Patent Application
20180015652
Injection molding systems have been developed having flow control mechanisms that control the movement of a valve pin over the course of an injection cycle based on measuring pressure of injection fluid directly with a pressure sensor disposed with an injection fluid flow channel or the cavity of a mold.
In accordance with the invention there is provided in an apparatus (10) for controlling flow of fluid injection material (18, 100a, 100b) from an injection molding machine to a mold cavity (30), wherein the apparatus comprises: a manifold (40) receiving the injected fluid mold material, the manifold having one or more fluid delivery channels (42, 44, 46) that delivers the injected fluid material (100a, 100b) through a gate (32, 34, 36) to the mold cavity (30);
The controller (16) preferably includes instructions that operate to display a visually recognizable format of the sensed pressure as either sensed pressure of the drive fluid (DF) or pressure of the injection fluid (100a, 100b) that correlates to the sensed pressure (DF) of the drive fluid.
The controller (16) can includes instructions that instruct the piston (40p) to travel to a selected maximum upstream position during the course of the injection cycle that leaves a space or volume (30s) within which drive fluid (DF) resides during the first portion of the injection cycle.
The maximum upstream position of the piston (40p) is typically selected such that an upstream end surface (40e) of the piston (40p) is spaced an axial distance of between 0.1 and 2.0 mm from an opposing undersurface (20uws) of an upstream wall of the upstream drive chamber (30u).
The maximum upstream position of the piston (40p) can be selected such that an upstream end surface (40e) of the piston (40p) is spaced an axial distance of between 0.25 and 1.0 mm from an opposing undersurface (20uws) of an upstream wall of the upstream drive chamber (30u).
An upstream surface (40e) of the piston (40p) typically remains spaced at least a selected axial distance greater than 0.1 mm away from an undersurface (20uws) of the housing (40h) or upstream drive chamber (30U) during the entire course of the injection cycle.
The pressure sensor assembly can include a source of drive fluid (14) that is drivable into and out of the upper drive chamber (30u) through the restriction valve (600) and upstream drive fluid channel (704), the restriction valve (600) being controllably openable by the controller (16) to a selected degree to enable flow of drive fluid (DF, FEX) into and out of the upstream drive chamber (30u) at a selectable rate of flow to control rate of travel of the piston (40p), the restriction valve (600) being controllably closable to controllably stop flow of drive fluid (DF) into and out of the upstream drive chamber (30u) and to stop movement of the piston (40p).
The controller (16) can includes instructions that instruct the piston (40p) to travel, subsequent to the first portion of the injection cycle, to a second position for a second portion of the injection cycle where a distal end (1155) of the valve pin (1041) is positioned relative to the gate such that flow of injection fluid (100a, 100b) is selectively controlled.
The instructions of the controller (16) can operate to drive the piston (40p) to the second position in response to receipt of a first trigger signal from the pressure sensor (603e, 603ec) that is indicative of a first selected target pressure.
The controller (16) can include instructions that instruct the piston (40p) to travel, subsequent to the second portion of the injection cycle, to a third position for a third portion of the injection cycle where a distal end (1155) of the valve pin (1041) is positioned relative to the gate such that flow of injection fluid (100a, 100b) is selectively controlled.
The instructions of the controller (16) can operate to drive the piston (40p) to the third position in response to receipt of a second trigger signal from the pressure sensor (603e, 603ec) that is indicative of a second selected target pressure.
The first position can be a position where a distal end (1155) of the valve pin (1041) is positioned relative to the gate (32, 34, 36) such that flow of injection fluid (100a, 100b) is not significantly restricted and injection fluid (100a, 100b) flows at a maximum speed or a relatively high speed or velocity or pressure at and through the gate and the second position is a position wherein the distal end (1155) of the valve pin (1041) is disposed axially intermediate a gate closed (40gc) and a fully gate open position such that the end (1155) of the valve pin (1041) restricts or reduces rate or velocity of flow or pressure of the injection fluid (100a, 100b) flowing through or exerted at the gate to a selected reduced velocity or pressure that is less than a maximum rate of flow or pressure.
The second position can be a position where a distal end (1155) of the valve pin (1041) is positioned relative to the gate (32, 34, 36) such that flow of injection fluid (100a, 100b) is (a) not significantly restricted and injection fluid (100a, 100b) flows at a relatively high speed or velocity or pressure at and through the gate or (b) such that the distal end (1155) of the valve pin (1041) is disposed axially intermediate a gate closed (40gc) and a fully gate open position such that the end (1155) of the valve pin (1041) restricts or reduces rate or velocity of flow or pressure of the injection fluid (100a, 100b) flowing through or exerted at the gate to a selected reduced velocity or pressure that is less than a maximum velocity or pressure.
The controller (16) can include instructions that instruct the actuator (40p) to drive the valve pin (1041) upstream beginning from the gate closed position to the first position for the first portion of the injection cycle and subsequently to one or more different subsequent positions for one or more different subsequent portions of the injection cycle in response to receipt by the controller (16)) of one or more trigger signals from the pressure sensor (603ec, 603e) corresponding to one or more selected sensed target pressures.
One or more of the second and third positions can be positions where a distal end (1155) of the valve pin (1041) is positioned relative to the gate such that flow of injection fluid (100a, 100b) is not significantly restricted and injection fluid (100a, 100b) flows at a relatively high speed or velocity or pressure at and through the gate or such that the distal end (1155) of the valve pin (1041) is disposed axially intermediate a gate closed and a fully gate open position such that the end (1155) of the valve pin (1041) restricts or reduces rate or velocity of flow or pressure of the injection fluid (100a, 100b) flowing through or exerted at the gate to a selected reduced velocity or pressure that is less than a maximum rate of flow or pressure.
In another aspect of the invention there is provided a method of measuring pressure of an injection fluid material (100a, 100b) injected into an apparatus (10) for controlling rate of flow of the injection fluid material (18, 100a, 100b) from an injection molding machine to a mold cavity (30), wherein the apparatus comprises: a manifold (40) receiving the injected fluid material, the manifold having one or more fluid delivery channels (42, 44, 46) that delivers the injected fluid material (100a, 100b) through a gate (32, 34, 36) to the mold cavity (30), an actuator (20a, 940, 941, 942) comprising a piston (40p) interconnected to a valve pin (1040, 1041, 1042) drivable along a drive path that extends between a gate closed position where a distal end (1155) of the valve pin (1040, 1041, 1042) (1041) obstructs (GC) the gate and an upstream open position where the distal end (1155) of the valve pin is withdrawn upstream to enable injection fluid material (100a, 100b) to flow through the gate (32, 34, 36), wherein the piston (40p) is housed within a piston housing (20h) in an arrangement that forms an upstream drive chamber (30u) and a downstream drive chamber (30d), the upstream drive chamber having a drive fluid port (50, 52) fluid sealably interconnected via an upstream drive fluid channel (704) to a restriction valve (600), the piston (40p) being drivable upstream and downstream by drive fluid (14) pumped into and out of the upstream drive chamber (30u) through the drive fluid port (50, 52), drive fluid channel (704) and restriction valve (600),
In another aspect of the invention there is provided a method of measuring pressure of an injection fluid material (100a, 100b) comprising operating a pressure sensing assembly as described above.
In another aspect of the invention there is provided an apparatus (10) for controlling the rate of flow of fluid injection material (18, 100a, 100b) from an injection molding machine to a mold cavity (30), the apparatus comprising:
In such an apparatus the controller (16) preferably includes instructions that operate to execute a display (1300) of a visually recognizable format corresponding to the sensed pressure or uses the received signal in an algorithm to control movement of the piston (40p).
The controller (16) preferably includes instructions that operate to display a visually recognizable format (310) of the sensed pressure as either sensed pressure of the drive fluid (DF) or pressure of the injection fluid (100a, 100b) that correlates to the sensed pressure (DF) of the drive fluid.
The controller (16) can include instructions that instruct the piston (40p) to travel to a selected maximum upstream position during the course of the injection cycle that leaves a space or volume (30s) within which drive fluid (DF) resides during the first portion of the injection cycle.
The maximum upstream position of the piston (40p) is typically selected such that an upstream end surface (40e) of the piston (40p) is spaced an axial distance of between 0.1 and 2.0 mm from an opposing undersurface (20uws) of an upstream wall of the upstream drive chamber (30u).
The maximum upstream position of the piston (40p) is typically selected such that an upstream end surface (40e) of the piston (40p) is spaced an axial distance of between 0.25 and 1.0 mm from an opposing undersurface (20uws) of an upstream wall of the upstream drive chamber (30u).
An upstream surface (40e) of the piston (40p) preferably remains spaced at least a selected axial distance of 0.1 mm or greater away from an undersurface (20uws) of the housing (40h) or upstream drive chamber (30U) during the entire course of the injection cycle.
The assembly typically includes a source of drive fluid (14) that is drivable into and out of the upper drive chamber (30u) through the restriction valve (600) and upstream drive fluid channel (704), the restriction valve (600) being controllably openable by the controller (16) to a selected degree to enable flow of drive fluid (DF, FEX) into and out of the upstream drive chamber (30u) at a selectable rate of flow to control rate of travel of the piston (40p), the restriction valve (600) being controllably closable to controllably stop flow of drive fluid (DF) into and out of the upstream drive chamber (30u) and to stop movement of the piston (40p).
The controller (16) can include instructions that instruct the piston (40p) to travel, subsequent to the first portion of the injection cycle, to a second position for a second portion of the injection cycle where a distal end (1155) of the valve pin (1041) is positioned relative to the gate such that flow of injection fluid (100a, 100b) is selectively controlled.
The instructions of the controller (16) preferably operate to drive the piston (40p) to the second position in response to receipt of a first trigger signal from the pressure sensor (603e, 603ec) that is indicative of a first selected target pressure.
The controller (16) can include instructions that instruct the piston (40p) to travel, subsequent to the second portion of the injection cycle, to a third position for a third portion of the injection cycle where a distal end (1155) of the valve pin (1041) is positioned relative to the gate such that flow of injection fluid (100a, 100b) is selectively controlled.
The instructions can operate to drive the piston (40p) to the third position in response to receipt of a second trigger signal from the pressure sensor (603e, 603ec) that is indicative of a second selected target pressure.
One or more of the second and third positions are preferably positions where a distal end (1155) of the valve pin (1041) is positioned relative to the gate such that flow of injection fluid (100a, 100b) is not significantly restricted and injection fluid (100a, 100b) flows at a relatively high speed or velocity or pressure at and through the gate or where the distal end (1155) of the valve pin (1041) is disposed axially intermediate a gate closed and a fully gate open position such that the end (1155) of the valve pin (1041) restricts or reduces rate or velocity of flow or pressure of the injection fluid (100a, 100b) flowing through or exerted at the gate to a selected reduced velocity or pressure that is less than a maximum rate of flow or pressure.
The controller (16) typically includes instructions that instruct the actuator (40p) to drive the valve pin (1041) upstream beginning from the gate closed position to the first position for the first portion of the injection cycle and subsequently to one or more of the second and third positions for the second and third portions of the injection cycle in response to receipt by the controller (16)) of the first and second trigger signals.
In another aspect of the invention there is provided a method of measuring pressure of an injection fluid material (100a, 100b) comprising operating an assembly as described above.
The above and further advantages of the invention may be better understood by referring to the following description in conjunction with the accompanying drawings in which:
FIG. 5AAA shows a plot also corresponding to the velocity versus position plot of
FIG. 5BBB shows a plot also corresponding to the velocity versus position plot of
As shown in
In alternative embodiments, the center gate 32 and associated actuator 940 and valve pin 1040 can remain open at, during and subsequent to the times that the lateral gates 34, 36 are opened such that fluid material flows into cavity 30 through both the center gate 32 and one or both of the lateral gates 34, 36 simultaneously.
When the lateral gates 34, 36 are opened and fluid material NM is allowed to first enter the mold cavity into the stream 102p that has been injected from center nozzle 22 past gates 34, 36, the two streams NM and 102p mix with each other. If the velocity of the fluid material NM is too high, such as often occurs when the flow velocity of injection fluid material through gates 34, 36 is at maximum, a visible line or defect in the mixing of the two streams 102p and NM will appear in the final cooled molded product at the areas where gates 34, 36 inject into the mold cavity. By injecting NM at a reduced flow rate for a relatively short period of time at the beginning when the gate 34, 36 is first opened and following the time when NM first enters the flow stream 102p, the appearance of a visible line or defect in the final molded product can be reduced or eliminated.
The rate or velocity of upstream withdrawal of pins 1041, 1042 starting from the closed position is controlled via controller 16,
A “controller,” as used herein, refers to electrical and electronic control apparati that comprise a single box or multiple boxes (typically interconnected and communicating with each other) that contain(s) all of the separate electronic processing, memory and electrical signal generating components that are necessary or desirable for carrying out and constructing the methods, functions and apparatuses described herein. Such electronic and electrical components include programs, microprocessors, computers, PID controllers, voltage regulators, current regulators, circuit boards, motors, batteries and instructions for controlling any variable element discussed herein such as length of time, degree of electrical signal output and the like. For example a component of a controller, as that term is used herein, includes programs, controllers and the like that perform functions such as monitoring, alerting and initiating an injection molding cycle including a control device that is used as a standalone device for performing conventional functions such as signaling and instructing an individual injection valve or a series of interdependent valves to start an injection, namely move an actuator and associated valve pin from a gate closed to a gate open position. In addition, although fluid driven actuators are employed in typical or preferred embodiments of the invention, actuators powered by an electric or electronic motor or drive source can alternatively be used as the actuator component.
As shown in
The user programs controller 16 via data inputs on a user interface to instruct the hydraulic system 700 via control of the degree of openness of the restriction valve 600 to drive pins 1041, 1042 at an upstream velocity of travel that is reduced relative to a maximum velocity that the hydraulic system 700 can drive the pins 1041, 1042 to travel. The reduced velocity at which the actuator 941 and associated valve pin 1041 are driven is determined by a predetermined profile of reduced drive fluid pressures that is followed by the controller 16 based on the metered pressure exiting valve 600 that is sensed by sensor 603 in line 703 and sent to the controller 16 during an injection cycle, the controller 16 controlling the degree of openness of valve 600 which in turn controls the degree of pressure exiting valve 600 in line 703.
As described below, the controller 16 drives the actuator 941/valve pin 1041 at the profile of reduced pin withdrawal rate or velocity either until a position sensor such as 951, 952 detects that an actuator 941, 952 or an associated valve pin (or another component), has reached a certain position (e.g. as in
In an alternative embodiment, the user can program controller 16 via to instruct the hydraulic system 700 to drive pins 1041, 1042 at the profile of reduced velocity of upstream travel for a predetermined amount of time. In such an embodiment, the reduced pin withdrawal rate or velocity is executed for a preselected amount of time that is less than the time of the entire injection cycle, the latter part of the injection cycle being executed with the pins 1041, 1042 being withdrawn at a higher velocity typically the highest velocity at which the hydraulic system is capable of driving the pins 1041, 1042. A typical amount of time over which the pins are instructed to withdraw at a reduced velocity is between about 0.25 and about 10 seconds, more typically between about 0.5 and about 5 seconds, the entire injection cycle time typically being between about 4 seconds and about 30 seconds, more typically between about 6 seconds and about 12 seconds. In such an embodiment, the periods of time over which the pins 1041, 1042 are withdrawn at reduced velocities are typically determined empirically by trial and error runs. One or more, typically multiple, trial injection cycle runs are carried out to make specimen parts from the mold. Each trial injection cycle run is carried out using a different period or periods of time at which the pins 1041, 1042 are withdrawn at one or more reduced velocities over the trial period(s) of time, and the quality of the parts produced from all such trial runs are compared to determine the optimum quality producing time(s) of reduced velocity pin withdrawals. When the optimum time(s) have been determined, the controller is programmed to carry out an injection cycle where the pin withdrawal velocities of pins 1041 are reduced for the predetermined amounts of time at the predetermined reduced withdrawal rates.
The pins 1041 can be controllably withdrawn at one or more reduced velocities (less than maximum) for one or more periods of time over the entirety of the length of the path RP over which flow of mold material 1153 is restricted. Preferably the pins are withdrawn at a reduced velocity over more than about 50% of RP and most preferably over more than about 75% of the length RP. As described below with reference to
The trace or visible lines that appear in the body of a part that is ultimately formed within the cavity of the mold on cooling above can be reduced or eliminated by reducing or controlling the velocity of the pin 1041, 1042 opening or upstream withdrawal from the gate closed position to a selected intermediate upstream gate open position that is preferably 75% or more of the length of RP.
RP can be about 1-8 mm in length and more typically about 2-6 mm and even more typically 2-4 mm in length. As shown in
The velocity of withdrawal of the valve pins 1041, 1042 is determined by regulation of the flow of hydraulic drive fluid that is pumped from a supply 14 to the actuators 941, 942 through flow restrictor valve 600,
According to the invention, the degree of openness of the flow restrictor valve 600 is adjusted in response to sensing with sensors 603, 603e, 603ec,
In the
The valve 600 typically comprises a restrictor valve that is controllably positionable anywhere between completely closed (0% open) and completely open (100% open). Adjustment of the position of the restrictor valve 600 is typically accomplished via a source of electrical power that controllably drives an electromechanical mechanism that causes the valve to rotate such as a rotating spool that reacts to a magnetic or electromagnetic field created by the electrical signal output of the controller 16, namely an output of electrical energy, electrical power, voltage, current or amperage the degree or amount of which can be readily and controllably varied by conventional electrical output devices. The electro-mechanism is controllably drivable to cause the valve 600 to open or close to a degree of openness that is proportional to the amount or degree of electrical energy that is input to drive the electro-mechanism. The velocity of upstream withdrawal travel of the pins 1041, 1042 are in turn proportional to the degree of openness of the valve 600. Thus the rate of upstream travel of the pins 1041, 1042 is proportional to the amount or degree of electrical energy that is input to the electro-mechanism drives valves 600. The electro-mechanism that is selected for driving the valve 600 establishes in the first instance the maximum amount of electrical energy or power (such as voltage or current) that is required to open the valve to its 100% open position.
The user can implement a reduced upstream velocity of the pins 1041, 1042 over a given upstream length of travel or over a given amount of time by inputting to the controller 16 a profile of reduced exit fluid pressures that are implemented by adjusting the electrical drive mechanism that operates metering valve 600 to less than 100% of the maximum amount of electrical energy or power input (voltage or current) needed to open the valve 600 to 100% open at which setting maximum drive fluid pressure and, a fortiori, maximum actuator/pin velocity occurs.
In one embodiment, the user can implement reduced actuator/pin withdrawal velocity profiles by inputting reduced exit pressure profiles (or other data corresponding thereto) versus actuator/pin position into the controller 16. Exit pressure is the pressure of the valve drive fluid that exits either the metering valve 600 or the upstream drive chamber 30u of the actuator 20a during the upstream withdrawal portion of the injection cycle. In the examples provided, the exit pressure would be the pressure in one of lines 703, 705 or 707 as sensed by a respective one of sensors 603, 605, 607 or as sensed by a sensor 603ec, 603e in the actuator chamber 30u, 30s or in the drive fluid line interconnecting and between the input port 600p of valve 600 and the drive chamber 30u. In another embodiment, the user can implement reduced actuator/pin withdrawal velocity profiles by inputting to the controller 16 reduced exit pressure profiles or other data corresponding thereto) versus time of withdrawal beginning from the time at which the gate is closed.
The user can also preselect the length of the path of travel RP, RP2 of the valve pin or other end of reduced velocity position of the valve pin or other component over the course of travel of which the material flow through the gate is restricted and input such selections into the controller 16. In an alternative embodiment the user can preselect the length of time during which the gate is restricted by a valve pin travelling over a restricted path length RP, RP2 and input such a selection into the controller 16.
The controller 16 includes conventional programming or circuitry that receives and executes the user inputs. The controller may include programming or circuitry that enables the user to input as a variable a selected pin velocity rather than a percentage of electrical output, the programming of the controller 16 automatically converting the inputs by the user to appropriate instructions for reduced energy input to the electro-mechanism that drives the valve 600.
Typically the user selects a profile of metered exit drive fluid pressures that corresponds to reduced pin withdrawal velocities that are less than about 90% of the maximum velocity (namely the velocity when the valve 600 is fully open), more typically less than about 75% of the maximum velocity and even more typically less than about 50% of the maximum velocity at which the pins 1041, 1042 are drivable by the hydraulic system. The actual maximum velocity at which the actuators 941, 942 and their associated pins 1041, 1042 are driven is predetermined by selection of the size and configuration of the actuators 20a, 941, 942, the size and configuration of the restriction valve 600 and the degree of pressurization and type of hydraulic drive fluid selected for use by the user. The maximum drive rate of the hydraulic system is predetermined by the manufacturer and the user of the system and is typically selected according to the application, size and nature of the mold and the injection molded part to be fabricated.
As shown by the series of examples of programs illustrated in
As shown in
Most preferably, the actuator, valve pin, valves and fluid drive system are adapted to move the valve pin between a gate closed position and a maximum upstream travel position that defines an end of stroke position for the actuator and the valve pin. Most preferably the valve pin is moved at the maximum velocity at one or more times or positions over the course of upstream travel of the valve pin past the upstream gate open position. Alternatively to the hydraulic system depicted and described, a pneumatic or gas driven system can be used and implemented in the same manner as described above for a hydraulic system.
Preferably, the valve pin and the gate are configured or adapted to cooperate with each other to restrict and vary the rate of flow of fluid material 1153,
In one embodiment, as the tip end 1142 of the pin 1041 continues to travel upstream from the gate closed GC position (as shown for example in
In embodiments, where the tip 1142 has reached the end of restricted flow path RP2 and the tip 1142 is not necessarily in a position where the fluid flow 1153 is not still being restricted, the fluid flow 1153 can still be restricted to less than maximum flow when the pin has reached the changeover position COP2 where the pin 1041 is driven at a higher, typically maximum, upstream velocity FOV. In the examples shown in the
In another alternative embodiment, shown in
In the
At the expiration of the predetermined reduced velocity drive time, the pins 1041, 1042 are typically driven further upstream past the COP, COP2 position to a maximum end-of-stroke EOS position. The upstream COP, COP2 position is downstream of the maximum upstream end-of-stroke EOS open position of the tip end 1142 of the pin. The length of the path RP or RP2 is typically between about 2 and about 8 mm, more typically between about 2 and about 6 mm and most typically between about 2 and about 4 mm. In practice the maximum upstream (end of stroke) open position EOS of the pin 1041, 1042 ranges from about 8 mm to about 18 inches upstream from the closed gate position GC.
The controller 16 includes a processor, memory, user interface and circuitry and/or instructions that receive and execute the user inputs of percentage of maximum valve open or percentage of maximum voltage or current input to the motor drive for opening and closing the restriction valve, time duration for driving the valve pin at the selected valve openings and reduced velocities.
With regard to embodiments where the use of a position sensor is employed,
The actuator 20a as shown comprises a housing 20h and a piston 40 having an O-ring or other fluid seal mechanism 120 mounted in a circumferential groove formed in the circumferential surface of the piston head that extends around the circumference of the piston 40. The O-ring or fluid seal mechanism 120 is typically comprised of a highly friction resistant polymeric material that is resiliently compressible. The O-ring or seal 120 is formed and adapted to be seated within a complementary groove such that the O-Ring compressibly engages against the inner wall surface 30w of chamber 30 to form a circumferential seal surface PS that forms two opposing fluid sealed upstream chamber 30u and downstream chamber 30d within master chamber 30. The upstream drive chamber 30u is interconnected to and communicates with a source of pressurized fluid 200f (typically hydraulic oil or gas such as air) via fluid delivery ports 50, 52 which when pumped into chamber 30u exerts a downstream force 200 on the upstream end 40e of piston 40. Piston 40 can conversely be driven upstream by pumping pressurized hydraulic fluid 200f through ports 60, 62 into downstream chamber 30d thus exerting upstream drive force 150 on the downstream surface 40d of the piston 40.
As shown in
In the
In these embodiments, the fluid pressure that the sensors 603e, 603ec are sensing is more accurately indicative of the injection fluid pressure IFUP of the injection fluid 100a, 100b that is being exerted on the tip end 1142 of the valve pin 1041 by the injection fluid during the course of the injection fluid. Fluid pressure that is disposed in the exiting drive fluid stream that is upstream of the metering valves 600 that is sensed by the sensors 603, 605, 705 does not account accurately for the injection fluid pressure IFUP exerted on the drive fluid pressure through the valve pin in the same manner as the sensors 603e or 603ecdetect such pressure in the drive fluid that is resident in the upper drive chamber 30u or fluid flow channel 704 that is downstream of the port 600p to a restrictor valve 600.
In the
In the
In an alternative embodiment, the controller 16 can instruct the piston 40p to travel fully upstream into engagement with the undersurface 20uws subsequent to a preselected portion of the duration of the injection cycle where the valve 600 is closed and the piston 40p is held stationary in a position where the preselected axial distance X discussed above is maintained between the piston surface 40e and the undersurface 20uws. Thus in such an alternative embodiment, the controller 16 can include instructions that instruct the piston 40p to be driven completely upstream at some point during the course of an injection cycle to a position where the top surface 40e′ engages the undersurface 20uws where all of the drive fluid is driven out FEX of the upper chamber 30u and through valve 600 after the piston 40p has previously been instructed to remain stationary at a position spaced X distance as described above for a preselected portion of the duration of the injection cycle.
The program of the controller 16 can include instructions that instruct the piston 40p to travel, subsequent to instructing the piston 40p to travel to and be held for the selected period of time in the static position where the top surface 40e′ is maintained at the distance X from undersurface 20uws, to another (second) subsequent preselected axial position for another subsequent preselected period of time. Such a subsequent axial position can be selected to be a “fill” position where the distal end 1155 of the valve pin 1041 is positioned relative to the gate such that flow of injection fluid 100a, 100b is not significantly restricted and injection fluid 100a, 100b flows at a relatively high speed or velocity or pressure at and through the gate. Such a fill position can be selected so that injection fluid flows at the maximum velocity or pressure under or to which the drive fluid pump system is capable of pumping the drive fluid. The instructions typically execute the instruction to drive the piston to the second subsequent preselected axial position in response to receipt of a signal from the pressure sensor 603e, 603ec when the sensed signal matches a preselected target or trigger pressure that is typically preselected by a user and stored within a memory of the controller 16. The controller includes instructions that automatically compare the received pressure sensor 803e, 603ec signal to the stored target or trigger pressure and carry out instruction to drive the piston to the second subsequent preselected axial position.
Another (second or third) subsequent axial position that the piston can be driven to can be selected to be a “pack position” where the distal end 1155 of the valve pin is disposed axially intermediate the gate closed and fully gate open positions such that the end 1155 of the valve pin 1041 restricts or reduces the rate or velocity of flow or the pressure of the injection fluid 100a, 100b flowing through or exerted at the gate to a “pack rate” or “pack pressure” or some selected reduced velocity or pressure that is less than the fill rate or fill pressure. A pack rate of flow or pack pressure is typically selected such that the flow or pressure of injection fluid at or through the gate operates to prevent the injection fluid 100a, 100b from shrinking after the injection fluid 100a, 100b has travelled through the gate into the cavity and has begun to cool or has cooled down within the cavity. The instructions typically execute the instruction to drive the piston to the second or third subsequent preselected axial position in response to receipt of a signal from the pressure sensor 603e, 603ec when the sensed signal matches another (second or third) preselected target or trigger pressure that is typically preselected by a user and stored within a memory of the controller 16. The controller includes instructions that automatically compare the received pressure sensor 803e, 603ec signal to the stored (second or third) target or trigger pressure and carry out instruction to drive the piston to the another (second or third) subsequent preselected axial position.
Control over the withdrawal (upstream) velocity of actuator or pin movement can be accomplished by controlling the degree of fluid pressure that exits the metering valve 600 which in turn is controlled by controlling the degree of openness of the fluid restriction valve 600. A profile of exit fluid pressures versus time or pin position is determined in advance and input to the controller which includes a program and instructions that automatically adjust the position of valve 600 based on the real time pressure signal received from sensor 603 (or 605 or 607) to adjust the exit pressure of the drive fluid in line 703 (or 705 or 707) which in turn adjusts the rate or velocity of upstream movement of the actuator 941/valve pin 1041 (and/or actuators 1040, 1042 and valve pins 940, 942).
In an alternative embodiment, the actuators can be controlled to cause the valve pins 1041, 1042, 1043 to travel beginning from an upstream gate open position (such as the maximum upstream position), downstream at a reduced velocity for one or more portions of the downstream path of travel from the gate open to the gate closed position. Controller 16 or 176 can also include an interface that enables the user to input any selected degree of electrical energy or power needed to operate the motors 940, 941, 942 at less than full speed any portion or all of the downstream portion of an injection cycle as shown and described with reference to
The user inputs such selections into the controller 16 or 176. Where a position sensor and a protocol for selection of the velocities over selected path lengths is used, the user also selects the length of the path of travel RP, RP2 of the valve pin or the position of the valve pin or other component over the course of travel of which the valve 600 is to be maintained partially open and inputs such selections into the controller 16 or 176. The controller 16 or 176 includes conventional programming or circuitry that receives and executes the user inputs. The controller may include programming or circuitry that enables the user to input as a variable a selected pin velocity rather than a degree of electrical energy input to the motors, the programming of the controller 16 automatically converting the inputs by the user to appropriate instructions for reduced energy input to the motors at appropriate times and pin positions as needed to carry out a pin profile such as in
Typically the user selects one or more reduced pin velocities that are less than about 90% of the maximum velocity at which the motors 940, 941, 942 can drive the pins, more typically less than about 75% of the maximum velocity and even more typically less than about 50% of the maximum velocity at which the pins 1041, 1042 are drivable by the electric motors. The actual maximum velocity at which the actuators 941, 942 and their associated pins 1041, 1042 are driven is predetermined by selection of the size and configuration of the actuators 941, 942. The maximum drive rate of the motors 940, 941, 942 is predetermined by the manufacturer and the user of the motors and is typically selected according to the application, size and nature of the mold and the injection molded part to be fabricated.
In one embodiment, after the pins 1041 have been withdrawn upstream to an upstream position where the flow of injection fluid material is no longer restricted (and thus at maximum flow rate), the pins 1041 can be withdrawn at maximum rate of upstream travel or velocity in order to shorten the injection cycle time. Alternatively, when the pins 1041 have been withdrawn to a position upstream where maximum injection flow rate is occurring, the pins 1041 can continue to be withdrawn at a reduced rate of travel or velocity to ensure that injection fluid does not flow through the gates 34 at a rate that causes a defect in the molded part.
Similarly, on downstream closure of the pins 1041 after they have reached their maximum upstream withdrawal positions, the rate of travel of the pins is preferably controlled by controller 176 such that the pins 1041 travel downstream to a fully gate closed position at a reduced rate of travel or velocity that is less than the maximum rate of downstream travel or velocity over some portion or all of the stroke length between fully upstream and closed.
Graphs such as shown in
The four different graphs of
In the
In the
Through a user interface,
Screen 1300,
A profile 1310 includes (x, y) data pairs, corresponding to time values 1320 and pressure values 1330 which represent the desired pressure sensed by the pressure transducer for the particular nozzle being profiled. The screen shown in
The screen also allows the user to select the particular valve pin they are controlling displayed at 1390, and name the part being molded displayed at 1400. Each of these parameters can be adjusted independently using standard windows-based editing techniques such as using a cursor to actuate up/down arrows 1410, or by simply typing in values on a keyboard. As these parameters are entered and modified, the profile will be displayed on a graph 1420 according to the parameters selected at that time.
By clicking on a pull-down menu arrow 1391, the user can select different nozzle valves in order to create, view or edit a profile for the selected nozzle valve and cavity associated therewith. Also, a part name 1400 can be entered and displayed for each selected nozzle valve.
The newly edited profile can be saved in computer memory individually, or saved as a group of profiles for a group of nozzles that inject into a particular single or multi-cavity mold. To create a new profile or edit an existing profile, first the user selects a particular nozzle valve of the group of valves being profiled. The valve selection is displayed at 1390. The user inputs an alpha/numeric name to be associated with the profile being created, for family tool molds this may be called a part name displayed at 1400. The user then inputs a time displayed at 1340 to specify when injection starts. A delay can be with particular valve pins to sequence the opening of the valve pins and the injection of melt material into different gates of a mold.
The user then inputs the fill (injection) pressure displayed at 1350. In the basic mode, the ramp from zero pressure to max fill pressure is a fixed time, for example, 0.3 seconds. The user next inputs the start pack time to indicate when the pack phase of the injection cycle starts. The ramp from the filling phase to the packing phase is also fixed time in the basic mode, for example, 0.3 seconds.
The final parameter is the cycle time which is displayed at 1380 in which the user specifies when the pack phase (and the injection cycle) ends. The ramp from the pack phase to zero pressure may be instantaneous when a valve pin is used to close the gate, or slower in a thermal gate due to the residual pressure in the cavity which will decay to zero pressure once the part solidifies in the mold cavity.
User input buttons 1415 through 1455 are provided for purposes of enabling the user to save and load target profiles. Button 1415 permits the user to close the screen. When this button is clicked, the current group of profiles will take effect. Cancel button 1425 is used to ignore current profile changes and revert back to the original profiles and close the screen. Read Trace button 1435 is used to load an existing and saved target profile from memory. The profiles can be stored in memory contained in one or more of the operator interface 21, in random access or permanent memory contained in the controller. Save trace button 1440 is provided for purposes of enabling a user to save the current profile. Read group button 1445 is provided for purposes of enabling a user to load an existing profile or set of profiles. Save group button 1450 is provided for purposes of enabling a user to save the current group of target profiles for a group of nozzle valve pins. The process tuning button 1455 is provided for purposes of enabling a user to change the settings (for example, the gains) for a particular nozzle valve in a control zone. Also displayed is a pressure range 1465 for the injection molding application.
In a preferred embodiment, the controller (16) includes instructions that instruct the actuator piston 40p,
One example of the use of such a pressure detection system is where at the start of the injection cycle when the piston 40p is disposed in the fully downstream gate closed position 40gc,
In the example just described, the first position (1311 pressure of 15,000 psi) could be a “fill” cavity position or a pre-fill position and the second position (at 1312 pressure of 7500 psi) could be a “pack” position.
As can be readily imagined the first portion of the duration of the injection cycle can be defined or determined by the amount of time that elapses between the time that the piston 40p first moves to the first axially spaced X position and the time that the pressure sensor 603ec, 603e detects the target pressure, opens the valve 600 and drives the piston to the second or third position. Alternatively the first portion of the duration of the injection cycle during with the piston 40p resides in the first position can be preselected by the user. In either case, the piston 40p is held in the first position for some period of time or portion of the injection cycle with the restriction valve 600 closed and with the sensor(s) 603ec, 603e acting to sense, detect pressure of the drive fluid and send a signal indicative of sensed pressure to the controller 16. The same is true with respect to the subsequent second or third positions and the subsequent second or third periods of time or portions of the duration of the injection cycle.
While specific embodiments of the present invention have been shown and described, it will be apparent that many modifications can be made thereto without departing from the scope of the invention. For example, in one embodiment the controller can be mounted on a hydraulic power unit.
Thus as described, the control data can comprise a profile of values of a condition of the injected polymer material or a condition or position of a selected component of the injection molding apparatus that is specified to occur at each point in time over the course or duration of an injection cycle when a part is produced in the mold cavity. Thus a profile defines a set of conditions, events or positions to which the injection material or the component of the apparatus is adjusted to attain over the course of a particular injection cycle. Typical injection material conditions that can be specified and controlled are pressure of the injection material at selected positions within a flow channel of the manifold, within an injection nozzle or within the mold cavity. Typical conditions or positions of components of the apparatus that can be controlled and comprise a profile are the position of the valve pin, the position of the screw of the barrel of the injection molding machine and position of an actuator piston. Such profiles are disclosed in detail in for example U.S. Pat. No. 6,464,909 and U.S. Pat. No. 8,016,581 and U.S. Pat. No. 7,597,828, the disclosures of which are incorporated by reference as if fully set forth herein.
This application is a continuation-in-part of and claims the benefit of priority to U.S. application Ser. No. 15/442,173 filed Feb. 24, 2017 which is in turn a continuation of U.S. application Ser. No. 14/708,533 (7127US1) filed May 11, 2015 which is a continuation of international application PCT/US2013/071667 filed Nov. 25, 2013 the disclosures of both which are incorporated herein by reference in their entirety as if fully set forth herein. This application is also a continuation in part of and claims the benefit of priority to U.S. application Ser. No. 14/930,692 filed Nov. 3, 2015 (7117US1) which is a continuation of U.S. application Ser. No. 13/569,464 filed Aug. 8, 2012 (7117U50), the disclosures of all of the foregoing of which are incorporated by reference in their entirety as if fully set forth herein. This application is also a continuation in part of and claims the benefit of priority to U.S. application Ser. No. 15/291,721 filed Oct. 12, 2016 (7134US2) which is a continuation of U.S. application Ser. No. 14/311,785 filed Jun. 23, 2014 which is a continuation-in-part of U.S. application Ser. No. 13/484,336 filed May 31, 2012 which is a continuation of PCT/US2011/062099 filed Nov. 23, 2011, the disclosures of all of the foregoing of which are incorporated by reference in their entirety as if fully set forth herein. This application is also a continuation in part of and claims the benefit of priority to U.S. application Ser. No. 15/286,917 filed Oct. 6, 2016 (7135US2) which is a continuation of U.S. application Ser. No. 14/325,443 filed Jul. 8, 2014 the disclosures of all of the foregoing of which are incorporated by reference in their entirety as if fully set forth herein. This application is also a continuation in part of and claims the benefit of priority to U.S. application Ser. No. 14/567,308 filed Dec. 11, 2014 (7100U54) which is a divisional of U.S. application Ser. No. 13/484,336 filed May 31, 2012 which is a continuation of and claims the benefit of priority of PCT/US11/62099 filed Nov. 23, 2011 which in turn claims the benefit of priority to U.S. Provisional Application Ser. No. 61/475,340 filed Apr. 14, 2011 and to U.S. Provisional Application Ser. No. 61/416,583 filed Nov. 23, 2010, the disclosures of all of the foregoing of which are incorporated by reference herein in their entirety as if fully set forth herein. This application is also a continuation in part of and claims the benefit of priority to U.S. application Ser. No. 15/215,774 filed Jul. 21, 2016 (7118US2) which is a continuation of U.S. application Ser. No. 14/834,586 filed Aug. 25, 2015, the disclosures of all of the foregoing of which are incorporated by reference herein in their entirety as if fully set forth herein. The disclosures of all of the following are incorporated by reference in their entirety as if fully set forth herein: International Application Publication No. WO2012/074879, U.S. Patent Application Publication No. 2012/0248644, International Application Publication No. 2012/087491, U.S. Patent Application Publication No. 2012/0248652, U.S. Pat. No. 5,894,025, U.S. Pat. No. 6,062,840, U.S. Pat. No. 6,294,122, U.S. Pat. No. 6,309,208, U.S. Pat. No. 6,287,107, U.S. Pat. No. 6,343,921, U.S. Pat. No. 6,343,922, U.S. Pat. No. 6,254,377, U.S. Pat. No. 6,261,075, U.S. Pat. No. 6,361,300 (7006), U.S. Pat. No. 6,419,870, U.S. Pat. No. 6,464,909 (7031), U.S. Pat. No. 6,599,116, U.S. Pat. No. 7,234,929 (7075US1), U.S. Pat. No. 7,419,625 (7075US2), U.S. Pat. No. 7,569,169 (7075US3), U.S. patent application Ser. No. 10/214,118, filed Aug. 8, 2002 (7006), U.S. Pat. No. 7,029,268 (7077US1), U.S. Pat. No. 7,270,537 (7077US2), U.S. Pat. No. 7,597,828 (7077US3), U.S. patent application Ser. No. 09/699,856 filed Oct. 30, 2000 (7056), U.S. patent application Ser. No. 10/269,927 filed Oct. 11, 2002 (7031), U.S. application Ser. No. 09/503,832 filed Feb. 15, 2000 (7053), U.S. application Ser. No. 09/656,846 filed Sep. 7, 2000 (7060), U.S. application Ser. No. 10/006,504 filed Dec. 3, 2001, (7068) and U.S. application Ser. No. 10/101,278 filed Mar., 19, 2002 (7070), U.S. Pat. No. 8,297,836 (7087), U.S. Pat. No. 8,328,549 (7096) and international applications PCT/US2011/062099 (7100) and PCT/US2011/062096 (7100), PCT/US2014/043612, PCT/US2013/075064 filed Dec. 13, 2013, PCT/US2014/019210 filed Feb. 28, 2014, PCT/US2014/031000 and PCT/US2014/032658.
| Number | Date | Country | |
|---|---|---|---|
| 61475340 | Apr 2011 | US | |
| 61416583 | Nov 2010 | US |
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| Parent | 13484336 | May 2012 | US |
| Child | 14567308 | US |
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| Parent | 14708533 | May 2015 | US |
| Child | 15442173 | US | |
| Parent | PCT/US2013/071667 | Nov 2013 | US |
| Child | 14708533 | US | |
| Parent | 13569464 | Aug 2012 | US |
| Child | 14930692 | US | |
| Parent | 14311785 | Jun 2014 | US |
| Child | 15291721 | US | |
| Parent | PCT/US2011/062099 | Nov 2011 | US |
| Child | 13484336 | US | |
| Parent | 14325443 | Jul 2014 | US |
| Child | 15286917 | US | |
| Parent | PCT/US2011/062099 | Nov 2011 | US |
| Child | 13484336 | US | |
| Parent | 14834586 | Aug 2015 | US |
| Child | 15215774 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 15442173 | Feb 2017 | US |
| Child | 15715906 | US | |
| Parent | 14930692 | Nov 2015 | US |
| Child | PCT/US2013/071667 | US | |
| Parent | 15291721 | Oct 2016 | US |
| Child | 13569464 | US | |
| Parent | 13484336 | May 2012 | US |
| Child | 14311785 | US | |
| Parent | 15286917 | Oct 2016 | US |
| Child | PCT/US2011/062099 | US | |
| Parent | 14567308 | Dec 2014 | US |
| Child | 14325443 | US | |
| Parent | 15215774 | Jul 2016 | US |
| Child | PCT/US2011/062099 | US |
