Extrusion Dies : Aluminium, Rubber & Plastic Extrusion Die Designs

One of the many important extrusion equipments that play a critical role in achieving the accurate shape of the extruded profile in an extrusion die. An extrusion die needs to be cut just perfectly so that it helps in producing the right profile shapes and design. The defining properties of a good die are that it should be able to deliver the desired extruded profile with a constant and average pace. There are a lot of factors and challenges that need to be kept in mind while designed an extrusion die like the die swell that occurs due to the deformation through the jet on the melt exit from the die, managing the die balance at varying speeds in extrusion and mitigating the die wear and tear that takes place due to high pressure situations.

Types of Extrusion Dies
Extrusion dies are basically of three types:

Aluminium Extrusion Die Design
Taking up each at a time, we first talk of aluminum extrusion dies. Aluminium extrusion dies are classified into basic two types: flat dies and hollow dies. Hollow dies is a self explanatory term. Such dies are partly or completely hollow in parts. Porthole and pancake are two of the popular aluminium die styles. Semi hollow dies close the hollow void partially.

Flat or solid aluminium extrusion dies are normal dies without any hollow spaces between them. They are usually used in the production of solid shapes in extruded profiles. Apart from the two absolute extremes, die design can also be a mix of both these shapes, that is, a combination of solid and hollow shapes.

Rubber Extrusion Die Design

Of the important considerations in rubber extrusion die design are; ensuring a uniform of flow of rubber through all the parts of the die, flexibility to make room for corrections and avoiding the occurrence of dead spots as far as possible. A uniform rubber flow needs to be ensured in order to avoid any troubles that might arise due to friction created by the trapped rubber. Also the die swell issue needs to be taken care of. The popular types of rubber extrusion dies are preform die, final die and coin die.

Plastic Extrusion Die Design
Plastic extrusion die can either of regular, standard dies, or a complex, custom die made according to the extrusion requirement specifications. Some of the commonly used dies for plastic extrusion are: sheeting or coat hanger dies, available in single as well as multi channel design, that evenly distribute the melt, pipe and tube dies, coating and slot coating dies, in line dies and more. Complex shape and design profile dies can be produced too. But at the some time there are points that need to be kept in mind while deciding on a dies design. Analyze and ensure if a complex die design is required at all, wherever there are chances of melt trapping, eliminate the design completely if possible, or at least modify, target uniform interior and exterior wall thickness and the symmetrical profiles.

Tags:- Extrusion Dies : Aluminium, Rubber & Plastic Extrusion Die Designs

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