Efficiency and cost savings in product development help companies bring products to market faster, improve profitability, invest more in innovation, allocate resources more effectively, and improve customer satisfaction. 

Sheet metal parts enjoy wide application in different industries including automotive, aerospace, and construction. Now, sheet metal fabrication is one of the most popular manufacturing processes. Rapid sheet metal prototypes play a vital role in testing and validating designs before committing to full-scale production, reducing the risk of costly errors and delays. This article discusses the best ways to maximize efficiency and reduce costs with rapid sheet metal prototypes.

What Are Sheet Metal Parts?

Sheet metal parts are thin metal components that can be manufactured using methods like stamping, bending, and stretching. These parts have a consistent thickness, usually no more than 6mm, throughout the manufacturing process. Sheet metal parts are distinct from castings, forgings, and machined parts. Examples of sheet metal parts include the outer shell of a car and stainless steel kitchenware.

Modern sheet metal processing technologies include wire winding, laser cutting, heavy machining, metal bonding, metal drawing, plasma cutting, precision welding, roll forming, metal sheet bending, die forging, waterjet cutting, and more.


Designing for Efficiency in Rapid Sheet Metal Prototypes

The sheet metal design process should follow principles such as ease of flattening, reasonable processing technology, reasonable styling and structure, uniform wall thickness, and cost-effectiveness to improve processing efficiency. When designing, the following points should be considered:

1. Consider the strength design of the sheet metal

Strength design directly affects the durability and service life of the product. In the design process, conflicts may arise when trying to increase the strength of the sheet metal. Therefore, attention should be paid to strength design to avoid conflicts.

2. Consider the relationship between sheet metal thickness and design dimensions

Sheet metal parts are processed from flat sheets, and thicker sheets are more difficult to process. It is necessary to ensure that the designed sheet metal can be unfolded onto a plane without interference.

3. Consider the manufacturing process of sheet metal

After the design is completed, whether the processing and production processes are easy to operate, whether they will increase the product cost, and a series of issues that affect production efficiency and safety should be considered. 

Most sheet metal prototype parts can be produced by laser cutting, bending, riveting, and welding. The bending process is particularly important. Generally, the bending radius (R) should be at least one sheet thickness (T). 


Different materials have different requirements for bending radius: copper is relatively soft, so the bending radius can be as small as 0.5T (copper is often used for current flow, and some automotive OEMs require R ≥ T to avoid heat concentration); the recommended bending radius for stainless steel sheet is 2T. 

When the bending edge is parallel to the material fiber direction, there are small cracks on the outer side of the bending angle.

4. Consider the design of sheet metal assembly and installation

Consideration should be given to the rationality and convenience of assembly to reduce problems that may arise during assembly.

5. Consider the connection and fixing methods between sheet metal parts

The connection and fixing methods between sheet metal parts are crucial factors to consider in design. Generally, sheet metal parts are connected by screws, welding, rivets, etc. 

1) Pull rivets, self-riveting, and welding are commonly used for single parts (which may also be composed of multiple components).

Riveting is not recommended for load-bearing parts. And self-riveting is widely used.

Welding is a permanent connection of two or more metal components by melting material. Spot welding mainly serves for connecting parts with a thickness of ≤3mm. 

2) Drawing holes + screw assembly and pressure-riveted nuts + screw assembly are commonly used for joining between different parts.

There are two types of perforated tapping: drawing holes + screw assembly and perforation + self-tapping screws. Drawing holes + screw assembly is more recommended due to the low failure rate and high reliability. PEM's pressure-riveted nuts (similar to pressure-riveted studs and other products) are commonly used.


6. Consider the ease of maintenance

Reasonable and excellent sheet metal design can greatly reduce maintenance difficulty.

Streamlining the Manufacturing Process

Besides efficient design, working with an experienced sheet metal fabrication company can also help to streamline the manufacturing process and ensure that the prototype is produced to the highest quality standards.

Rapid Sheet Metal Prototype FAQs

1. What files are needed for manufacturing rapid sheet metal prototypes?

STP. files for 3D dimensions. CAD files for the unfolded views. 2D files in PDF for tolerance indications.

Other files are necessary when surface treatment is required, such as AI files for silk screening and color codes for painting or powder coating.

2. What are the materials available for rapid sheet metal prototypes?

Nearly all metals have sheet metal forms. The most commonly used ones are aluminum, stainless steel, mild steel, copper, brass, etc. The choice of material for rapid sheet metal prototypes will depend on the specific requirements of the application, including strength, weight, corrosion resistance, and cost.

3. What are the surface treatments available for rapid sheet metal prototypes?

There are a variety of surface treatments that can be applied to rapid sheet metal prototypes, including anodizing, plating, powder coating, sandblasting, polishing, and more. These treatments can be used to improve the aesthetics, durability, and resistance to corrosion and wear of the finished product. The choice of surface treatment will depend on the specific requirements of the application.

4. What are the tolerances of rapid sheet metal prototypes?

The tolerances for rapid sheet metal prototypes are typically lower than those for CNC machined parts. This is because processes such as bending and welding can introduce variability in the final dimensions of the part, and sheet metal is thin and soft, making it more prone to distortion. However, these features do not usually lead to assembly problems, so extremely tight tolerances may not be necessary. The specific tolerances required will depend on the intended use of the part and the requirements of the customer. It is important to work with a trusted supplier who has experience in rapid sheet metal prototyping to ensure that the final product meets the required specifications.