Friday, 7 February 2014

Solid Edge SheetMetal Workshop 1

Sheet metal - Any of a group of metals thinner than 3/16 of an inch can be called as sheet metal.

Material - The two most common sheet metals for construction use are sheet steel and sheet aluminum, though sheets of brass, copper and other materials are also commonly available.

Sheet steel and aluminum are made by passing large pieces of metal, called slabs, through a series of huge rollers to gradually reduce their thickness. Sheet steel then often goes through a galvanizing process in which it is coated with zinc for better resistance to the elements.

Sheet aluminum may go through an additional process called anodizing, in which a color coat is chemically bonded to the aluminum – a deep bronze color is the most common in construction.

Specification - Sheet metal is typically referred to by its gauge, which is the thickness of the metal – the smaller the gauge number, the thicker the metal is.

Some sheet metal, particularly that used in the manufacture of steel studs and other steel-framing members, may also be referred to by its thickness in mils (1 mil = 1/1000 of an inch). Most of the sheet metal that you will find in use for construction purposes ranges from 12 to 22 gauge, or approximately 97 to 27 mm thick.

Gauge

inch

mm

30

0.0157

0.3988

28

0.0187

0.4750

26

0.0217

0.5512

24

0.0276

0.7010

22

0.0336

0.8534

20

0.0396

1.0058

18

0.0516

1.3106

16

0.0635

1.6129

14

0.0785

1.9939

12

0.1084

2.7534

10

0.1382

3.5103

8

0.1681

4.2697

Applications

Sheet metal parts are used in a wide range of application ranging from domestic air-conditioners and computer hoods to nuclear plants and aircrafts.

Processes and Equipments

Cutting and Forming

Most construction sheet metal, such as that used for roof and wall flashings, is thin, light and easy to work with. For most cutting tasks, the only tool needed is a pair of aviation snips. Aviation snips are like big scissors for sheet metal, and are universally available as straight-cutting

Bending

Professionally, sheet metal is bent in a large forming tool called a brake. The sheets are fed into the machine and then bent to the desired angle, leaving a sharp and accurate crease in the metal. Brakes can be found in sheet metal shops and many heating and air conditioning shops.

Shearing

Large sheets are typically cut into sheet metal stock using a shear.

clip_image002 A Shear

Press Brake

A press brake can be used to bend sheet metal.

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Forming

In forming, a sheet is clamped around the edge and formed into a cavity by a punch. The metal is stretched by membrane forces so that it conforms to the shape of the tools. The membrane stresses in the sheet far exceed the contact stresses between the tools and the sheet, and the through-thickness stresses may be neglected except at small tool radii.

Figure shows a schematic section of a typical stamping die.

.clip_image005

After bending or rolling, SheetMetal parts are often combined to form the final objects like a funnel or a duct, etc. Different types of sheet metal forms & joints :

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