Introduction to Basic Manufacturing Processes and ... - always yours

Sheet Metal Work 363
4. Blanking. It is a operation in which the punch removes a portion of material called
blank from the strip of sheet metal of the necessary thickness and width using
suitable punch and die of press tool in press machine.
5. Punching. It is the operation of producing circular holes on a sheet metal by a
punch and die. The material punched out is removed as waste. Piercing, on the
other hand, is the process of producing holes of any desired shape in the part or
sheet using suitable punch and die of press tool in press machine.
6. Notching. It is a process to cut a specified shape of metal from the side or edge
of the stock using suitable punch and die.
7. Slitting. When shearing is conducted along a line, the process is referred to as
slitting. It cuts the metal sheet lengthwise using suitable punch and die of press tool
in press machine.
8. Lancing. It makes a cut part way across a sheet and creates a bend along the cut
using suitable punch and die.
9. Nibbling. It is an operation of cutting any shape from sheet metal without special
tools. It is done on a nibbling machine.
10. Trimming. It is the operation of cutting away excess metal in a flange or flash from
a sheet metal part using suitable punch and die of press tool in press machine.
11. Bending. Bending is the operation of deforming a sheet around a straight axis. The
neutral plane lies on this straight axis. In bending all sheet material are stressed
beyond the elastic limit in tension on the outside and in compression on the inside
of the bend. There is only one line, the natural line that retains its original length.
The neutral axis lies at a distance of 30 to 50% of thickness of the sheet from the
inside of the bend. Stretching of the sheet metal on the outside makes the stock
thinner. Bending is sometimes called as forming, which involves angle bending, roll
bending, roll forming, seaming and spinning.
18.11 QUESTIONS
1. Explain various hand tools used in sheet metal work?
2. Name the metals commonly used in sheet metal work.
3. Write short notes on:
(a) Punching
(b) Piercing
(c) Blanking (d) Slitting
(e) Bending (f) Lancing
4. Discuss the different sheering operations performed on sheet metal.
5. Explain the difference between punching, blanking and piercing.
6. Discuss the various types of hammers used in sheet metal work.
7. Describe the process of bending.
8. Write short notes on:
(a) Drawing (c) Shearing
(d) Riveting (e) Hollowing
(f) Planishing
9. Name various tools, machine and equipments used in sheet metal shop.