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Design Guidelines for Sheet Metal Fabrication

Use these practical design checkpoints to prepare sheet metal parts for efficient fabrication, more predictable fit, and cleaner production outcomes.

Component Sizes for Sheet Metal Parts

Minimum Dimensions

Flat Part	0.30 in. × 0.30 in. 7.6 mm × 7.6 mm
Formed Part	0.55 in. × 0.55 in. 14.0 mm × 14.0 mm

Maximum Dimensions

Size	38 in. × 46 in. 965 mm × 1,168 mm
Bend Length	46 in. 1,168 mm

Tolerances

Feature	Single Surface	Multi Surface
Linear dimensions	Specified at quote	Reviewed by feature relationship
Angular features	Reviewed by bend geometry	Reviewed by accumulated bends
Hole location	Feature-specific review	Reviewed across formed surfaces
Bend relationship	Part geometry dependent	Accumulated feature review

Sheet Metal Material Thickness Range

Available thickness is selected against the chosen material, part envelope, feature pattern, and forming plan.

Thickness	CR Steel	HR Steel	Galvanized	Aluminum	Stainless	Copper	Brass
0.024 in.	Available	—	Available	Available	—	—	—
0.032 in.	Available	Available	Available	Available	Available	—	—
0.040 in.	Available	Available	Available	Available	Available	Available	Available
0.050 in.	Available	Available	Available	Available	Available	Available	Available
0.063 in.	Available	Available	Available	Available	Available	Available	Available
0.080 in.	Available	Available	Available	Available	Available	Available	Available
0.100 in.	Available	Available	Available	Available	Available	—	—
0.125 in.	Available	Available	Available	Available	Available	—	—
0.160 in.	Available	Available	—	Available	Available	—	—
0.190 in.	Available	—	—	Available	Available	—	—
0.250 in.	—	—	—	Available	—	—	—
0.375 in.	—	—	—	Available	—	—	—

Sheet Metal Surface Finish Guide

Use a short visual reference to compare standard fabrication finishes with cosmetic surface requirements before a design is released.

Design for Sheet Metal Bending

Plan bend direction, inside radius, tool access, and material grain together. Practical details early in the model make formed dimensions easier to control.

Understanding Brake Lines

A press brake leaves a natural witness where force is applied. Define appearance-critical surfaces early so the fabrication sequence can account for them.

Feature Proximity to Bends

Keep cut features clear of active bend zones. Adequate clearance protects holes and slots from distortion during forming.

Extending Features Through Bends

Where a profile crosses a bend, evaluate the feature shape together with material stretch and the required formed profile.

Fabricating Designs with Features Along a Bend

Coordinate lances, tabs, slots, and formed details with the press-brake path so the selected tool can reach the intended geometry.

Minimum Flange Lengths

Give each flange enough material for stable tool contact. Short returns are reviewed against the stock, bend radius, and target geometry.

Hardware Inserts near Bends

Place inserted hardware where forming tools can reach the bend without collision, and sequence insertion with finishing requirements in mind.

The Challenge with Hardware Holes and Inserts near Bends

Holes and inserts can affect formed geometry when they sit too close to a bend. Reserve material and tool clearance around each critical interface.

Solving the Challenge with Material Relief

A strategically placed relief gives material room to stretch during forming without pulling a critical feature out of position.

Bend design connects the flat pattern to the finished component. Keep the intended shape, visible surfaces, tool access, and dimensional relationships visible before the fabrication route is fixed.

Bending Design Guidelines for Sheet Metal Fabrication

A stable bend plan begins with the material and thickness, then checks the inside radius, flange length, feature relationship, and the way the part will be handled after forming.

Understanding Brake Lines

Brake contact leaves a process relationship that can matter on visible surfaces. Use practical bend direction and selected finish requirements to guide where that relationship belongs.

Brake Line and Surface Considerations

Cosmetic-side bend planning

Plan the visible side and contact direction early when surface appearance is a requirement.

Formed-side bend planning

Keep the structural geometry, material grain, and tool approach aligned around the intended return.

Feature Proximity to Bends

Compare the selected feature with its nearest bend zone before release. The practical direction depends on material behavior, whether a feature is visible, and the required formed geometry.

Design Situation	Practical Direction
Feature close to an active bend	Reserve clearance or review whether the operation can be sequenced after forming.
Critical location across a bend	Use the model to assess accumulated movement and the required final relationship.
Feature in a visible surface	Plan bend orientation and finishing together so the surface requirement remains clear.
Complex formed profile	Review the part as a complete setup before committing to the selected feature route.

Extending Features Through Bends

A feature that crosses a bend should be considered as a formed system rather than an isolated cutout. The following diagram positions reserve the expected material movement.

Feature stops before the bend

The flat pattern keeps the opening clear of active material stretch.

Excess material at the bend

Review whether material accumulation would distort the final formed profile.

Cut-out extended through the bend

A controlled extension can relieve the contact zone and preserve the intended feature.

Material removed along the bend

Use a selected relief when the feature and formed profile require extra clearance.

Detailed feature choices are most effective when they are reviewed as part of the full sheet component: flat-pattern geometry, bend sequence, tool access, hardware, finish, and the final assembly relationship.

Fabricating Designs with Features Along a Bend

Coordinate every cutout, tab, louver, or inserted component with the bends that surround it. This gives the manufacturing review enough context to identify suitable relief and reliable order of operations.

Minimum Flange Lengths

A flange must provide enough material for stable contact and the required finished shape. Short return conditions are checked against the stock, radius, and tooling approach before release.

Hardware Inserts near Bends

Place hardware so the forming path and installation sequence can remain practical. The most suitable arrangement depends on local clearance, part stiffness, and the selected surface treatment.

Hardware and Relief Planning

Hardware clearance at a bend

Keep enough clearance for forming tools and the intended insert operation.

Relief around a formed interface

A suitable relief lets material move without disturbing the required critical feature.

Design Guidelines for Common Sheet Metal Features

Tabs and slots

Keep mating details accessible and clear of bends.

Notches and corners

Use practical relief at formed intersections.

Holes and cutouts

Maintain spacing that suits the selected stock.

Return flanges

Keep forming contact and clearance visible in the part geometry.

Formed steps

Review height, bend direction, and neighboring feature access.

Hardware holes

Reserve clearance for installation and adjacent forming tools.

Corner relief

Use relief where material needs room to stretch during forming.

Mating details

Coordinate repeated features with the intended assembly relationship.

Visible surfaces

Identify surfaces that need cosmetic handling or protected packaging.

Check your design against these rules in a quote.

Contents

Design Guidelines for Sheet Metal Fabrication

Component Sizes for Sheet Metal Parts

Minimum Dimensions

Maximum Dimensions

Tolerances

Sheet Metal Material Thickness Range

Sheet Metal Surface Finish Guide

Design for Sheet Metal Bending

Understanding Brake Lines

Feature Proximity to Bends

Extending Features Through Bends

Fabricating Designs with Features Along a Bend

Minimum Flange Lengths

Hardware Inserts near Bends

The Challenge with Hardware Holes and Inserts near Bends

Solving the Challenge with Material Relief

Bending Design Guidelines for Sheet Metal Fabrication

Understanding Brake Lines

Brake Line and Surface Considerations

Cosmetic-side bend planning

Formed-side bend planning

Feature Proximity to Bends

Extending Features Through Bends

Feature stops before the bend

Excess material at the bend

Cut-out extended through the bend

Material removed along the bend

Fabricating Designs with Features Along a Bend

Minimum Flange Lengths

Hardware Inserts near Bends

Hardware and Relief Planning

Hardware clearance at a bend

Relief around a formed interface

Design Guidelines for Common Sheet Metal Features

Tabs and slots

Notches and corners

Holes and cutouts

Return flanges

Formed steps

Hardware holes

Corner relief

Mating details

Visible surfaces

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