US20060000572A1 - Method and apparatus for injection foaming molding - Google Patents

Method and apparatus for injection foaming molding Download PDF

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Publication number
US20060000572A1
US20060000572A1 US10/522,840 US52284005A US2006000572A1 US 20060000572 A1 US20060000572 A1 US 20060000572A1 US 52284005 A US52284005 A US 52284005A US 2006000572 A1 US2006000572 A1 US 2006000572A1
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United States
Prior art keywords
melt
injection
blowing agent
mold
temperature
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Abandoned
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US10/522,840
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English (en)
Inventor
Tatsuya Tanaka
Kazuo Yamaguchi
Takeshi Muguruma
Seiji Nishi
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Kobe Steel Ltd
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Kobe Steel Ltd
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Assigned to KABUSHIKI KAISHA KOBE SEIKO SHO (KOBE STEEL, LTD.) reassignment KABUSHIKI KAISHA KOBE SEIKO SHO (KOBE STEEL, LTD.) ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: MUGURUMA, TAKESHI, NISHI, SEIJI, TANAKA, TATSUYA, YAMAGUCHI, KAZUO
Publication of US20060000572A1 publication Critical patent/US20060000572A1/en
Abandoned legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D25/00—Special casting characterised by the nature of the product
    • B22D25/02—Special casting characterised by the nature of the product by its peculiarity of shape; of works of art
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D17/00—Pressure die casting or injection die casting, i.e. casting in which the metal is forced into a mould under high pressure
    • B22D17/20—Accessories: Details
    • B22D17/2015—Means for forcing the molten metal into the die
    • B22D17/2061—Means for forcing the molten metal into the die using screws
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D19/00—Casting in, on, or around objects which form part of the product
    • B22D19/14—Casting in, on, or around objects which form part of the product the objects being filamentary or particulate in form
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D25/00—Special casting characterised by the nature of the product
    • B22D25/005—Casting metal foams
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C1/00—Making non-ferrous alloys
    • C22C1/08—Alloys with open or closed pores
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C1/00—Making non-ferrous alloys
    • C22C1/08—Alloys with open or closed pores
    • C22C1/083—Foaming process in molten metal other than by powder metallurgy
    • C22C1/087—Foaming process in molten metal other than by powder metallurgy after casting in solidified or solidifying metal to make porous metals

Definitions

  • the present invention relates to a method and apparatus for injection foaming molding for foaming a melt of a light alloy to form a foaming molded product.
  • a thickener and a blowing agent are added to a melted metal followed by agitating, the whole mold is heated to the melting point of the foamed metal or higher, the agitation is terminated to start a foaming process, in which the air within the mold is released by expanding a number of bubbles generated by thermal decomposition of the blowing agent to allow a foam metal to fill the inner portion of the mold entirely, thereby blocking the mold in a sealed state to form an uniform cell structure under equilibration of the pressure by the rise of internal pressure by the bubbles, and the resulting foam metal is cooled and coagulated in the mold.
  • a hydrogenated metal is mixed to a melted metal and decomposed, and the metal is foamed by generation of hydrogen gas. Further, a second alloyed melted metal is supplied from a halfway screw while extruding a mixture of a melted metal and a hydrogenated metal by a first screw at a gas decomposition temperature or lower to perform a continuous foaming molding by generation of decomposed gas.
  • a molded product is obtained by compressing a blowing agent and a metal powder, heating the resulting semi-finished material within a mold to a melting temperature range to allow the material to foam followed by cooling.
  • a foam metal is obtained by adding 0.1-5%, based on weight, of titanium hydroxide to a metal having a melting point of 420° C. or higher, uniformly dispersing it by agitation, then injecting the melt to a mold, reheating the melt in the mold to 630° C. or higher to allow the melt to foam followed by cooling and coagulation.
  • Technique 1 needs much time for the heating since the melted metal is heated and agitated in the mold, and has a problem with the productivity since the same mold is also used for the cooling after foaming. Further, a large mold is needed to form a large molded product. In case of a large mold, since the heating and cooling depends on only the heat conductive electric heating from the wall surface, and a metal having a physical property of excellent heat insulating property is formed as the foamed body at the time of cooling, further much time is needed as a result.
  • Technique 2 although a metal body can be continuously formed by foaming with hydrogen gas similarly to Technique 1, a molded product of a desired three-dimensional shape or a molded product of a complicated shape cannot be formed since a function of injecting into a mold is not provided. Since the control for holding constant mixing ratio of the melted metal to the blowing agent such as titanium hydride or magnesium hydride can be performed only by the screw rotating speed with instability, the feed rate of the blowing agent cannot be kept constant, nor is the foaming ratio stabilized. Accordingly, the dispersion of product quality (foaming state) is increased.
  • the blowing agent such as titanium hydride or magnesium hydride
  • Technique 3 it is needed to uniformly mix the powder for obtaining a uniform foamed body, and this requires much time and an increased cost. Although a three-dimensional shaped product can be obtained, the control of temperature and time in the foaming by gas decomposition and the melting of the metal powder is difficult, therefore it is difficult to obtain a foaming molded product having uniform cells.
  • Technique 4 although a three-dimensional shape can be molded, much time is needed to reheat the melt to 630° C. or higher in the mold similar to the problem of Technique 1, and there is a problem with the production efficiency. Since there is a need for increasing a temperature of the mold to 630° C. or higher, cost for the mold is high. In case of a large mold, the temperature control of the melt in the mold is difficult to increase the dispersion of quality.
  • the present invention thus has an object to provide a method and apparatus for injection foaming molding of a light alloy, which can minimize the difference in foaming state between batches with good productivity.
  • the present invention involves a method for injection foaming molding of a light alloy comprising the steps of; holding a melt of a light alloy containing a thickener and a blowing agent decomposing at a high temperature to generate a gaseous component in respectively specified percentages at a temperature lower than the decomposition temperature of the blowing agent; agitating the melt to allow the thickener and the blowing agent to disperse; measuring a predetermined amount of the melt for the injection into a mold; and then injecting the melt into the mold to produce a foaming molded article of the light alloy, in which the melt is temperature-adjusted to a temperature higher than the decomposition temperature of the blowing agent and also inhibited to foam by pressuring at least immediately before the injection.
  • the thickener and the blowing agent are preliminarily added to the melt in the specified percentages, the difference in foaming state between batches is minimized.
  • the decomposition of the blowing agent is caused immediately before the injection, the foaming of the melt is inhibited since the inner capacity of a measuring part is made constant, and the melt is laid in the pressured state. Therefore, since the melt releases the pressure at once within the mold immediately after the injection and foams to spread into every corner of the mold, the transfer property of the mold is enhanced to enable the formation of a foaming molded article of a complicated shape. Since the heating of the mold to the decomposition temperature of the blowing agent or higher is dispensed, the productivity is improved.
  • the present invention further involves a method for injection foaming molding of a light alloy comprising the steps of; holding a melt of a light alloy containing a thickener and a blowing agent decomposing at a high temperature to generate a gaseous component in respectively specified percentages at a temperature lower than the decomposition temperature of the blowing agent; introducing the melt to an injection molding device having an agitating function, a measuring function and an injecting function; agitating the melt to allow the thickener and the blowing agent to disperse; measuring a predetermined amount of the melt for the injection into a mold; and injecting the melt into the mold to produce a foaming molded article of the light alloy, wherein the melt is temperature-adjusted to the decomposition temperature of the blowing agent or higher and also inhibited to foam by pressuring at least immediately before the injection.
  • the melt containing the thickener and the blowing agent in the specified percentages are held at a temperature lower than the decomposition temperature of the blowing agent, then introduced into the injection molding device, and agitated within the injection molding device, the thickener and the blowing agent are dispersed to minimize the difference in foaming state between batches.
  • the decomposition of the blowing agent is caused immediately before the injection, the foaming of the melt is inhibited since the inner capacity of a measuring part is made constant, and the melt is laid in the pressured state. Therefore, since the melt releases the pressure at once within the mold immediately after the injection and foams to spread into every corner of the mold, the transfer property of the mold is enhanced to enable the formation of a foaming molded article of a complicated shape. Further, since the heating of the mold to the decomposition temperature of the blowing agent or higher is dispensed, the productivity is improved.
  • the method for injection foaming molding of the light alloy of the present invention is characterized in that the temperature of the melt is lower than the decomposition temperature of the blowing agent at the time of agitating the melt.
  • the blowing agent can be uniformly dispersed without decomposition in the melt by holding the temperature of the melt at a temperature lower than the decomposition temperature of the blowing agent at the time of agitating the melt.
  • the present invention involves a method for injection foaming molding of a light alloy comprising the steps of; agitating a melt of a light alloy containing a predetermined amount of a thickener to allow the thickener to disperse; supplying an inert gas as a blowing agent into the melt in a specified percentage while agitating to allow the inert gas to disperse; measuring a predetermined amount of the melt for the injection into a mold; and then injecting the melt to the mold to produce a foaming molded article of the light alloy, wherein the melt is inhibited to foam by pressuring the melt at least until the injection is performed after the supply of the inert gas.
  • the melt containing the thickener is agitated to allow the thickener to disperse, and a predetermined amount of the inert gas is supplied into the melt and evenly dispersed by agitation with a screw, whereby a foaming molded article having a substantially uniform cell structure can be formed. Since the measuring part is laid in the pressured state before the injection, the foaming of the inert gas in the melt is inhibited. Therefore, since the melt releases the pressure at once in the mold immediately after the injection and foams to spread into every corner of the mold, the transfer property of the mold is enhanced to enable the formation of a foaming molded article of a complicated shape. Since the heating of the mold to the decomposition temperature of the blowing agent or higher is dispensed, the productivity is improved.
  • the method for injection foaming molding of the light alloy of the present invention is characterized in that the pressuring is performed by a pressing force caused by the agitation with the screw.
  • the predetermined amounts of the thickener and the blowing agent added to the melt can be dispersed by agitation, and the measuring part can be laid in the pressured state by the pressuring force by the screw for feeding the melt to the front part of a barrel. Therefore, the foaming of the blowing agent in the melt can be inhibited.
  • the method for injection foaming molding of the light alloy of the present invention is also characterized in that the melt is injected in an injection amount reduced by a foaming portion relative to the inner capacity of the mold to break the pressuring, whereby the melt is allowed to foam within the mold to obtain the foaming molded article.
  • the melt is injected into the mold in an injection amount reduced by the foaming portion relative to the inner capacity of the mold, whereby the mold opening at the foaming is dispensed, and the size and shape of the foaming molded article can be precisely controlled.
  • the method for injection foaming molding of the light alloy of the present invention is characterized in that the melt is injected in an injection amount equal to the inner capacity of the mold, and the mold is opened by the capacity of a foaming portion to break the pressuring, whereby the melt is allowed to foam to obtain the foaming molded article.
  • the present invention further involves a method for injection foaming molding of a light alloy comprising the steps of; adjusting the temperature of a melt of a light alloy containing a thickener and a blowing agent decomposing at a high temperature to generate a gaseous component in respectively specified percentages to a temperature lower than the decomposition temperature of the blowing agent; supplying the melt into a barrel having a screw provided to be rotatable, protrudable and retreatable; agitating the melt by rotating the screw to allow the thickener and the blowing agent to disperse; measuring the melt in a measuring part formed in a front portion of the barrel by retreating the screw with rotation; and adjusting the temperature of the melt to the decomposition temperature of the blowing agent or higher while inhibiting the foaming of the melt by pressuring the melt in the measuring part the capacity of which is made constant by stopping the retreat of the screw at least immediately before the injection; and injecting the melt into a mold by protruding the screw to obtain a foaming molded article.
  • the melt of the light alloy to be supplied into the barrel contains the thickener and the blowing agent in the specified percentages, the thickener and the blowing agent are uniformly dispersed in a kneading part in the barrel. Since the melt is injected after measuring, the difference in foaming state between batches is minimized. Although the decomposition of the blowing agent is caused immediately before the injection, the capacity is made constant state by stopping the screw, and the foaming of the melt is inhibited while laying the melt in the pressured state. Therefore, since the melt releases the pressure at once within the mold immediately after the injection and foams to spread into every corner of the mold, the transfer property of the mold is enhanced to enable the formation of a foaming molded article of a complicated shape. Since the heating of the mold to the decomposition temperature of the blowing agent or higher is dispensed, the productivity is improved.
  • the present invention also involves a method for injection foaming molding of a light alloy using an apparatus for injection foaming molding having a barrel containing a screw and a cylinder communicating with a front portion within the barrel through a communicating passage and containing a plunger, the method comprising; (a) a supplying process for supplying the melt of the light alloy containing a thickener and a blowing agent decomposing at a high temperature to generate a gaseous component in respectively specified percentages, which is temperature-adjusted and held at a temperature lower than the decomposition temperature of the blowing agent, into the barrel; (b) an agitating process for agitating the melt by rotating the screw within the barrel to allow the thickener and the blowing agent to disperse; (c) a measuring process for introducing and measuring the melt from the barrel to a measuring part formed in the front portion within the cylinder by retreating the plunger through the communicating passage; (d) a pressuring process for adjusting the temperature of the melt to the decomposition temperature of the blow
  • the melt containing the thickener and the blowing agent in the specified percentages is held at a temperature lower than the decomposition temperature of the blowing agent, then introduced into the injection molding device, and agitated within the injection molding device, the thickener and the blowing agent are dispersed to minimize the difference in foaming state between batches.
  • the decomposition of the blowing agent is caused immediately before the injection, the capacity is made constant by stopping the plunger to inhibit the foaming of the melt while laying the melt in the pressured state. Therefore, since the melt releases the pressure at once within the mold immediately after the injection and foams to spread into every corner of the mold, the transfer property of the mold is enhanced to enable the formation of a foaming molded article of a complicated shape. Since the heating of the mold to the decomposition temperature of the blowing agent or higher is dispensed, the productivity is improved.
  • the present invention involves a method for injection foaming molding of a light alloy comprising the steps of; holding a melt of the light alloy containing a thickener and a blowing agent decomposing at a high temperature to generate a gaseous component in respectively specified percentages at a temperature lower than the decomposition temperature of the blowing agent; agitating the melt to allow the thickener and the blowing agent to disperse; measuring a predetermined amount of the melt for the injection into a mold; and injecting the melt into the mold through an injection nozzle to produce a foaming molded article of the light alloy, wherein the temperature of the melt is raised to the decomposition temperature of the blowing agent or higher at least immediately before the injection into the mold.
  • the thickener and the blowing agent are preliminarily added to the melt in the specified percentages, the difference in foaming state between batches is minimized. Since the temperature of the melt to be injected is raised to the decomposition temperature of the blowing agent or higher at least immediately before the injection into the mold, the reheating of the mold to the decomposition temperature of the blowing agent or higher is dispensed, the cooling time of the mold is also shortened, and the productivity is thus improved.
  • the method for injection foaming molding of the light alloy of the present invention is characterized in that the temperature of the melt is raised to the decomposition temperature of the blowing agent or higher at the time of passing through the nozzle.
  • the thickener and the blowing agent are preliminarily added to the melt in the specified percentages, the difference in foaming state between batches is minimized. Since the temperature of the melt to be injected is raised to the decomposition temperature of the blowing agent or higher at the time of passing through the nozzle, the reheating of the mold to the decomposition temperature of the blowing agent or higher is dispensed, the cooling time of the mold is also shortened, and the productivity is thus improved.
  • the present invention involves an apparatus for injection foaming molding of a light alloy
  • a cylindrical member for receiving a melt of a light alloy containing a thickener and a blowing agent decomposing at a high temperature to generate a gaseous component, wherein the melt is agitated by an agitating means provided rotatably in the inner portion to allow the thickener and the blowing agent to disperse; a movable member provided to be protrudable and retreatable within the cylindrical member, the movable member forming a measuring part for measuring the melt in cooperation with the cylindrical member at the tip of the cylindrical member by retreating, and injecting the melt with the gaseous component generated therein into a mold communicating with the measuring part by protruding; and a position retaining means for retaining the position of the movable member against an increase in internal pressure of the cylindrical member in the generation of the gaseous component, so that the melt after the completion of the measurement can be retained in the pressured state to inhibit the foaming thereof.
  • the melt including the thickener and the foaming agent preliminarily added in specified percentages can be supplied to the cylindrical member, the difference in foaming state between batches is minimized. Since the position of the movable member can be retained by the position retaining means to keep constant capacity of the measuring part in the cylindrical member although the decomposition of the blowing agent is caused immediately before the injection, the melt can be laid in the pressured state while inhibiting the foaming of the melt. Therefore, since the melt releases the pressure at once within the mold immediately after the injection and foams to spread into every corner of the mold, the transfer property of the mold is enhanced to enable the formation of a foaming molded article of a complicated shape. Since the heating of the mold to the decomposition temperature of the blowing agent or higher is dispensed, the productivity is improved.
  • the apparatus for injection foaming molding of the light alloy of the present invention is characterized in that the position retaining means is a solenoid valve provided in a hydraulic circuit of a hydraulic cylinder for protruding and retreating the movable member so as to be capable of interrupting the incoming and outgoing of oil to a hydraulic cylinder.
  • the protruding and retreating of the movable member can be easily controlled. Therefore, the position of the movable member can be controlled according to the foaming state of the blowing agent, and the melt can be easily held in the pressured state.
  • the apparatus for injection foaming molding of the light alloy of the present invention is characterized in that the movable member is composed of a rotatable agitating screw.
  • the thickener and the blowing agent in the melt supplied into the cylindrical member can be evenly dispersed.
  • the apparatus for injection foaming molding of a light alloy of the present invention is characterized in that the cylindrical member comprises a barrel for agitating the melt and a cylinder connected thereto to introduce and measure the agitated melt, and the movable member is a plunger provided within the cylinder.
  • the present invention further involves an apparatus for injection foaming molding of a light alloy
  • the barrel comprising a temperature adjusting means capable of adjusting the temperature of the melt from a temperature lower than the decomposition temperature of the blowing agent to the decomposition temperature or higher, in which the gaseous component can be generated by adjusting the temperature of the melt to the decomposition temperature of the blowing agent or higher by the temperature adjusting means; a screw provided within the barrel to be rotatable, protrudable and retreatable and adapted to agitate the melt by rotating to allow the thickener and the blowing agent to disperse, to form a measuring part in cooperation with the barrel at the tip of the barrel by retreating, and to inject the measured melt from the barrel into a mold by protruding; and a position retaining means for retaining the position of the screw against an increase in internal pressure of the barrel in
  • the melt containing the thickener and the blowing agent preliminarily added thereto can be supplied into the barrel and surely dispersed, the difference in foaming state of every injection is minimized.
  • the temperature of the melt in the barrel can be easily adjusted to control the state of the blowing agent in the melt, and the difference in foaming state between batches can be further minimized. Further, since the temperature can be adjusted so as to cause the decomposition of the blowing agent immediately before the injection and the capacity of the measuring part within the barrel can be kept constant by the position retaining means for the screw, the foaming of the melt can be inhibited to lay the melt in the pressured state.
  • the transfer property of the mold is enhanced to enable the formation of a foaming molded article of a complicated shape. Since the heating of the mold to the decomposition temperature of the blowing agent or higher is dispensed, the productivity is improved.
  • the present invention involves an apparatus for injection foaming molding of a light alloy
  • a barrel for receiving a melt of a light alloy containing a thickener and a blowing agent decomposing at a high temperature to generate a gaseous component
  • the barrel having a first temperature adjusting means capable of adjusting the temperature of the melt to a temperature lower than the decomposition temperature of the blowing agent, in which the melt is agitated with a screw provided rotatably in the inner portion to allow the thickener and the blowing agent to disperse
  • a cylinder connected to the barrel and having a second temperature adjusting means capable of adjusting the temperature of the melt to the decomposition temperature of the blowing agent or higher
  • a plunger provided within the cylinder to be protrudable and retreatable and adapted to form a measuring part for measuring the melt in cooperation with the cylinder at the tip of the cylinder by retreating and to inject the measured melt from the cylinder to a mold by protruding; and a position retaining means for retaining the
  • the melt containing the thickener and the blowing agent preliminarily added thereto can be supplied into the barrel and surely dispersed, the difference in foaming state in every injection is minimized. Since the position of the movable member can be retained by the position retaining means to keep constant capacity of the measuring part in the cylindrical member although the decomposition of the blowing agent is caused immediately before the injection, the foaming of the melt can be inhibited while laying the melt in the pressured state. Therefore, since the melt releases the pressure at once within the mold immediately after the injection an d foams to spread into every corner of the mold, the transfer property of the mold is enhanced to enable the formation of a foaming molded article of a complicated shape.
  • the cylinder enables a precise measurement of the melt. Therefore, since the difference of melt injection amounts between batches for injection molding is minimized, a molded product is precisely produced.
  • the present invention involves an apparatus for injection foaming molding of a light alloy
  • a cylindrical member for receiving the melt of the light alloy containing a thickener and a blowing agent decomposing at a high temperature to generate a gaseous component, in which the melt is agitated by an agitating means provided rotatably in the inner portion to allow the thickener and the blowing agent to disperse; a movable member provided to be protrudable and retreatable within the cylindrical member, which forms a measuring part for measuring the melt in cooperation with the cylindrical member at the tip of the cylindrical member by retreating and injects the melt to a mold communicating with the measuring part through an injection nozzle by protruding; and a nozzle heating means capable of heating the melt to the decomposition temperature of the blowing agent or higher at the time of passing the melt through the nozzle.
  • the melt containing the thickener and the blowing agent preliminarily added thereto can be supplied into the barrel and surely dispersed, the difference in foaming state in every injection is minimized. Since the melt is injected through the injection nozzle, the injection pressure can be increased. The temperature of the melt is raised to the decomposition temperature of the blowing agent or higher when the melt is passed through the nozzle, or immediately before the injection into the mold, whereby the blowing agent is decomposed to generate the gaseous component. Accordingly, since the melt foams at once within the mold immediately after the injection, the heating of the mold to the decomposition temperature of the blowing agent or higher is dispensed and the productivity is improved.
  • FIG. 1 is a general illustrative view showing one embodiment according to an apparatus for injection foaming molding of a light alloy of the present invention
  • FIG. 2 is a general illustrative view showing another embodiment of the apparatus for injection foaming molding of a light alloy of the present invention
  • FIG. 3 is a view showing an essential part of the embodiment of the apparatus for injection foaming molding of a light alloy of the present invention, which illustrates a molding process
  • FIG. 4 is a view showing an essential part of the embodiment of the apparatus for injection foaming molding of a light alloy of the present invention, which illustrates the molding process
  • FIG. 5 is a view showing an essential part of the other embodiment of the apparatus for injection foaming molding of a light alloy of the present invention, which illustrates the molding process.
  • FIG. 1 shows one embodiment of the present invention.
  • An apparatus for injection foaming molding 1 according to this embodiment is composed of an injection molding device 3 and a mold clamping device 17 as shown in FIG. 1 .
  • the injection molding device 3 comprises; a feed port 8 for supplying a melt of a light alloy containing a thickener and a blowing agent decomposing at a high temperature to generate a gaseous component; a cylindrical member A for agitating the melt supplied from the feed port 8 by an agitating means 4 provided rotatably to allow the thickener and the blowing agent to disperse; a movable member B provided to be protrudable and retreatable within the cylindrical member A, which forms a measuring part 6 for measuring the melt in cooperation with the cylindrical member A at the tip of the cylindrical member A by retreating and injects the melt with the gaseous component generated therein into a mold 24 communicating with the measuring part 6 by protruding; and a position retaining means C for retaining the position of the movable member B against an increase in internal pressure of the cylindrical member A in the generation of the gaseous component so that the melt after the completion of the measurement can be held in the pressured state to inhibit the foaming thereof.
  • a barrel 7 that is the cylindrical member A for agitating the melt comprises a temperature adjusting means 10 for adjusting the temperature of the melt 2 of the light alloy supplied and the melt 2 of the light alloy supplied to an injection part 9 .
  • the injection part 9 for injecting the melt 2 measured by the measuring part 6 into the mold 24 is provided at the tip of the barrel 7 .
  • the melt 2 of the light alloy supplied surely moves to the lower portion within a kneading part 5 by its own weight.
  • the injection part 9 has an L-shaped passage 11 , wherein the passage of the melt 2 of the light alloy is vertical in kneading and agitating and horizontal in injection. Accordingly, even in the case, as shown in FIG. 1 , where the injection molding device 3 is connected to the mold clamping device 17 , the setting area of the apparatus for injection foaming molding 1 can be minimized as much as possible.
  • a nozzle part 13 having a valve means 12 is provided at the tip of the L-shaped passage 11 provided at the lower end of the barrel 7 .
  • This tip part is allowed to abut on the mold 24 which horizontally slides to open and close by the mold clamping device 17 .
  • the lower end opening part of a hopper 14 for receiving the melt of the light alloy melted in a melting furnace (not shown) and storing it in the melted state is connected to the feed port 8 in the upper portion of the barrel 7 .
  • the hopper 14 comprises a temperature control means such as a heating heater.
  • the melt 2 in the hopper 14 can be controlled, for example, to a constant temperature equal to or higher than a liquid phase temperature and lower than the foaming temperature of the blowing agent, or equal to or higher than the decomposition temperature of the blowing agent.
  • the hopper 14 further comprises a feeder for quantitatively supplying the thickener and the blowing agent to be added to the melt 2 of the light alloy.
  • the powdery thickener and the blowing agent can be quantitatively supplied by this feeder to minimize the difference in foaming state between batches.
  • the melt of the light alloy containing predetermined amounts of the thickener and the blowing agent may be supplied directly to the hopper 14 .
  • the thickener to be added to the melt 2 of the light alloy a known one such as calcium can be used.
  • a known metallic hydroxide including titanium hydroxide can be applied. Titanium hydroxide causes gas decomposition at about 640° C.
  • the liquid phase line temperature is 630° C.
  • the liquid phase line temperature or higher described later means a temperature of 630° C. or higher
  • the titanium hydroxide can be dispersed by agitation without causing any decomposition by holding the melt temperature, for example, at 630° C. by the temperature adjusting means 10 of the barrel.
  • the hopper 14 is filled with an inert gas 18 such as Ar supplied by an inert gas feeding unit 16 to seal the level of the melt 2 of the light alloy with the inert gas 18 .
  • the position retaining means C is provided at the upper end of the barrel 7 that is the cylindrical member A.
  • the position retaining means C comprises a drive motor 19 and a screw hydraulic cylinder 21 connected to the drive motor 19 .
  • a through spline hole is provided in the drive shaft of the drive motor 19 , and a spline shaft provided at the upper portion of the screw 4 rotatably inserted into the barrel 7 is inserted through to permit the transmission of a rotational driving force and the axial movement of the screw 4 .
  • the screw hydraulic cylinder 21 having a vertically protruding and retreating cylinder rod 2 is connected to the upper portion of the drive motor 19 .
  • the screw 4 is connected to the cylinder rod 20 of the screw hydraulic cylinder 21 , and arranged in a cantilever form so that the lower end is free within the barrel 7 . Therefore, a stirring blade of the screw 4 is protruded (moved downward) through the drive motor 19 by downwardly protruding the cylinder rod 20 of the screw hydraulic cylinder 21 , whereby the melt 2 of the light alloy collected in the lower end part within the barrel 7 can be passed to the L-shaped passage 11 and injected into the mold 24 through the nozzle part 13 .
  • the measuring part 6 When the screw hydraulic cylinder 21 is operated to move the screw 4 that is the movable member B upward in the axial direction, the measuring part 6 is formed in a lower portion within the barrel 7 .
  • the measuring part 6 can be properly set by the retreating quantity of the screw hydraulic cylinder 21 so as to provide a capacity necessary for obtaining a molded product.
  • a valve means 12 of the nozzle part 13 is closed except the time of injection. As the valve means 12 , similar ones as those described later can be applied.
  • the circumferential surface of the barrel 7 and the injection part 9 is covered with the temperature adjusting means 10 .
  • the temperature adjusting means 10 is composed of a plurality of vertically separated heating heaters. The temperature of the melt of the light alloy in the barrel 7 can be adjusted at least in two systems by these heating heaters. Accordingly, the temperature control can be performed separately in the upper portion and lower portion of the barrel 7 to control the decomposition of the blowing agent in the melt 2 .
  • the mold clamping device 17 comprises a link housing 26 raised on a base 25 , a fixed board 28 fixed to the housing 26 through a horizontal tie bar 27 , a fixed mold 24 b fixed to the fixed board 28 , a movable board 29 sidably inserted and supported relative to the tie bar 27 , and a movable mold 24 a fixed to the movable board 29 so as to be openable and closable by sliding horizontally relative to the fixed mold 24 b .
  • a mold clamping cylinder 30 is fixed to the outer surface center of the link housing 26 , and the tip of the cylinder rod 31 of the mold clamping cylinder 30 is connected to the center part of the movable board 29 .
  • the link housing 26 is connected to the movable board 29 through a plurality of links 32 which are folded when the both are mutually approached, and substantially linearly arranged in the horizontal direction when the both are separated.
  • An extrusion cylinder 33 is provided on the side surface of the movable board 29 on the link housing 26 side, and an extrusion rod 34 of the extrusion cylinder 33 is connected to a product protruding mechanism of the movable mold 24 a through the movable board 29 . Accordingly, in this mold clamping device 17 , the cylinder rod 31 of the mold clamping cylinder 30 is protruded to extend the links 32 linearly into a stretched state, whereby the movable mold 24 a can be strongly pressed to the fixed mold 24 b . The release of a product is performed by protruding the extrusion rod 34 of the extrusion cylinder 33 to operate the product protruding mechanism.
  • the melt 2 of the light alloy is allowed to foam at once within the mold 24 after the injection by the apparatus for injection foaming molding 1 described above, the melt 2 spreads into every corner of the mold 24 . Accordingly, the transfer property to the mold 24 is enhanced to enable the formation of a foaming molded article of a complicated shape. Further, since the heating of the mold to the decomposition temperature of the blowing agent or higher is dispensed, the productivity is improved.
  • the melt 2 of the light alloy is fed mechanically or by a means such as an electromagnetic pump from a melting furnace (not shown) into the hopper 14 .
  • a melting furnace a high frequency induction furnace, an electromagnetic induction heating furnace, or the like can be used regardless of the kind.
  • the melt 2 of the light alloy in the hopper 14 is temperature-adjusted to a temperature of the liquid phase line temperature or higher and lower than the decomposition temperature of the blowing agent, and held at an uniform temperature by a temperature control means such as heating heaters or the like provided on the hopper 14 .
  • the thickener and the blowing agent are quantitatively supplied to the melt 2 of the light alloy by the feeder (not shown) provided on the hopper 14 .
  • an agitating means for agitating the melt 2 of the light alloy in the hopper 14 may be provided to impart an agitating effect.
  • the melt 2 of the light alloy put in the hopper 14 is supplied to the upper portion of the barrel 7 while gas-sealing it, the melt 2 of the light alloy is temperature-adjusted to and held at a temperature of the liquid phase line temperature or higher and lower than the decomposition temperature of the blowing agent by the heating heater, and the melt 2 of the light alloy is agitated by rotating the screw 4 in the kneading part 5 within the barrel 7 to allow the thickener and the blowing agent to disperse. Accordingly, by keeping the blowing agent at a temperature lower than the foaming temperature at the time of agitation, whereby the blowing agent can be uniformly dispersed because it is powdery.
  • an inert gas quantitative feeding unit (not shown) is provided on the barrel 7 corresponding to the kneading part 5 , whereby inert gas that is the blowing agent can be supplied to the melt in a specified percentage when the thickener is allowed to disperse by agitation, and the inert gas is evenly dispersed into the melt 2 .
  • the melt 2 of the light alloy is pushed downwardly within the barrel 7 by a pushing force accompanying the rotation of the screw 4 ; a load is applied to the axially upper portion of the screw 4 .
  • a fixed back pressure is set on the screw hydraulic cylinder 21 constituting the position retaining means, and when an internal pressure overcoming the back pressure is generated in the barrel 7 , the screw 4 is moved axially upward and retreated to a predetermined position set according to a molded product volume.
  • the melt 2 of the light alloy is measured in the measuring part 6 between the screw 4 and the L-shaped passage 11 .
  • the screw 4 may be retreated without rotation by the screw hydraulic cylinder 21 , or retreated with rotation by the screw hydraulic cylinder 21 .
  • a backflow preventive means such as a check ring is preferably provided at the tip of the screw 4 , and by providing it, the melt 2 of the light alloy can be smoothly carried down, at the time of retreating, and measured in the measuring part 6 according to the molded product volume.
  • the nozzle part 13 of the L-shaped passage 11 is closed by the valve means 12 .
  • the melt 2 is laid in the pressured state at least immediately before the injection to inhibit the foaming by temperature-adjusting so as to be heated to the decomposition temperature of the blowing agent within the measuring part 6 by the heating heaters, and promoting the decomposition of the blowing agent within the measuring part 6 the capacity of which is made constant by stopping the retreat of the screw 4 . Since the measuring part 6 can be laid in the pressured state also by the pushing force of the melt 2 by the rotation of the screw 4 , the foaming of the blowing agent raised in temperature to the decomposition temperature of the blowing agent can be inhibited.
  • the melt 2 is then injected into the mold 24 by opening the valve means 12 of the nozzle part 13 and protruding the screw 4 , and the melt 2 inhibited to foam is allow to rapidly foam within the mold 24 lower in pressure than in the barrel 7 , whereby the formation of a molded article is performed.
  • the pressure of the gaseous component is released at once by sliding and opening the movable mold 24 a by the volume of a foaming portion after the injection to allow the melt 2 of the light alloy to foam in the sliding direction, whereby a foaming molded article in which foamed cells are uniformly dispersed can be obtained.
  • a skin layer is formed on the surface where the melt 2 comes in contact with the mold 24 .
  • the pressure of the gaseous component restricted to expand in the melt 2 of the light alloy is suddenly released by injecting the melt 2 of the light alloy into the mold 24 and opening the mold 24 substantially simultaneously with the injection or after the injection, the foamed melt 2 of the light alloy sufficiently spreads into minute parts in the mold 24 , and a foaming molded article of a complicated shape can be formed.
  • the pressure of the gaseous component is released at once in the mold 24 after the injection to allow the melt 2 of the light alloy to foam, and a foaming molded article in which foamed cells are uniformly dispersed can be obtained.
  • the size and shape of a foaming molded article can be precisely controlled without being influenced by the stopping precision in opening the mold, the parallel degree of the mold, or the like.
  • the thickener and the blowing agent are preliminarily added to the melt 2 of the light alloy to be supplied into the barrel 7 in respectively specified percentages, the variations of the resulting molded product between injections can be minimized. Since the thickener and the blowing agent are uniformly dispersed in the kneading part 5 within the barrel 7 , a molded product with uniformly dispersed foamed cells can be obtained. Further, according to such an injection, the difference in foaming state between batches is minimized.
  • the gaseous component is generated by decomposition of the blowing agent immediately before the injection
  • the capacity of the measuring part 6 is made constant by stopping the screw 4 to inhibit the foaming of the melt (the expansion of the gaseous component). Therefore, the melt 2 of the light alloy is made to release the pressure at once within the mold 24 immediately after the injection to foam, whereby the melt can be filled into every corner of the mold 24 . Accordingly, the transfer property to the mold 24 is enhanced, the productivity is improved, and the formation of a foaming molded article of a complicated shape can be performed.
  • an apparatus for injection foaming molding 40 of this embodiment comprises two members of a horizontal plunger type injection part 9 different from that of the apparatus for injection foaming molding 1 and the same vertical barrel 7 as that of the apparatus 1 .
  • FIG. 2 is a general illustrative view showing the apparatus for injection foaming molding 40 of a light alloy of this embodiment.
  • the apparatus for injection foaming molding 40 has substantially the same structure for the barrel 7 and the mold clamping device 17 as the apparatus for injection foaming molding 1 except the horizontal plunger type injection part 9 .
  • a melt of a light alloy a thickener and a blowing agent, those described above are applicable.
  • This apparatus for injection foaming molding 40 of a light alloy comprises an injection molding device 43 , and a mold clamping device 17 .
  • the injection molding device 43 comprises a barrel 47 having an agitating function, the barrel being composed of a kneading part 45 having a feed port 58 for supplying a melt 2 containing a thickener and a blowing agent decomposing at a high temperature to generate a gaseous component in respectively specified percentages at an upper portion and a screw 44 provided in the inner portion to be rotatable, protrudable and retreatable, in which the melt 2 is agitated by the screw 44 to allow the thickener and the blowing agent to disperse, and a storage part 46 formed by retreating the screw 44 ; and a plunger injection machine 50 having a measuring function and an injecting function, the machine comprising a cylinder 42 a front portion of which is connected to the lower end of the barrel 47 through a communicating passage 41 provided at the lower end of the cylinder 42 , and a plunger 48
  • the mold clamping device 17 comprises a mold 24 for allowing the melt 2 injected from the plunger injection machine 50 to foam.
  • the apparatus also comprises a temperature adjusting means 51 for adjusting the temperature of the melt 2 of the light alloy supplied from the feed port 58 to the barrel 47 and the melt 2 of the light alloy supplied to the plunger injection machine 50
  • a nozzle part 52 having a valve means 12 is provided at the tip of the plunger injection machine 50 of the apparatus for injection foaming molding 40 .
  • the tip part abuts on the mold 24 which is horizontally slid to open and close by the mold clamping device 17 .
  • a hopper 53 has the same structure as the hopper 14 described above, and comprises a feeder and a temperature control means such as a heating heater.
  • the barrel 47 also has the same structure as in the apparatus for injection foaming molding 1 of the above-mentioned embodiment.
  • a screw hydraulic cylinder 56 having a vertically protruding and retreating cylinder rod 55 is connected to the upper portion of a drive motor 54 , and the screw 44 is connected to the cylinder rod 55 of the screw hydraulic cylinder 56 through the drive motor 54 . Therefore, the cylinder rod 55 of the screw hydraulic cylinder 56 is protruded down to protrude (move down) the stirring blade of the screw 44 through the drive motor 54 , whereby the melt 2 of the light alloy collected in the lower end within the barrel 47 is supplied into the cylinder 42 of the plunger injection machine 50 through the communicating passage 41 .
  • the screw hydraulic cylinder 56 is adapted so that a storage part 46 can be formed at a lower portion within the barrel 47 when it is moved axially upward. Further, this cylinder has a sufficient stroke to move the plunger from the position for forming the storage part 46 to the position capable of closing the communicating passage 41 .
  • the temperature adjusting means 51 is composed of a plurality of separated heating heaters. By controlling the heating heaters, at least the melt 2 of the light alloy in the barrel 47 can be adjusted to a temperature lower than the decomposition temperature of the blowing agent added thereto, and at least the melt 2 of the light alloy in the cylinder 42 can be adjusted to a temperature allowing the blowing agent added thereto to decompose to generate the gaseous component or higher.
  • the plunger injection machine 50 is connected to the barrel 47 through the communicating passage 41 formed at the lower end of the barrel 47 .
  • the plunger injection machine 50 comprises the cylinder 42 having the nozzle part 52 with the valve means 12 in the front portion and the plunger 48 protrudable and retreatable within the cylinder 42 .
  • the plunger 48 is driven by the hydraulic pressure of the plunger hydraulic cylinder 57 .
  • a measuring part 49 is formed in the front portion of the cylinder 42 .
  • the capacity of the measuring part 49 can be properly set by the retreating quantity of the plunger 48 to attain a capacity necessary for providing a molded product.
  • the plunger hydraulic cylinder 57 has a sufficient stroke to move the plunger 48 from the position for forming the measuring part 49 to the position capable of closing the connection passage 41 connected to the vicinity of the tip of the cylinder 42 by protruding.
  • the plunger 48 is provided so as to close the communicating passage 41 when the injection is completed. Accordingly, the melt 2 of the light alloy for the next molding injection can be supplied into the barrel 47 immediately after the injection.
  • the valve means 12 of the nozzle part 52 is laid in a closed state except the time of injection.
  • a one adapted to block the nozzle by a mechanical or spring type shut-off valve provided at the tip of the nozzle can be used.
  • the melt 2 can be inhibited to foam in the state where the gaseous component is generated within the melt 2 at least immediately before the injection, and made to foam at once into the mold 24 after the injection. Therefore, the melt 2 spreads into every corner of the mold 24 , whereby the transfer property to the mold 24 is enhanced, and the productivity is improved. Further, the formation of a foaming molded article of a complicated shape can be performed. The maintenance and management of the apparatus can be facilitated by constituting the barrel 47 and the injection part from two separate members.
  • the melt 2 of a light alloy is put into a hopper 53 from the melting furnace described above in the same manner.
  • a thickener and a blowing agent decomposing at a high temperature to generate a foaming gas are added to the melt 2 in respectively specified percentages, and the resulting melt is temperature-adjusted to a liquid phase line temperature or higher and a temperature lower than the decomposition temperature of the blowing agent by a temperature control means of the hopper 53 .
  • a supplying process for supplying the temperature-adjusted melt 2 of the light alloy into the barrel 47 is performed.
  • the thickener and the blowing agent to be added to the melt 2 may be put into the hopper 53 by providing a feeder on the hopper 53 , or the melt 2 containing predetermined amounts of the thickener and the blowing agent may be put into the hopper 53 .
  • the melt 2 is then supplied to the upper portion of the barrel 47 , adjusted to and held at the liquid phase line temperature or higher and a temperature lower than the decomposition temperature of the blowing agent, and the thickener and the blowing agent are uniformly dispersed in an agitating process for agitating the melt 2 by rotating the screw 44 in the kneading part 45 within the barrel 47 .
  • an inert gas quantitative feeding unit (not shown) is provided to the barrel 47 corresponding to the kneading part 45 , whereby inert gas that is the blowing agent can be supplied to the melt 2 in a specified percentage at the time of dispersing the thickener by agitation, and uniformly dispersed into the melt 2 .
  • the plunger 48 of the plunger injection machine 50 is protruded to the position for closing the communicating passage 41 as shown in FIG. 3 .
  • the screw 44 in the barrel 47 is retreated with rotation, whereby the storage part 46 is formed between the screw 44 and the communicating passage 41 instead of the above-mentioned measuring part 6 , and a primary measurement is performed in this storage part 46 .
  • the storage part 46 is adjusted by the retreating quantity of the screw 44 so as to have a capacity larger than the amount of the melt to be injected.
  • the screw 44 may be retreated without rotation, or retreated with rotation.
  • the backflow preventive means described above can be provided at the tip of the screw 44 .
  • a measuring process for introducing the melt 2 from the barrel 47 to the measuring part 49 formed at the front portion within the cylinder 42 through the communicating passage 41 by opening the communicating passage 41 to retreat the plunger 48 of the plunger injection machine 50 is performed.
  • the screw 44 within the barrel 47 is protruded (moved down) simultaneously with the retreat of the plunger 48 as shown in FIG. 4 .
  • a pressuring force by the screw 44 is worked to press the melt 2 of the light alloy into the measuring part 49 formed at the front portion of the cylinder 42 with a positive pressure while the plunger 48 retreats to a predetermined position set according to the molded product volume, whereby the melt is secondarily measured.
  • melt 2 including the thickener and the blowing agent preliminarily added in the specified percentages is held at a temperature lower than the decomposition temperature of the blowing agent, and then introduced to and agitated in an injection molding device 43 , the thickener and the blowing agent are uniformly dispersed to minimize the difference in foaming state in every injection.
  • the communicating passage 41 is closed by the screw 44 , as shown in FIG. 5 , to prevent the backflow of the melt 2 of the light alloy from the measuring part 49 .
  • the nozzle part 52 at the tip of the cylinder 542 of the plunger injection machine 50 is closed by the valve means 12 .
  • the melt 2 is temperature-adjusted to the decomposition temperature of the blowing agent or higher at least immediately before the injection by each temperature adjusting means 51 , and the decomposition within the measuring part 49 the capacity of which is made constant by stopping the retreat of the plunger 48 is promoted, whereby a pressuring process for laying the melt in the pressured state to inhibit the foaming thereof is performed.
  • the blowing agent gradually starts the decomposition to generate the gaseous component as the melt 2 of the light alloy is heated to the decomposition temperature of the blowing agent within the measuring part 49 by the temperature adjusting means 51 , the foaming of the melt 2 is inhibited by pressuring since the increase in capacity is suppressed by the back pressure of the plunger 48 .
  • an injection foaming process for injecting the melt 2 inhibited to foam in the pressurizing process into the mold 24 communicating with the front portion within the cylinder 42 followed by foaming by protruding the plunger 48 is performed to form a molded article.
  • a method for injecting the melt 2 of the light alloy in an injection amount equal to the inner capacity of the mold 24 into the mold 24 and opening the mold by a foaming portion to obtain the foaming molded article similarly to the above-mentioned method, and a method for injecting the melt 2 of the light alloy into the mold 24 in an amount reduced by the foaming portion to obtain the foaming molded article within the mold with a constant capacity can be applied.
  • the foaming of the melt 2 (the expansion of the gaseous component) is inhibited in a state where the capacity is made constant by stopping the plunger 48 although the blowing agent is decomposed to generate the gaseous component immediately before the injection
  • the pressure is released at once in the mold 24 immediately after the injection to allow the melt to foam, whereby the melt 2 can spread into every corner of the mold 24 .
  • the transfer property to the mold 24 is enhanced to enable the formation of a foaming molded article of a complicated shape.
  • the transfer property and the moldability of a foaming molded article of a complicated shape can be further improved by depressurizing the mold by a pressure reducing means similarly to the above-mentioned embodiment.
  • inert gas When inert gas is supplied to the melt 2 in a specified percentage as a blowing agent by an inert gas quantitative feeding unit (not shown) by use of the apparatuses for injection foaming molding 1 and 40 as described above, the inert gas is also dispersed by agitation in the kneading parts 5 and 45 of the barrels 7 and 47 , and a predetermined amount of the melt 2 is measured for the injection into the mold 24 , and then the melt is injected into the mold 24 .
  • the temperature is raised by the temperature adjusting means 10 and 51 before the injection to the mold 24 , the expansion of the gaseous component is promoted.
  • the increase in capacity is suppressed by stopping the retreat of the screw 4 in the apparatus for injection foaming molding 1 and by stopping the retreat of the plunger 48 in the apparatus for injection foaming molding 40 , and in such a pressured state, the foaming of the melt 2 (the expansion of the gaseous component) is inhibited.
  • the screw 4 and the plunger 48 are protruded while opening the valve means 12 of the nozzle parts 13 and 52 to inject the melt 2 of the light alloy into the mold 24 , whereby the pressuring force acting on the melt 2 is released at once to allow the melt to foam, whereby the formation of a molded article is performed.
  • the inert gas is supplied in the specified percentage and uniformly dispersed into the melt 2 even in the use of the inert gas as the blowing agent, a foaming molded article having a substantially uniform cell structure can be formed while minimizing the difference in foaming state between injections.
  • a predetermined amount of the thickener is added to the melt 2 of the light alloy supplied from the melting furnace to the hopper 53 similarly to the above. At this time, the temperature is adjusted to the liquid phase line temperature or higher by the temperature control means of the hopper 53 .
  • the temperature-adjusted melt 2 is supplied into the barrel 47 , and agitated in the kneading part 45 while adjusting the temperature to the liquid phase line temperature or higher to thereby disperse the thickener.
  • a high-temperature Ar gas is supplied from the inert gas quantitative feeding unit (not shown) to the melt 2 , whereby the Ar gas is also dispersed into the melt 2 .
  • the melt 2 is then fed to the storage part 46 in the lower portion of the barrel 47 .
  • the drive by the cylinder is not necessarily required for the feed of the melt 2 to the storage part.
  • the measured melt 2 is raised in temperature by the temperature adjusting means 51 within the measuring part 49 before the injection to promote the expansion of the Ar gas included therein.
  • the capacity is made constant by stopping the plunger 48 to inhibit the foaming, and the pressure is released at once in the mold 24 immediately after the injection to allow the melt to foam, the melt spreads into every corner of the mold 24 and a foaming molded article with foamed cells uniformly dispersed therein can be thus obtained.
  • An apparatus for injection foaming molding of this embodiment has the same device structure as the above-mentioned apparatus for injection foaming molding 1 or the apparatus for injection foaming molding 40 except the points described below. Accordingly, only the different points will be described, omitting the description for the similar points.
  • This apparatus for injection foaming molding is adapted to disperse, measure and then inject a melt of a light alloy containing a thickener and a blowing agent decomposing at a high temperature to generate a gaseous component into a mold through an injection nozzle, and comprises a nozzle heating means capable of raising the temperature of the melt to the decomposition temperature of the blowing agent or higher when passing the melt through the nozzle in the injection.
  • a known heating means such as a resistance heating heater or induction heating heater provided on the circumference of the injection nozzle can be used, and the induction heating heater capable of shortening the temperature rising time is more preferably used.
  • the temperature of the melt is adjusted to a temperature lower than the decomposition temperature of the blowing agent to inhibit the foaming at the time of measuring, and raised to the decomposition temperature of the blowing agent or higher at the time of the passage to the injection nozzle or immediately before the injection into the mold to allow the melt to rapidly foam in the mold after the injection by the gaseous component generated by the decomposition of the blowing agent at the time of the passage to the injection nozzle (immediately before the injection into the mold). Therefore, the reheating of the mold to the decomposition temperature of the blowing agent or higher is dispensed, and the productivity is enhanced.
  • a shutter member may be provided in the hopper and the feed port part of the barrel connected thereto to intermittently supply the melt from the hopper to the barrel. According to this, the addition of the thickener and the blowing agent in the specified percentages to the melt stored in the hopper can be facilitated.
  • the primary measurement is performed in the storage part 46 formed in the front portion of the barrel 47 by retreating the screw 44 , and the melt 2 is introduced to and measured in the measuring part 49 , which is formed in the front portion within the cylinder 42 by retreating the plunger 48 , from the barrel 47 through the communicating passage 41 by protruding the screw 44 .
  • the melt 2 may be introduced to and measured in the measuring part 49 , which is formed by retreating the plunger 48 while rotating the screw 44 without retreating successively to the agitation by the screw 44 .
  • the screw hydraulic cylinder 56 can be dispensed to simplify the device structure, and the primary measuring operation can be omitted.
  • a pressure detection means such as a pressure gauge or pressure sensor may provided in the hydraulic circuit of the screw hydraulic cylinders 21 and 56 and the plunger hydraulic cylinder 57 to detect the back pressure generated in the screw or plunger 48 at the time of raising the temperature of the melt to the decomposition temperature of the blowing agent or higher. According to this, the temperature rising state of the melt 2 or the decomposition degree of the blowing agent can be estimated from the change in the back pressure accompanied by the temperature rise of the melt 2 .
  • the pressure of the hydraulic cylinder can be controlled by use of the detection value as a control parameter to control the foaming state of the melt 2 .
  • the melt 2 is controlled in such a manner that the melt 2 is partially foamed before injection, the partially foamed melt 2 is pressured to inhibit the further foaming, and the resulting melt 2 is injected into the mold 24 , whereby the unfoamed part is suddenly foamed in the mold 24 , the melt 2 before the injection (at the time of measuring) can be controlled to a desired foaming state.
  • the partial foaming of the melt 2 may be performed not by the pressure control of the hydraulic cylinder but by the position control of the hydraulic cylinder.
  • the melt is adjusted to the decomposition temperature of the blowing agent or higher and inhibited to foam by pressuring at least immediately before injection, the difference in foaming state between batches is minimized. Since the capacity in the measuring part is made constant although the decomposition of the blowing agent is caused immediately before the injection, the melt is inhibited to foam in the pressured state. Therefore, since the melt releases the pressure at once in the mold immediately after the injection to foam, the melt spreads into every corner of the mold. Accordingly, the transfer property to the mold is enhanced to enable the formation of a foaming molded article of a complicated shape. Since the heating of the mold to the decomposition temperature of the blowing agent or higher is dispensed, the productivity is improved.

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  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
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  • Extrusion Moulding Of Plastics Or The Like (AREA)
US10/522,840 2002-07-31 2003-07-30 Method and apparatus for injection foaming molding Abandoned US20060000572A1 (en)

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JP2002-223322 2002-07-31
JP2002223322A JP2004058130A (ja) 2002-07-31 2002-07-31 軽合金の射出発泡成形方法及び射出発泡成形装置
PCT/JP2003/009698 WO2004011686A1 (ja) 2002-07-31 2003-07-30 射出発泡成形方法及び射出発泡成形装置

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WO2013067567A1 (de) * 2011-11-10 2013-05-16 Mold-Thix-Consulting Bueltermann Gmbh Vorrichtung, anlage und verfahren zum druckgiessen von metallischem material im thixotropen zustand
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JP6146878B2 (ja) * 2015-01-09 2017-06-14 東芝機械株式会社 射出装置、成形装置及び成形方法
JP6443270B2 (ja) * 2015-09-02 2018-12-26 トヨタ自動車株式会社 発泡金属の製造方法
CN107498018A (zh) * 2017-09-30 2017-12-22 昆山盛事达机械有限公司 半固态镁合金注射成型机前置螺杆旋转装置
CN108405831A (zh) * 2018-03-20 2018-08-17 北京科技大学 通过压铸过程制备泡沫铝及铝合金异型件的方法

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US7694714B2 (en) * 2005-12-09 2010-04-13 Husky Injection Molding Systems Ltd. Metal molding
US20080311418A1 (en) * 2007-06-18 2008-12-18 Husky Injection Molding Systems Ltd. Metal-Molding System and Process for Making Foamed Alloy
US7699092B2 (en) * 2007-06-18 2010-04-20 Husky Injection Molding Systems Ltd. Metal-molding system and process for making foamed alloy
WO2013067567A1 (de) * 2011-11-10 2013-05-16 Mold-Thix-Consulting Bueltermann Gmbh Vorrichtung, anlage und verfahren zum druckgiessen von metallischem material im thixotropen zustand
US9339867B2 (en) 2011-11-10 2016-05-17 Mold-Thix-Consulting Bueltermann Gmbh Device, system and method for die-casting metallic material in the thixotropic state
US9802246B2 (en) 2011-11-10 2017-10-31 Mold-Thix-Consulting Bueltermann Gmbh Device, system and method for die-casting metallic material in the thixotropic state
CN112427622A (zh) * 2020-11-23 2021-03-02 清华大学 泡沫铝铸造成形方法

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DE60311673T2 (de) 2007-11-22
KR20050026529A (ko) 2005-03-15
EP1553194B1 (de) 2007-02-07
WO2004011686A1 (ja) 2004-02-05
CN1308473C (zh) 2007-04-04
AU2003252353A1 (en) 2004-02-16
EP1553194A1 (de) 2005-07-13
DE60311673D1 (de) 2007-03-22
KR100689168B1 (ko) 2007-03-09
EP1553194A4 (de) 2005-11-30
JP2004058130A (ja) 2004-02-26
CN1671872A (zh) 2005-09-21

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