Devices and methods for melting materials

Abstract

A molten material supply unit includes a heating cylinder. The heating cylinder may receive and heat the material in a substantially vacuum condition. A molding apparatus may include a pressurizing and charging unit in addition to the molten material supply unit. The pressurizing and charging unit is adapted to receive the melted material from the molten material supply unit and to charge the melted material into a die under pressure.

1 . A molten material supply unit comprising a heating cylinder constructed and arranged for receiving and heating the material in a substantially vacuum condition.  
     
     
         2 . A molten material supply unit as in  claim 1 , further including a vacuum device communicating with the heating cylinder and being arranged and constructed to generate a reduced pressure within the heating cylinder.  
     
     
         3 . A molten metal supply unit as in  claim 2 , wherein the vacuum device comprises a vacuum pump that is disposed adjacent to the heating cylinder in a position near an inlet of the heating cylinder.  
     
     
         4 . A molten material supply unit as in  claim 1 , the material is supplied into the heating cylinder in the form of rods that have a predetermined length.  
     
     
         5 . A molten material supply unit as in  claim 4 , wherein the rods are made of metal.  
     
     
         6 . A molten material supply unit as in  claim 4 , further including a pusher device that is adapted to push the rods into the heating cylinder.  
     
     
         7 . A molten material supply unit as in  claim 4 , further including a preheating device that is adapted to heat the rods so as to preheat and soften the rods before the rods are pushed by the pusher device.  
     
     
         8 . A molten material supply unit as in  claim 6 , further including a squeezing member disposed at an inlet of the heating cylinder, the squeezing member having a diameter slightly smaller than the diameter of the rods.  
     
     
         9 . A molten material supply unit as in  claim 1 , wherein the heating cylinder has an inner wall that is covered with a protective layer that does not chemically react with the melted material within the heating cylinder.  
     
     
         10 . A molten material supply unit as in  claim 9 , wherein the protective layer is made of at least one material selected from the group consisting of ceramic, ceramic-metal composite and chromium oxide.  
     
     
         11 . A molding apparatus for molding a material using a die, comprising: 
 a molten material supply unit having a heating cylinder that is constructed and arranged to heat and melt the material in a substantially vacuum condition; and    a pressurizing and charging unit that is adapted to receive the melted material from the molten material supply unit and to discharge the melted material into the die under pressure.    
     
     
         12 . A molding apparatus as in  claim 11 , wherein the molten material supply unit and the pressurizing and charging unit are further arranged and constructed to discharge the melted material in a substantially vacuum condition.  
     
     
         13 . A molding apparatus as in  claim 11 , wherein the pressurizing and charging unit comprises a charging cylinder and a piston that is movable within the charging cylinder, the piston serving to pressurize and inject the melted material from the charging cylinder.  
     
     
         14 . A molding apparatus as in  claim 13 , wherein the heating cylinder has an inner wall that is covered with a protective layer that does not chemically react with the melted material within the charging cylinder.  
     
     
         15 . A molding apparatus as in  claim 14 , wherein the protective layer comprises one or more materials selected from the group consisting of ceramic, ceramic-metal composite and chromium oxide.  
     
     
         16 . A molding apparatus as in  claim 13 , wherein the heating cylinder communicates with the charging cylinder via an inlet formed in the charging cylinder, the piston is movable between a retracted position and an advanced position, which retracted and advanced positions will respectively open and close the inlet.  
     
     
         17 . A molding apparatus as in  claim 11 , further including a first hot nozzle communicating with the charging cylinder, the melted material being charged through the first hot nozzle.  
     
     
         18 . A molding apparatus as in  claim 17 , wherein the first hot nozzle includes a flow channel for discharging the melted material and an inner wall of the flow channel is covered with an electrical-insulation layer that does not chemically react with the melted material.  
     
     
         19 . A molten material supply unit as in  claim 18 , wherein the electrical-insulation layer comprises a ceramic material.  
     
     
         20 . A molding apparatus as in  claim 17 , further comprising the die, wherein the die comprises a plurality of cavities, a runner block, and a plurality of second hot nozzles, the runner block having a plurality of branch channels, wherein melted material discharged from the first hot nozzle is injected into the cavities through the branch channels and the corresponding second hot nozzles.  
     
     
         21 . A molding apparatus as in  claim 20 , wherein a plurality of pressurizing and charging units are disposed in parallel with each other and have respective first hot nozzles communicating with the branch channels.  
     
     
         22 . A molding apparatus for molding a material using a die, comprising a molten material supply unit having a heating cylinder that is constructed and arranged to heat and melt the material in a substantially vacuum condition.  
     
     
         23 . A molding apparatus as in  claim 22 , wherein the material is supplied into the heating cylinder in the form of a plurality of rods having a predetermined length.  
     
     
         24 . A molding apparatus as in  claim 23 , wherein the rods are made of metal.  
     
     
         25 . A molding apparatus as in  claim 23 , further including a pusher device for pushing the rods into the heating cylinder.  
     
     
         26 . A molding apparatus as in  claim 25 , further including a preheating device for preheating the rods to a predetermined temperature prior to the pushing device pushing the rods.  
     
     
         27 . A molding apparatus as in  claim 26 , further including a squeezing member disposed at or around an inlet of the heating cylinder, the squeezing member having an inner diameter that is slightly smaller than the diameter of the rods.  
     
     
         28 . A molding apparatus as in  claim 22 , wherein the heating cylinder has an inner wall that is covered with a protective layer that does not chemically react with the melted material disposed within the heating cylinder.  
     
     
         29 . A molding apparatus as in  claim 28 , wherein the protective layer comprises one or more materials selected from the group consisting of ceramic, ceramic-metal composite and chromium oxide.  
     
     
         30 . A molding apparatus as in  claim 28 , wherein the pushing device comprises a piston arranged and constructed to contact a rear end of each rod and to move each rod by a predetermined stroke in order to push the rods into the heating cylinder, the predetermined stroke being determined in response to the volume of a cavity defined within the die.  
     
     
         31 . A molding apparatus as in  claim 30 , further including a stacker that stores a plurality of rods and supplies the rods one after another to the pushing device, the pushing device being arranged and constructed to sequentially push the rods into the heating cylinder.  
     
     
         32 . A molding apparatus as in  claim 31 , wherein the stacker includes a heater arranged and constructed to preheat the rods before the rods are supplied to the pusher device.  
     
     
         33 . A method of melting a material, comprising: 
 heating and melting the material within a heating cylinder in a substantially vacuum condition; and    discharging the melted material from the heating cylinder.    
     
     
         34 . A method as in  claim 33 , wherein the heating cylinder receives the material as a plurality of rods having a predetermined length.  
     
     
         35 . A method as in  claim 33 , further including preheating the rods before the heating cylinder receives the rods.  
     
     
         36 . A method of molding a material using a die, comprising: 
 heating and melting the material within a heating cylinder in a substantially vacuum condition and further injecting the melted material into the die in a substantially vacuum condition.    
     
     
         37 . An apparatus adapted to melt a material selected from the group consisting of a magnesium alloy and an aluminum alloy, comprising: 
 a heating cylinder having an inlet and outlet, the inlet being adapted to receive the material to be melted; and    a vacuum pump communicating with the heating cylinder and being arranged and constructed to generate a reduced pressure within the heating cylinder.    
     
     
         38 . An apparatus as in  claim 37 , further including a squeezing or scraping member disposed at the inlet of the heating cylinder, the squeezing or scraping member having an opening for receiving the material, which is provided in the form of a rod, supplied into the inlet, wherein a substantially airtight seal is created between the squeezing or scraping member and the material rod.  
     
     
         39 . An apparatus as in  claim 38 , wherein a channel is defined within the squeezing or scraping member, the channel having a first end that opens towards the opening at a position that is opposite to the material rod to be supplied, and a second end that communicates with the vacuum pump.  
     
     
         40 . An apparatus as in  claim 38 , wherein the opening of the squeezing or scraping member has a diameter slightly smaller than the diameter of the material rod.  
     
     
         41 . An apparatus as in  claim 37 , further comprising a die sealingly coupled to the outlet of the heating cylinder.  
     
     
         42 . An apparatus as in  claim 41 , further including a squeezing or scraping member disposed at the inlet of the heating cylinder, the squeezing or scraping member having an opening for receiving the material, which is provided in the form of a rod, supplied into the inlet, wherein a substantially airtight seal is created between the squeezing or scraping member and the material rod.  
     
     
         43 . An apparatus as in  claim 42 , wherein a channel is defined within the squeezing or scraping member, the channel having a first end that opens towards the opening at a position that is opposite to the material rod to be supplied, and a second end that communicates with the vacuum pump.  
     
     
         44 . An apparatus as in  claim 42 , wherein the opening of the squeezing or scraping member has a diameter slightly smaller than the diameter of the metal rod.  
     
     
         45 . A method comprising: 
 heating a material into a softened state,    inserting the softened material through an inlet of a melting chamber, wherein the softened material forms a substantially airtight seal with the inlet,    melting the softened material within the melting chamber,    reducing the pressure inside the melting chamber and    discharging the melted material from the melting chamber substantially in the absence of air.    
     
     
         46 . A method as in  claim 45 , further comprising: 
 supplying the melted material discharged from the melting chamber under pressure to a die, the melted material being supplied to the die substantially in the absence of air, and    molding the melted material within a cavity of the die substantially in the absence of air.    
     
     
         47 . A method as in  claim 45 , wherein the melting and pressure reducing steps are performed substantially simultaneously.  
     
     
         48 . A method as in  claim 45 , further comprising shearing the softened material after inserting the softened material into the melting chamber and before substantially melting the softened material.  
     
     
         49 . A method as in  claim 45 , further comprising cooling melted material disposed within a discharge outlet of the melting chamber when the melted material is not being discharged from the melting chamber, wherein the melted material at least partially solidifies and substantially seals the outlet.  
     
     
         50 . A method as in  claim 49 , further comprising: 
 shearing the softened material after inserting the softened material into the melting chamber and before substantially melting the softened material,    supplying the melted material discharged from the melting chamber under pressure to a die, the melted material being supplied to the die substantially in the absence of air, and    molding the melted material within a cavity of the die substantially in the absence of air, and wherein the melting and pressure reducing steps are performed substantially simultaneously.    
     
     
         51 . An apparatus comprising: 
 first means for heating a material into a softened state,    second means for melting the material into substantially a liquid state, the second means comprising an inlet adapted to receive the softened material,    third means for inserting the softened material through the inlet of the second means, whereby the softened material forms a substantially airtight seal with the inlet,    fourth means for reducing the pressure inside the second means and    fifth means for discharging the melted material from the second means substantially in the absence of air.    
     
     
         52 . An apparatus as in  claim 51 , further comprising: 
 means for supplying the melted material discharged from the second means under pressure to a die, the melted material being supplied to the die substantially in the absence of air, and    means for molding the melted material within a cavity of the die substantially in the absence of air.    
     
     
         53 . An apparatus as in  claim 51 , wherein the second means and the fourth means are arranged and constructed to operate substantially simultaneously.  
     
     
         54 . An apparatus as in  claim 51 , further comprising means for shearing the softened material after inserting the softened material into the second means and before substantially melting the softened material.  
     
     
         55 . An apparatus as in  claim 51 , further comprising means for cooling melted material disposed within a discharge outlet of the second means when the melted material is not being discharged from the second means, wherein the melted material at least partially solidifies and substantially seals the outlet of the second means.  
     
     
         56 . An apparatus as in  claim 55 , further comprising: 
 means for shearing the softened material after inserting the softened material into the second means and before substantially melting the softened material,    means for supplying the melted material discharged from the second means under pressure to a die, the melted material being supplied to the die substantially in the absence of air, and    molding the melted material within a cavity of the die substantially in the absence of air, and wherein the second means and the fourth means are arranged and constructed to operate substantially simultaneously.