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Aluminium glossary


 
 
       

This page refers to the topic of designing dies for aluminum extrusion and includes a list of good practices and recommendations for the design of dies for extrusion aluminum profiles.

 
     
 
The die can extrude from one to several profiles depending on the size and weight of extruded profiles. Theoretically can extrude profiles of any profile sections - the shape is limited only by the die strength and plastic properties of aluminum.

Reducing the diameter of a circle circumscribing of the profile, improves the flow of aluminum through a die, reduces the load of die in the extrusion process, that contributes to improving the quality of extruded profiles and extending the lifetime of the die.
 

Different categories of dies:

 
  •  Flat Die - extruded profile is without any void spaces.

  • Spider Die - It is a die, whose mandrel is held inplace by legs attached to it. Its design reminds a spider legs. Obtained from their profile contains void spaces.

  • Bridging Die - It is a die where mandrel is held inplace by a bridge mounted on the back of the die. Obtained from their profile contains void spaces.

  • Hollow Die - is a die where mandrel is held in place by a legs attached to the ring with the chambers. Obtained from their profile contains void spaces.

  • Hollow Die Connected - die with diagonal connection between the mandrel and the die from which we obtain a profile does not contain void spaces for extruding profiles with very deep pockets.

  • Die of special construction - die for extrusion profiles with not standard shapes.
     

Photo: Hollow die  

Photo: Aluminium die

 

In order to determine the location of profile cavities on the die is affected by the following factors:

  • In the die with a few cavities it is important that all cavities were in the same distance from the center of the die.

  • In the die with a single cavity, it is important that all walls of the profile were in the same distance from the center of the die.

  • In the die with several cavities, if it possible, should be applied profile geometry rotation around the center of die or the mirroring of the profile geometry.

  • Do not place parts of the profile wall outside of the maximum circle in practice it is a size of the press container. There are possible exceptions to this rule, it is requires construction of a special feeder for the die. Important is to select the right bolster and preservation of a minimum distance from the geometry of the profile to the wall of bolster.

  • Location of the cavities in the die, should lead to guarantee maximum strength of the die, provide a good flow of aluminum and do not block the exits profiles through the backer and bolster.
     

In designation of the amount of cavities in the die, is affected by the following factors.

  • The maximum and minimum length of the billet.

  • The maximum and minimum length of the profile on the working table.

  • Profile weight per meter.

  • The shape and size of the profile geometry.

In order to determine the location of profile cavities on the die is affected by the following factors:

  • In the die with a few cavities it is important that all cavities were in the same distance from the center of the die.

  • In the die with a single cavity, it is important that all walls of the profile were in the same distance from the center of the die.

  • In the die with several cavities, if it possible, should be applied profile geometry rotation around the center of die or the mirroring of the profile geometry.

  • Do not place parts of the profile wall outside of the maximum circle in practice it is a size of the press container. There are possible exceptions to this rule, it is requires construction of a special feeder for the die.

  • Important is to select the right bolster and preservation of a minimum distance from the geometry of the profile to the wall of bolster.

  • Location of the cavities in the die, should lead to guarantee maximum strength of the die, provide a good flow of aluminum and do not block the exits profiles through the backer and bolster.

Calculate the die bearing length.

  • One of the most important properties of the die is the bearing length.

  • By changing the bearing length, we control the flow of metal through a die.

  • The objective is to obtain equal output speeds for all the walls of the profile.

  • The longer of the bearing length, the greater the resistance to the flow of aluminum.

  • By increasing the length of the bearing large wall of profile can be slowed to match the output speed of the thinner walls of the profile.

  • There are many formulas for calculating the length of the bearings, in practice this process is difficult and requires extensive experience in this field.

In practice, the length of the bearing should not be less than twice the wall thickness of the profile.



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