Are you totally new to the sheet metal design and don’t know even the sheet metal design fundamentals? Are you wondering about some top guidelines for creating an optimized sheet metal design? Don’t worry you have landed here on the right page. Below I have described all these things.
First of all, let me define Sheet Metal Design…
What is Sheet Metal Design
Sheet Metal design is the documentation that contains all the specifications needed for manufacturing a sheet metal part or component. Many software’s are available to produce such designs.
But there are many cases when there are found some manufacturability errors in the designs. These errors occur due to the difference between the way how the parts are created in the designing software and the way how they are actually manufactured. In order to avoid or minimize such cases of errors due to which the designs have to be reproduced with revisions or changes, you must follow some design guidelines.
Below I have shared the most important Sheet Metal Design Guidelines to avoid rejections and ECO‘s due to the engineering error in the part design.
Sheet Metal Design Guidelines
Follow the following Sheet Metal Design Guidelines while designing a sheet metal part or component in order to optimize your design for manufacturability:
Holes are very important and frequently used feature of sheet metal design. They are created by performing the punching operation. Correct size and position of the holes matter a lot while designing the parts.
The diameter of holes should always be greater than the thickness of the sheet. Spacing between two holes should be equal to or greater than 2 times the thickness of the sheet so that the holes may not be deformed during forming operations. Space between an edge of the sheet and a hole near it should be equal to or greater than the thickness of the sheet. Spacing between a bend and a hole should be equal to the sum of the bend radius and the value 1.5 times the sheet thickness.
Bends are another critical feature of the sheet metal design. They are created by performing bending operation. The specifications of bends (like bend radius, size of bend relief, etc.) should be seriously considered while designing the parts.
Bending radius should be at least 1.5 times the sheet thickness. Bend Relief should be provided to prevent tearing of the metal while bending. The width of a bend relief should be at least equal to 1.5mm or the sheet thickness, whichever is greater. If you are planning to provide multiple bends on the same plane, the bend should be in the same direction.
Notches are the features created by a shearing process called notching. In this process of metal removal, the metal part near an edge of the sheet is removed.
Width of a notch should be less than 1.5 times the sheet thickness. The radius of corners of notches should be 0.5 times the sheet thickness. Length of notches should not be more than 5 times the sheet thickness. The distance of a notch from a bend should be enough so that it may not cause distortion of the sheet.
A curl in the sheet metal is the hollow circular roll at an edge of the sheet. It is created by the curling process.
The minimum outside radius of a curl should be twice the sheet thickness.
A raised portion in the sheet metal is called embossment. It is produced by a stamping process (actually known as embossing).
The depth of embossment should never be more than 3 times the sheet thickness.
The distance between two extruded holes in sheet metal should be at least 6 times the thickness of the sheet or more than that. The distance between an extruded hole and an edge of the sheet metal part should be at least 3 times the thickness of the sheet or more than that.
Hemming is the process of rolling back the edge of the sheet metal sheet over itself. It doubles the sheet layer near its edge in order to strengthen it. It also helps in avoiding injuries due to a sharp edge.
The distance between a hem and a hole should be at least equal to or more than the sum of the radius of the hem plus two times the sheet thickness. The distance between a hem and a bend should be at least 5 times the thickness of the material if the bend is internal and 8 times the thickness if the bend is external.
The minimum distance between two countersinks should be 8 times the sheet thickness. The minimum distance between the edge of a countersink and an edge of the sheet should be 4 times the thickness of the sheet.
The diameter of a dimple should be equal to or less than 6 times the sheet thickness. The inside depth of a dimple should be equal to or less than the inside radius.
Other Important Sheet Metal Design Guidelines
- Try to avoid designing large parts with small flanges as far as possible.
- Collars should be provided around the pierced area. It helps in increasing stiffness.
- Lugs or Flanges should be provided perpendicular to or less than 45 deg. to the grain direction.
- Chamfers on corners should be provided. It helps in increasing stiffness.
- Bends at edges should be provided. It decreases the changes of metal tearing.
So these are some of the most important Sheet Metal Design Guidelines that you must follow to optimize your design. I hope all of the points are clear to you. What other guidelines do you think should be followed? Please share your knowledge in the comments below. And if you have any doubt, ask that too in the comments below. If you really liked the article, please don’t forget to share it with others also through social media.
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