Designers and engineers play a critical role in determining not only how a part looks and functions but also how efficiently it can be manufactured. When it comes to deep draw stamping, product performance and production efficiency are closely tied to design choices. A seemingly small decision in wall thickness, radius, or tolerances can be the difference between a cost-effective part and one plagued with delays, excess scrap, or unplanned tooling expenses.
At Larson Tool & Stamping, we’ve spent over a century refining the art and science of metal stamping, and we know that manufacturability begins at the design stage. In this article, we’ll share essential considerations that every product designer should know to ensure their part can be efficiently and cost-effectively deep drawn.
1. Material Selection Matters
The first design decision with major manufacturing impact is material choice. Different metals respond to the deep draw process in very different ways.
- Formability: Materials such as low-carbon steels, aluminum, brass, and certain stainless steels generally perform well in deep draw applications. High-strength alloys or brittle materials may crack or tear during forming unless carefully engineered.
- Thickness: Uniform sheet thickness ensures predictable flow during forming. Inconsistent or excessive thickness can lead to wrinkling or tool wear.
- Surface Finish: Coated or surface-treated materials may require special tooling to prevent galling or scratching.
- Cost vs. Performance Tradeoff: The cheapest material is not always the most cost-effective. For example, a slightly more expensive alloy may reduce scrap rates and extend tool life, resulting in lower total part cost.
Tip for Designers: Collaborate with your stamping partner early to validate your material choice against your part geometry. At Larson Tool & Stamping, we often run forming simulations to confirm whether a chosen material is practical for production.
2. Understand Geometric Limits of Deep Drawing
The geometry of your design directly impacts manufacturability. Deep drawing has well-established guidelines that balance formability, tool life, and part performance.
- Depth-to-Diameter Ratio: A common rule of thumb is that the reduction from the initial diameter to the drawn diameter should not exceed 50% of its diameter in the first draw. Greater depths may require multiple drawing operations, increasing cost.
- Corner Radii: Sharp inside or outside corners are a red flag for tearing or thinning. A minimum radius of 6–8 times the material thickness is often recommended.
- Wall Height Uniformity: Dramatically different wall heights in the same part can cause uneven metal flow, leading to wrinkling or fractures.
- Flanges and Features: Large flanges, embossments, or holes near draw areas complicate the process. These features are often best added in secondary operations rather than during the draw itself.
Tip for Designers: If your design requires complex geometries, expect to accommodate progressive tooling or multiple operations. Working with an experienced stamper early in the design stage can help balance complexity with cost.
3. Tolerances: Design for Realistic Precision
It’s natural for designers to specify tight tolerances, but excessive precision can drive up costs unnecessarily.
- Critical vs. Non-Critical Features: Identify which dimensions truly impact part function. Features that don’t interface with mating components can often have more relaxed tolerances.
- Process Capabilities: Deep draw stamping naturally produces some variation due to material flow. Attempting to hold unnecessarily tight tolerances may require costly secondary machining.
- Stack-Up Considerations: In assemblies, tolerances stack up. Overly tight tolerances on multiple parts can create avoidable challenges in assembly.
Tip for Designers: A tolerance study during the design stage can help balance functional requirements with manufacturability. Larson Tool & Stamping often works with customers to refine tolerance schemes that meet performance needs without inflating cost.
4. Surface Finish and Secondary Operations
The end-use of your part may require specific surface qualities or added features, but these should be balanced against manufacturability.
- As-Drawn Surfaces: Deep draw stamping generally produces a clean surface, but tool marks or light draw lines may appear. For parts requiring high cosmetic standards, polishing or post-finishing may be needed.
- Holes, Slots, and Embossments: These are best added in later stamping operations, not during the deep draw. Adding them too early can interfere with material flow.
- Coatings and Plating: If your part requires corrosion resistance or decorative finishes, design dimensions should account for coating thickness.
Tip for Designers: Incorporating post-draw finishing needs into the design phase prevents costly surprises later. Larson Tool & Stamping has in-house finishing and secondary operations expertise, which allows us to guide customers through these considerations.
5. Tooling Considerations
Your design dictates the complexity—and cost—of the tooling required to produce it.
- Tooling Complexity: Sharp corners, deep draws, or complex features increase tooling costs and lead time.
- Tool Wear: Materials with high hardness or abrasiveness will shorten tool life. Designers should weigh this when selecting alloys.
- Lead Times: Intricate tooling requires longer design and build times. Planning ahead avoids delays in product launch.
Tip for Designers: Simplifying a part design—even slightly—can dramatically reduce tooling costs. Early collaboration with Larson Tool & Stamping’s tool engineering team can identify these opportunities.
6. Cost Drivers and How to Minimize Them
Design decisions have direct implications on cost. Some of the biggest drivers include:
- Material Utilization: Poor nesting of parts from sheet stock increases scrap. Designing with efficient blank layouts in mind can lower material cost.
- Number of Operations: The more forming and finishing steps required, the higher the cost. Designing for manufacturability often means reducing secondary operations.
- Part Complexity: Every added feature, radius change, or tolerance requirement impacts cost.
- Production Volumes: Higher volumes justify more complex tooling, while lower volumes may benefit from simpler designs.
Tip for Designers: Ask your stamping partner for a design-for-manufacturability (DFM) review. Larson Tool & Stamping routinely provides these evaluations to help customers balance part performance with production efficiency.
7. Partnering with Your Stamper Early Pays Off
One of the biggest mistakes we see is designers finalizing a part design without manufacturer input, only to discover later that it requires costly redesigns.
- Prototyping and Simulation: We can run forming simulations and prototype parts to validate manufacturability before committing to tooling.
- Design Optimization: Small changes—such as adjusting a radius or tolerance—can make a big difference in reducing cost and improving quality.
- Risk Mitigation: By working together early, risks of cracking, springback, or excessive scrap can be identified and solved proactively.
Tip for Designers: Think of your stamping partner as an extension of your design team. At Larson Tool & Stamping, we pride ourselves on collaborative problem-solving that benefits our customers’ bottom line.
Conclusion: Designing with Manufacturability in Mind
Deep draw stamping offers unmatched efficiency and precision when parts are designed with manufacturability in mind. For product designers, that means carefully considering material selection, geometric limits, tolerances, surface requirements, tooling, and cost drivers from the very beginning.
By collaborating early with an experienced stamper like Larson Tool & Stamping, designers can avoid costly redesigns, reduce lead times, and ensure that their parts are both functional and cost-effective.
Learn more about specific areas to consider when designing parts for metal stamping. Follow this link to obtain our free Metal Stamping Design Guide: https://larsontool.com/metal-stamping-design-guide/
For over 100 years, Larson Tool & Stamping has partnered with customers to bring complex designs to life. Whether you are developing a new product or refining an existing one, our team is ready to provide technical insight and manufacturing expertise that make your designs not only possible but profitable.
Let’s get your project forming smoothly from the start. Reach out to our team today and experience the Larson difference.
About Larson Tool & Stamping Company
Since its inception in 1920 in Attleboro, MA, Larson Tool & Stamping Company has been making a difference as a valued supplier of precision metal stampings and assemblies to hundreds of companies in the United States. Larson provides high-quality, cost-effective solutions with our wide range of capabilities that include forming, stamping, deep drawing, machining, assembly, brazing, coining, and water-jetting. Through significant investment in leading-edge manufacturing equipment and the loyal support from customers and co-workers, Larson perpetuates the commitment made by our founders to do whatever is necessary to meet and exceed customer expectations.
