Summary
Plymouth Foundry, Inc. (PFI) was commissioned to manufacture two precision castings for a bridge refurbishing project. This one-time order required PFI to leverage advanced 3D scanning, modeling, and printing technologies to produce high-quality castings with stringent specifications. The process involved creating a 3D model from an existing rough casting, modifying it to include necessary drafts and filets, and utilizing a combination of printed sand molds and greensand molds for cost-effective production. The project exemplifies PFI’s capabilities in delivering complex castings with precision and efficiency.
Project Specifications
- Customer: Bridge refurbishment project
- Order: One-time order for two castings
- Material: Not specified, typical casting materials include iron or steel
- Accuracy: ±0.008 inches for 3D printed patterns
Uses and Applications
The castings were intended for use in a bridge refurbishing project, highlighting their application in critical infrastructure repair and maintenance. Such castings are essential for ensuring the structural integrity and longevity of bridges, which are vital components of transportation networks.
Manufacturing Process
Initial Scanning and 3D Modeling
- The project began with PFI scanning the provided rough casting to create an accurate 3D model. This step was crucial for capturing the precise dimensions and features of the original casting.
3D Model Modification
- An external pattern shop modified the initial 3D model to include drafts and necessary filets. This refined model was essential for producing a functional and high-quality casting.
3D Printing of Block Pattern
- The modified 3D model was used to print a block pattern with PFI’s Stratasys F370, an industrial-grade 3D printer. This printer is capable of handling a variety of materials, including carbon fiber and thermoplastic polyurethane, with high accuracy.
Mold Creation
- The block pattern was used to create a greensand mold, which served as a backing material. This method is more cost-effective than printing the entire mold using a 3D sand printer.
- The printed pattern, along with gating and risers generated using PFI’s Polyworks Modeler and Magma Soft software, was mounted to create the complete mold package. This software allows for solidification simulation, increasing the likelihood of defect-free castings on the first production run.
Assembly and Pouring
- The entire mold package was assembled and set into the greensand mold. This meticulous assembly process ensured the stability and precision of the mold during the casting process.
- The molten metal was poured into the prepared molds, filling the cavity to form the final castings.
Quality Control Steps
PFI implemented several quality control measures to ensure the success of the casting project:
3D Scanning and Modeling
Accurate initial scanning and detailed 3D modeling were 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
Plymouth Foundry’s ability to integrate advanced technologies in 3D scanning, modeling, and printing with traditional foundry practices enabled the successful completion of a complex casting project for bridge refurbishment. The project underscored PFI’s commitment to quality and precision, delivering castings that meet stringent specifications and contribute to the safety and durability of critical infrastructure.
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