Heater for a manifold of an injection molding apparatus

Abstract

An injection molding apparatus includes a manifold having a manifold channel for receiving a melt stream of moldable material and delivering the melt stream to a mold cavity through a nozzle channel of a nozzle and a mold gate. A heater is coupled to the manifold. The heater includes a heater plate that is formed by an extrusion process and at least one channel for receiving a heating element.

1 . An injection molding apparatus comprising: 
 a manifold having a manifold channel, said manifold channel receiving a melt stream of moldable material from a source;    a nozzle coupled to said manifold, said nozzle having a nozzle channel for receiving said melt stream from said manifold channel; and    a heater coupled to said manifold, said heater including a heater plate and a heating element, wherein a surface of the heater plate has a channel therein and the heating element is fully received within the channel and wherein said heater plate is an extruded metal plate.    
     
     
         2 . The injection molding apparatus of  claim 1 , wherein said heater plate is made from a material selected from the group consisting of: aluminum, aluminum alloys, copper and copper alloys.  
     
     
         3 . The injection molding apparatus of  claim 2 , wherein said heater plate of said heater includes a planar contact surface for abutting a surface of said manifold.  
     
     
         4 . The injection molding apparatus of  claim 3 , wherein said channel includes a groove portion that opens to said heater plate surface and an undercut portion, wherein said undercut portion is an enlarged area below said groove portion.  
     
     
         5 . The injection molding apparatus of  claim 4 , wherein said heating element has an outer diameter that is larger than said groove portion of said channel and that is substantially equal to a diameter of said undercut portion of said channel.  
     
     
         6 . The injection molding apparatus of  claim 3 , wherein said heater plate includes a flange, wherein said flange is clamped around said heater element.  
     
     
         7 . The injection molding apparatus of  claim 6 , wherein said heater plate also includes a base and fasteners and said flange is fastened to said base by said fasteners to provide a clamping force around said heater element to retain said heater element in said channel.  
     
     
         8 . The injection molding apparatus of  claim 3 , wherein said channel is provided in said contact surface and said heating element contacts said surface of said manifold.  
     
     
         9 . The injection molding apparatus of  claim 1 , wherein said heater plate includes at least two channels for receiving at least two heating elements, wherein at least two of said heating elements is powered independently.  
     
     
         10 . The injection molding apparatus of  claim 1 , wherein said heater plate includes at least two channels for receiving at least two heating elements, wherein at least two of said heating elements is powered in series.  
     
     
         11 . The injection molding apparatus of  claim 1 , wherein said heater plate includes at least two channels for receiving at least two heating elements, wherein at least two of said heating elements is powered in parallel.  
     
     
         12 . A method of manufacturing a heater for a hot runner manifold, said method comprising: 
 extruding a heater plate from a raw form to a final form using a die, said heater plate including a channel;    machining said channel to have a groove portion and an undercut portion, wherein said undercut portion is wider than said groove portion;    cutting said heater plate to a length based on the configuration of the manifold; and    placing a heating element into contact with said undercut portion of said heater plate channel, wherein said heater plate is coupled to the manifold for providing heat thereto.    
     
     
         13 . The method of  claim 12 , further comprising; 
 machining a contact surface of said heater plate to maximize contact between said contact surface and a surface of the manifold.    
     
     
         14 . The method of  claim 13 , further comprising: 
 machining ends of said heater plate to accommodate installation of heating element terminations.    
     
     
         15 . The method of  claim 14 , further comprising: 
 machining relief holes in said heater plate, said relief holes being provided to accommodate connections of other components to the surface of the manifold.    
     
     
         16 . The method of  claim 12 , wherein placing said heating element into said channel includes pressing and deforming said heating element into said groove in order to maximize contact between said heating element and said undercut portion.  
     
     
         17 . A heater for a manifold, said heater comprising: 
 a single extruded heater plate having a first surface and a second surface, said second surface for abutting a surface of the manifold;    a channel provided in said first surface; and    a heating element fully received within said channel and exposed to said first surface, wherein said heating element is removable from said channel.    
     
     
         18 . The heater of  claim 17 , wherein said heating element is flattened in said channel to maximize contact between said heating element and said heater plate.  
     
     
         19 . The heater of  claim 17 , wherein said heating element is replaceable.  
     
     
         20 . The heater of  claim 19 , wherein said channel includes a groove portion that opens to said first surface of said heater plate and an undercut portion, wherein said undercut portion is an enlarged area below said groove portion.  
     
     
         21 . The heater of  claim 20 , wherein said heating element has an outer diameter that is larger than said groove portion of said channel and that is substantially equal to a diameter of said undercut portion of said channel.