Extrusion toolings are pre-heated before they are loaded into the extrusion press. If extrusion toolings are not heated to the correct temperature then there is the risk of premature die failure, incorrect metal flow, and sticking billets. Most extrusion plants set the die oven at a fixed temperature in the range 450 – 500 °C and rely on time to control the temperature.

The benefit of preheating:

• Reduce the risk of premature die failure.
• Achieve thermal stability in a lesser number of billet cycle
• Reduce the amount of scrap produced at the start of a production run attributed to uneven metal flow.
• Avoid the cost of the lost production associated with sticking billets.

 

Depending on need, the extrusion die can be preheated to a uniform temperature or non-uniform temperature. HyperXtrude allows simulating the extrusion process with both conditions. 

Option 1: Preheat die to a uniform temperature

• Refer to Tutorial #1 to specify uniform temperature to die.

Option 2: Preheat die to non-uniform temperature

• Setup coupled analysis containing both flow and tool mesh
• Define a TCL function to initialize temperature trend at the beginning of the extrusion cycle.
  • Refer to the attached example.

  • #------------------------------------------------
    # In this function, lateral temperature trend is defined. Top end of is at 450 deg C with lateral taper of 20 deg.
    #------------------------------------------------
    proc dietempv {x y z t} {
         
        # data to be modified ------------------------
        set dieTemp 450;# die initial temperature (this is assumed to be max temperature here)
        set dieTempTaper 20;
     
        # Die center is assumed will be always at origin.
        set die_diameter 355.611;
        #------------------------------------------------- 
         
        #----do not modifiy this section---------------
        set die_radius [expr {$die_diameter/2.0}];
        set taper_y_loc $y;
     
        # this eq. will work even if y is +/- value. the y location is with repective die bottom as 0.
        set abs_Y_loc [expr {$die_radius + $taper_y_loc} ];
        set deltaT [expr { ($dieTempTaper/$die_diameter)*$abs_Y_loc }];
        set dieTemp [expr $dieTemp-$dieTempTaper+$deltaT];
     
        return $dieTemp
    }

 

• open *.hx file and source above *.tcl file.  
• 
• Open *.grf file and write the following lines at end of the file. Make sure component names are referenced correctly.

• BEGIN FUNCTIONS
  EXPRESSION dietemp "{x y z t} { dietempv $x $y $z $t }"
  END
   
   
  BEGIN PROBLEMDATA
    
  SetToolComponentData Die3D {
    InitialTemperature = dietemp
  }
  END

• Run simulation.
• The following image shows the initial temperature in Die: uniform and with taper.