Metal Stamping Design Guidelines
- Metal Stamping |
- Dec 29, 2025
Designing components for metal stamping does not only consist of successfully meeting the functional requirements. The success of a metal stamped part is achieved by balancing the geometry, how the material behaves, the limitations of the tools used to stamp and the efficiency of producing the stamped part on a mass production basis. When a designer does not use the standard design guidelines, he or she will almost always encounter issues like cracking, burrs, damage to the tool, and increased costs during mass production.
This blog contains an outline of the industry-design guidelines used by OEMs (Original Equipment Manufacturers) and Tier-1 suppliers as of 2026. These guidelines and principles will help manufacturers produce stamped parts with consistent quality, extended tool life and cost-effective methods for general automotive, electrical, EV, and industrial applications.
Stamping Process Overview
Metal stamping is a mechanical process in which flat sheet metal is cut and formed by means of high-speed and high-pressure machines that use precision dies and presses. Various operations can be performed during stamping, such as blanking, piercing, bending, and forming.
Unlike the processes of metal removal, which depend on controlling the flow of material, stamping relies on controlling the flow of the material for forming a part. Therefore, the part geometry must be designed to enable an optimum form and use of the material for maximum stability. The design guidelines will assist in providing manufacturers with predictable production stamping processes that can be repeated and are suitable for high volume production.
Special Features of Metal Stamping Relevant to Design
There are many component manufacturing advantages that result from the application of metal stamping, however, these advantages can only be realised if components are designed in accordance with proper design practices.
When creating a new part, it is important to consider the following key aspects of design:
1) High repeatability among large quantities of components;
2) Consistent dimensional specifications;
3) Automation compatibility .
Components manufactured using metal stamping are typically best suited to the use of progressive die and transfer die operations that provide for multiple processes to be performed in sequence.
Designs that support these aspects will minimise shutting down presses, amortising tooling costs over a longer period of time, reducing the number of secondary operations, and extending the total life of the tooling for that part.
Types of Metal Stamping and Design Impact
Different stamping methods place different constraints on part design. Understanding this relationship helps designers avoid geometries that are difficult or expensive to manufacture.
Common metal stamping methods include:
- Progressive stamping, which is an excellent way to create a large-volume part with multiple features
- Transfer stamping, is useful when a part is either larger or has more complex geometries in its design;
- Deep draw stamping is which will create a part of greater depth and material flow.
The specific design rules such as feature location, bending sequence and carrier requirements may vary depending on a particular stamping process being used. Therefore, it is critical that there be early alignment between design intent and stamping process, as this will improve the ability to manufacture the part.
Metal Stamping Design Considerations
The Guidelines are based on practical manufacturing experience and represent the essential foundation for metal stamping design. These guidelines are critical to preventing defects and failures of tool.
Hole and Slot Design
Stampings have an extremely high level of failure due to holes and slots. Inadequate size and spacing of holes increases the stress on punches and causes distortion and premature wear of tools.
Design guidelines include:
- The minimum diameter for a hole must equal 1.2 times the thickness (1.2T) of the material.
- When working with harder materials, the recommendation is to provide a thickness (T) of 1.5 so as not to damage punches.
- A hole should be located at least 2T away from the edge of the part.
- The minimum spacing between holes is 2T from each other.
By adhering to these guidelines, the shearing of holes can be performed with clean edges and the ability to produce parts with the same size and shape nearly every time.
Guidelines for Bending and Forming
In bending operations, the outer surface of the material is subjected to tensile stress. Failure to create the proper bend geometry is one of the leading causes of cracking and producing inaccurate angles.
Key bending rules:
- The inside radius of the bend should be equal to or greater than the thickness (1T) of the material.
- When the inside radius is smaller than thickness of the material, chance of cracking increases significantly.
- The minimum height of the bend flange should be equal to 2.5T plus the radius of the bend.
- When a flange is too short, there is usually a decrease in repeatability and forming stability.
Designing using proper bend geometry will help improve the durability of the part and stability of forming.
Grain Direction Considerations
Sheet metal has a defined grain direction due to the rolling process. Ignoring grain orientation can cause unpredictable failures during forming.
Bending sheet metal perpendicular (or at a 90-degree angle) is preferred when possible, therefore, bent parts are less likely to fail in a destructive manner. When bent parallel (or in-line), the probability of failure increases significantly, particularly with high-strength steels and other tempered alloys.
When designing critical components, the engineer should specify the direction of the grain on the engineering drawings.
Feature Placement Near Bends
Features that are placed very close to the location where the bend will be made may experience deformation during the process which will result in either scrap or rework.
Design rules include:
- Placement of holes is at least 2.5T plus the bend radius from the bend line.
- If a bend will occur reasonably close to a flat section, the engineer should provide a relief notch for the material at the bend location.
- Bend relief width should be at least 2T
- Bend relief length should be equal to the bend radius plus material thickness
By following the placement guidelines for holes and other features, sheet metal designers can prevent distortion and maintain better dimensional control of the parts they produce.
Notches and Tabs Design Rules
Notches and tabs are commonly used for locating and assembly, but poor proportions make them vulnerable to damage.
Recommended guidelines:
- Minimum notch or tab width should be 1.5T
- Feature length should not exceed five times its width
Balanced proportions improve structural stability and reduce breakage during stamping and handling.
Tolerances, Burrs, and Flatness
Over-tight tolerances significantly increase manufacturing cost without improving functionality.
Key considerations:
- Typical angular tolerance for a 90-degree bend is ±1 degree
- Burrs are inherent to stamping and usually measure up to 10 per cent of material thickness
- The direction of the burr should be clearly specified on the drawings
- Avoid flatness requirements tighter than 0.003 inches per inch unless functionally required
Unnecessary tolerance tightening often leads to secondary operations such as coining or machining.
Possible Defects Caused by Poor Design
Manufacturing defects are often the result of design decisions rather than process errors. Experienced stamping manufacturers frequently observe the following issues.
Common defects include:
- Cracking of parts by tightly bend radii and/or incorrect orientation of the grain in the material
- Excessive burrs resulting from improper clearance or hole size
- Distortion of holes due to features being placed too close to the bend
- Warping & springback from unachievable flatness requirements
- Premature tool wear from very small holes being cut in thick or hard materials.
By designing the part with the realities of manufacturing in mind, some of these defects will occur less frequently throughout the long production run.
Design for Manufacturability Checklist for OEMs
Before releasing a stamped part for tooling, OEMs should confirm:
- The grade of material and thickness is clearly identified
- The hole size and spacing conform to minimum guidelines
- Bend radii and flange heights abide by industry accepted standards
- The grain direction is identified when applicable
- Bend relief areas are identified when necessary
- The burr direction is described in the drawings
- The tolerances are functionally justified
This checklist helps prevent late-stage redesigns and production delays.
Conclusion
Metal stamping design guidelines are not theoretical; rather, they are practical design methodologies derived from many years of experience in producing products in high-volume production settings.
Applying these guidelines during the early stages of product development will help Original Equipment Manufacturers (OEMs) decrease defects, increase tool lifespan, and provide a consistent level of quality, even at a large scale. In highly competitive sectors like electric vehicles (EVs), automobiles, and electrical equipment, efficiently designed stamped parts result in a significant operational and cost-benefit to the manufacturers.
Ultimately, designing a product for metal stamping is about bringing together the manufacturing realities and the engineering objectives of the product’s design.
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