Challenges in the Extrusion Design
For most of the companies that are engaged in extrusion, every one would agree that obtain the final shape of the extruded profile is the most time consuming and challenging task. Often it is seen that a dozen or so trials are required before finally the correct die cut is obtained that will result in the correct shape. Some of these challenges are with regard to:

• Die swell
  In case of plastic extrusion, as the melt leaves the die there is a tendency of large deformation throughout the free jet. This is known as die swell and may result in actual contraction of the flow section especially near the die region.
  
  
• Die imbalance
  An unbalanced die can result in the extrudate leaving the die at varying speeds this can lead to deformation.
  
• Coextrusion
  The main challenge in the co extrusion process is to ensure a perfect interface between the two materials.
  
  
• Die Deformation
  Die deformation takes place due to high internal pressure: this is true while extruding wide and thin films.
  
  

Types of Extrusion Dies
Broadly extrusion dies can be classified into three categories:

• Aluminium Extrusion Dies
• Rubber Extrusion Dies
• Plastic Extrusion Dies