Molding apparatus and method for making a cutting tool

Abstract

A molding apparatus for making a cutting tool includes a cylindrically shaped elastic bag having an internal cavity for receiving a granulated material, such as a mixture of cobalt and carbide. The profile of the interior cavity substantially corresponds to the shape of the cutting tool being produced. The ends of the bag are open to provide access to the interior cavity of the bag. A substantially rigid tubular-shaped pressure sleeve encloses an outer circumference of the elastic bag. A pair of end caps operate to seal the open ends of the elastic bag and are engageable with the ends of the pressure sleeve. The granulated material can be formed into a solid coherent structure by placing the assembled mold containing the granulated material into a hydrostatic press for applying a substantially uniform compressive load to the outer periphery of the elastic bag.

1 . A mold for forming a cutting tool from one or more granulated materials, the mold comprising: 
 a bag having an internal cavity for receiving a predetermined amount of the granulated material, the internal cavity having a profile substantially corresponding to a shape of the cutting tool;    a first passage connecting the internal cavity to an exterior of the bag; and    a first end cap removeably engageable with the elastic bag for preventing fluidic communication between the exterior of the bag and the interior cavity through the first passage.    
     
     
         2 . The mold of  claim 1  further comprising: 
 a cylindrically shaped sleeve enclosing at least a portion of the exterior of the bag, the sleeve having a first end and a second end, the first end being engageable with the first end cap.    
     
     
         3 . The mold of  claim 2  further comprising: 
 a second passage connecting the internal cavity of the bag to the exterior of the bag; and    a second end cap removeably engageable with the bag to prevent fluidic communication between the interior cavity and the exterior of the bag through the second passage, and wherein the second end of the sleeve is engageable with the second end cap.    
     
     
         4 . The mold of  claim 2  further comprising: 
 a second passage connecting the internal cavity of the bag to the exterior of the bag;    a second end cap engageable with the second end of the bag for preventing fluidic communication between the interior cavity of the bag and the exterior of the bag through the second passage, and wherein the second end of the sleeve is engageable with the second end cap; and    a seal disposed between and adjoining the second end of the bag and the second end cap.    
     
     
         5 . The mold of  claim 1 , wherein the first end cap further comprises a boss engageable with the interior cavity of the bag.  
     
     
         6 . The mold of  claim 1  further comprising a first transition member engagable with the internal cavity.  
     
     
         7 . The mold of  claim 2 , wherein the first end cap includes a notched region for receiving the first end of the sleeve.  
     
     
         8 . The mold of  claim 1  further comprising a strap for connecting the bag to the first end cap.  
     
     
         9 . The mold of  claim 5  further comprising a core pin connected to an end surface of the boss and extending therefrom for producing an internal passage in the cutting tool.  
     
     
         10 . The mold of  claim 5  further comprising a transition member engageable with an end surface of the boss.  
     
     
         11 . The mold of  claim 2 , wherein the sleeve includes at least one notched region adjoining one of the first and second ends of the sleeve.  
     
     
         12 . The mold of  claim 2 , wherein a wall of the sleeve defines at least one orifice for fluidically connecting an exterior region of the sleeve with an inner cavity of the sleeve.  
     
     
         13 . The mold of  claim 2 , wherein an interior surface of the sleeve and an exterior surface of the bag define an annulus for receiving a high-pressure fluid.  
     
     
         14 . The mold of  claim 1 , wherein the mold is made from a resilient elastic material.  
     
     
         15 . The mold of  claim 14 , wherein the resilient elastic material is urethane.  
     
     
         16 . A molding apparatus for producing a cutting tool from one or more granulated materials, the molding apparatus comprising: 
 an elongated cylindrically shaped bag defining a hollow internal cavity for receiving a predetermined quantity of the granulated materials, the internal cavity having a profile configured to substantially mirror an external profile of the cutting tool, the bag having a first end surface defining a first passage and a second end surface defining a second passage, the first and second passages connecting an exterior region of the bag with the internal cavity of the bag;    a first end cap having an end surface engageable with the first end surface of the bag for preventing fluid communication between the interior cavity of the bag and the exterior region of the bag;    a second end cap having an end surface engageable with the second end surface of the bag for preventing fluid communication between the interior cavity of the bag and the exterior region of the bag; and    a sleeve enclosing at least a portion of the exterior of the bag, the pressure sleeve having a first end engageable with the first end cap and a second end engageable with the second end cap.    
     
     
         17 . The molding apparatus of  claim 16  further comprising: 
 a core pin connected to the first end cap for forming a passage in the cutting tool, wherein the core pin extends into the interior cavity of the bag when the first end is engaged with the first passage of the bag.    
     
     
         18 . The molding apparatus of  claim 17 , wherein the core pin has a substantially linear rod-like configuration.  
     
     
         19 . The molding apparatus of  claim 17 , wherein at least a portion of the core pin is configured as a spiral.  
     
     
         20 . The molding apparatus of  claim 16 , wherein an end of the sleeve is engagable with the end surface of one of the first and second end caps.  
     
     
         21 . The molding apparatus of  claim 16 , wherein the first end cap includes a notch adjoining the end surface of the first end cap and a circumferential edge surface of the first end cap, and further wherein a first end of the sleeve is engageable with the notch in the first end cap.  
     
     
         22 . The molding apparatus of  claim 21 , wherein the second end cap includes a notch adjoining the end surface of the second end cap and circumferential edge surface of the second end cap, and further wherein a second end of the sleeve is engageable with the notch in the second end cap.  
     
     
         23 . The molding apparatus of  claim 1 , wherein the sleeve includes at least one notched region adjoining one of a first and second ends of the sleeve.  
     
     
         24 . The molding apparatus of  claim 1 , wherein a wall of the sleeve defines at least one orifice for fluidically connecting an exterior region of the sleeve with an inner cavity of the sleeve.  
     
     
         25 . The molding apparatus of  claim 16 , wherein an inner surface of the sleeve is displaced from an external peripheral surface of the bag, the inner surface of the sleeve and the external peripheral surface of the bag defining a annulus capable of receiving a fluid under high pressure.  
     
     
         26 . The mold of  claim 16 , wherein the mold is made from a resilient elastic material.  
     
     
         27 . The mold of  claim 26 , wherein the resilient elastic material is urethane.  
     
     
         28 . A method for forming a cutting tool from a granulated mixture of one or more materials, the method comprising the steps of: 
 assembling a mold by attaching a first end cap having a core pin to a first end of an elastic bag having an interior cavity;    placing a fill sleeve over the bag and engaging an end of the fill sleeve with the first end cap;    filling the interior cavity of the bag with a predetermined quantity of the granulated mixture; and    vibrating the bag, end cap, and fill sleeve assembly while filling the interior cavity of the bag with the granulated mixture.    
     
     
         29 . The method of  claim 28  further comprising the steps of: 
 disengaging the fill sleeve from the first end cap and removing the fill sleeve from around the bag;    and wherein the step of assembling the mold further comprises the step of placing a pressure sleeve over the bag and engaging a first end of the fill sleeve with the first end cap, and attaching a second end cap to a second end of the bag, wherein the end cap engages a second end of the pressure sleeve.    
     
     
         30 . The method of  claim 29  further comprising the step applying a predetermined pressure load substantially uniformly over at least a portion of an exterior of the assembled mold so as to compress the granulated materials into a substantially solid unitary piece.  
     
     
         31 . The method of  claim 30 , wherein an isostatic press is used to apply the pressure load to the exterior of the assembled mold.  
     
     
         32 . The method of  claim 29  further comprising the steps of: 
 disassembling the mold by disengaging the first end cap form the first end of the pressure sleeve and the first end of the bag, and disengaging the second end cap from the second end of the pressure sleeve and the second end of the bag; and    extracting the cutting tool from the bag.