When you submit a design to Hoosier Pattern, ever wonder about the process of getting your molds and cores printed, cleaned, tested, and then delivered? In this article, we are taking a 2,000-foot view to show you our 3D Sand Printing process from design to completion. There’s a lot to cover, so let’s get started:
To begin our process, you will submit your model, preferably a STEP or Parasolid file, to Hoosier Pattern for approval. The software we use for our CAD work is called Cimatron. To create the job boxes, we use a program called Netfabb. Our team will inspect your 3D model to make sure we do not see any issues before printing.
3D Sand Printing
Once the 3D model is thoroughly reviewed and the job box configured, we begin sand printing. First, the sand is mixed with an activator. Then the recoater will lay a layer of sand (.28 mm). Next, the print head will disperse the binder (furan) where the mold is supposed to be. This process repeats until the job box is complete.
Generally speaking, printing a job box takes around 16 to 20 hours. The size of the job box is 70.86″ x 39.37″ x 27.55″, equivalent to the size of a refrigerator. However, if your mold or core is larger than that, we will print the pieces individually and then piece them together for the foundry to pour. Large parts are printed with lift holes to make the extraction from the job box easier. Regarding the weight of these job boxes, 3,900 pounds, or almost 2 tons, is the maximum weight we can print.
Once a job box is completed, now begins the sand-cleaning process. Our trained staff will wipe down the assembled cores and use pressurized air to clean specific areas. To help further enhance the cleaning process, we will use zip ties, welding wires, or even 3D-printed objects to help get those hard-to-reach areas. To better understand how this process works, please see our YouTube video here.
Hoosier Pattern’s quality assurance for 3D-printed sand parts is distinguished by its two-check system. The first check involves a grid of squares on each part. The employee scratches their respective square to indicate the completed detail. The second check consists of an auditor who inspects the piece for any imperfections that may negatively impact the casting, such as erosion caused by air hoses or scratches made by wire. If the part passes the audit test, the auditor scratches the box on the grid, and the product is ready for packing and shipping.
Packing and Shipping
Hoosier Pattern’s packing process also includes quality checkpoints. Before packing, the packers verify that each part has two squares scratched off on the grid to ensure it has been audited and is ready for shipping. Additionally, employees take pictures inside the crate during the packing process. This step serves as a reference in case any product arrives broken, helping to determine whether the product was improperly packed or if the transit was too rough. Although rare, such issues offer opportunities to refine and improve the process.
If the part is extremely fragile, we will print it in a printed box — the media or sand around the core helps to keep the product secure during shipping. Once your product arrives, please go to our “How-to” tutorial page to see how you can clean your cores upon delivery.
To learn more about Additive Manufacturing, please visit our 3D Sand Printing page.
As always, if you have any questions about our process or need additional information for your next job. Please contact our Additive Manufacturing Manager, Todd Yoder, at (260) 724-9430 or go to our contact page.