Molding Apparatus

Abstract

A method and apparatus for low pressure molding are disclosed. The molding apparatus comprises a frame, a mold assembly and a transmission assembly. The mold assembly may comprise a first mold and a second mold, the second mold being coupled to the frame. The transmission assembly may be coupled to the frame and to the first mold. A motor may be coupled to the transmission assembly for moving the first mold relative to the second mold. A pneumatic actuator may also be coupled to the transmission assembly for increasing clamping pressure between the first mold and the second mold.

What is claimed is: 
     
         1 . A molding apparatus comprising:
 a frame;   a mold assembly having a first mold and a second mold, the second mold coupled to the frame;   a transmission assembly coupled to the frame and to the first mold, the transmission assembly including a rotatable gear and a shaft, the gear being configured such that rotation of the gear moves the shaft and the first mold;   a motor coupled to the transmission assembly, the motor being configured to turn the gear to move the first mold relative to the second mold; and   a pneumatic actuator coupled to the transmission assembly, the pneumatic actuator being configured to turn the gear to increase clamping pressure between the first mold and the second mold.   
     
     
         2 . The molding apparatus of  claim 1 , wherein the gear comprises outer teeth and wherein the outer teeth are engaged by the motor and the pneumatic actuator. 
     
     
         3 . The molding apparatus of  claim 2 , wherein the gear comprises a central thread, wherein the shaft is a threaded shaft, and wherein the central thread engages the threaded shaft. 
     
     
         4 . The molding apparatus of  claim 1 , additionally comprising one or more guides configured to maintain alignment of the first mold and the second mold during relative movement therebetween. 
     
     
         5 . The molding apparatus of  claim 4 , wherein at least one guide comprises a shaft that extends through an aperture in the first mold. 
     
     
         6 . The molding apparatus of  claim 1 , further comprising at least one counterbalance assembly that counterbalances the weight of the first mold. 
     
     
         7 . The molding apparatus of  claim 6 , wherein the at least one counterbalance assembly comprises at least one piston operatively connected between the first mold and the frame, the piston being located within a chamber, wherein downward movement of the first mold moves the piston within the chamber, creating a change in pressure in the chamber such that the changed pressure provides an upward force on the piston and the first mold. 
     
     
         8 . The molding apparatus of  claim 1 , further comprising a controller, wherein the controller is configured to control pressure of molding material injected into the mold assembly to between 3 psi and 15 psi of a predetermined molding material pressure. 
     
     
         9 . The molding apparatus of  claim 8 , wherein the controller is configured to control pressure of molding material injected into the mold assembly to between 3 psi and 8 psi of a predetermined molding material pressure. 
     
     
         10 . The molding apparatus of  claim 1 , further comprising a measurement mechanism configured to measure the volume of molding material injected into the mold assembly. 
     
     
         11 . The molding apparatus of  claim 1 , further comprising a heated reservoir configured to melt molding material. 
     
     
         12 . The molding apparatus of  claim 11 , wherein the reservoir includes baffles defining channels therebetween. 
     
     
         13 . The molding apparatus of  claim 12 , wherein the baffles are configured to provide a predetermined maximum distance to a heated surface for molding material located in the reservoir. 
     
     
         14 . The molding apparatus of  claim 13 , wherein the predetermined maximum distance is 17 millimeters. 
     
     
         15 . A method for molding using a mold apparatus comprising a first mold and a second mold, the first mold being moveable relative to the second mold, the method comprising:
 operating a motor to bring first and second molds into and out of interface engagement with each other;   operating a pneumatic actuator to apply clamping pressure between the first mold and the second mold;   monitoring the pressure of the molding material in the mold assembly; and   monitoring the volume of molding material injected into the mold assembly.   
     
     
         16 . The method of  claim 15 , wherein the motor operates on a first gear to move the first mold and wherein the pneumatic actuator operates on the first gear to apply clamping pressure between the first mold and the second mold. 
     
     
         17 . The method of  claim 15 , further comprising controlling the pressure of the molding material in the mold assembly to between to between 3 psi and 15 psi of a predetermined molding material pressure.