CA2030761A1 - Casting apparatus - Google Patents
Casting apparatusInfo
- Publication number
- CA2030761A1 CA2030761A1 CA002030761A CA2030761A CA2030761A1 CA 2030761 A1 CA2030761 A1 CA 2030761A1 CA 002030761 A CA002030761 A CA 002030761A CA 2030761 A CA2030761 A CA 2030761A CA 2030761 A1 CA2030761 A1 CA 2030761A1
- Authority
- CA
- Canada
- Prior art keywords
- piston
- die
- speed
- control
- actuator
- 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.)
- Abandoned
Links
- 238000005266 casting Methods 0.000 title claims abstract description 36
- 229910052751 metal Inorganic materials 0.000 claims abstract description 30
- 239000002184 metal Substances 0.000 claims abstract description 30
- 238000013500 data storage Methods 0.000 claims abstract description 4
- 230000033001 locomotion Effects 0.000 claims description 17
- 238000000034 method Methods 0.000 claims description 12
- 230000009471 action Effects 0.000 claims description 5
- 238000004891 communication Methods 0.000 claims description 4
- 229910045601 alloy Inorganic materials 0.000 abstract description 34
- 239000000956 alloy Substances 0.000 abstract description 34
- 230000008018 melting Effects 0.000 abstract description 3
- 238000002844 melting Methods 0.000 abstract description 3
- 230000006870 function Effects 0.000 description 6
- 230000008901 benefit Effects 0.000 description 5
- 230000004941 influx Effects 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
- 230000005499 meniscus Effects 0.000 description 2
- 229910001092 metal group alloy Inorganic materials 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 230000000630 rising effect Effects 0.000 description 2
- 238000013019 agitation Methods 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000011960 computer-aided design Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 238000010494 dissociation reaction Methods 0.000 description 1
- 230000005593 dissociations Effects 0.000 description 1
- 230000008014 freezing Effects 0.000 description 1
- 238000007710 freezing Methods 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
Classifications
-
- 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
- B22D17/02—Hot chamber machines, i.e. with heated press chamber in which metal is melted
- B22D17/04—Plunger machines
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D18/00—Pressure casting; Vacuum casting
-
- 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
-
- 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
- B22D17/32—Controlling equipment
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Injection Moulding Of Plastics Or The Like (AREA)
- Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
Abstract
ABSTRACT:
"CASTING APPARATUS"
A casting apparatus for low melting point alloys comprises a dispensing cylinder 5 and a piston 7 driven by a rotary driven linear actuator 31. A
rotary motor 42 drives the actuator and the cylinder is connected to a die 26 during a dispensing stroke of the piston. Control means 52 controls the speed of the motor to thereby control the speed of the piston and the rate at which molten metal is dispensed into the die. A data storage means 56 holds data defining a characteristic of piston speed as a function of time during the dispensing stroke and enables the rate at which metal rises in the die to be controlled in a manner which takes account of variation in die cross-section.
"CASTING APPARATUS"
A casting apparatus for low melting point alloys comprises a dispensing cylinder 5 and a piston 7 driven by a rotary driven linear actuator 31. A
rotary motor 42 drives the actuator and the cylinder is connected to a die 26 during a dispensing stroke of the piston. Control means 52 controls the speed of the motor to thereby control the speed of the piston and the rate at which molten metal is dispensed into the die. A data storage means 56 holds data defining a characteristic of piston speed as a function of time during the dispensing stroke and enables the rate at which metal rises in the die to be controlled in a manner which takes account of variation in die cross-section.
Description
"CA~TIN~ APPARATUS"
This invention relates to casting apparatus and in particular but not exclusively to the casting o~
low melting point alloys for use in mouldiny plastics materials.
It is known from EP-A-0177257 to provide casting apparatus in which molten metal is dispensed into a die from a dispensing cylinder by action o~ a piston slidable in the cylinder and driven by an actuator comprising a hydraulic or pneumatic cylinder~ The piston continues to pressurise the molten metal after filling of the die during a period in which the metal in the die cools and solidifies.
A microprocessor is in this arrangement provided for controlling the sequential operation of the actuator and its associated flow valve.
It is also known from GB-A-420728 to provide a rotary driven actuator for urging a piston in a dispensing cylinder and a control circuit is provided for switching on and o~f a rotary motor which drives the actuator.
It is an object of the present invention to provide casting apparatus having an actuator which controls the piston more precisely and more conveniently than has previously been possible.
According to the present invention there is disclosed casting apparatus comprising a dispensing cylinder receiving molten metal in use, a piston slidably received in the cylinder, a rotary driven -linear actuator operable to drive the piston in the cylinder, rotary drive means operable to drive the actuator and communicating means communicating during a dispensing strok2 of the piston between the cylinder and a die ~or dispensing molten metal to the die, wherein the apparatus further comprises control .
- . ,. - -~
- : ~
, 20307~1 means operable to control the rotational speed of the drive means to thereby control the speed of the piston and thereby control the rate at which molten metal is dispensed into the die.
An advantage of such apparatus is that the piston speed can be directly controlled throughout the dispensing stroke whereas in each of the prior art apparatus referred to above there is no provision for monitoring the actuator speed and correcting any deviation in speed from a preferred value.
The apparatus of the present invention thereby provides greater control and repeatability which is of particular importance in maintaining quality of casting.
Preferably the control means is provided with data storage means receiving in use data defining a desired characteristic of piston spsed as a function of time during the dispensing stroke and is operable to control the drive means such that the instantaneous speed of the piston is substantially equal to that of the desired characteristic during filling of the die.
An advantage of such an arrangement is that the piston speed can be varied during the dispensing stroke in a repeatable manner which can be tailored to suit the requirements of a particular die having a specific internal shape. By adjusting the i characteristic of piston speed it is possible to ~-avoid imperfections in the resulting casting which are associated with the elevation speed at which the ~-level of molten metal rises within the die. By adjusting the characteristic of piston speed it is possible to maintain the elevation rate within preferred maximum and minimum values and to avoid turbulent ef~ects associated with rapid change in elevation rate.
.: . . : . : . :
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20307~1 Preferably the drive means includes a rotary motor and slippable torque transmitting means transmitting rotary motion from the motor to the actuator whereby torque continues to be transmitted to the actuator after the piston is arrested by back pressure in the cylinder after the die is full.
Conveniently the torque transmitting means comprises a clutch having means for adjusting the torque transmitted to thereby adjust the pressure of molten metal in the die when filled.
The clutch may be electromagnetically operated and adjustable by mechanical or electromechanical adjustment means.
Preferably the apparatus includes an actuator sensor responsive to the speed of rotation at which the linear actuator is driven, a motor sensor responsive to the speed of rotation of the motor and -control means connected to the respective sensors and operable to control the speed of the motor.
The distance travelled by the actuator may therefore be controlled using a closed feedback loop ;~
in an accurate manner.
Advantageously the torque transmitting means is adjustable by means actuated by the control means. -Where the torque limiting means is a clutch it may therefore be electromagnetically actuated by signals -from the control means. , Preferably the rotary driven linear actuator comprises first and second cooperating screw threaded members, the drive means being operable to provide relative rotational movement between the first and second members resulting in relative linear motion by screw action and connecting means which connects the first and second members to the cylinder and piston respectively so as to provide actuating movement therebetween.
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203076~
Advantageously the first member i5 a screw threaded shaft and the second member is a cooperatiny nut which nut includes ball bearing means so that the nut and shaft together comprise a ball scre~J.
An advantage of using such a ball screw is that the screw action is accompanied by minimal ~rictional losses and minimal lost motion so that the piston position is accurately and smoothly controllable even at very slow actuation speeds.
According to a further aspect of the present invention there is disclosed a method of castiny comprising the steps of placing a dispensing cylinder receiving molten metal in communication with a die and driving a piston in the cylinder by means of a rotary driven linear actuator such that molten metal is dispensed into the die during a dispensing stroke of the piston, and operating a control means to control the rotational speed of a rotary drive means driving the actuator to thereby control the rate at which molten metal is dispensed into the die.
Preferably the method includes the steps of operating the control means to control the speed of ~; ;
the drive means such that during filling of the die the piston speed is substantially equal to a desired characteristic of piston speed as a function of time.
Advantageously the characteristic of piston speed against time is selected such that the level of molten metal in the die rises at an elevation rate which increases from zero to a minimum preferred value above which the elevation rate is thereafter maintained during the filling of the ~ie.
The method may include the step of continuing to apply torque to the rotary driven linear actuator `~
after the die has become filled with molten metal until the metal in the die has substantially solidified.
, ,: : , .: , .
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-. : - : -,: : - . : :. : - :, : -- :
: - :: - , , : ~- - .: '.' ' . ' , , :., ' . . : .: :: ~ . :, . .
.
: , . ; , , , . ~:
, :. , : : - :
: . - :
-` 2030761 An advantage of this method is that any chanye of volume of the metal within the die ~an be compensated by an influx or efflux o~ molten alloy under pressure applied by the piston.
Preferably the method includes the step of varying the rotational speed at wh.ich the rotary driven linear actuator is driven during a time period in which the die is progressively filled with molten metal such that the level of molten metal within the die rises at a predetermined rate.
An advantage of this method is that the internal shape of the die can be taken account of i.n controlling the rate of influx of molten alloy in a manner which ensures that the die is completely filled without formation of surface defects. ,.
Particular embodiments of the present invention will now be described by way of example only and with reference to the accompanying drawings of which:-Figure 1 is a partly sectioned elevation of casting apparatus;
Figure 2 is a partly sectioned elevation of the ., actuator of the casting apparatus of Figure l;
Figure 3 is a sectional elevation of a die for use with the casting apparatus of Figures 1 and 2; and Figure 4 is a graph of piston speed against time illustrating the characteristic of dispensed flow rate suitable for filling the die of Figure 3.
In Figure 1 a casting apparatus 1 is suitable for casting metal alloys having low melting temperatures for example having solidus temperatures in the range of 35C to 300C. The apparatus 1 has a tank 2 in which is held a quantity of molten alloy 3 which fills the tank to a normal level 4. A
cylinder 5 is located within the tank 2 and immersed in the molten alloy 3. The cylinder 5 extends vertically upwardly from a mounting block 6 upon :, :-: :
This invention relates to casting apparatus and in particular but not exclusively to the casting o~
low melting point alloys for use in mouldiny plastics materials.
It is known from EP-A-0177257 to provide casting apparatus in which molten metal is dispensed into a die from a dispensing cylinder by action o~ a piston slidable in the cylinder and driven by an actuator comprising a hydraulic or pneumatic cylinder~ The piston continues to pressurise the molten metal after filling of the die during a period in which the metal in the die cools and solidifies.
A microprocessor is in this arrangement provided for controlling the sequential operation of the actuator and its associated flow valve.
It is also known from GB-A-420728 to provide a rotary driven actuator for urging a piston in a dispensing cylinder and a control circuit is provided for switching on and o~f a rotary motor which drives the actuator.
It is an object of the present invention to provide casting apparatus having an actuator which controls the piston more precisely and more conveniently than has previously been possible.
According to the present invention there is disclosed casting apparatus comprising a dispensing cylinder receiving molten metal in use, a piston slidably received in the cylinder, a rotary driven -linear actuator operable to drive the piston in the cylinder, rotary drive means operable to drive the actuator and communicating means communicating during a dispensing strok2 of the piston between the cylinder and a die ~or dispensing molten metal to the die, wherein the apparatus further comprises control .
- . ,. - -~
- : ~
, 20307~1 means operable to control the rotational speed of the drive means to thereby control the speed of the piston and thereby control the rate at which molten metal is dispensed into the die.
An advantage of such apparatus is that the piston speed can be directly controlled throughout the dispensing stroke whereas in each of the prior art apparatus referred to above there is no provision for monitoring the actuator speed and correcting any deviation in speed from a preferred value.
The apparatus of the present invention thereby provides greater control and repeatability which is of particular importance in maintaining quality of casting.
Preferably the control means is provided with data storage means receiving in use data defining a desired characteristic of piston spsed as a function of time during the dispensing stroke and is operable to control the drive means such that the instantaneous speed of the piston is substantially equal to that of the desired characteristic during filling of the die.
An advantage of such an arrangement is that the piston speed can be varied during the dispensing stroke in a repeatable manner which can be tailored to suit the requirements of a particular die having a specific internal shape. By adjusting the i characteristic of piston speed it is possible to ~-avoid imperfections in the resulting casting which are associated with the elevation speed at which the ~-level of molten metal rises within the die. By adjusting the characteristic of piston speed it is possible to maintain the elevation rate within preferred maximum and minimum values and to avoid turbulent ef~ects associated with rapid change in elevation rate.
.: . . : . : . :
:." . ., . : . , : - , .:
, - , : .
20307~1 Preferably the drive means includes a rotary motor and slippable torque transmitting means transmitting rotary motion from the motor to the actuator whereby torque continues to be transmitted to the actuator after the piston is arrested by back pressure in the cylinder after the die is full.
Conveniently the torque transmitting means comprises a clutch having means for adjusting the torque transmitted to thereby adjust the pressure of molten metal in the die when filled.
The clutch may be electromagnetically operated and adjustable by mechanical or electromechanical adjustment means.
Preferably the apparatus includes an actuator sensor responsive to the speed of rotation at which the linear actuator is driven, a motor sensor responsive to the speed of rotation of the motor and -control means connected to the respective sensors and operable to control the speed of the motor.
The distance travelled by the actuator may therefore be controlled using a closed feedback loop ;~
in an accurate manner.
Advantageously the torque transmitting means is adjustable by means actuated by the control means. -Where the torque limiting means is a clutch it may therefore be electromagnetically actuated by signals -from the control means. , Preferably the rotary driven linear actuator comprises first and second cooperating screw threaded members, the drive means being operable to provide relative rotational movement between the first and second members resulting in relative linear motion by screw action and connecting means which connects the first and second members to the cylinder and piston respectively so as to provide actuating movement therebetween.
.~. . . .
.: -:
.: , : -- : . . :
...
, .
203076~
Advantageously the first member i5 a screw threaded shaft and the second member is a cooperatiny nut which nut includes ball bearing means so that the nut and shaft together comprise a ball scre~J.
An advantage of using such a ball screw is that the screw action is accompanied by minimal ~rictional losses and minimal lost motion so that the piston position is accurately and smoothly controllable even at very slow actuation speeds.
According to a further aspect of the present invention there is disclosed a method of castiny comprising the steps of placing a dispensing cylinder receiving molten metal in communication with a die and driving a piston in the cylinder by means of a rotary driven linear actuator such that molten metal is dispensed into the die during a dispensing stroke of the piston, and operating a control means to control the rotational speed of a rotary drive means driving the actuator to thereby control the rate at which molten metal is dispensed into the die.
Preferably the method includes the steps of operating the control means to control the speed of ~; ;
the drive means such that during filling of the die the piston speed is substantially equal to a desired characteristic of piston speed as a function of time.
Advantageously the characteristic of piston speed against time is selected such that the level of molten metal in the die rises at an elevation rate which increases from zero to a minimum preferred value above which the elevation rate is thereafter maintained during the filling of the ~ie.
The method may include the step of continuing to apply torque to the rotary driven linear actuator `~
after the die has become filled with molten metal until the metal in the die has substantially solidified.
, ,: : , .: , .
: . ... , - :.: :
-:: ,. . :, - :. - . :
-. : - : -,: : - . : :. : - :, : -- :
: - :: - , , : ~- - .: '.' ' . ' , , :., ' . . : .: :: ~ . :, . .
.
: , . ; , , , . ~:
, :. , : : - :
: . - :
-` 2030761 An advantage of this method is that any chanye of volume of the metal within the die ~an be compensated by an influx or efflux o~ molten alloy under pressure applied by the piston.
Preferably the method includes the step of varying the rotational speed at wh.ich the rotary driven linear actuator is driven during a time period in which the die is progressively filled with molten metal such that the level of molten metal within the die rises at a predetermined rate.
An advantage of this method is that the internal shape of the die can be taken account of i.n controlling the rate of influx of molten alloy in a manner which ensures that the die is completely filled without formation of surface defects. ,.
Particular embodiments of the present invention will now be described by way of example only and with reference to the accompanying drawings of which:-Figure 1 is a partly sectioned elevation of casting apparatus;
Figure 2 is a partly sectioned elevation of the ., actuator of the casting apparatus of Figure l;
Figure 3 is a sectional elevation of a die for use with the casting apparatus of Figures 1 and 2; and Figure 4 is a graph of piston speed against time illustrating the characteristic of dispensed flow rate suitable for filling the die of Figure 3.
In Figure 1 a casting apparatus 1 is suitable for casting metal alloys having low melting temperatures for example having solidus temperatures in the range of 35C to 300C. The apparatus 1 has a tank 2 in which is held a quantity of molten alloy 3 which fills the tank to a normal level 4. A
cylinder 5 is located within the tank 2 and immersed in the molten alloy 3. The cylinder 5 extends vertically upwardly from a mounting block 6 upon :, :-: :
- 2~30761 which it is supported and receives a piston 7 ~7hich is axially slidable within the cylinder. The mounting block 6 rests upon supports 8 and 9.
The cylinder 5 defines a cylindrical dispensing chamber 10 and the mounting block 6 defines a conduit 11 communicating between the chamber and a three port ball valve 12. The ball valve 12 has a ball 13 mounted on a stem 14 and located between valve seats 15 and 16 within a valve chamber 17 defined by the ball valve.
The valve 12 is provided with a first port 18 which communicates with the interior of the tank 2 so as to supply molten alloy to the valve, a second port 19 communica~ing with the conduit 11 so as to be in communication with the dispensing chamber 10 and a third port 20 communicating with a dispensing channel 21. The stem 14 is axially movable by action of a ball valve actuator 22 such that the ball can be positioned to close either the first port 1~ or the third port 20.
The dispensing channel 21 extends out of the tank 2 and communicate's with a flow valve 23 which is actuated by a rotary flow valve actuator 24 to open or close the flow path through the flow valve. A
further portion 25 of the dispensing channel 21 communicates between the flow valve 23 and a die 26.
The dispensing channel 21 is formed in a fixed -~
member 27 which is separable from the mounting block 6 such that the block can be removed from the tank.
The fixed member 27 includes a domed surface portion 28 locating in a corresponding recess ~9 formed in the mounting block 6 for ease of alignment of the dispensing channel 21 with the third port 20 on refitting the mounting block 6 within the tank 2.
The tank 2 and the dispensing channel 21 are surrounded in insulating material 30 to maintain an ,, " ~ , :
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2~307~1 even temperature throughout.
The piston 7 is driven by an actuating means 3 which is represented schematically in Figure 1 and is shown in detail in Figure 2.
The actuating means 31 includes a screw threaded shaft 32 on which is received a screw threaded nut 33 including ball bearing means (not shown) such that the shaft and nut together comprise a ball screw 34. The screw threaded shaft 32 includes screw threads 35 of part circular cross-section adapted to cooperate with the ball bearing means of the nut 33. The construction o~
the ball screw 34 is such that relative rotational movement between the nut 33 and the shaft 32 results in linear relative movement as in the case of known screw and nut combinations.
The nut 33 is rigidly connected to the piston 7 by means of a vertically extending tube 36 having a threaded coupling 37 at its lower end 38 allowing the piston to be bolted to the tube 36.
The screw threaded shaft 32 extends vertically and coaxially within the tube 36 and has an upper end 39 received in a bearing 40 which is connected to a tubular casing 41.
The casing 41 extends vertically with the tube 36 being coaxially received within the casing and the ~ -bearing 40 facilitates rotation of the shaft 32 relative to the casing but prevents longitudinal relative motion between the casing and the shaft 32.
A motor 42 has a driven shaft 43 arranged to drive an input pulley 44 of an adjustable clutch 45 via a toothed drive belt 46 and the clutch has an output shaft 47 rigidly connected in axial alignment with the screw threaded shaft 32. The clutch 45 comprises a solenoid actuated disc clutch having means for adjusting the pressure applied between the : : : : , ,. : , , ~ : : :: : .
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2~30~1 discs (not shown) to thereby provide means for settiny the maximum torque transmitted by the clutch.
A take-off pulley 48 is connected to the oukput shaft 47 of the clutch 45 and is connected by means of a toothed belt 49 to an actuator tachometer 50 ~or sensing actuator speed. A motor tachometer 51 is connected to the motor 42 for sensing the motor speed.
A digital elect,ronic control unit 52 is connected to receive output signals from the actuator tachometer 50 and the motor tachometer 51 indicating the rotational speeds o~ the screw threaded shaft 32 and the motor 42 respectively. As indicated schematically in Figure 1 the control unit 52 is connected to provide command signals to the motor 42 to regulate its speed, to the actuating solenoid of the clutch 45, to the ball valve actuator 22 to actuate the valve 12 and to the flow valve actuator 24 to control the actuation of the flow valve 23.
Upper and lower inductive proximity switches 53 and 54 respectively are connected to the casing 41 at vertically spaced apart locations and are arranged to sense the maximum and lower limits of normal travel of the nut 33 along the screw threaded shaft 32. -Output signals from the proximity switches 53 and 54 ~ -are connected at inputs to the control unit 52.
The control unit 52 is provided with a memory 56 for recei~ing data defining the preferred characteristic of speed of piston 7 as a function of time during a dispensing stroke of the piston. The selection of the preferred characteristic is described below with reference to Figures 3 and 4.
In use to dispense moltsn alloy 3 into the die 26 the piston is raised as shown in Figure 1 to its normal upper limit of travel with the chamber 10 ~illed with molten alloy. The ball valve 12 is moved into a position in which the ball 13 is fully ,: . . , , . :
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g raised by actuation of the ball valve actuator 22 thereby closing the first port 18. The ball valve 12 in this position provides communication between the conduit 11 and the dispensing channel 21.
An operator programmes the control unit 52 with the necessary data to achieve the optimum flow rate of molten alloy into the die 26, the flow rate being dependent on the internal shape of the die. This data is stored in the memory 56. The clutch 45 is set to provide a predetermined limit of torque such that torque across the clutch below a threshold limit will result in one-to-one transmission of drive through the clutch and torque exceeding the limit will result in slippage of the output shaft ~7 relative to the speed at which the clutch is driven by the motor 42 whilst a set value of torque continues to be transmitted.
The motor 42 is then driven at an initial speed under the control of the control unit 52 such that the clutch 45 is driven by the drive belt 46, the output shaft 47 of the clutch being correspondingly driven to thereby drive the screw threaded shaft 32 at an initial rate of rotation. Rotation of the shaft 32 results in linear movement of the nut 33 relative to the shaft, the direction of rotation of the motor being selected to be such that the nut moves downwards relative to the shaft. Since the nut 33 is rigidly connected to the piston 7 the piston moves correspondingly downwards and displaces molten alloy from the chamber 10. Alloy flows from the chamber 10 through the conduit 11, through the valve 12 into the dispensing channel 21, through the flow valve 23, through the further portion 25 of the dispensing channel 21 and into the die 26.
Throughout this flow path the insulation 30 retains the molten alloy at a temperature above its solidus ::: : : ~ :, -,. : . -: :
: :-: , . . -:
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~ 10 --temperature.
As the molten alloy is progressively dispensed from the chamber 10 the rate at which alloy is dispensed and the precise volume which has been displaced is monitored by the control unit 52 by means of signals received from the actuator tachometer 50 which provides a signal directly proportional to the rotational speed of the shaft 32, the travel of the piston being calculated by integrating the signal.
The control unit 52 adjusts the speed o~ the motor 42 during the dispensing operation in order to achieve a predetermined characteristic of piston speed against time. Since the actual displacement of the piston 7 is measured by the control unit and the speed of the piston directly regulated by the control unit this constitutes a closed loop feedback system providing precise control of the dispensing operation.
When the die 26 is completely filled with molten alloy the incompressibility of the liquid alloy 3 arrests the motion of the piston 7 such that the torque experienced across the clutch 45 exceeds the threshold limit to which it is set and the clutch ~5 therefore begins to slip. The halting of the piston 7 is sensed by the control unit 52 which then sets the motor 42 to run at a speed which maintains a set level of torque across the clutch 45 so as to bias the piston 7 downwardly and maintain a constant level of pressure in the dispensing flow path. The metal alloy within the die 26 is allowed to cool and solidify and in doing so undergoes a change of volume, either an increase or decrease, depending on the composition of the alloy. ~ decrease in volume will be accompanied by a slight influx of molten alloy to the die and the piston will move down , ~ . ~, , , -;' ' ~:` , , ~ , ~ "- '' "- . .
, .
--`` 2~3~761 accordingly by a small amount.
After solidification the control unit actuates the flow valve actuator 24 to turn off the flo~l valve 23 and the die 26 is removed from the casting apparatus 1 and replaced with the sarne die after removal of the solidified casting or with a further empty die.
The control unit 52 then actuates the ball valve actuator to lower the ball 13 so as to close the third port 20 and open the first port 18. The direction of rotation of the motor 42 i8 reversed and the piston 7 is then raised to create suction within the chamber 10 and draw molten alloy 3 from the tank 2 which constitutes a reservoir. The dispensing operation can then be repeated as described above after first opening the valve 23.
During extended periods between casting operations the piston 7 may be raised and lowered with the ball valve in its fully lowered position such that molten alloy from the tank 2 is cyclically drawn into and expelled from the chamber 10 in order to ensure that adequate agitation of the alloy is maintained to prevent dissociation of its constituent metals. During this recycling the upper and lower proximity switches 53 and 54 provide inputs to the control unit 52 as to when the piston has reached its operating limits of travel.
Figures 3 and 4 illustrate the manner in which the movement of piston 7 is controlled in order to tailor the characteristic of piston speed against time to suit a particular application. In the example of Figure 3 an alternative die 60 defines a cavity 61 having a shape resembling that of an inverted bottle. The shape of cavity 61 is symmetrical about a vertical axis and includes a cylindrical upper portion 62 of uniform . . .
.
" ': . ~ ~ . , ' . , 2~3~7fil cross-section. A lower portion 63 of ca~ity 61 has a reduce~ cross-section and is connected to the cylindrical upper portion 62 by a flared portion 6~
which merges smoothly and continuously with the upper and lower portions 61 and 62 respectively~
The die 60 is filled through an inlet 65 communicating with the lower portion 63 and is connected in use with the nozzle 55 of the apparatus of Figures 1 and 2.
Figure 4 illustrates graphically the preferred characteristic of speed S of piston 7 as a function of time t during a dispensing operation in which molten alloy is dispensed from the cylinder 5 into the cavity 61. During an initial time period A the piston begins to move smoothly and with gradually increasing speed from its rest position and the flow rate of molten alloy into the cavity 61 increases in direct proportion to this speed S. This gradual pick-up in flow rate ensures that the rising level of molten alloy remains substantially free from turbulence without the formation of jets. At the end of period A the elevation rate at which the level of molten alloy within the cavity 61 is rising will have reached a preferred minimum value above which the elevation rate is to be maintained during the filling of the cavity. If the level rises at a slower rate then surface imperfections in the casting result from the tendency to freezing of the meniscus formed at the interface between the alloy surface and the walls of the die 60. The flow of metal over the frozen meniscus results in unwanted lines being formed on the resulting casting.
As the level of alloy rises within the flared portion 64 it is necessary for the piston speed S to be accelerated during a further time period B in order that the elevation rate should remain constant :, ,, :
~` 203~761 in spite of the increasing cross-sectional area encountered by the alloy. When the level reaches the cylindrical upper portion 62 however the uniform cross-section of this portion requires a constant piston speed S during a further time period C.
When the cavity 61 becomes entirely filled with molten alloy the piston speed S drops rapidly during a further time period D. Contraction of the alloy during coolin~ occurs during a further time period E
requiring further motion of the piston as further alloy is injected into the die under continued piston pressure. Finally when no further alloy is able to enter the die some motion of the piston during a final time period F will result from imperfect sealing between the piston and cylinder.
Throughout periods B and C of the above dispensing operation the speed S of the piston 7 is controlled such that the alloy level rises at an elevation rate which is greater than or equal to the preferred minimum elevation rate and which is not greater than a preferred maximum elevation rate depending upon the particular shape of the cavity 61. If the elevation rate is too high then excessive pressures within the die result at the end of period C when the die becomes entirely filled and this can result in unwanted flashes being formed on joint faces of the die. When filling more complex die cavities there is an additional hazard in filling too ~uickly in that unwanted voids can result in the casting due to entrapment of air.
The preferred characteristic of S as a function of t for a given die may be arrived at empirically with the speed characteristic being adjusted to remove surface imperfections or voids found in castings resulting from trial dispensing operationsO Once a satisfactory casting has been : .
,. .. . . . .
, . ., : : . : , .
: :
.
.
2~33076~
produced from a given speed characteristic it has been found that subsequent castings using th~ same speed charac~zristic show a high degree of reproducability with consequent high ~ields of high quality castings.
The characteristic of S as a function of t may also be arrived at for new die shapes by theoretical calculation based on empirical values obtained from dies of simple shape. Such calculations may conveniently be expressed as algorithms processed in a computer in which informati.on concerning the shape of the die cavity is entered ~irectly from computer aided design data.
The memory 56 may comprise an electrically erasable programmable read-only memory or alternatively may comprise other known data storage means.
The apparatus and method of the present invention may be used with a cylinder and piston of ;~
different diameter and capacity where appropriate for dies of different volume so that it will be necessary to input to the control means the relevant parameters -of piston and cylinder currently in use.
The torque transmitting means may alternatively be a magnetic clutch.
In an alternative apparatus and method the piston speed may be regulated without including the step of sensing the haltin~ of the piston 7 by the control unit 520 The motor may instead be set to run at a reduced speed which maintains a constant level of pressure in the filled die under the control of the control unit 52 after a predetermined time interval equal to the time taken to fill the die.
' ,:. . ,, - ,. -- ~ . . - :
': ' '' ' ': . '' . :"': , , ' ' ':
,' '' ' ` ~ ' . ' ' ' ~, ~ ;' '
The cylinder 5 defines a cylindrical dispensing chamber 10 and the mounting block 6 defines a conduit 11 communicating between the chamber and a three port ball valve 12. The ball valve 12 has a ball 13 mounted on a stem 14 and located between valve seats 15 and 16 within a valve chamber 17 defined by the ball valve.
The valve 12 is provided with a first port 18 which communicates with the interior of the tank 2 so as to supply molten alloy to the valve, a second port 19 communica~ing with the conduit 11 so as to be in communication with the dispensing chamber 10 and a third port 20 communicating with a dispensing channel 21. The stem 14 is axially movable by action of a ball valve actuator 22 such that the ball can be positioned to close either the first port 1~ or the third port 20.
The dispensing channel 21 extends out of the tank 2 and communicate's with a flow valve 23 which is actuated by a rotary flow valve actuator 24 to open or close the flow path through the flow valve. A
further portion 25 of the dispensing channel 21 communicates between the flow valve 23 and a die 26.
The dispensing channel 21 is formed in a fixed -~
member 27 which is separable from the mounting block 6 such that the block can be removed from the tank.
The fixed member 27 includes a domed surface portion 28 locating in a corresponding recess ~9 formed in the mounting block 6 for ease of alignment of the dispensing channel 21 with the third port 20 on refitting the mounting block 6 within the tank 2.
The tank 2 and the dispensing channel 21 are surrounded in insulating material 30 to maintain an ,, " ~ , :
: . - : , , ; , -, -.
,: .
- . . : , . :
: : i ,. ~
2~307~1 even temperature throughout.
The piston 7 is driven by an actuating means 3 which is represented schematically in Figure 1 and is shown in detail in Figure 2.
The actuating means 31 includes a screw threaded shaft 32 on which is received a screw threaded nut 33 including ball bearing means (not shown) such that the shaft and nut together comprise a ball screw 34. The screw threaded shaft 32 includes screw threads 35 of part circular cross-section adapted to cooperate with the ball bearing means of the nut 33. The construction o~
the ball screw 34 is such that relative rotational movement between the nut 33 and the shaft 32 results in linear relative movement as in the case of known screw and nut combinations.
The nut 33 is rigidly connected to the piston 7 by means of a vertically extending tube 36 having a threaded coupling 37 at its lower end 38 allowing the piston to be bolted to the tube 36.
The screw threaded shaft 32 extends vertically and coaxially within the tube 36 and has an upper end 39 received in a bearing 40 which is connected to a tubular casing 41.
The casing 41 extends vertically with the tube 36 being coaxially received within the casing and the ~ -bearing 40 facilitates rotation of the shaft 32 relative to the casing but prevents longitudinal relative motion between the casing and the shaft 32.
A motor 42 has a driven shaft 43 arranged to drive an input pulley 44 of an adjustable clutch 45 via a toothed drive belt 46 and the clutch has an output shaft 47 rigidly connected in axial alignment with the screw threaded shaft 32. The clutch 45 comprises a solenoid actuated disc clutch having means for adjusting the pressure applied between the : : : : , ,. : , , ~ : : :: : .
~:: .. . . .
: . , - . :. , :~
. - . , ,., .. : , - . -. . . : . . ~
~ . , .. .. .
2~30~1 discs (not shown) to thereby provide means for settiny the maximum torque transmitted by the clutch.
A take-off pulley 48 is connected to the oukput shaft 47 of the clutch 45 and is connected by means of a toothed belt 49 to an actuator tachometer 50 ~or sensing actuator speed. A motor tachometer 51 is connected to the motor 42 for sensing the motor speed.
A digital elect,ronic control unit 52 is connected to receive output signals from the actuator tachometer 50 and the motor tachometer 51 indicating the rotational speeds o~ the screw threaded shaft 32 and the motor 42 respectively. As indicated schematically in Figure 1 the control unit 52 is connected to provide command signals to the motor 42 to regulate its speed, to the actuating solenoid of the clutch 45, to the ball valve actuator 22 to actuate the valve 12 and to the flow valve actuator 24 to control the actuation of the flow valve 23.
Upper and lower inductive proximity switches 53 and 54 respectively are connected to the casing 41 at vertically spaced apart locations and are arranged to sense the maximum and lower limits of normal travel of the nut 33 along the screw threaded shaft 32. -Output signals from the proximity switches 53 and 54 ~ -are connected at inputs to the control unit 52.
The control unit 52 is provided with a memory 56 for recei~ing data defining the preferred characteristic of speed of piston 7 as a function of time during a dispensing stroke of the piston. The selection of the preferred characteristic is described below with reference to Figures 3 and 4.
In use to dispense moltsn alloy 3 into the die 26 the piston is raised as shown in Figure 1 to its normal upper limit of travel with the chamber 10 ~illed with molten alloy. The ball valve 12 is moved into a position in which the ball 13 is fully ,: . . , , . :
:~ - ; . . .
:, :.
::: :.- : . ~ . -, ~ , ' ' '. . " . . ' ' ' ' ' ' , ` ~
~ . . , , : . ' `" 2030761.
g raised by actuation of the ball valve actuator 22 thereby closing the first port 18. The ball valve 12 in this position provides communication between the conduit 11 and the dispensing channel 21.
An operator programmes the control unit 52 with the necessary data to achieve the optimum flow rate of molten alloy into the die 26, the flow rate being dependent on the internal shape of the die. This data is stored in the memory 56. The clutch 45 is set to provide a predetermined limit of torque such that torque across the clutch below a threshold limit will result in one-to-one transmission of drive through the clutch and torque exceeding the limit will result in slippage of the output shaft ~7 relative to the speed at which the clutch is driven by the motor 42 whilst a set value of torque continues to be transmitted.
The motor 42 is then driven at an initial speed under the control of the control unit 52 such that the clutch 45 is driven by the drive belt 46, the output shaft 47 of the clutch being correspondingly driven to thereby drive the screw threaded shaft 32 at an initial rate of rotation. Rotation of the shaft 32 results in linear movement of the nut 33 relative to the shaft, the direction of rotation of the motor being selected to be such that the nut moves downwards relative to the shaft. Since the nut 33 is rigidly connected to the piston 7 the piston moves correspondingly downwards and displaces molten alloy from the chamber 10. Alloy flows from the chamber 10 through the conduit 11, through the valve 12 into the dispensing channel 21, through the flow valve 23, through the further portion 25 of the dispensing channel 21 and into the die 26.
Throughout this flow path the insulation 30 retains the molten alloy at a temperature above its solidus ::: : : ~ :, -,. : . -: :
: :-: , . . -:
-.. .. ~:, ;~ , :~ -:~ : , 20307~
~ 10 --temperature.
As the molten alloy is progressively dispensed from the chamber 10 the rate at which alloy is dispensed and the precise volume which has been displaced is monitored by the control unit 52 by means of signals received from the actuator tachometer 50 which provides a signal directly proportional to the rotational speed of the shaft 32, the travel of the piston being calculated by integrating the signal.
The control unit 52 adjusts the speed o~ the motor 42 during the dispensing operation in order to achieve a predetermined characteristic of piston speed against time. Since the actual displacement of the piston 7 is measured by the control unit and the speed of the piston directly regulated by the control unit this constitutes a closed loop feedback system providing precise control of the dispensing operation.
When the die 26 is completely filled with molten alloy the incompressibility of the liquid alloy 3 arrests the motion of the piston 7 such that the torque experienced across the clutch 45 exceeds the threshold limit to which it is set and the clutch ~5 therefore begins to slip. The halting of the piston 7 is sensed by the control unit 52 which then sets the motor 42 to run at a speed which maintains a set level of torque across the clutch 45 so as to bias the piston 7 downwardly and maintain a constant level of pressure in the dispensing flow path. The metal alloy within the die 26 is allowed to cool and solidify and in doing so undergoes a change of volume, either an increase or decrease, depending on the composition of the alloy. ~ decrease in volume will be accompanied by a slight influx of molten alloy to the die and the piston will move down , ~ . ~, , , -;' ' ~:` , , ~ , ~ "- '' "- . .
, .
--`` 2~3~761 accordingly by a small amount.
After solidification the control unit actuates the flow valve actuator 24 to turn off the flo~l valve 23 and the die 26 is removed from the casting apparatus 1 and replaced with the sarne die after removal of the solidified casting or with a further empty die.
The control unit 52 then actuates the ball valve actuator to lower the ball 13 so as to close the third port 20 and open the first port 18. The direction of rotation of the motor 42 i8 reversed and the piston 7 is then raised to create suction within the chamber 10 and draw molten alloy 3 from the tank 2 which constitutes a reservoir. The dispensing operation can then be repeated as described above after first opening the valve 23.
During extended periods between casting operations the piston 7 may be raised and lowered with the ball valve in its fully lowered position such that molten alloy from the tank 2 is cyclically drawn into and expelled from the chamber 10 in order to ensure that adequate agitation of the alloy is maintained to prevent dissociation of its constituent metals. During this recycling the upper and lower proximity switches 53 and 54 provide inputs to the control unit 52 as to when the piston has reached its operating limits of travel.
Figures 3 and 4 illustrate the manner in which the movement of piston 7 is controlled in order to tailor the characteristic of piston speed against time to suit a particular application. In the example of Figure 3 an alternative die 60 defines a cavity 61 having a shape resembling that of an inverted bottle. The shape of cavity 61 is symmetrical about a vertical axis and includes a cylindrical upper portion 62 of uniform . . .
.
" ': . ~ ~ . , ' . , 2~3~7fil cross-section. A lower portion 63 of ca~ity 61 has a reduce~ cross-section and is connected to the cylindrical upper portion 62 by a flared portion 6~
which merges smoothly and continuously with the upper and lower portions 61 and 62 respectively~
The die 60 is filled through an inlet 65 communicating with the lower portion 63 and is connected in use with the nozzle 55 of the apparatus of Figures 1 and 2.
Figure 4 illustrates graphically the preferred characteristic of speed S of piston 7 as a function of time t during a dispensing operation in which molten alloy is dispensed from the cylinder 5 into the cavity 61. During an initial time period A the piston begins to move smoothly and with gradually increasing speed from its rest position and the flow rate of molten alloy into the cavity 61 increases in direct proportion to this speed S. This gradual pick-up in flow rate ensures that the rising level of molten alloy remains substantially free from turbulence without the formation of jets. At the end of period A the elevation rate at which the level of molten alloy within the cavity 61 is rising will have reached a preferred minimum value above which the elevation rate is to be maintained during the filling of the cavity. If the level rises at a slower rate then surface imperfections in the casting result from the tendency to freezing of the meniscus formed at the interface between the alloy surface and the walls of the die 60. The flow of metal over the frozen meniscus results in unwanted lines being formed on the resulting casting.
As the level of alloy rises within the flared portion 64 it is necessary for the piston speed S to be accelerated during a further time period B in order that the elevation rate should remain constant :, ,, :
~` 203~761 in spite of the increasing cross-sectional area encountered by the alloy. When the level reaches the cylindrical upper portion 62 however the uniform cross-section of this portion requires a constant piston speed S during a further time period C.
When the cavity 61 becomes entirely filled with molten alloy the piston speed S drops rapidly during a further time period D. Contraction of the alloy during coolin~ occurs during a further time period E
requiring further motion of the piston as further alloy is injected into the die under continued piston pressure. Finally when no further alloy is able to enter the die some motion of the piston during a final time period F will result from imperfect sealing between the piston and cylinder.
Throughout periods B and C of the above dispensing operation the speed S of the piston 7 is controlled such that the alloy level rises at an elevation rate which is greater than or equal to the preferred minimum elevation rate and which is not greater than a preferred maximum elevation rate depending upon the particular shape of the cavity 61. If the elevation rate is too high then excessive pressures within the die result at the end of period C when the die becomes entirely filled and this can result in unwanted flashes being formed on joint faces of the die. When filling more complex die cavities there is an additional hazard in filling too ~uickly in that unwanted voids can result in the casting due to entrapment of air.
The preferred characteristic of S as a function of t for a given die may be arrived at empirically with the speed characteristic being adjusted to remove surface imperfections or voids found in castings resulting from trial dispensing operationsO Once a satisfactory casting has been : .
,. .. . . . .
, . ., : : . : , .
: :
.
.
2~33076~
produced from a given speed characteristic it has been found that subsequent castings using th~ same speed charac~zristic show a high degree of reproducability with consequent high ~ields of high quality castings.
The characteristic of S as a function of t may also be arrived at for new die shapes by theoretical calculation based on empirical values obtained from dies of simple shape. Such calculations may conveniently be expressed as algorithms processed in a computer in which informati.on concerning the shape of the die cavity is entered ~irectly from computer aided design data.
The memory 56 may comprise an electrically erasable programmable read-only memory or alternatively may comprise other known data storage means.
The apparatus and method of the present invention may be used with a cylinder and piston of ;~
different diameter and capacity where appropriate for dies of different volume so that it will be necessary to input to the control means the relevant parameters -of piston and cylinder currently in use.
The torque transmitting means may alternatively be a magnetic clutch.
In an alternative apparatus and method the piston speed may be regulated without including the step of sensing the haltin~ of the piston 7 by the control unit 520 The motor may instead be set to run at a reduced speed which maintains a constant level of pressure in the filled die under the control of the control unit 52 after a predetermined time interval equal to the time taken to fill the die.
' ,:. . ,, - ,. -- ~ . . - :
': ' '' ' ': . '' . :"': , , ' ' ':
,' '' ' ` ~ ' . ' ' ' ~, ~ ;' '
Claims (11)
1. Casting apparatus (1) comprising a dispensing cylinder (5) receiving molten metal in use, a piston (7) slidably received in the cylinder, a rotary driven linear actuator (31) operable to drive the piston in the cylinder, rotary drive means (42) operable to drive the actuator and communicating means (12, 21, 23, 25) communicating during a dispensing stroke of the piston between the cylinder and a die (26) for dispensing molten metal to the die, wherein the apparatus further comprises control means (52) operable to control the rotational speed of the drive means to thereby control the speed of the piston and thereby control the rate at which molten metal is dispensed into the die.
2. Casting apparatus as claimed in claim 1 wherein the control means is provided with data storage means (56) receiving in use data defining a desired characteristic of piston speed as a function of time during the dispensing stroke and is operable to control the drive means such that the instantaneous speed (S) of the piston is substantially equal to that of the desired characteristic during filling of the die.
3. Casting apparatus as claimed in any preceding claim wherein the drive means includes a rotary motor (42) and slippable torque transmitting means (45) transmitting rotary motion from the motor to the actuator whereby torque continues to be transmitted to the actuator after the piston is arrested by back pressure in the cylinder after the die is full.
4. Casting apparatus as claimed in claim 3 wherein the torque transmitting means comprises means for adjusting the torque transmitted to thereby adjust the pressure of molten metal in the die when filled.
5. Casting apparatus as claimed in any of claims 3 and 4 including an actuator sensor (50) responsive to the speed of rotation at which the linear actuator is driven, a motor sensor (51) responsive to the speed of rotation of the motor and wherein the control means is connected to the respective sensors and operable to control the speed of the motor.
6. Casting apparatus as claimed in any preceding claim wherein the rotary driven linear actuator comprises first and second cooperating screw threaded members (32, 33), the drive means being operable to provide relative rotational movement between the first and second members resulting in relative linear motion by screw action and connecting means (41, 37) which connects the first and second members to the cylinder and piston respectively so as to provide actuating movement therebetween.
7. Casting apparatus as claimed in claim 6 wherein the first member is a screw threaded shaft (32) and the second member is a cooperating nut (33) which nut includes ball bearing means so that the nut and shaft together comprise a ball screw (34).
8. A method of casting comprising the steps of placing a dispensing cylinder (5) receiving molten metal in communication with a die (26) and driving a piston (7) in the cylinder by means of a rotary driven linear actuator (31) such that molten metal is dispensed into the die during a dispensing stroke of the piston, and operating a control means (52) to control the rotational speed of a rotary drive means (42) driving the actuator to thereby control the rate at which molten metal is dispensed into the die.
9. A method of casting as claimed in claim 8 including the step of operating the control means to control the speed of the drive means such that during filling of the die the piston speed is substantially equal to a desired characteristic of piston speed (S) as a function of time.
10. A method of casting as claimed in claim 9 wherein the characteristic of piston speed against time is selected such that the level of molten metal in the die rises at an elevation rate which increases from zero to a minimum preferred value above which the elevation rate is thereafter maintained during the filling of the die.
11. A method of casting as claimed in any of claims 8, 9 and 10 including the step of setting a torque transmitting means (45) transmitting torque from the motor to the actuator so as to transmit a value of torque which delivers a predetermined pressure of molten metal in the die when filled.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8927088.8 | 1989-11-30 | ||
| GB898927088A GB8927088D0 (en) | 1989-11-30 | 1989-11-30 | Casting apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2030761A1 true CA2030761A1 (en) | 1991-05-31 |
Family
ID=10667199
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002030761A Abandoned CA2030761A1 (en) | 1989-11-30 | 1990-11-23 | Casting apparatus |
Country Status (8)
| Country | Link |
|---|---|
| EP (1) | EP0430616A1 (en) |
| JP (1) | JPH03268854A (en) |
| KR (1) | KR910009367A (en) |
| AU (1) | AU625361B2 (en) |
| BR (1) | BR9006064A (en) |
| CA (1) | CA2030761A1 (en) |
| GB (2) | GB8927088D0 (en) |
| ZA (1) | ZA909470B (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4310310A1 (en) * | 1993-03-30 | 1994-10-06 | Frech Oskar Gmbh & Co | Press-in unit |
| DE4440768C1 (en) * | 1994-11-15 | 1996-07-25 | Bachmann Giesserei & Formen | Device for casting metals |
| GB2300231A (en) * | 1995-03-31 | 1996-10-30 | Trimcote Ltd | Fluid dispenser |
| JPH10272550A (en) * | 1997-03-31 | 1998-10-13 | Ryobi Ltd | Method for supplying molten metal and device for supplying molten metal |
| EP1057560A1 (en) | 1999-06-01 | 2000-12-06 | Oskar Frech Gmbh & Co. | Injection unit for a pressure diecasting machine |
| CN117564258B (en) * | 2024-01-16 | 2024-03-29 | 卡耐夫集团(山西)管道系统有限公司 | Casting equipment for pipe production and use method |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB420728A (en) * | 1932-12-10 | 1934-12-06 | Franz Braun Ag | Improvements in and relating to injection moulding machines for plastic materials |
| DE644695C (en) * | 1932-12-11 | 1937-05-11 | Franz Braun Akt Ges | Injection molding machine for plastic masses |
| FR1396544A (en) * | 1964-03-13 | 1965-04-23 | Press for injection molding of plastics | |
| GB8425182D0 (en) * | 1984-10-05 | 1984-11-14 | Frys Metals Ltd | Casting apparatus |
| JPS61220817A (en) * | 1985-03-28 | 1986-10-01 | Fanuc Ltd | Measuring and kneading system for injection molding machine |
| JPH0722813B2 (en) * | 1989-01-30 | 1995-03-15 | 宇部興産株式会社 | Injection device |
-
1989
- 1989-11-30 GB GB898927088A patent/GB8927088D0/en active Pending
-
1990
- 1990-11-21 AU AU66792/90A patent/AU625361B2/en not_active Expired - Fee Related
- 1990-11-23 CA CA002030761A patent/CA2030761A1/en not_active Abandoned
- 1990-11-26 ZA ZA909470A patent/ZA909470B/en unknown
- 1990-11-26 KR KR1019900019148A patent/KR910009367A/en not_active Withdrawn
- 1990-11-26 EP EP90312824A patent/EP0430616A1/en not_active Withdrawn
- 1990-11-29 GB GB9025955A patent/GB2238497B/en not_active Expired - Fee Related
- 1990-11-29 BR BR909006064A patent/BR9006064A/en not_active Application Discontinuation
- 1990-11-29 JP JP2326120A patent/JPH03268854A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| GB2238497A (en) | 1991-06-05 |
| GB8927088D0 (en) | 1990-01-31 |
| GB9025955D0 (en) | 1991-01-16 |
| ZA909470B (en) | 1991-08-28 |
| EP0430616A1 (en) | 1991-06-05 |
| KR910009367A (en) | 1991-06-28 |
| AU625361B2 (en) | 1992-07-09 |
| GB2238497B (en) | 1993-04-07 |
| BR9006064A (en) | 1991-09-24 |
| AU6679290A (en) | 1991-06-06 |
| JPH03268854A (en) | 1991-11-29 |
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| FZDE | Dead |