DFM seeks to optimize part designs for manufacturing feasibility. When applied effectively, both metal formers and their customers experience significant advantages.
Benefits for the customer include:Benefits for the metal former include:
Improved scalability: Well-designed parts can be scaled up for higher production volumes with minimal adjustments, reducing long-term costs. When a part is designed around a stamping die’s capabilities, metal formers can meet increased part demands when orders increase. If the part is poorly designed and the die already struggles to meet demands, increasing part volumes will prove difficult because fixes may be required before the part can be stamped.
Lower tooling and maintenance costs: Producing a part with features that align with the die’s capabilities reduces strain on tools and increases their lifespans. For example, holes that are too small lead to broken punches and sheared die sections, requiring more frequent sharpening and replacement of the tool steels. Complex form features sometimes require cams or other more complex tooling features that add upfront tooling costs can increase maintenance costs over the life of the die. -
Higher production efficiency: DFM-optimized part designs reduce scrap rates, tool wear and machine downtime, leading to greater productivity. - Reduced defect rates: A design that accommodates stamping-die constraints lowers the likelihood of stamping defective parts.
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Increased customer satisfaction: A metal former that delivers high-quality parts on time strengthens relationships and enhances business opportunities. - Competitive advantage: Efficient production processes allow metal formers to remain competitive in pricing and reliability.
Best Practices for Designing to Die Capabilities, Constraints
Implementing best practices such as proper material selection, appropriate bend radii and thoughtful hole placement ensures that parts not only are manufacturable but also optimized for long-term production success. To achieve a successful stamped part, engineers must understand what a stamping die is capable of producing. Metal forming dies are highly efficient tools, but they have inherent limitations. Designing around these constraints ensures manufacturability without compromising function.
Key considerations for designing die-friendly parts:
Material selection: Choosing the right material is crucial. Some materials, such as high-strength steels or exotic alloys, can be challenging to stamp and may require special die materials or additional operations. Selecting material that balances strength and formability improves efficiency.
Bend radii, forming limits: Avoiding overly sharp bends is essential to preventing cracking and excessive stress on the die. A rule of thumb: Design bend radii that are at least equal to the material thickness.
Bend leg: Avoid designing bends with a short leg length. The bend height, measured from the tangency point of the form radius, should be at least 2.5 times the material thickness.
Hole, slot sizing and placement: Holes located too closely to bends, edges or other holes can become distorted. Best practice: Place holes at least 1.5 times the material thickness away from bends, edges and other holes to prevent tearing or deformation. Ideally, the holes and slots should have a diameter that is equal to, or greater than, the material thickness being punched.
Tolerances, GD&T: Overly tight tolerances increase manufacturing difficulty. Unless critical, designers should apply tolerances to parts in a way that aligns with standard stamping-die capabilities.
Minimizing secondary operations: Features that require post-stamping operations, such as tapping or welding, increase cost and production time. Where feasible, designers should integrate features that can be stamped directly. In-die tapping and hardware insertion are viable options. While they increase initial tooling costs, the piece-part price will be much lower than if those features had to be performed as secondary operations.
Proper use of progressive and transfer dies: Understanding whether a part will be made using a progressive die (ideal for high-volume production) or a transfer die (for more complex, lower-volume parts) can significantly influence design choices.
Edge quality: Ensuring smooth edges by designing appropriate clearance in cutting operations reduces the need for deburring and secondary finishing.
Coining, embossing: Adding embossed features or coined surfaces can enhance part strength and eliminate the need for additional components—improving both performance and cost-effectiveness.
Collaboration, Simulation Net Best Results
A crucial aspect of DFM in metal stamping is the early and continuous collaboration between designers and manufacturers. When engineers consult with stamping experts during the design phase, they gain valuable insights into what is feasible and cost-effective. This proactive approach prevents costly redesigns and ensures an optimized final product from the start.
By fostering collaboration between design engineers and manufacturers, DFM leads to a streamlined, cost-effective and high-quality manufacturing process. In an era wherein these attributes define success, embracing DFM is not just an option, it’s a necessity, whether for electronics, automotive, consumer goods or industrial manufacturing. Ultimately, achieving the intricate balance between design complexity and manufacturability is key to success in metal stamping. With proper planning, metal formers can produce innovative, high-performance components while keeping production costs under control. Embracing DFM principles will continue to drive advancements in the industry, benefiting everyone in the process and ensuring a win-win scenario. MF
View Glossary of Metalforming Terms
See also: Rockford Toolcraft, Inc.
