Extrusion Molding Technology
Extrusion molding is a method of continuously molding
plastic molded articles having the same cross-sectional shape over its length
such as rainwater guttering, gray colored drain water pipe, etc.
A dedicated extrusion molding machine is required for carrying out extrusion
molding. In addition, dies are also required for obtaining the shape of the
molded item. A die for extrusion molding is generally called an extrusion die.
There are various types of extrusion dies such as the
following.
- Straight die
- Cross-head die
- Flat die
- Die for solids
- Die for films
- Die for pipes
- Die for coverings
Extrusion dies are prepared from stainless steel,
nickel-chromium steel, or alloy tool steel. The dies are hard-chrome plated or
surface treated so as to withstand corrosion and wear.
The holder part of the die is made of a soft steel such as S50C, etc.
The holder part of the die is made of a soft steel such as S50C, etc.
The shape and design of the die are very important
factors determining the quality of the molded item. The processing conditions
such as the speed of extrusion are also important factors.
Extrusion molding is the second most frequently used
method of molding plastic molded articles next only to injection molding.
Unlike injection molding, once a die is prepared, a relatively large quantity
can be produced from the die. Therefore, this can be said to be a molding
method that finds a lot of applications in the equipment manufacturing
industry.
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