go for every project. However, some projects are better suited for sand printing and some for hard tooling depending on the elements and goals for the project itself. But how can it be determined which method best fits your particular needs? We may have the answers you’re looking for.

When to Use 3D Printing

Prototyping

Sand printed molds and cores can only be used once, which makes them the perfect option for prototypes. If you have more than one design for a potential part, prototyping can be used to determine which mold or casting is the best option. All of the designs can be sand printed quickly, simultaneously, and at a cheaper cost. Each mold will be individually identified, which prevents confusion when it reaches the customer. Since all 3D printed sand parts start with a CAD file, parts can also easily be tweaked and re-printed.

Low Volume Production

The term “low volume” can be defined differently by every company. We define “low volume” as anywhere from 10-500 units per year. It may not be the best choice for a company to invest in the traditional tooling process if a part will only be used for a short amount of time. Sand printing may be the best option for smaller or temporary projects.

Strict Deadlines

Sand printing is the best choice when projects require a fast turnaround. At Hoosier Pattern, many of our employees have a foundry background, so we understand how critical deadlines can be. Our standard turnaround time for 3D sand prints is 10 days. This is 10 days from the time the order is placed to the time the project will be back on the foundry floor.

Our 10-day turnaround time has changed the game for many of our customers. In the past, it could have taken several months for a tool to be completed and reach a foundry. After we receive the CAD file, we plug it into a job box. Our job box is roughly the size of an average refrigerator and takes 20-22 hours to print. Because this turnaround time is so fast, we are sometimes able to do rush orders. Our employees do everything they can to ensure a customer has their product when they need it.

Geometrically Complex Parts

It's not uncommon during the process of conventional patternmaking for engineering changes to appear. Even the smallest change can pose a problem to the castings once the tooling has been produced. Since 3D printed sand begins with a CAD file, engineers are able to design and create geometrically complex casting castings to be manufactured the way they were intended to be.

Compromises don't need to be made in order to have high-functioning manufacturability while maintaining a low cost.

When to Use Traditional Tooling

High Volume Production

Although 3D printed sand molds are more cost and time effective, there are project scenarios in which traditional tooling is a better fit. For example, it doesn't make sense to have single-use molds made for a part that is going to be produced thousands of times—in the long run, a traditional pattern is going to be more cost efficient.

Tool Life

3D printed sand molds and cores can't compete with the lifespan and durability of a hard tool. While 3D printed sand is made for one-time use instances, hard tooling molds are made to withstand thousands—or even hundreds of thousands—of uses.

Still wondering which process is right for you? Our engineers at Hoosier Pattern will help you make the best choice for your specific needs. We will be honest with you and let you know whether your project is best suited for 3D sand printing or traditional tooling.

Contact us today to learn more about our process and how we can use our expertise to benefit your business.