Compression molding using a self aligning and activating mold system

Abstract

A compression molding system and method, including a mold set and one or more hydraulic cylinders ( 42,44 ) that create a self-aligning and self-activating operating unit. The hydraulic cylinders can include a combination of activation and clamping cylinders. The mold set includes a first and second mold section ( 22,24 ) and a source of heat ( 87 ) is provided to heat the mold set. The mold sections are constructed of individual plates or bar ( 16 ), and machined to define a mold cavity ( 25 ). Reinforcement plates ( 38,41 ) can be attached to the mold sections and add structure and integrity to the system. A computer control system ( 56 ) interprets data from the activation hydraulic cylinders and monitors and controls hydraulic fluid flow into and out of each cylinder and a power unit pumps hydraulic fluid into and out of the chambers within the activation and clamping cylinders ( 42,44 ).

We claim:  
     
         1 . An apparatus for compression molding a charge of material into a work piece comprising: 
 a mold set including a first mold section and a second mold section;    at least one activation cylinder mounted to one of said first and second mold sections, said at least one activation cylinder being adapted for extending and retracting a first cylinder rod, said cylinder rod slidably extending through an aperture in said one mold section and having an end attached to the other of said first and second mold sections; and    a source of heat for the mold set.    
     
     
         2 . The apparatus of  claim 1  wherein said at least one activation cylinder comprises a hydraulic cylinder having extension and retraction chambers each connected to a controllable source of pressurized hydraulic fluid.  
     
     
         3 . The apparatus of  claim 1 , wherein said source of heat for said mold set comprises steam.  
     
     
         4 . The apparatus of  claim 1 , wherein said source of heat for the mold set comprises hot oil.  
     
     
         5 . The apparatus of  claim 1 , wherein said source of heat for the mold set comprises resistance heat.  
     
     
         6 . The apparatus of  claim 1 , further comprising at least one clamping cylinder mounted to one of said first and second mold sections, said at least one clamping cylinder being adapted for extending and retracting a second cylinder rod having a second end releasably mounted to the other of said first and second mold sections.  
     
     
         7 . The apparatus of  claim 6  wherein said at least one clamping cylinder comprises a hydraulic cylinder having extension and retraction chambers each connected to a controllable source of pressurized hydraulic fluid.  
     
     
         8 . The apparatus of  claim 1 , further including a computer control system connected to the compression molding apparatus to control the mold process and insure that said first and second mold sections remain substantially parallel to each other during operation.  
     
     
         9 . The apparatus of  claim 8  further comprising linear transducers encased in said activation cylinders, wherein said transducers transmit continuous linear position data to said computer control system, and wherein said computer control system interprets incoming data from said at least one activation cylinder and monitors and controls hydraulic fluid flow into and out of said retraction and extension chambers.  
     
     
         10 . The apparatus of  claim 7  further comprising linear transducers encased in the activation cylinders, wherein said transducers transmit continuous linear position data to a computer control system, and wherein said computer control system interprets incoming data from said at least one activation cylinder and said at least one clamping cylinder and monitors and controls hydraulic fluid flow into and out of said retraction and extension chambers.  
     
     
         11 . The apparatus of  claim 1 , wherein said first and second mold sections are comprised of a plurality of individual plates connected together.  
     
     
         12 . The apparatus of  claim 1 , wherein said first and second mold sections are comprised of a plurality of solid steel bar-stock pieces connected together.  
     
     
         13 . The apparatus of  claim 6 , wherein said first and second mold sections are comprised of a plurality of individual plates connected together.  
     
     
         14 . The apparatus of  claim 6 , wherein said first and second mold sections are comprised of a plurality of bar-stock pieces connected with together.  
     
     
         15 . The apparatus of  claim 1 , wherein said first mold section and second mold section in a closed position have an interior surface that defines a mold cavity.  
     
     
         16 . The apparatus of  claim 1  further comprising support pillars affixed to one of said first and second mold sections.  
     
     
         17 . The apparatus of  claim 1 , wherein said at least one activation cylinder is arranged on a periphery of said mold set.  
     
     
         18 . The apparatus of  claim 1 , wherein said at least one activation cylinder is positioned substantially in the center of said mold set.  
     
     
         19 . The apparatus of  claim 6 , wherein said at least one activation cylinder and said at least one clamping cylinder are arranged on a periphery of said mold set.  
     
     
         20 . The apparatus of  claim 19 , wherein said at least one activation cylinder and said at least one clamping cylinder are arranged in opposing orientation to each other.  
     
     
         21 . The apparatus of  claim 19 , wherein said at least one activation cylinder and said at least one clamping cylinder are arranged in an alternating layout.  
     
     
         22 . The apparatus of  claim 1 , wherein one of said first and second mold sections includes a plurality of stopping blocks.  
     
     
         23 . The apparatus of  claim 1 , wherein the charge of material is molded at a force of 75 to 350 psi.  
     
     
         24 . The apparatus of  claim 1 , wherein said mold set includes reinforcement plates attached along an exterior surface of said mold set.  
     
     
         25 . The apparatus of  claim 6 , wherein said mold set includes reinforcement plates attached along an exterior surface of said mold set.  
     
     
         26 . A method of compression molding using an apparatus including a mold set having first and second mold sections, means to heat the mold set, at least one activation cylinder connected to one of the first and second mold sections, the at least one activation cylinder including a retraction chamber, an extension chamber and a first cylinder rod having a first cylinder rod end attached to the other of the first and second mold sections, and at least one clamping cylinder connected to one of the mold sections, the at least one clamping cylinder including a second retraction chamber, a second extension chamber and a second cylinder rod having a second cylinder rod end releasably mounted to the other of the mold sections, the method comprising the steps of: 
 heating the mold set;    placing a charge of material to be formed on one of the first and second mold sections;    moving one of the mold sections towards the other mold section;    actuating the second cylinder rod to meet the one mold section and actuating a lock member to releasably hold the second cylinder rod end to the one mold section; and    pressing the mold sections together at a predetermined pressure for a predetermined time to mold the charge of material.    
     
     
         27 . The method of  claim 26 , wherein the step of moving one of the mold sections includes pumping fluid out of the extension chamber and into the retraction chamber of the at least one activation cylinder.  
     
     
         28 . The method of  claim 26 , wherein the charge of material is molded at a force of 75 to 350 psi.  
     
     
         29 . The method of  claim 26 , further comprising the step of: 
 releasing the lock member thereby releasing the second cylinder rod from said one mold section.    
     
     
         30 . The method of  claim 29  further comprising the step of: 
 moving the one mold section away from the other mold section.  
 
     
     
         31 . The method of  claim 30 , wherein the step of moving the one mold section away from the other mold section includes evacuating the fluid from the retraction chamber of the activation cylinder and pumping the fluid back into the extension chamber.  
     
     
         32 . The method of  claim 31  further comprising the step of: 
 removing the formed material.  
 
     
     
         33 . The method of  claim 32  further comprising the step of: 
 retracting the clamping cylinder rod thereby increasing accessibility to the formed material.  
 
     
     
         34 . A method of compression molding using an apparatus including a mold set having first and second mold sections, a means to heat the mold set, and at least one activation cylinder mounted to one of the first and second mold sections, the activation cylinder including a retraction chamber and an extension chamber and further including a cylinder rod having a cylinder rod end mounted to the other of the first and second mold sections, the method comprising the steps of: 
 heating the mold set;    placing a charge of material to be formed on the one of the mold sections;    moving one mold section towards the other mold section;    pressing the mold sections together at a predetermined pressure for a predetermined time to mold the charge of material.    
     
     
         35 . The method of  claim 34 , wherein the charge of material is molded at a force of 75 to 350 psi.  
     
     
         36 . The method of  claim 34 , wherein the step of moving the one mold section towards the other mold section includes pumping fluid out of the extension chamber and into the retraction chamber of the at least one activation cylinder.  
     
     
         37 . The method of  claim 34  further comprising the step of: 
 moving the one mold section away from the other mold section.  
 
     
     
         38 . The method of  claim 37 , wherein the step of moving the one mold section away from the other mold section includes evacuating the fluid from the retraction chamber of the at least one activation cylinder and pumping the fluid back into the extension chamber.  
     
     
         39 . The method of  claim 38  further comprising the step of: 
 removing the formed material.