Sheet Metal Fabrication: What Engineers Should Check Before Getting a Quote
Getting a quote for sheet metal fabrication seems simple: send the drawing, specify the material, and wait for the price.
In practice, many quotation problems start before the supplier even calculates the cost.
For engineers and product developers, a few details on the drawing can significantly affect the manufacturing process, tooling requirements, cost, and final part quality.
1. Material Specification
Material selection is one of the first things a sheet metal fabricator needs to understand.
Common materials include stainless steel, carbon steel, aluminum, galvanized steel, and copper alloys. But simply writing “stainless steel” may not be enough.
The specific grade and material condition can affect forming behavior, strength, surface finish, and production cost.
If the material grade is important to the application, it should be clearly identified on the drawing.
2. Sheet Thickness
Sheet thickness directly affects bending, forming, cutting, and tooling requirements.
A small change in thickness can also affect the final dimensions of a formed part.
For precision sheet metal fabrication, it is better to specify the required thickness and allowable tolerance rather than relying on a general material description.
3. Critical Dimensions and Tolerances
Not every dimension needs the same tolerance.
If all dimensions are given very tight tolerances, manufacturing costs may increase without providing any real benefit to the final assembly.
A better approach is to identify the dimensions that are actually critical to function, assembly, or performance.
This helps the fabricator focus inspection and process control where they matter most.
4. Bend Radius
Bend radius is another important consideration.
A radius that is too small for the selected material and thickness may increase the risk of cracking, deformation, or inconsistent forming.
Engineers should consider the relationship between material, thickness, bend direction, and required radius during the design stage.
5. Hole-to-Edge Distance
Holes located too close to a bend or edge can create manufacturing problems.
During forming, the material around the hole may deform or distort. In some cases, the hole may need to be moved or formed after another operation.
A manufacturability review before production can help identify these issues early.
6. Surface Finish
Surface requirements should also be clear.
Depending on the application, the part may require deburring, polishing, brushing, plating, powder coating, painting, or another finishing process.
If appearance is important, the drawing should identify the required surface and finish standard.
A Better Approach to Sheet Metal Fabrication
Good sheet metal fabrication starts before the machine is turned on.
A supplier should be able to review the drawing and identify potential manufacturing risks before production begins.
For OEM projects, this early review can help reduce unnecessary tooling changes, production delays, and unexpected costs.
The goal is not simply to manufacture the drawing.
The goal is to make sure the drawing can be manufactured consistently at the required quality and cost.
