Exercise No.: Date: / /

TITLE: Study and Design of Press Tool

OBJECTIVES:

After the completion of this exercise students will be able to know:

Desirable Properties of good cutting tools

Types of cutting tools

Basic geometry of single point cutting tool

Different angles associated with single point cutting tool

Importance of different angles of single point cutting tool in cutting process

PRESS OPERATIONS:

The various press operations are as under:

(1) Blanking (2) Punching (3) Trimming (4) Shaving (5) Notching

(6) Perforating (7) Slitting (8) Lancing (9) Nibbling (10) Bending

(11) Drawing (12) Squeezing

Blanking: It is the process of producing a flat piece of material by cutting the

desired shape, in one operation. Here the article punched out is the ‘blank’ and is

the required product.

Punching: It is the operation by which various shaped holes are made in sheet

metal. It is similar to blanking except material punched out is scrap.

Trimming: Trimming is a process in which the outer perimeter of a formed or

flat part is cut away to give the piece part its finished or partially finished profile.

Shaving: It is the operation of removing the thin strips of metal from the

edges in order to make the product more accurate in dimensions.

Notching: Notching is a cutting operation that removes material from the edge

of the work piece.

Perforating:Perforating is a piercing operation that involves punching a large

number of closely spaced holes.

Work piece

Slitting: It is the operation of making incomplete holes in work piece.

Lancing: Lancing is an 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, and louvers..

Nibbling:The nibbling process cuts a contour by producing a series of

overlapping slits or notches.

Bending: In this operation, the sheet metal is bent up to desired angle with use of

punch-die set.

Drawing: It is process of forming a flat work piece into hollow shape by means

of punch which causes the blank to flow into a die cavity.

Squeezing:

In this operation, the metal is caused to flow from die cavity by

application of compressive force in order to get the desired

shape.Classification of dies

According to type of operation.

1) Shearing – Blanking, piercing, punching, perforating, notching,

lancing, slitting.

2) Bending – Forming, curling, angle bending.

3) Drawing – Cupping, forming flanges and tubes.

4) Squeezing – Coining, embossing and extruding.

According to specific construction

11 Single operation dies – (a) Cutting dies (b) Forming dies

11 Multi operation dies - (a) Compound dies (b) Combination dies

(c) Progressive dies

Simple Cutting Die & Assembly

Types of cutting dies

Simple die

Compound die

Progressive die

Simple Die:

They perform single cutting operation such at one stroke of ram at the

same station these dies are called simple die. In this die, blanking operation

is performed during each stroke of the ram.

Compound Dies:-

They perform two cutting operations such as blanking, piercing, notching

punching etc in each stroke of the ram at the same station. These dies are

called compound die. In this die, piercing and blanking operation is

performed during each stroke of the ram. For producing a washer with the

help of compound die, the first operation is blanking and then piercing

operation is performed with compound dies. We can produce washers or

link of chain of bicycle.

Progressive Dies:-

TWO OR MORE CUTTING, BENDING, FORMING OR CURLING OR

COMBINED OPERATIONS ARE PERFORMED IN EACH STROKE OF THE

RAM AT DIFFERENT STATIONS IN THESE DIES. WORK PIECE IN

PROGRESSIVE DIES TRAVELS FROM ONE STATION TO ANOTHER,

SEPARATE OPERATIONS BEING PERFORMED AT EACH STATION

USUALLY THE WORK PIECE IS RETAINED IN THE STOCK UNTIL IT

REACHES FINAL STATION. ALL STATIONS WORK SIMULTANEOUSLY BUT

AT DIFFERENT POINTS ALONG THE WORK STRIP. WORK STRIP

ADVANCES ONE STATION AT EACH STROKE OF RAM. STAMPING OF

TRANSFORMER OR ELECTRIC MOTOR, KEYS FROM SHEET METAL ARE

THE BEST EXAMPLES PRODUCED BY PROGRESSIVE DIES. FIGURE

ILLUSTRATES THE PROGRESSIVE DIE. PROPERTIES OF GOOD

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QUIZ:

1. Enlist the desirable properties of good cutting tool material.

2. Show with neat sketch the elements of Single Point Cutting tool.

3. Explain different cutting edge angles with neat sketch.

4. Explain the sign convention for back rake angle and end rake

angle.

5. Justify the suitability of positive and negative back rake angles.

6. Explain the various relief angles with neat sketch.

EVALUATION:

Participation /

InvolvementDiscipline Understanding Total

4 2 4 10

Date: Signature of faculty member