SHEET METAL PROCESSING

WAQAS AHMED

BS Mechanical Engineering

SHEET METAL PROCESS

Sheet metal is simply metal formed into thin and flat pieces. It is one of the fundamental forms used in metalworking, and can be cut and bent into a variety of different shapes.

SHEET METAL

The raw material for sheet metal manufacturing processes is the output of the rolling process. Typically, sheets of metal are sold as flat, rectangular sheets of standard size. If the sheets are thin and very long, they may be in the form of rolls

TYPES OF OPERATION

Before deciding on the processes), one should determine whether a particular sheet metal can be formed into the desired shape without failure. The sheet metal operations done on a press may be grouped into two categories.

I ) cutting(shearing) ii ) forming

SHEET METAL OPERATIONS

Forming operation Cutting operation

Bending Roll forming Spinning Deep Drawing Stretch forming

Shearing Blanking          Piercing       Notching Perforating              Slitting              Lancing

BENDING

Bending is a metal forming process in which a force is applied to a piece of sheet metal, causing it to bend at an angle and form the desired shape.

BENDING TYPES

V-bending Air Bending

BENDING TYPES

Rotary Bending

Wiping Die

ROLL FORMING

The process is performed on a roll forming line in which the sheet metal stock is fed through a series of roll stations. Each station has a roller, referred to as a roller die, positioned on both sides of the sheet. The shape and size of the roller die may be unique to that station, or several identical roller dies may be used in different positions.

ROLL FORMING

SPINNING

Spinning, sometimes called spin forming, is a metal forming process used to form cylindrical parts by rotating a piece of sheet metal while forces are applied to one side. A sheet metal disc is rotated at high speeds while rollers press the sheet against a tool, called a mandrel, to form the shape of the desired part. Spun metal parts have a rotationally symmetric, hollow shape, such as a cylinder, cone, or hemisphere.

SPINNING

DEEP DRAWING

Deep drawing is a metal forming process in which sheet metal is stretched into the desired part shape. A tool pushes downward on the sheet metal, forcing it into a die cavity in the shape of the desired part. The tensile forces applied to the sheet cause it to plastically deform into a cup-shaped part. Deep drawn parts are characterized by a depth equal to more than half of the diameter of the part.

DEEP DRAWING

STRETCH FORMING

Stretch forming is a metal forming process in which a piece of sheet metal is stretched and bent simultaneously over a die in order to form large contoured parts. Stretch forming is performed on a stretch press, in which a piece of sheet metal is securely gripped along its edges by gripping jaws. The gripping jaws are each attached to a carriage that is pulled by pneumatic or hydraulic force to stretch the sheet.

STRETCH FORMING

SHEARING

Shearing, also known as die cutting is a process which cuts stock without the formation of chips or the use of burning or melting. Strictly speaking, if the cutting blades are straight the process is called shearing; if the cutting blades are curved then they are shearing-type operations.

SHEARING

BLANKING

Blanking is the operation of cutting a flat shape from sheet metal. The product punched out is called the “blank” and the required product of the operation the hole and the metal left behind is discarded as waste.

BLANKING

PUNCHING OR PIERCING

It is a cutting operation by which various shaped holes are made in sheet metal. Punching is similar to blanking except that in punching, the hole is the desired product. The material punched out from the hole being .

PUNCHING OR PIERCING

NOTCHING

Notching is a metal-cutting process used on sheet metal or thin bar stock, sometimes on angle sections or tube. A shearing or punching process is used in a press, so as to cut vertically down and perpendicular to the surface, working from the edge of a work piece.

NOTCHING

PERFORATING

A perforation is a small hole in a thin material or web. There is usually more than one perforation in an organized fashion, where all of the holes are called a perforation. The process of creating perforations is called perforating, which involves puncturing the work piece with a tool.

PERFORATING

SLITTING PROCESS

Slitting is a process of cutting larger width coils into narrower width coils with repetitive accuracy at a high speed. 

SLITTING PROCESS

LANCING

Lancing is a punching operation in which the work piece is sheared and bent with one strike of the die. A key part of this process is that there is not reduction of material, only a modification in its geometry. This operation is used to make tabs, vents.

LANCING