Summary
Plymouth Foundry, Inc. (PFI) recently undertook a project to design and manufacture new pattern equipment using advanced 3D printing technologies. The project aimed to address the challenges posed by old and worn existing pattern equipment, which caused machining problems and scrap castings due to core movement. By leveraging 3D printing for the sand cores and molds, Plymouth Foundry successfully created precise and reliable casting solutions. This case study outlines the specifications, uses, manufacturing process, and quality control measures implemented in this project.
Project Specifications
- Order: One-time order for new pattern equipment
- Material: Polyurethane for the pattern, Greensand for the mold backing
- Accuracy: ±0.008 inches for 3D printed patterns
- Molding Machine: 20” x 26” Roberts Sinto Automatic Molding Machine
Uses and Applications
The new pattern equipment was designed for producing castings with complex coring requirements. The primary application was in situations where precision and stability of the interior cores were critical to prevent machining issues and reduce scrap rates. The printed sand cores and molds provided enhanced stability, ensuring high-quality castings suitable for various engineering applications.
Manufacturing Process
Initial Design and 3D Modeling
Using the 3D model furnished by the customer, Plymouth Foundry collaborated with an outside pattern shop to design the new pattern equipment. The complicated coring and new pattern were developed using advanced CAD software.
3D Printing of Block Pattern
The new pattern was printed in polyurethane using the Stratasys F370 3D printer. This printer is capable of printing with a variety of materials, including carbon fiber and thermoplastic polyurethane, with high accuracy.
Mounting and Gating
The newly printed block pattern was mounted and gated. The pattern was used to create a Greensand mold, which serves as a backing material to the printed sand mold and cores.
Simulation and Optimization
Using the Polyworks Modeler (Magma Soft) software, Plymouth Foundry performed a solidification simulation to optimize the gating and riser system. This step ensured that the casting process would yield high-quality results.
Final Assembly and Pouring
The entire mold package, including the printed sand mold and cores, was assembled before being set into the Greensand mold. The block pattern facilitated the creation of the Greensand mold using the Roberts Sinto Automatic Molding Machine. The molten metal was then poured into the prepared molds, filling the cavity to form the final castings.
Quality Control Steps
Plymouth Foundry implemented several quality control measures to ensure the success of the casting project:
Initial 3D Modeling
Accurate initial modeling was critical for capturing and replicating the required features of the casting.
Simulation Software
Using Polyworks Modeler and Magma Soft software for solidification simulation minimized the risk of defects and improved the chances of achieving a solid casting on the first attempt.
Precision 3D Printing
The Stratasys F370 printer provided high accuracy in pattern creation, crucial for maintaining tight tolerances.
Inspection and Verification
Each stage of the process, from pattern creation to final assembly, was meticulously inspected to ensure adherence to specifications.
Conclusion
By utilizing cutting-edge 3D printing technology and advanced software for simulation and optimization, Plymouth Foundry was able to deliver a high-quality, reliable solution that met the customer’s requirements. This innovative approach not only solved the issues with the old pattern equipment but also set a new standard for precision and efficiency in casting manufacturing.
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