Sheet metal components are widely used in industries such as electronics, automotive, machinery manufacturing, and household appliances. Although they may seem simple, designing sheet metal parts that are both reliable and cost-effective is far from easy. A small oversight can lead to deformation during processing, assembly difficulties, or even increased manufacturing costs.

Sheet metal components are widely used in industries such as electronics, automotive, machinery manufacturing, and household appliances. Although they may seem simple, designing sheet metal parts that are both reliable and cost-effective is far from easy. A small oversight can lead to deformation during processing, assembly difficulties, or even increased manufacturing costs.

To help designers mitigate risks early, we have summarized some typical mistakes to avoid when designing sheet metal parts. By paying careful attention during the design stage, the manufacturability and overall quality of the parts can be significantly improved.

Precision galvanized sheet bending process for metal fabrication — showing accurate folds and corrosion-resistant finish.

Design Guidelines for 3D Models Without Bends

In actual production, we often encounter solid 3D models without any bends. Such models usually cannot be automatically unfolded by software. Since metal sheets are inherently flat, processing them into the desired part shape requires bending, forming, cutting, welding, and other manufacturing processes.

Therefore, if you design a metal sheet part as a solid model, please provide a CAD file that clearly indicates the bend locations. Even if the model appears folded, the bend positions must be explicitly marked.

Additionally, since the raw material is a single metal sheet, the thickness of the entire part must be uniform. For example, if the part is designed using 1 mm thick stainless steel, the entire part must maintain a thickness of 1 mm.

Designing Perfect Vertical Sheet Metal Bends

When using a press brake to bend metal sheets, the bend usually cannot form a perfect 90° angle. This is because the tip of the bending tool is rounded, which introduces a certain radius at the bend.The bend radius can be estimated by measuring the length of the bend area and dividing it by two. This radius is determined by the tool used for the bend. If dimensional accuracy is critical for your design, make sure to specify the bend radius in your model.
Common Bend Radii
  • Inside Bend Radius (material inside): Typically 0.5–1 times the material thickness. For sheet metal bends, the inner radius is usually around this range.
  • Outside Bend Radius (material outside): Equal to the inside radius plus the material thickness.
    Formula:Rout=Rin+t
    • t: material thickness
      Example: For a sheet thickness of 1 mm and an inner bend radius of 0.762 mm, the outer bend radius is 0.762+1≈1.7620.762 + 1 approx 1.7620.762+1≈1.762 mm.

Design Recommendations

Although different bend radii can be used for each bend, to reduce costs, it is recommended to standardize bend radii as much as possible. This avoids frequent tool changes for the manufacturer and saves time and labor.By planning the bend radius in advance, you can prevent manufacturing issues during the design stage and improve both the accuracy and manufacturability of the part.

Avoid Placing Holes Too Close to Bend Lines

In sheet metal design, holes are often added for assembly purposes. The distance between a hole and the bend edge (edge margin) is a critical factor to ensure smooth forming and structural integrity. If a hole is too close to the bend line, the material may stretch or compress during bending, which can cause hole deformation, tearing, or cracking, ultimately affecting part strength and assembly accuracy.As a general guideline, the edge margin should be at least 2.5 times the sheet thickness to ensure even material stress during bending. For larger holes, the margin should be increased proportionally to prevent cracking around the hole during bending.Proper hole-to-bend spacing not only ensures bending quality but also improves part strength and assembly reliability, making it a key detail in sheet metal design.

Selecting the Appropriate Metal Sheet

In sheet metal design, selecting the appropriate metal sheet is critical to ensuring part performance, durability, and manufacturability. For example, parts intended for outdoor use should be made of corrosion-resistant materials, such as stainless steel or carbon steel with surface protection, while aluminum alloys may be more suitable for lightweight structural components.

When choosing materials, factors to consider include expected mechanical performance, corrosion resistance, appearance, manufacturability, and electrical conductivity.

Material TypeCharacteristicsCommon Applications
Low Carbon SteelLow cost, good machinability, weldableGeneral sheet metal enclosures, chassis
Hot-Dip Galvanized SteelStrong corrosion resistanceOutdoor or humid environment sheet metal parts
Stainless SteelCorrosion-resistant, aesthetic, moderate strengthKitchen equipment, medical devices, decorative parts
(304, 316, etc.)
Aluminum Alloy Sheets (5052, 6061, etc.)Lightweight, corrosion-resistant, easy to formAerospace, transportation, lightweight enclosures
Copper/BrassConductive, wear-resistant, aestheticElectrical components

Selecting Appropriate Surface Finishes

In sheet metal design, choosing the right surface finish is crucial for both part performance and appearance. Surface finishes generally serve two purposes: protecting the part and enhancing its appearance, with some finishes providing both.

Appearance-Focused Finishes

Screen Printing: Used to add text or graphics on the part surface; purely decorative and offers no corrosion protection.

Powder Coating: Improves aesthetics while providing some level of protection. However, if the coating is scratched, the underlying metal may still be exposed and susceptible to corrosion.

Protection-Focused Chemical Treatments

Chemical Conversion Coatings: Alter the metal surface chemistry to protect the part, such as galvanizing or chromate conversion.

Galvanized / Annealed Galvanized Steel: Suitable for steel used in corrosive environments, providing a protective zinc layer.

Note: Annealed galvanized steel should not be welded directly, as it releases hazardous gases. Parts should be welded first and then galvanized.

Chromate Conversion: Provides corrosion protection and serves as a primer layer for subsequent painting, while maintaining electrical conductivity.

Aluminum-Specific Treatments

Anodizing: Adds metallic color options to aluminum parts while enhancing corrosion resistance.Example: Colorful anodized finishes on flashlight housings combine aesthetic appeal with protective functionality.

Key Considerations

Choose surface finishes based on the part’s operating environment, manufacturing process, and functional requirements.For parts requiring both protection and aesthetics, consider finishes like powder coating or anodizing that serve dual purposes.

Choose a Reliable Sheet Metal Fabrication Partner

Designing and fabricating sheet metal parts may seem complex, but with an experienced partner, the entire process can be smooth and efficient.

Horizon has focused on sheet metal fabrication for many years, providing high-quality, precise part solutions for a wide range of industries. Whether it’s stainless steel, aluminum, or carbon steel, we utilize laser cutting, bending, stamping, and other processes to produce parts that meet your exact specifications.

Our services are not only efficient and reliable but also cost-effective, helping clients seamlessly transform designs into finished products.

Contact Horizon today for professional advice and a personalized quote, and let us turn your creative parts into reality.

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