Die and Punch
A die and punch assembly is a metal working process. That is convert raw material (sheet metal) into components. And also die is a tool to manufacturing of parts and component from sheet metal.The Compound die, combination die and progressive types of dies are produced in mass production quickly.
The die placed on a press. When the press moves upward direction and die is opened. As the press is moved down and die is closed. The sheet metal move through die which is open and fed into the die a precise amount with each press. The die is a closed together, the die performed work on the metal and finish parts are ejected from the die. The die sheet metal operation such a ways like as punching, bending and coining.
Die key is made of tool steel to withstand high shock load, sharp cutting of edge and resist the abrasive forces involved.
Components of die:
For punching and blanking operation which the simple cutting dies are used.
Main components of die as
- Die holder
- Die block
- Punch plate
- Stripper plate
- Back up plate
- Guide pin
The die block contain with die cavity. The shape of cavity is replica of require shape of component. That is female part of die block.
The die block is mounted on die holder and supported with bloster plate. Both die holder and block is mounted on press bed.
Punch plate hold the punch and attached to top ram of press.
It is male part of die assembly and also that fastened to ram press through punching plate. Which punch matches with die shape. This punches the metal strip again the die and necessary operation. Small clearance available between die and punch.
During the forming and cutting operation when the stripper plate is used to strip the sheet metal.
The guide pin is used to align the upper and lower half and also used for die changed from one operation complete to start another operation.
Back up plate:
The intensity of pressure does not reach the punch holder which is placed on die. It is also called as pressure plate. The pressure plates distribute the pressure over wider area.
It is distance between ram moments from upper position to lower position.
Types of dies:
It is classified based on press operation and method of work metal operation.
(A) classified based on press operation
- Cutting Dies
- Forming Dies
(1) Cutting Dies
The cutting dies are used to cutting or shear the metal.
common cutting dies are below
- Blanking dies
- Piercing dies
- perforating dies
- notching dies
- shaving dies
- trimming dies
- nibbling dies
(2) Forming dies
That dies have change the appearance of the blank without removing any stock. There types are
- Bending dies
- Drawing dies
- Squeeze dies
(B) Classified based on method of operation
- Simple dies
- compound dies
- combination dies
- progressive dies
- transfer dies
- multiple dies
The simple die is also known as single action die. When the sheet metal process die perform only one operation in single stroke of press. It operation may be as one type of cutting and forming operation. The dies set are simple configuration.
The compound die are performed one (or) two more operation at single stroke of press. In compound die process used any one of cutting or forming type.
A washer is manufactured in single stroke of press as shown in figure. Including the operation piercing and blanking in one stroke of press movement. It die have more saving time as compared to simple die.
The combination die can be performed one or more operation in single stroke of press. It is different from other operation. The cutting operations are combined with forging operation.
More than one operation can be performed in single stroke of press by using progressive die. The die combination having series of die and punch as shown in figure. Where one set of die and punch is called “station”.
Each station punch performs on the work piece during a single stroke of press. After that the work piece transfer to another next station of die set. Where next another operation carried out on the sheet metal. It can be made to cut and form a part in successive station of die.
The progressive die consists of as shown in figure. The piercing form performed on first station of press. Next, the metal piece is move to another operation. In between the distance of both operations is called advance.
Now the second stroke of metal blanking operation carried out in the sheet metal. For this blanking operation use of blanking punch and piercing operation done by use of piercing punch. The washer discards from the strip of blanking punch station and the piercing punch from a hole on strip for next washer. Against the metal is advanced and operation continued. Every stroke of press to be generates one component. The number of operation require on work piece deciding the number of station.
The transfer types of dies are consist of multiple station dies in which metal blank moving from one station to next station like progressive die. The major differed is the progressive die having stroke move one station to another station. But transfer die having already cut blanks are transfer from station to station. The deep drawing operation carried by this die.
The multiple dies are performed produce two or more work piece at a time. It is also called as gang die.