Injection molding flow control apparatus and method

• US 9,604,399 B2
• Filed: 05/11/2015
• Issued: 03/28/2017
• Est. Priority Date: 11/23/2010
• Status: Active Grant

• Current Assignee: Synventive Molding Solutions Incorporated
• Original Assignee: Synventive Molding Solutions Incorporated
• Inventors: Yang, Lin, Galati, Vito, Antunes, Sergio
• Primary Examiner(s): Heitbrink, Jill
• Application Number:
  US14/708,533
• Publication Number:
  US 20150239162A1
• Time in Patent Office: 687 Days
• US Class Current: 1/1
• CPC Class Codes: B29C 2045/1792 Machine parts driven by an electric motor, e.g. electric servomotor
• CPC Class Codes: B29C 2045/2712 Serial gates for moulding articles in successively filled serial mould cavities
• CPC Class Codes: B29C 2045/2824 Needle valves driven by an electric motor
• CPC Class Codes: B29C 2045/2865 having position detecting means
• CPC Class Codes: B29C 2045/2872 with at least three positions, e.g. two different open positions to control the melt flow
• CPC Class Codes: B29C 2945/76006 Pressure
• CPC Class Codes: B29C 2945/76076 duration
• CPC Class Codes: B29C 2945/76083 Position
• CPC Class Codes: B29C 2945/76277 nozzles
• CPC Class Codes: B29C 2945/7628 manifolds
• CPC Class Codes: B29C 2945/76381 Injection
• CPC Class Codes: B29C 2945/76545 Flow rate
• CPC Class Codes: B29C 2945/76568 Position
• CPC Class Codes: B29C 2945/76598 linear movement
• CPC Class Codes: B29C 2945/76602 derivative, change thereof
• CPC Class Codes: B29C 2945/76755 nozzles
• CPC Class Codes: B29C 2945/76859 Injection
• CPC Class Codes: B29C 2945/76933 The operating conditions are corrected immediately, during the same phase or cycle
• CPC Class Codes: B29C 2945/76936 The operating conditions are corrected in the next phase or cycle
• CPC Class Codes: B29C 2945/76939 Using stored or historical data sets
• CPC Class Codes: B29C 2945/76993 : Remote, e.g. LAN, wireless LAN
• CPC Class Codes: B29C 45/03 : Injection moulding apparatus transfer moulding B29C45/02
• CPC Class Codes: B29C 45/2703 : Means for controlling the runner flow, e.g. runner switches, adjustable runners or gates
• CPC Class Codes: B29C 45/2708 : Gates B29C45/2703 takes precedence
• CPC Class Codes: B29C 45/2806 : consisting of needle valve systems B29C45/2896 takes precedence
• CPC Class Codes: B29C 45/281 : Drive means therefor
• CPC Class Codes: B29C 45/76 : Measuring, controlling or regulating measuring in general G01; controlling or regulating in general G05
• CPC Class Codes: B29C 45/7613 : the termination of flow of material into the mould
• CPC Class Codes: B29C 45/77 : of velocity or pressure of moulding material
• CPC Class Codes: B29C 45/80 : of relative position of mould parts
• CPC Class Codes: B29K 2105/0067 : Melt
• CPC Class Codes: G05B 15/02 : electric
• CPC Class Codes: G05D 7/0635 : by action on throttling means G05D7/0688, G05D7/0694 take precedence

Abstract

An apparatus for controlling the rate of flow of fluid mold material from an injection molding machine to a mold cavity, the apparatus comprising: a manifold having a fluid delivery channel, an actuator interconnected to a valve pin having a tip end drivable between a first position, a second position upstream and a third position upstream of the second position, the actuator and the valve pin being translationally driven by a valve system adjustable between a start position, a plurality of intermediate drive rate positions and a high drive rate position, a pressure sensor and a controller, the pressure sensor sensing a metered pressure of a drive fluid, the controller instructing the valve system to drive valve pin continuously upstream and including instructions that instruct the valve system to move according to a predetermined profile of metered pressures from the start position to selected intermediate drive rate positions and subsequently to the high drive rate position.

Claims

1. An apparatus for controlling the rate of flow of fluid mold material from an injection molding machine to a mold cavity, the apparatus comprising:

a manifold receiving the injected fluid mold material, the manifold having a delivery channel that delivers the injected fluid material to a first gate leading to the mold cavity;

an actuator interconnected to a valve pin having a tip end drivable along a drive path that extends between a first position where the tip end of the valve pin obstructs the first gate to prevent the injection fluid material from flowing into the cavity, a second position upstream of the first position wherein the tip end of the valve pin restricts flow of the injection fluid through the first gate along at least a portion of the length of the drive path extending between the first position and the second position, and a third position upstream of the second position where the injection fluid material flows freely through the first gate without restriction from the tip end of the pin,

the actuator and the valve pin being translationally driven at a controllable rate of travel by a valve system that is controllably adjustable between a start position, a plurality of intermediate drive rate positions and a high drive rate position, the actuator being driven upstream at a corresponding plurality of intermediate rates of travel when the valve system is in one or more of the plurality of intermediate drive rate positions and at a higher rate of travel than the plurality of intermediate rates of travel when the valve system is in the high drive rate position;

a position sensor,

a pressure sensor,

a controller,

the position sensor sensing the position of the valve pin and sending a signal indicative of the position of the pin to the controller;

the pressure sensor sensing a metered pressure of a drive fluid flowing out of an exit of the valve system, the metered pressure corresponding to a drive rate position of the valve system, the pressure sensor sending a signal indicative of the metered pressure to the controller;

the controller instructing the valve system to drive the actuator and the valve pin continuously upstream from the start position to the second position to the third position;

the controller including instructions that instruct the valve system to move according to a predetermined profile of metered pressures versus pin positions from the start position to selected ones of the plurality of intermediate drive rate positions that correspond to the profile of metered pressures and subsequently move from the selected ones of the plurality of intermediate drive rate positions to the high drive rate position on receipt by the controller of a signal from the position sensor that is indicative of the valve pin having reached the second position.

2. The apparatus of claim 1 further comprising an electrical signal generating device interconnected to the valve system to controllably drive the valve system to selected degrees of openness, the electrical signal generating device generating an electrical signal of controllably variable degree of output, the valve system being adjustable in degree of openness that is approximately proportional to the degree of output of the electrical signal.

3. The apparatus of claim 2 wherein the electrical signal generating device is interconnected to the controller, the controller instructing the electrical signal generating device to generate electrical signals of varying degrees of output that correspond to a degree of openness of the one or more intermediate drive rate positions and the third drive rate position of the valve system.

4. The apparatus of claim 1 wherein the portion of the drive path over which the flow of injected material is restricted is at least about 30% of the length of the drive path between the first position and the second position.

5. The apparatus of claim 1 wherein the length of the drive path between the first position and the second position is between about 1 mm and about 5 mm.

6. The apparatus of claim 3 wherein the length of the drive path between the first position and the second position is between about 1 mm and about 5 mm.

7. The apparatus of claim 1 wherein the valve pin and actuator are driven at a a maximum rate of upstream travel that the valve system is capable of driving the actuator at when the valve system is in the high drive rate position.

8. The apparatus of claim 1 wherein the rate of travel of the valve pin corresponding to the highest of the one or more intermediate drive positions of the valve system is less than about 75% of the rate of travel of the valve pin corresponding to the high drive position.

9. The apparatus of claim 1 wherein the positions of the valve system each have a different degree of openness, the actuator and valve pin being driven at a velocity that is proportional to the degree of openness of the positions of the valve system, the controller instructing the generation of an electrical signal that adjusts the valve system to a degree of openness that is proportional to a degree of output of the electrical signal, the controller being programmable to instruct the generation of one or more first electrical signals having one or more corresponding first selected degrees of output that moves the valve system to the one or more intermediate drive rate positions to drive the actuator at one or more first velocities in an upstream direction, the controller being programmed to instruct the generation of a second electrical signal when the controller receives a signal from the position sensor that the tip end of the valve pin has reached the second position, the second electrical signal having a second selected degree of output that moves the valve system to the high drive rate position that drives the actuator at a second velocity that is higher than the one or more first velocities.

10. The apparatus of claim 9 wherein the valve system is driven to a degree of openness that is approximately proportional to the degree of output of the electrical signal.

11. A sequentially gated molding system comprising a mold having first and second gates leading to a common cavity and a manifold having first and second fluid flow channels respectively delivering a fluid mold material through the first and second gates into the cavity, the system comprising:

a first valve controlling delivery of the fluid material through the first gate into the cavity beginning at a first time;

a second valve controlling delivery of the fluid material through the second gate beginning at a second time subsequent to the first time such that the fluid material has entered the cavity through the first gate and approached the second gate prior to the second time;

the second valve comprising an an actuator interconnected to a valve pin having a tip end drivable along a drive path that extends between a first position where the tip end of the valve pin obstructs the second gate to prevent the injection fluid material from flowing into the cavity, a second position upstream of the first position wherein the tip end of the valve pin restricts flow of the injection fluid through the second gate along at least a portion of the length of the drive path extending between the first position and the second position, and a third position upstream of the second position where the injection fluid material flows freely through the second gate without restriction from the tip end of the pin,

the actuator and the valve pin being translationally driven at a controllable rate of travel by a valve system that is controllably adjustable between a start position, a plurality of intermediate drive rate positions and a high drive rate position, the actuator being driven upstream at a corresponding plurality of intermediate rates of travel when the valve system is in one or more of the plurality of intermediate drive rate positions and at a higher rate of travel than the plurality of intermediate rates of travel when the valve system is in the high drive rate position;

a position sensor,

a pressure sensor,

a controller,

the position sensor sensing the position of the valve pin and sending a signal indicative of the position of the pin to the controller;

the pressure sensor sensing a metered pressure of a drive fluid flowing out of an exit of the valve system, the metered pressure corresponding to a drive rate position of the valve system, the pressure sensor sending a signal indicative of the metered pressure to the controller;

the controller instructing the valve system to drive the actuator and the valve pin continuously upstream from the start position to the second position to the third position;

the controller including instructions that instruct the valve system to move according to a predetermined profile of metered pressures versus pin positions from the start position to selected ones of the plurality of intermediate drive rate positions that correspond to the profile of metered pressures and subsequently move from the selected ones of the plurality of intermediate drive rate positions to the high drive rate position on receipt by the controller of a signal from the position sensor that is indicative of the valve pin having reached the second position.

12. A method of performing an injection molding cycle in an injection molding apparatus comprising:

a manifold that receives an injection fluid mold material, the manifold having a delivery channel that delivers the injection fluid mold material under an injection pressure to a first gate of a mold cavity,

an actuator drivably interconnected to a valve pin having a tip end drivable along a drive path that extends between a first position where the tip end of the valve pin obstructs the gate to prevent the injection fluid material from flowing into the cavity, a second position upstream of the first position wherein the tip end of the valve pin restricts flow of the injection fluid along at least a portion of the length of the drive path extending between the first position and the second position, and a third position upstream of the second position where the injection fluid material flows freely without restriction from the tip end of the pin through the first gate,

the actuator being driven by a valve system that is controllably adjustable between a start position, a plurality of intermediate drive rate positions and a high drive rate position, the actuator being driven upstream at a plurality of corresponding intermediate rates of travel when the valve system is in one of the plurality of intermediate drive rate positions and at a higher rate of travel than the plurality of intermediate rates of travel when the valve system is in the high drive rate position,

the valve system including a fluid flow line routing a drive fluid out of an exit of the valve system under a metered pressure,

the method comprising;

selecting the length of travel between the first position and the second position,

sensing the metered pressure of the drive fluid within the fluid flow line,

sensing the position of the valve pin,

selecting a profile of metered pressures versus position of the valve pin where the profile of metered pressures correspond to selected ones of the plurality of intermediate drive rate positions,

beginning an injection cycle with the tip end of the valve pin in the first position and the valve system in the start position,

adjusting the valve system according to the selected profile to operate at the selected ones of the plurality of intermediate drive rate positions to drive the tip end of the valve pin continuously upstream from the first position to the second position,

sensing the position of the valve pin to determine when the tip end of the valve pin has reached the second position,

adjusting the valve system to operate at the high drive rate position to drive the tip end of the valve pin continuously upstream at the higher rate of travel when the tip end of the valve pin has been determined in the step of sensing to have reached the second position.

13. The method of claim 12 wherein the step of adjusting the valve system to operate at the one or more selected intermediate drive rate positions is begun after the injection fluid mold material has been previously injected into the cavity through another gate and the fluid mold material has travelled through the cavity past the first gate.

14. The method of claim 12 wherein the step of adjusting the valve system to operate at the one or more selected intermediate drive rate positions comprises adjusting the valve system to operate at a single intermediate drive rate position.

15. The method of claim 12 wherein the high drive rate position of the valve system drives the actuator at a rate of travel that is a maximum at which the valve system is capable of driving the actuator.

16. The method of claim 12 wherein the valve system is interconnected to an electrical signal generating device operable to generate an electrical signal of controllably variable degree, the valve system being adjustable in position to increase the flow of drive fluid to a degree that is proportional to the degree of electrical signal input by the electrical signal generating device to the valve system, the steps of adjusting the valve system comprising operating the electrical signal generating device to adjust the positions of the valve system.

17. The method of claim 12 wherein each of the start, intermediate drive rate and high drive rate positions of the valve system have a different degree of openness, the drive fluid of the valve system driving the actuator and the valve pin at a rate that is approximately proportional to the degree of openness of the positions of the valve system, the one or more intermediate drive rate positions having a degree of openness that is less than the degree of openness of the high drive rate position.

18. The method of claim 12 wherein the length of travel between the first position and the second position along the drive path is selected to be between about 1 mm and about 5 mm.

19. The method of claim 12 wherein the step of sensing includes sensing the position of the valve pin with a position sensor that automatically sends one or more signals indicative of the position of the tip end of the valve pin to a control mechanism that automatically adjusts the positions of the valve system in response to receipt of the one or more signals from the position sensor.

20. The method of claim 19 wherein the control mechanism comprises an electrical signal generating device operable to generate an electrical signal of controllably variable degree, the valve system being adjustable in position to a degree of openness that is approximately proportional to the degree of electrical signal input by the electrical signal generating device to the valve system, the steps of adjusting the valve system comprising operating the electrical signal generating device to controllably adjust the degree of electrical signal input to the valve system.

21. The method of claim 12 wherein the tip end of the valve pin restricts flow of the injection fluid along the entire length of the drive path extending between the first position and the second position.

22. A method of performing an injection molding cycle in an injection molding apparatus comprising:

an injection molding machine and a manifold that receives an injected mold material from the injection molding machine, the manifold having a delivery channel that delivers the mold material under an injection pressure to a first gate of a mold cavity,

an actuator interconnected to a valve pin driving the valve pin from a first position where the tip end of the valve pin obstructs the gate to prevent the injection fluid material from flowing into the cavity, upstream to a second position upstream of the gate where the mold material flows at a high rate through the gate and continuously upstream from the start position through one or more intermediate positions between the first position and the second position wherein the tip end of the valve pin restricts flow of the injection mold material to one or more rates less than the high rate,

a valve system for controllably driving the valve pin, the valve system being controllably movable from a start position to a plurality of intermediate drive rate positions and a high drive rate position, the high drive rate position driving the pin upstream at a high rate of travel, the intermediate drive rate positions driving the pin upstream at one or more intermediate rates of travel that are less than the high rate of travel,

the valve system including a fluid flow line routing a drive fluid out of an exit of the valve system under a metered drive pressure,

the method comprising;

selecting one or more lengths of time for the valve system to operate or reside in one or more of the plurality of intermediate drive rate positions,

beginning an injection cycle with the tip end of the valve pin in the first position and the valve system in the start position,

sensing the metered pressure of the drive fluid within the fluid flow line,

selecting a profile of metered pressures versus the selected one or more lengths of time where the profile of metered pressures correspond to selected ones of the plurality of intermediate drive rate positions,

adjusting the valve system according to the selected profile to operate at the selected ones of the plurality of intermediate drive rate positions for the selected one or more lengths of time to drive the valve pin continuously upstream.

23. The method of claim 22 wherein the step of adjusting comprises operating the valve system at one or more selected intermediate drive rate positions for the length of an entire injection cycle where the pin travels from the first position to an end of stroke position with the valve system in one or more selected intermediate drive rate positions.

24. The method of claim 22 further comprising adjusting the valve system to operate at the high drive rate position to drive the tip end of the valve pin continuously upstream at the high rate of travel upon expiration of the selected one or more lengths of time.

25. The method of claim 24 wherein the valve system is adjusted to operate at the one or more intermediate drive rate positions after the mold material has been injected into the cavity through another gate and has travelled through the cavity past the first gate.

26. The method of claim 24 wherein the valve system is adjusted to operate at a single intermediate drive rate position for a single selected length of time.

27. The method of claim 24 wherein the valve system is interconnected to an electrical signal generating device operable to generate electrical signals of controllably variable output, the valve system being adjustable in drive rate position to increase the flow of drive fluid to a degree that is proportional to the degree of output of the electrical signals, the steps of adjusting the valve system comprising operating the electrical signal generating device to generate electrical signals that adjust the drive rate positions of the valve system according electrical signals of selected degree of output.

28. The method of claim 24 wherein each of the drive rate positions of the valve system have a degree of openness, the drive fluid of the valve system driving the actuator and the valve pin at a rate that is proportional to the degree of openness of the positions of the valve system, the one or more intermediate drive rate positions having a degree of openness that is less than the degree of openness of the high drive rate flow position.

29. The method of claim 24 wherein the length of travel between the first position and the one or more intermediate positions along the drive path is between about 1 mm and about 5 mm.

30. An apparatus for controlling the rate of flow of mold material to a mold cavity, the apparatus comprising:

an injection molding machine and a manifold that receives the injected mold material from the machine, the manifold having a delivery channel that delivers the mold material at one or more flow rates through a gate to the mold cavity,

an actuator interconnected to a valve pin having a tip end, the actuator being drivable to move the valve pin along a path of travel starting from a downstream gate closed position continuously upstream to and through a series of successively upstream intermediate upstream gate open positions and further continuously upstream to a high upstream gate open position,

a valve system in fluid communication with the actuator to drive the actuator with drive fluid at one or more rates of travel, the valve system having a start position, a plurality of intermediate drive rate positions and a high drive rate position, the start position holding the valve pin in the gate closed position, the high drive rate position driving the actuator upstream at a selected high velocity, the plurality of intermediate drive rate positions driving the actuator upstream at one or more corresponding velocities that are less than the selected high velocity,

a controller interconnected to the valve system, the controller being adapted to control movement of the valve system between the start position, the plurality of intermediate drive rate positions and the high drive rate position,

a pressure sensor sensing a metered pressure of a drive fluid flowing out of an exit of the valve system, the metered pressure corresponding to a drive rate position of the valve system, the pressure sensor sending a signal indicative of the metered pressure to the controller;

the controller including instructions that instruct the valve system to move from the start position to selected ones of the plurality of intermediate drive rate positions according to a predetermined profile of metered pressures versus one or more preselected amounts of time and further drives the valve system to move from the selected ones of the plurality of intermediate drive rate positions to the high drive rate position on expiration of the one or more preselected amounts of time.

31. The apparatus of claim 30 wherein the positions of the valve system each have a corresponding degree of openness, the controller being adapted to generate an electrical signal of selectable degree of output, the degree of openness of the positions of the valve system being proportional to the degree of output of the electrical signal generated by the controller.

32. The apparatus of claim 31 wherein the output of the electrical signal is one or more of electrical energy, electrical power, voltage, current or amperage.

33. The apparatus of claim 31 wherein the degree of openness of the positions of the valve system each have a corresponding rate of flow of the drive fluid that is proportional to the corresponding degree of openness of the positions of the valve system.

34. The apparatus of claim 31 wherein

the tip end of the valve pin obstructs the gate to prevent the mold material from flowing into the cavity in the first position, the mold material flows at the high rate through the gate in the second position and the tip end of the valve pin restricts the flow of the mold material to less than the high rate in the one or more intermediate upstream positions between the first position and the second position, and

wherein the valve pin is in one or more of the intermediate upstream positions when the valve system is in the one or more intermediate drive rate positions.

35. The apparatus of claim 30 wherein the rate of travel of the actuator that corresponds to a highest of the one or more intermediate drive rate positions of the valve system is less than about 75% of the rate of travel of the actuator that corresponds to the high drive rate position of the valve system.

36. The apparatus of claim 30 wherein each of the positions of the valve system have a corresponding degree of openness, the actuator being driven at a velocity that is proportional to the degree of openness of the positions of the valve system, the electrical signals generated by the controller each having a degree of output that adjusts the valve system to a degree of openness that is proportional to the degree of output of the electrical signals.

37. The apparatus of claim 34 wherein the controller is programmable to automatically generate one or more first electrical signals having one or more corresponding first selected degrees of output that move the valve system to the one or more intermediate drive rate positions to drive the actuator continuously upstream at one or more corresponding first velocities that are less than the high velocity, the controller generating a second electrical signal on expiration of the one or more predetermined amounts of time, the second electrical signal having a second selected degree of output that moves the valve system to the high drive rate position to drive the actuator at the high velocity.

38. The apparatus of claim 30 wherein the controller includes electrical or electronic instructions interconnected to an electrical signal generator that automatically instructs the electrical signal generator to generate the electrical signals that drive the valve system to move from the start position to the one or more intermediate drive positions and to remain in the one or more intermediate drive positions for the one or more predetermined amounts of time and further instructs the electrical signal generator to generate an electrical signal that drives the valve system to move from the one or more intermediate drive positions to the high drive position on expiration of the one or more predetermined amounts of time.

39. The apparatus of claim 38 wherein each of the positions of the valve system have a corresponding degree of openness, the actuator being driven at a velocity that is proportional to the degree of openness of the positions of the valve system, the electrical signals generated by the controller each having a degree of output that adjusts the valve system to a degree of openness that is proportional to the degree of output of the electrical signals.

40. The apparatus of claim 39 wherein the output of the electrical signal is one or more of electrical energy, electrical power, voltage, current or amperage.

41. A sequentially gated molding system comprising a mold having first and second gates leading to a common cavity and a manifold having first and second fluid flow channels respectively delivering a fluid mold material through the first and second gates into the cavity, the system comprising:

a first valve controlling delivery of the fluid material through the first gate into the cavity beginning at a first time;

a second valve controlling delivery of the fluid material through the second gate beginning at a second time subsequent to the first time such that the fluid material has entered the cavity through the first gate and approached the second gate prior to the second time;

the second valve comprising an an actuator interconnected to a valve pin having a tip end, the actuator being drivable to move the valve pin along a path of travel starting from a downstream gate closed position continuously upstream to and through a series of successively upstream intermediate upstream gate open positions and further continuously upstream to a high upstream gate open position,

a valve system in fluid communication with the second actuator to drive the second actuator with drive fluid at one or more rates of travel, the valve system having a start position, a plurality of intermediate drive rate positions and a high drive rate position, the start position holding the valve pin in the gate closed position, the high drive rate position driving the second actuator upstream at a selected high velocity, the plurality of intermediate drive rate positions driving the actuator upstream at one or more corresponding velocities that are less than the selected high velocity,

a controller interconnected to the valve system, the controller being adapted to control movement of the valve system between the start position, the plurality of intermediate drive rate positions and the high drive rate position,

a pressure sensor sensing a metered pressure of a drive fluid flowing out of an exit of the valve system, the metered pressure corresponding to a drive rate position of the valve system, the pressure sensor sending a signal indicative of the metered pressure to the controller;

the controller including instructions that instruct the valve system to move from the start position to selected ones of the plurality of intermediate drive rate positions according to a predetermined profile of metered pressures versus one or more preselected amounts of time and further drives the valve system to move from the selected ones of the plurality of intermediate drive rate positions to the high drive rate position on expiration of the one or more preselected amounts of time.