Sheet metal embossing is often the most direct way to create raised text, tactile dots, or a simple relief pattern that can be felt by hand. The feature is formed in the metal itself, so it does not depend on a thin layer of ink or an applied label.
We used this approach on a 1 mm SGCC galvanized steel part. A simplified custom steel die, costing about $600 for this project, formed tactile features approximately 0.3–0.5 mm high. The forming operation worked, but excess powder buildup during finishing softened the feature profile. Some parts remained visually recognizable but no longer felt distinct enough, so the coating had to be stripped and reapplied.
The case showed that tactile markings must be evaluated through the complete manufacturing process. Forming creates the geometry; finishing determines how much of that geometry remains in the delivered part.
Sheet Metal Embossing Is a Forming Operation
Embossing uses tooling to deform a local area of the sheet into raised or recessed text, symbols, logos, dots, or patterns. Powder coating and wet painting are separate finishing operations that add protection and color after the shape has been formed.
The available marking methods produce different results:
| Process | Result on the Part | Suitability for a Pronounced Tactile Feature |
|---|---|---|
| Conventional screen printing | A relatively thin ink layer on the surface | Best for visual graphics; usually provides little tactile definition |
| Laser marking or engraving | Color change, surface texture, or recessed material removal | Useful for identification, but the tactile result depends on the specific laser process and depth |
| Die embossing | A raised profile formed in the metal | Well suited to integral raised text, dots, and simple relief patterns |
Laser processing is not limited to recessed lettering. Deep engraving can remove the surrounding material and leave a design standing above the newly lowered background. On 1 mm sheet, however, this approach also affects remaining material thickness and may require significant processing time.
UV relief printing can build up tactile dots when an applied material is acceptable. Adhesion, abrasion, cleaning, and service conditions then become part of the design decision. A metal feature formed with a die behaves differently because the base sheet provides the underlying shape.
A $600 Die Formed the Features in 1 mm SGCC
For this project, we produced a simplified steel die from the customer’s character layout and pressed the features into the galvanized sheet. The raised profile came from the sheet itself rather than from an adhesive element or accumulated ink.
The tooling cost was approximately $600 for this specific project. That cost covered dedicated tooling for the required layout; it is not a universal price for every embossing die. For a small order, the tooling represents a large share of the unit cost. For repeat production, the same investment can be spread across more parts.
The right sheet metal embossing method also depends on the feature arrangement and the equipment available. A full custom pattern die is not always required. Some layouts can be produced by positioning a standard forming tool one feature at a time. TRUMPF, for example, shows Braille formed with a special cup tool designed for close feature spacing in its punching tool applications.
Before ordering tooling, the fabricator needs the final artwork, expected quantity, sheet specification, required feature profile, and information about possible repeat orders.
Thin Sheet Must Be Evaluated on Both Sides
Emboss height is only one design variable. Narrow strokes, closely spaced dots, sharp transitions, and an aggressive forming height can increase the risk of poor definition or local distortion. Raising the punch stroke is not a complete solution because more forming can also increase sheet deformation.
Tooling manufacturer Mate recommends considering character height, stroke width, material thickness, ductility, press tonnage, and the size of the embossed area together. Its guidance also favors keeping the form only as high as necessary to limit distortion. These relationships are covered in its embossed logo design guidance.
A conventional embossed feature usually leaves a corresponding recess on the opposite side. The drawing should therefore account for backside clearance, mating surfaces, seals, mounting hardware, and any area that must remain flat. Features intended for repeated touch should also avoid sharp or abrasive edges.
Raised Lettering and Braille Require Different Criteria
Raised lettering, decorative relief, and Braille can all be tactile, but they do not share the same dimensional requirements. Decorative text may be approved by appearance and feel. Braille is a functional reading system with defined dot shape, diameter, height, and spacing.
Under the U.S. ADA accessibility requirements for applicable signs, Braille dots must have a domed or rounded shape and a finished height of 0.6–0.9 mm. The standard also controls dot diameter and spacing. The project’s 0.3–0.5 mm formed height should therefore be treated as project data rather than a general Braille specification. When compliance is required, the finished part must be designed and inspected to the applicable standard. The dimensions are listed in the U.S. Access Board requirements for Braille.
This distinction should be resolved before tooling is made. Otherwise, a feature may look acceptable while failing its intended tactile function.
Powder Coating Can Soften the Raised Profile
The forming operation was successful in this project. The failure occurred later, after powder coating. Some raised dots were still visible after curing, but their tactile definition had weakened.
“Covered by powder” does not necessarily mean that the entire feature disappeared beneath the coating. Local buildup and flow during curing can widen the transition at the base, round the profile, and reduce the contrast a fingertip detects between the flat sheet and the raised area. Because coating develops on both the feature and the surrounding surface, the finished result cannot be predicted by simply subtracting film thickness from emboss height.
Adding another coat would have increased the same risk. We stripped the original finish, repeated the required surface preparation, and reapplied a more controlled coat. The production yield and rework sequence are documented separately in our sheet metal powder coating defect case study.
The goal is not to apply the thinnest possible coat. The finish still needs adequate coverage, adhesion, cure, and protection. The process window must satisfy those requirements while preserving the tactile profile.
Define Powder Coating Thickness on the Finished Part
For coating-sensitive features, a small number of samples should pass through forming and finishing before the complete batch is released. Approval based only on the uncoated metal does not confirm the delivered result.
The drawing and inspection plan should define:
- Whether feature height applies to the formed metal or the finished, coated part.
- The feature cross-section, spacing, location, and functional requirement.
- The acceptable backside recess, surrounding flatness, and assembly clearance.
- The powder color, surface texture, and powder coating thickness range confirmed for the selected coating system.
- The inspection method for the final tactile and visual result.
A finished first article should be checked for coverage, appearance, feature profile, and tactile function. Where a formal Braille standard applies, touch alone cannot replace dimensional and layout inspection.
After approval, the finished sample can serve as a limit sample for production and final inspection. Recording the corresponding spray setup, racking orientation, and curing conditions also gives the coating operator a defined result to reproduce.
Successful sheet metal embossing depends on more than creating a raised shape in bare metal. The tooling, sheet behavior, backside geometry, coating requirements, and finished tactile result must be evaluated together. Doing that work before full production reduces the chance that a visually acceptable coating will erase the function that the feature was designed to provide.