Sheet metal operations

Guys, I have spent almost 4 years into the sheet metal industry and this is the reason I thought of making a collection of certain processes so that everyone can understand the basics of sheet metal operations.

Sheet metal operations can be classified into two types:

  1. Cutting
  2. Forming

In cutting, following types of operations are performed;

  • Punching
  • Blanking
  • Shearing
  • Perforating
  • Notching
  • Slotting
  • Trimming
  • Shaving

In forming, following types of operations are performed;

  • V-Bending
  • Drawings
  • Edge Bending
  • Flanging
  • Hemming
  • Seaming
  • Curling
  • Corrugated bending

Some other sheet metal operations are;

  1. Lancing
  2. Coining

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Blanking vs Piercing

Often people get confused with these two operations and its differences. Here I have listed the main difference between blanking and piercing.


In this operation, the hole is produced in the workpiece or the blank.


Blanking is the process of cutting the workpiece for further operation. The cutout part is the main object required or workpiece.

Let us explore some tricky things used by us in our daily lives

Did you ever observe a sheet metal cap on a bottle? Ever wondered how these threads are produced? Let's have a look.

bottle caps - How are they manufactured

Just have a deep look at this cap, you can see threads on inner face and impressions on the outer face. So did you imagine how this is going to happen? The process is called knurling, which uses a thread forming tool to produce threads on the Aluminium cap. The tool is passed from inside of the cap, while the cap is held in the chuck. This enables the threads to be knurled on the Aluminium cap. You can see the videos below to understand the tooling in a better way.

Video 1; Video 2

Watch my entire collection of Sheet metal operation on YouTube

Did you know the method of manufacturing Pipes from sheet metal? Have you heard of ERW pipes?

Now you will say, how come pipes topic came in between sheet metal, but there is a relation between sheet metal and pipes. Normal, seamless pipes are widely available in the market and are used for many purposes. But have you ever come across ERW pipes yet and do you know the process of manufacturing these ERW pipes?

While seamless pipes are extruded pipes, ERW pipes are manufactured by rolling sheet metal into circular shapes. ERW (Electric Resistance Welding) is the process of making the pipe by rolling the sheet into a cylinder, then heating and welding it to form as a continuous joint.

Not just circular, but square, rectangular sections can also be produced by ERW method.

I found this Video which best explains ERW manufacturing process, see here.

Seamless vs ERW sheet metal operations

How are pipes denoted, Pipe Sizing definition

There are basically two different systems being used for standard pipe designation, one is NPS and other is DN. Pipe sizes in NPS (Nominal Pipe Size) format are used as per ASME standard, whereas DN (Diameter Nominal) is used in ISO standards. Another Difference in the grading of these systems is the measurement value, the NPS uses inches, like 1, 2, 3, etc with denoting inch symbol in the chart. And the DN uses a metric value like 15, 20, 25 etc with denoting the mm value in the chart.ion

In addition to this, a standard to denote the wall thickness was established and the term was Schedule (SCH). Today, we are using schedule numbers namely, SCH 5, 5S, 10, 10S, 20, 30, 40, 40S, 60, 80, 80S, 100, 120, 140, 160, STD, XS AND XXS.


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