January 2012 Archives

(1) Stripper (Fig. 1)

(2) Blank holder (Fig. 2)

(3) Pressure pad (Fig. 3)

As can be understood from the respective figures, the structures are all the same. They are called by different names only depending on their purpose of use. The name indicates what is expected of the part.

A punch is a tool that is used by pressing it against a material. Normally a punch is used in combination with a die, and transfers the shape to the material.

A punch is called by various names, such as, punch, male die, and the words expressing a hole punching punch are needle, pin, and arrow, and a punch for drawing is also called "Bouzu" in Japanese. Recently, the names of punches are converging to punch and male die. In Japan, the Japanese Metal Press Industries Association has determined standard terminology (about a quarter century ago). At that time, the standard name was "punch". But the names that people are used to using are still surviving. Any term that is easy to get accustomed to is used frequently because of familiarity. There is no problem in using different terms as long as you have understood them and are using them.

This term is normally used in the form of a purpose word plus "punch". Examples are a blanking punch, a bending punch, a drawing punch, etc. Apart from this type of usage indicating the purpose of the punch, there is also the usage that indicates the shape of the punch such as, a straight punch, a stepped punch, etc.

The names of punches used in compound operations are difficult to understand, such as a total blanking punch, or a blanking and drawing punch, etc. In such compound operations, on the inside of a blanking punch are prepared hole punching dies, in the case of total blanking. A drawing die is prepared in the case of blanking and drawing.
We get confused as to whether to call it an outer shape blanking punch or to call it a hole punching die or a drawing die. The common expression in such cases is "compound punch". In individual expressions, such a punch can be called a "total blanking punch" or a "blanking and drawing punch", which would be easy to understand.
There are other punches with similar nuances, such as slitting or lancing punches that make a cut in the work, or "a cutting and bending punch" that bends the work, or "a hole punching and burring punch" that does exactly that.

The word "Die" is used very frequently in the preparation of dies and the press forming of products.
This word has the following meanings:

(1) Die ... Refers to the entire die. (Die)

In this case, the "die" is not used alone but is used along with a "mold". When used in this meaning, the word die is used after a word indicating its purpose of use. For example, a die can be called a "blanking" die. If the word "die" is used to refer to the entire die, many people may not understand it.
In addition, a "die" is used for forming shapes from plate-shaped or solid materials. These can be dies for press forming or dies for formation by forging.
When the word "die" is used to mean a "mold", it is used to refer to a die that prepares shapes from a molten material. These are molds used for injection molding or casting.
Therefore, use of the words "die" and "mold" is for referring to the entire die or mold
Also, a die can be made of metal, or can be made of sand (casting), or can be made of wood.

(2) Die ... When a die is separated into a top (upper) die and a bottom (lower) die, the word "die" in this case refers to the lower die. (Lower die)

Although it is very common to call this a bottom mold or a bottom die, sometimes it is merely called a "die". In this case, unless judgment is based on the context, a mistake can be made.

(3) Die ... This refers to a plate that constitutes the side in the die that receives the punch. (Die plate)

When people use the word "die" in spoken sentences such as "how is the die?", or "bring the die", or "the die is broken", etc., they mean the "die plate". Also, when used in expressions like "integrated die", or "insert type die", etc., the word "die" also refers to the "die plate".

(4) Die ... This refers to the shape of the punch receiving side of a plate that constitutes the punch receiving side. (Die)

There is no other expression other than "die" for expressing the side that receives the punch. The terms used in the work place may also be "the male die", "the female die", or the "millstone" (a drawing die), etc.
The word "die" refers to this part of a die in the expressions such as "die shape", "die radius", "the die is cracked", or "the polishing of the die", etc.

In daily usage, the term die only refers to the shape of the punch receiving side. Because this is difficult to understand, the word "die" is also used for referring to the plate or block constituting the die.
When you can correctly understand this word in its various forms of usage in conversations, then you can have confidence that you have understood press forming and dies quite well.