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2 A DEFINITIVE GUIDE TO DESIGN FOR MANUFACTURING SUCCESS

Sheet Metal Design Guidelines Issue XIV, Aug 2015

3 A DEFINITIVE GUIDE TO DESIGN FOR MANUFACTURING SUCCESS

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4 A DEFINITIVE GUIDE TO DESIGN FOR MANUFACTURING SUCCESS

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Welcome to another issue of the DFM Guidebook. We highly appreciate your feedback on our previous issues. Please continue to send us your comments and suggestions for subsequent issues.

This week our application engineers bring you design for sheetmetal guidelines.

New DFMPro 4.0 further strengthens its sheetmetal module by adding new rules to its library of existing rules integrated into its highly rated version 3.6. The new rules helps to address sheet metal design requirements like hole location and size, preferred sheet sizes and half shear parameters.

In this issue of DFM guidebook we cover some of the latest sheet metal guidelines of DFMPro 4.0. Read the guidebook for specific rules such as Preferred Sheet Sizes, Minimum Hole Diameter, Interference in Flat Pattern, Half-Shear Parameters and Hole to Part Edge Distance

If you have any feedback or questions on DFM guidebook, please write to us at info@dfmpro.com

Rahul Rajadhyaksha Senior Product Manager Geometric Limited

5 A DEFINITIVE GUIDE TO DESIGN FOR MANUFACTURING SUCCESS

Contents

Preferred Sheet Sizes .......................................................................................6

Minimum Hole Diameter ..................................................................................7

Interference in Flat Pattern ..............................................................................8

Half-Shear Parameters .....................................................................................9

Hole To Part Edge Distance............................................................................. 10

6 A DEFINITIVE GUIDE TO DESIGN FOR MANUFACTURING SUCCESS

Preferred Sheet Sizes

Length and width of a flattened sheet metal part should be as per the standard sheet sizes that

are available in the inventory.

Each organization has its standard or preferred sheet sizes which are in accordance with the

machine’s capability and setup. At the initial stage of the design, designer should be aware of

unfolded sheet size and availability of corresponding appropriate sheet sizes in the inventory. This

will help designer to take decision related to inventory management. Indirectly it helps to reduce

inventory of non-standard sheet sizes and cost of manufacturing.

Length and width of the flattened sheet metal part should be within the preferred sheet sizes

used for manufacturing, depending on the material and sheet thickness.

L = Sheet metal length

W = Sheet metal width

CL = Trimming clearance on length side

CW = Trimming clearance on width side

Note: For nested components, additional considerations will be required.

7 A DEFINITIVE GUIDE TO DESIGN FOR MANUFACTURING SUCCESS

Minimum Hole Diameter

If the punch diameter becomes too small to bear the shear force required to punch the hole over

a small area, it may lead to failure.

Where,

d1 = Hole diameter

t = Sheet metal thickness

8 A DEFINITIVE GUIDE TO DESIGN FOR MANUFACTURING SUCCESS

Interference in Flat Pattern

It is not feasible to manufacture a sheet metal part when its design involves interference during

unfolded state of sheet metal.

Interference in flat pattern should be avoided for ease of manufacturing as there should not be

any interference in sheet metal component design when sheet metal part is unfolded.

9 A DEFINITIVE GUIDE TO DESIGN FOR MANUFACTURING SUCCESS

Half-Shear Parameters

A Semi-shear or half-shear is a blind hole that is punched on the sheet metal surface. The ratio of

half-shear depth to sheet metal thickness should not be too large to avoid deformation and

fracture of the metal.

It is recommended that a maximum ratio of half-shear depth to sheet metal thickness should be

less than or equal to 0.6 times the sheet metal thickness.

t = Sheet metal thickness

h = Half-shear depth

10 A DEFINITIVE GUIDE TO DESIGN FOR MANUFACTURING SUCCESS

Hole To Part Edge Distance

To prevent distortion or tearing, hole should be sufficiently away from the part edge. It is

recommended that minimum distance from a hole to edge of a part should be at least 2 times

sheet thickness

T= Sheet metal thickness