(Photo courtesy WorldSkills UK)
When you start work on a new design, the most important thing to remember when setting the sheet metal specifications is delivering a high degree of manufacturability to your vendor. Manufacturability goes beyond simply making a weldable design.
Your designs should take all of the characteristics of sheet metal into consideration. Here are the top five most important things about sheet metal design that you should keep in mind. Follow these simple pointers and you will deliver specifications that your vendor will be able to succeed with.
5 Sheet Metal Specifications Steps for Success
1. Create a Bend Relief
The notch that must be created for proper sheet metal bending is called the bend relief. Flanges that lack a bend relief will suffer greater tearing and distortion of the surrounding material.
Solution: The depth of your bend relief should be equal to or greater than the inner bend radius of the bend.
2. Minimum Hole Size
When placing the holes in your draft, you should not make your holes so small that they could break the tool. As you decrease the size of a sheet metal hole, punches of smaller size will be needed, but if the punch size is too small, it could break during use.
Solution: The rule of thumb is to nsure the diameter of the hole is equal to or greater than the thickness of your sheet metal.
3. Minimum Clearance
It is important to maintain adequate clearance between a bend and hole in your sheet metal design; otherwise, the hole will become deformed.
Solution: When using sheet metal, keep the distance between your bend line and the edge of the hole at least 2x the thickness of your sheet metal.
4. Minimum Sheet Metal Bending Radius
The minimum bend radius will depend on the tool of choice and specific process used. The more malleable your sheet metal is, the smaller the inner bend radius may be.
Solution: Your minimum bend radius metal should be equal to the thickness when using mild steel sheet.
5. Minimum Flange Width
If the width of the flange is not properly proportioned, the tool will mark the sheet metal during the manufacturing process.
Solution: When indicating the intended flange widths in your draft, make sure that the width of the flange remains greater than 4x the thickness of your sheet metal.