When we talk about manufacturing process, we can't end our discussion without describing Sheet metal processes. The word “Sheet Metal” is
used for metal sheets of varying thickness. In our daily routine we often
encountered with sheet metal products. When you see a car the first thing you
like its body which is sheet metal product.
The metal desk which you used for arrange your books is a sheet metal
product. There are many others like file cabinets, air craft body, metal cans,
metal doors etc. are made by this process.
Sheet metal operation gives many advantages over forging or
casting process which makes it a most versatile operation. These products have
good strength with light weighted characteristic, versatility in shapes, low
cost, fast production rate and many more advantages which make is suitable for
every manufacturing industries.
Mainly sheet metal process can be divided into three types.
The first one is sheet metal cutting, second one is sheet metal bending or
forming and the last one is known as deep drawing. In this article we mainly
focus on sheet metal cutting operations and other two we will discuss into upcoming
articles. Subscribe our website to get articles directly in your inbox.
Sheet Metal Operations:
We will discuss about only cutting operations in this articles. Cutting is an operation by which we can separate a work
piece into parts. In this processes, force is applied above ultimate limit of
material which cause it to fail. It mainly involves sheering force, hence
sometimes it is known as sheet metal shearing processes.
To understand the concept of shearing of sheet metal let’s
look at the figure given below. The most comment tools are used for sheet metal
working are punch and die. Punch is located at upper side of the sheet and die
is at lower side. There is a small clearance between punch and die. When the
punch applied a downward blow on sheet which is placed over die, it sheer off at the clearance zone due to shearing force. The shearing force, edge finish and
other parameters are mainly depends on clearance between punch and die.
Types:
Sheet metal cutting operation can be further divided into
following types. I will suggest you to clearly watch the images and try to
understand through it.
Sheering:
Sheering is a process of converting large sheet into small
sheet by cut along a line. It is used to cut sheet into several parts. Mostly
is used to cut rectangular parts but any other shape can also be cut. The edges
form by cutting perpendicular to the plane of sheet. The clearance between
punch and die play major role in determining the shape and quality of the
sheared edges.
Blanking:
Blanking is an operation of removing a piece of metal from a
large sheet by punching with a predefine shaped punch. The removed part is
called blank and it is the useful part and rest sheet is scrap. This process is
used to cut gears, jewelry and complex parts.
Punching:
It is similar operation like blanking except, the desire
part is sheet and the blank is scrap. This process takes place on punching
press. The negative allowance is provided on the punch which gives positive
tolerance on sheet.
Fine Blanking:
This process is used to produce very smooth and square edges blank. In this process sheet is locked tightly at accurate place. It involves clearances of the order of 0.5 – 10 mm and dimension tolerances are order of 0.025 - 0.05 mm in most cases.
Piercing:
It is a punching process in which a cylindrical hole cut
from the sheet.
Perforating:
More than one holes cut on a sheet is known as perforating.
Slotting:
It is an operation of cutting rectangular hole on a sheet.
Notching:
It is a process of removing various shapes on edges. It
creates notches at edges, hence named notching.
Shaving:
Shaving is a finishing operation in which a minimum layer of
metal is removed from edges using punch and die system.
Parting:
It is a shearing operation in which the sheet is converted
into two or more piece by removing small blank from the sheet.
Lancing:
This is an operation in which punch is formed without removing the blank part. No metal removal takes place. The blank remain attached in bent form.
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Slitting:
Slitting is a process of cut straight line without removing any material as shown in figure.
Trimming:
Trimming general meaning is removing excess material from work piece. In this process metal is removed from edges by using punch and die.
These are main Sheet metal operations. If you find anything
missing, put it in comment box. If you like this article, don’t forget to share
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