CA1190021A - Method and apparatus for vertical die casting - Google Patents
Method and apparatus for vertical die castingInfo
- Publication number
- CA1190021A CA1190021A CA000395613A CA395613A CA1190021A CA 1190021 A CA1190021 A CA 1190021A CA 000395613 A CA000395613 A CA 000395613A CA 395613 A CA395613 A CA 395613A CA 1190021 A CA1190021 A CA 1190021A
- Authority
- CA
- Canada
- Prior art keywords
- molten metal
- cavity
- die casting
- plunger
- charging
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- Injection Moulding Of Plastics Or The Like (AREA)
Abstract
ABSTRACT
A vertical die casting method comprising the steps of initially charging molten metal into a cavity in a mold by the weight of the molten metal itself;
and then completing the charging of the molten metal into the cavity under pressure and the apparatus for carrying out the method.
A vertical die casting method comprising the steps of initially charging molten metal into a cavity in a mold by the weight of the molten metal itself;
and then completing the charging of the molten metal into the cavity under pressure and the apparatus for carrying out the method.
Description
The present inventlon relates to a method and apparatus for charging molten metal in a vertical die ca~ting.
As is well known the die castlng method hafl been widely employed among a varlety of casting methods owing to its hlgh-pres.iaioll performance. Among them, ln particular, the vertlcal casting method has bsen extensively used as it allows only a little amount of gas within the cast product.
However, as some gas is caught in the charge of molten metall a hlgh specific gravity of castlng is not obtalned. Furthermore, splashas oE molten metal solldify early in the mold as cold shut and a homogeneous product is not obtained.
Furthermore, the charging of the mol~en metal does not take place uniformly and gas presant in the mold is stirred and caught by the molten metal~ This fact also lead to unsatisfactory products.
Therefore, an object of the present lnventlon is to provide a method and an apparatus for productlon of cast products in a vertical dle casting which are free from the defects such as gas inclusions and cold shut. More spe~ifically, an object of the present invention is to provide a method and an apparatu~ for the production of cast metal which is characterized by a smooth and con~inuous casting free from the gas inclusions and cold shut.
According to the present invention, the molten metal is charged into the cavity due to its own ~eight at the initial stage, and then the charglng of the cavity ia completely effected by the pressurizing action of the pressure plungsr.
In the vertical die casting to which the present inventlon relates, the molten metal ls supplied into a sleeve while the gate is closed, and the gate i9 then opened so that the molten metal is charged from the sprue runner into the mold cavity due to the descending motion of a pressure plunger and a counter plunger. According to the present invention, the cavity ia charged ~&
... .. .. .. .... . .. . ...... .. . . . .. . .... .. . .... . . . .. .
wlth the molten metal at two stages. After the molten metal i~ ~upplled into the ~le~ve, the molten me~al is charged smoo~hly lnto the cavi~y vla ~he rulmer at the initial stage through lowerlng a lower sleeve by a descendlng mean~, and then the cavlty is comple~ely chasged with the molten metal ~hile press~rized by the pressurizing action of the descending pressure plunger at a specified speed.
Namely, accnrding ~o the present inventlon, the molten metal i8 8UpplLed into the sleeve while the lower sleeve, ae flrs~, ia brough~ ln~o contact with the upper sleeve ~o clo8e the gate. The lower ~leeve is then ~llowed to descend thereby ~o open ~he ga~e acco~panylng ~he descendlng motion of the pre~sure plung~r, B predetermlned amoun~ of molten metal is allowed to smoothly flow due to ~t~ own weight, and the pressure plunger gives pressure upon tha molten metal under the conditlon in which the flow of molten metal is not terminated, so that the molten metal is charged into the cavity through the sprue runner~ ther~by to obtain a satisfactory product withou~ splashes of molten metal, without the inclusion gases, and without cold shut, These and other objects and many of the attendant advantages of this invention will bé readily apprec$ated as the same becomes bettex understood by reference to ~he following detailed description of ~he preferred embodlment when considered in connection with the acco~panying drawlngs.
Fig. l is a diagram illustraeing a vertical die cas~ing according to a conventional art;
Figs. 2 and 3 are diagrams illustrating an apparatus and a manufacturlng process according to the present invention;
Fig. 4 is a view illustxating the sprue runner of the ambDdiment of Figs 7 2 and 3 on an enlarged scale; and Fig. S i8 a dlagram illustrating experimental data.
According t~ the conventionally eMployed general vertic~l die casting as shown ln Fig. 1, a pouring gate 9 is formed by a sleeve 5 that forms a sprue rulmer 4 connected to a cavity that ls defined by upper and lower mold~ I and
As is well known the die castlng method hafl been widely employed among a varlety of casting methods owing to its hlgh-pres.iaioll performance. Among them, ln particular, the vertlcal casting method has bsen extensively used as it allows only a little amount of gas within the cast product.
However, as some gas is caught in the charge of molten metall a hlgh specific gravity of castlng is not obtalned. Furthermore, splashas oE molten metal solldify early in the mold as cold shut and a homogeneous product is not obtained.
Furthermore, the charging of the mol~en metal does not take place uniformly and gas presant in the mold is stirred and caught by the molten metal~ This fact also lead to unsatisfactory products.
Therefore, an object of the present lnventlon is to provide a method and an apparatus for productlon of cast products in a vertical dle casting which are free from the defects such as gas inclusions and cold shut. More spe~ifically, an object of the present invention is to provide a method and an apparatu~ for the production of cast metal which is characterized by a smooth and con~inuous casting free from the gas inclusions and cold shut.
According to the present invention, the molten metal is charged into the cavity due to its own ~eight at the initial stage, and then the charglng of the cavity ia completely effected by the pressurizing action of the pressure plungsr.
In the vertical die casting to which the present inventlon relates, the molten metal ls supplied into a sleeve while the gate is closed, and the gate i9 then opened so that the molten metal is charged from the sprue runner into the mold cavity due to the descending motion of a pressure plunger and a counter plunger. According to the present invention, the cavity ia charged ~&
... .. .. .. .... . .. . ...... .. . . . .. . .... .. . .... . . . .. .
wlth the molten metal at two stages. After the molten metal i~ ~upplled into the ~le~ve, the molten me~al is charged smoo~hly lnto the cavi~y vla ~he rulmer at the initial stage through lowerlng a lower sleeve by a descendlng mean~, and then the cavlty is comple~ely chasged with the molten metal ~hile press~rized by the pressurizing action of the descending pressure plunger at a specified speed.
Namely, accnrding ~o the present inventlon, the molten metal i8 8UpplLed into the sleeve while the lower sleeve, ae flrs~, ia brough~ ln~o contact with the upper sleeve ~o clo8e the gate. The lower ~leeve is then ~llowed to descend thereby ~o open ~he ga~e acco~panylng ~he descendlng motion of the pre~sure plung~r, B predetermlned amoun~ of molten metal is allowed to smoothly flow due to ~t~ own weight, and the pressure plunger gives pressure upon tha molten metal under the conditlon in which the flow of molten metal is not terminated, so that the molten metal is charged into the cavity through the sprue runner~ ther~by to obtain a satisfactory product withou~ splashes of molten metal, without the inclusion gases, and without cold shut, These and other objects and many of the attendant advantages of this invention will bé readily apprec$ated as the same becomes bettex understood by reference to ~he following detailed description of ~he preferred embodlment when considered in connection with the acco~panying drawlngs.
Fig. l is a diagram illustraeing a vertical die cas~ing according to a conventional art;
Figs. 2 and 3 are diagrams illustrating an apparatus and a manufacturlng process according to the present invention;
Fig. 4 is a view illustxating the sprue runner of the ambDdiment of Figs 7 2 and 3 on an enlarged scale; and Fig. S i8 a dlagram illustrating experimental data.
According t~ the conventionally eMployed general vertic~l die casting as shown ln Fig. 1, a pouring gate 9 is formed by a sleeve 5 that forms a sprue rulmer 4 connected to a cavity that ls defined by upper and lower mold~ I and
2, a counter pl~ngar 7 ~s urged by a counter cylinder 8 to close ehe gate 9.
Molten metal 10 i8 ~upplled when the gate 1~ closed, a pre~sure plunger 12 19 lowered by a pressure cylinder 11, and the counter plunger 7 ls lowered by ~he counter cyllnder 8, ~o that the molten metal 10 i~ charged into the cavity 3 through the sprue runner 4 which i8 open.
To obtain sa~i~f~ctory cast products, no gas should be caught in the molten metal lO tha~ i8 charged in the cavlty 3, and no cold ~hut shoud exist in the molten metal, 50 that the produc~ should have a high specific gravl~y.
In charging the molten metal lO into the cavity 3, if the mol~en metal is charged only by the descending action of the counter plunger 7 whlle ~he pre~3ure plunger 12 does not pressurize the molten metal 10 in the sleeve, cold shut will develop in the molten metal 90 that unsatisfactory products are obtained.
To cope with this problem, the gate 9 iR closed by the counter plunger 7 in the inltial stage, and the counter plun~er 7 i~ ~llowed to descend after the molten metal lO i8 pre3surized by the pres~ure plunger 12~ In this case, the de~cending rate of ~he pressure plunger 12 iæ set ~o be faster ~han that of the counter plunger 7 taking the charging ra~e lnto considerai~on, and the ~peed of the plunger 12 iB see to a high value.
Therefore, pressure is exerted on the molten metal 10 by the pres~ure plunger 12 beore the descending counter plunger 7 passes over the gate 9, i.e., before the gate is completely opened, whereby the molten ~etal i~
lnJected at high speeds into the cavity 3 from the openlng of the gate.
Accordingly, splashes of molten metal adhere to ~he interior of the cavity 3 before it is fully charged with the molten metal; i.e., 8 par~ of the lten metal ~olidifles early and does not fuse together with the sub~equently charged molten metal, giving rise to the occurrence of cold shut.
The present invention will be explained more in detail w1th reference to one embodiment shown ln Flgs. 2 - 4 which i9 merely lllustrative of this invention and is not lntended to limit the scope of the present lnventlonO In these figures, the same reference numerals represent the same, or similar, parts in Fig. 1.
Symbol A denote~ a vertical dle casting apparatus as one embodiment accordlng to the present invention which i8 used to produce a cast products free from dePect~ such as gas inclusion and cold shut, in which reference numeral 3 iclentifles a cavity which is defined by an upper mold 1 and a lower mold 2; and reference numeral 13 identiEles a core secured withln the cavity 3. As shown in detail in Fig. 4, the cavity 3 is located at a position lower than the gate 9, and a sprue runner 4' is downwardly tilted at, for example, 5 to 45 extending from the gate 9 to the cavity.
An upper sleeve 5' is secured to the upper ~old 1, and a lo~er sleeve 5 , which is vertically movable with respece to the lower mold 2 and coupled to a hydraullc cylinder 14 that operates as a lowering and lifting means, is brought int~ close contact with the lower end of the upper sleeve 5' at the gate 9 thereby to close the gate. A counter pl~nger 7 is slidably inserted inside the lower sleeve 5 and is connected to a counter cylinder 8 located at a lower position~
A pressure plunger 12 is fitted into the upper sleeve 5' and is coupled to a pressure cylinder 11 located at an upper position. An extension 16 provided on the rod 15 is designed to be able to come into contact wi~h a limit switch 17 that is attached to a frame (not shown)~ The limit switch is connected to an hydraulic pump actuatlng device for the hydraulic cylinder 14, if need be via a suitable relay (no~ shown).
For the purpose of convenience, the ratio of sectional area of the pouring gate to the volume of product ~volume of the cav.ity) is O.Ol to 0.08 cm~l.
The hydraullc mechanism on the pressurlzing side of the pressure cyllnder ll is so designed that a pressure ratio determining device (not shown) may determine the relative pressure of the pressure plunger 12 relative to the counter plunger 7.
In the vertical die casting apparatus A, the lower sleeve 5 i~ ralsed during the initial stage by the lowering and lifting means l4 to come lnco intimate contact with the uppar sleeve 5', thereby to close the gate 9.
Under this condition, the predetermined amount of the molten metal 10 from a molten metal inlet 18 is supplied into the upper sleeve 5', and a piston of the pressure cyli~der ll is actuated to lower the pressure plunger 12.
When the extension 16 of rod 15 of the pressure plunger 12 comes into contact wi~h the limit switch 17 located at a preset position, the lowering and lifting means 14 is operated, via the relay, before the pressure plunger l2 reaches the molten metal 10~ whereby the lower sleeve 5 is lowered to open ~he gate 9.
Since the pressure plunger 12 has not yet reached a position enabling it to exert the pressure onto the ~olten metal, the molten metal lO flows by ~ts own weight lnto the cavity 3 through the sprue runner 4' ~hat is downwardly tilted at an angle~- from S to 45.
In this case, the molten metal lO flows naturally through the sprue runner that is downwardly tilted. To obtain an optimum flow rate and flow capacity, however, the rate of cross-sectional area of pouring gate to the volume of the product is preferably from 0.02 to 0.05 cm~l.
Thus, the apparatus a~cording to the present invention ls so designed that when more ~han lO~ of ~he molten metal to be charged lnto the cavity flows lnto the cavlty by its own weight, the pressure plunger 12 comes into contact with the molten me~al lO, lest the molten metal should cease to flow, and ~he molten metal lO ls pressurl~ed by the pres~ure plunger, so that it is charged under pressure into the cavity 3 through the sprue rumler 4'.
Here~ the above-mentioned problems of ~he conventional method arises if the molten metal gushes vigorotlsly into the cavity~ According to the present ~nventlon, therefore, the molten metal i~ preferably charged under pressure at a speed which does not exceed four times the ~peed at the gate at which the molten metal is allowed to flow by lts own weight, and, ~ore preferably, doe~
not exceed twice the speed at ~he initial ~tage.
The molten ~etal lO iB thus charged at a low rate into the cavlty 3.
Consequently, no eold shut is formed, gas i9 not agitated ln the cavity, and no ga~ i8 entrapped ln the ~olten metal~ so that a suitable die ca~ted product 1 obtalned.
Furthermorel since the molten me~al i9 charged at a low speed under a low pressure, the core i8 not llable to be damaged or eroded and even a sand core can be used.
When the charging of the molten metal i3 flnished, the molten metal is pressurized at a predetermined pressure by the pressure plunger 12 and then, the molten metal 1s pressurized again by the counter plunger 7~
Finall~, the mold is split to take out the pro~uct. The mold ls then reset, and the molt~n metal is supplied again.
Fig. 5 show~ the comparison results between the embodiment of the present invention ~nd the conventional art, in whlch the abscis~a represents the pressure P tkg/cm2) exerted on ~he molten metal by the pressure plunger, and the ordinate represents the specific gravity~tof the die ~ast product. It will be observed that the product of the pre~ent lnven~ion represen~ed by a curve C' has an increased density compared wlth the product of the conventional art represented by a curve C, and therefore the present invention can provide an i~proved product having a compact struc~ureO
The embodlment oE the present lnventlon, as descrlbed ahove, does not llmit the in~ention to the e~ample only. For instance, a core of the undercut type may be employed and the sprue runner may be curved, or any other sui able shape.
The invention can also be adapted for effectlng complicated profile die casting without uslng a core.
The charging rate and the charging capacity of the molten metal by lts own welght, the timing at which the pressuLe plunger comes into contact wlth the molten metal, the pressure to be exerted on the molten metal, and the charging rate under the pressure can be sultably determined~ Furthermore, the means for opening and closing the gate is not limited to the lower sleeve, but the ga~e may be opened and closed by the counter plunger~
According to the present invention as mentioned above, the lten metal is supplied lnto the sleeve while the ga~e is closed, and the gate is opened before the pressure is exerted on the molten metal by the pressure plunger, so that the molten metal is charged into the cavity as smoothly as po6sible by its own weight. The mol~en metal is charged at a slow speed without being pressurized, and does not gush into the cavity to adhere to the in~erior surfaces thereof followed by hardening. Thus 9 the molten metal is charged into the cavity in the form of laminated layerO Therefore, no cold shut is formed, gas is not stirred up in the cavity, no gas is captured by the molten metal, and an excellent die cast product is obtained.
Furthermore, the molten metal is char~ed under pressure by the pressure plunger after a 2redetermined amount of the molten metal i~ allowed to flow into the cavity by its own weight without interruption. ~herefore, the decrease of flow rate by the weight of the molten metal is compensated, and the molten metal is reliably charged at low speed and satisfactory products can be obtained wlthout cold shut and ga~ inclusion.
~ 7 --~, .... , ..... .... . . . . . ... .. . .. ..... .. , ... . .. ~, . ... . . . .
Th~ according to the present inventlon, excellent products ha~Lng undercut~ and cavltles can be obtained, using a cor~, wlthout difficulty, and the merits of the vertlcal die casting method can be fully utilized.
Molten metal 10 i8 ~upplled when the gate 1~ closed, a pre~sure plunger 12 19 lowered by a pressure cylinder 11, and the counter plunger 7 ls lowered by ~he counter cyllnder 8, ~o that the molten metal 10 i~ charged into the cavity 3 through the sprue runner 4 which i8 open.
To obtain sa~i~f~ctory cast products, no gas should be caught in the molten metal lO tha~ i8 charged in the cavlty 3, and no cold ~hut shoud exist in the molten metal, 50 that the produc~ should have a high specific gravl~y.
In charging the molten metal lO into the cavity 3, if the mol~en metal is charged only by the descending action of the counter plunger 7 whlle ~he pre~3ure plunger 12 does not pressurize the molten metal 10 in the sleeve, cold shut will develop in the molten metal 90 that unsatisfactory products are obtained.
To cope with this problem, the gate 9 iR closed by the counter plunger 7 in the inltial stage, and the counter plun~er 7 i~ ~llowed to descend after the molten metal lO i8 pre3surized by the pres~ure plunger 12~ In this case, the de~cending rate of ~he pressure plunger 12 iæ set ~o be faster ~han that of the counter plunger 7 taking the charging ra~e lnto considerai~on, and the ~peed of the plunger 12 iB see to a high value.
Therefore, pressure is exerted on the molten metal 10 by the pres~ure plunger 12 beore the descending counter plunger 7 passes over the gate 9, i.e., before the gate is completely opened, whereby the molten ~etal i~
lnJected at high speeds into the cavity 3 from the openlng of the gate.
Accordingly, splashes of molten metal adhere to ~he interior of the cavity 3 before it is fully charged with the molten metal; i.e., 8 par~ of the lten metal ~olidifles early and does not fuse together with the sub~equently charged molten metal, giving rise to the occurrence of cold shut.
The present invention will be explained more in detail w1th reference to one embodiment shown ln Flgs. 2 - 4 which i9 merely lllustrative of this invention and is not lntended to limit the scope of the present lnventlonO In these figures, the same reference numerals represent the same, or similar, parts in Fig. 1.
Symbol A denote~ a vertical dle casting apparatus as one embodiment accordlng to the present invention which i8 used to produce a cast products free from dePect~ such as gas inclusion and cold shut, in which reference numeral 3 iclentifles a cavity which is defined by an upper mold 1 and a lower mold 2; and reference numeral 13 identiEles a core secured withln the cavity 3. As shown in detail in Fig. 4, the cavity 3 is located at a position lower than the gate 9, and a sprue runner 4' is downwardly tilted at, for example, 5 to 45 extending from the gate 9 to the cavity.
An upper sleeve 5' is secured to the upper ~old 1, and a lo~er sleeve 5 , which is vertically movable with respece to the lower mold 2 and coupled to a hydraullc cylinder 14 that operates as a lowering and lifting means, is brought int~ close contact with the lower end of the upper sleeve 5' at the gate 9 thereby to close the gate. A counter pl~nger 7 is slidably inserted inside the lower sleeve 5 and is connected to a counter cylinder 8 located at a lower position~
A pressure plunger 12 is fitted into the upper sleeve 5' and is coupled to a pressure cylinder 11 located at an upper position. An extension 16 provided on the rod 15 is designed to be able to come into contact wi~h a limit switch 17 that is attached to a frame (not shown)~ The limit switch is connected to an hydraulic pump actuatlng device for the hydraulic cylinder 14, if need be via a suitable relay (no~ shown).
For the purpose of convenience, the ratio of sectional area of the pouring gate to the volume of product ~volume of the cav.ity) is O.Ol to 0.08 cm~l.
The hydraullc mechanism on the pressurlzing side of the pressure cyllnder ll is so designed that a pressure ratio determining device (not shown) may determine the relative pressure of the pressure plunger 12 relative to the counter plunger 7.
In the vertical die casting apparatus A, the lower sleeve 5 i~ ralsed during the initial stage by the lowering and lifting means l4 to come lnco intimate contact with the uppar sleeve 5', thereby to close the gate 9.
Under this condition, the predetermined amount of the molten metal 10 from a molten metal inlet 18 is supplied into the upper sleeve 5', and a piston of the pressure cyli~der ll is actuated to lower the pressure plunger 12.
When the extension 16 of rod 15 of the pressure plunger 12 comes into contact wi~h the limit switch 17 located at a preset position, the lowering and lifting means 14 is operated, via the relay, before the pressure plunger l2 reaches the molten metal 10~ whereby the lower sleeve 5 is lowered to open ~he gate 9.
Since the pressure plunger 12 has not yet reached a position enabling it to exert the pressure onto the ~olten metal, the molten metal lO flows by ~ts own weight lnto the cavity 3 through the sprue runner 4' ~hat is downwardly tilted at an angle~- from S to 45.
In this case, the molten metal lO flows naturally through the sprue runner that is downwardly tilted. To obtain an optimum flow rate and flow capacity, however, the rate of cross-sectional area of pouring gate to the volume of the product is preferably from 0.02 to 0.05 cm~l.
Thus, the apparatus a~cording to the present invention ls so designed that when more ~han lO~ of ~he molten metal to be charged lnto the cavity flows lnto the cavlty by its own weight, the pressure plunger 12 comes into contact with the molten me~al lO, lest the molten metal should cease to flow, and ~he molten metal lO ls pressurl~ed by the pres~ure plunger, so that it is charged under pressure into the cavity 3 through the sprue rumler 4'.
Here~ the above-mentioned problems of ~he conventional method arises if the molten metal gushes vigorotlsly into the cavity~ According to the present ~nventlon, therefore, the molten metal i~ preferably charged under pressure at a speed which does not exceed four times the ~peed at the gate at which the molten metal is allowed to flow by lts own weight, and, ~ore preferably, doe~
not exceed twice the speed at ~he initial ~tage.
The molten ~etal lO iB thus charged at a low rate into the cavlty 3.
Consequently, no eold shut is formed, gas i9 not agitated ln the cavity, and no ga~ i8 entrapped ln the ~olten metal~ so that a suitable die ca~ted product 1 obtalned.
Furthermorel since the molten me~al i9 charged at a low speed under a low pressure, the core i8 not llable to be damaged or eroded and even a sand core can be used.
When the charging of the molten metal i3 flnished, the molten metal is pressurized at a predetermined pressure by the pressure plunger 12 and then, the molten metal 1s pressurized again by the counter plunger 7~
Finall~, the mold is split to take out the pro~uct. The mold ls then reset, and the molt~n metal is supplied again.
Fig. 5 show~ the comparison results between the embodiment of the present invention ~nd the conventional art, in whlch the abscis~a represents the pressure P tkg/cm2) exerted on ~he molten metal by the pressure plunger, and the ordinate represents the specific gravity~tof the die ~ast product. It will be observed that the product of the pre~ent lnven~ion represen~ed by a curve C' has an increased density compared wlth the product of the conventional art represented by a curve C, and therefore the present invention can provide an i~proved product having a compact struc~ureO
The embodlment oE the present lnventlon, as descrlbed ahove, does not llmit the in~ention to the e~ample only. For instance, a core of the undercut type may be employed and the sprue runner may be curved, or any other sui able shape.
The invention can also be adapted for effectlng complicated profile die casting without uslng a core.
The charging rate and the charging capacity of the molten metal by lts own welght, the timing at which the pressuLe plunger comes into contact wlth the molten metal, the pressure to be exerted on the molten metal, and the charging rate under the pressure can be sultably determined~ Furthermore, the means for opening and closing the gate is not limited to the lower sleeve, but the ga~e may be opened and closed by the counter plunger~
According to the present invention as mentioned above, the lten metal is supplied lnto the sleeve while the ga~e is closed, and the gate is opened before the pressure is exerted on the molten metal by the pressure plunger, so that the molten metal is charged into the cavity as smoothly as po6sible by its own weight. The mol~en metal is charged at a slow speed without being pressurized, and does not gush into the cavity to adhere to the in~erior surfaces thereof followed by hardening. Thus 9 the molten metal is charged into the cavity in the form of laminated layerO Therefore, no cold shut is formed, gas is not stirred up in the cavity, no gas is captured by the molten metal, and an excellent die cast product is obtained.
Furthermore, the molten metal is char~ed under pressure by the pressure plunger after a 2redetermined amount of the molten metal i~ allowed to flow into the cavity by its own weight without interruption. ~herefore, the decrease of flow rate by the weight of the molten metal is compensated, and the molten metal is reliably charged at low speed and satisfactory products can be obtained wlthout cold shut and ga~ inclusion.
~ 7 --~, .... , ..... .... . . . . . ... .. . .. ..... .. , ... . .. ~, . ... . . . .
Th~ according to the present inventlon, excellent products ha~Lng undercut~ and cavltles can be obtained, using a cor~, wlthout difficulty, and the merits of the vertlcal die casting method can be fully utilized.
Claims (7)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A vertical die casting method comprising the steps of:
initially charging molten metal into a cavity in a mold by the weight of the molten metal itself; and then completing the charging of the molten metal into the cavity under pressure.
initially charging molten metal into a cavity in a mold by the weight of the molten metal itself; and then completing the charging of the molten metal into the cavity under pressure.
2. The vertical die casting method of claim 1, wherein the speed at which the charging is carried out under pressure is less than four times the speed at which the charging is carried out by the weight of the molten metal itself.
3. The vertical die casting method of claim 1, wherein the speed at which the charging is carried under pressure is less than twice that at which the charging is carried out by the weight of the molten metal itself.
4. A vertical die casting apparatus comprising:
an upper mold and a lower mold which define a cavity;
an upper sleeve and a lower sleeve which are positioned inside said molds;
means for lowering and lifting said lower sleeve;
a gate which is opened and closed by said lower sleeve;
a sprue runner which connects said gate and said cavity and which is tilted downwardly;
a pressure plunger which serves to pressurize molten metal to be charged into said cavity;
a means for actuating said pressure plunger;
limit means for actuating said lower sleeve-lowering and lifting means, said limit means being actuated by the movement of the pressure plunger;
a counter plunger which serves to pressurize the molten metal after the pressure plunger pressurizing is over; and a means for lowering and lifting said counter plunger.
an upper mold and a lower mold which define a cavity;
an upper sleeve and a lower sleeve which are positioned inside said molds;
means for lowering and lifting said lower sleeve;
a gate which is opened and closed by said lower sleeve;
a sprue runner which connects said gate and said cavity and which is tilted downwardly;
a pressure plunger which serves to pressurize molten metal to be charged into said cavity;
a means for actuating said pressure plunger;
limit means for actuating said lower sleeve-lowering and lifting means, said limit means being actuated by the movement of the pressure plunger;
a counter plunger which serves to pressurize the molten metal after the pressure plunger pressurizing is over; and a means for lowering and lifting said counter plunger.
5. The vertical die casting apparatus of claim 4, wherein said runner is tilted downwardly at from 5° to 45°.
6. The vertical die casting apparatus of claims 4 and 5, wherein the ratio of the sectional area of said gate to the volume of said cavity is 0.01 - 0.08 cm-1.
7. The vertical die casting apparatus of claims 4 and 5, wherein the ratio of the sectional area of said gate to the volume of said cavity is 0.02 - 0.05 cm-1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000395613A CA1190021A (en) | 1982-02-05 | 1982-02-05 | Method and apparatus for vertical die casting |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000395613A CA1190021A (en) | 1982-02-05 | 1982-02-05 | Method and apparatus for vertical die casting |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1190021A true CA1190021A (en) | 1985-07-09 |
Family
ID=4121979
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000395613A Expired CA1190021A (en) | 1982-02-05 | 1982-02-05 | Method and apparatus for vertical die casting |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1190021A (en) |
-
1982
- 1982-02-05 CA CA000395613A patent/CA1190021A/en not_active Expired
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