Valve pin plate injection molding apparatus

Abstract

Valve pin plate injection molding apparatus. An injection molding apparatus is disclosed comprising a manifold having a manifold channel, a nozzle having a nozzle channel in fluid communication with the manifold channel, and a valve pin plate coupled to an actuator that, when operated, moves the valve pin plate axially between a closed position and an open position. A die plate is spaced apart from the manifold and disposed between the manifold and the valve pin plate, the die plate having a valve pin passage extending therethrough. A valve pin extends through the valve pin passage and is releasably coupled to the valve pin plate by a valve pin seat, and a biasing member is biased against a support surface by the valve pin seat to create a supplemental coupling force that couples the valve pin to the valve pin seat when the valve pin plate is in the closed position.

Description

Technical Field

[0001] This application relates to the injection molding of valve pin plates, and more specifically to a valve pin plate having a plurality of valve pins releasably connected by corresponding valve pin seats. Background Technology

[0002] A valve pin plate is used to move multiple valve pins simultaneously between open and closed positions, each valve pin associated with a corresponding cavity. Valve pin plates are typically used in high-cavity molds to achieve closer spacing between adjacent cavities compared to the possible spacing achievable when each cavity is gated by a valve pin connected to a corresponding actuator. A challenge associated with valve pin plates is that, for example, if the associated cavity of a valve pin is damaged or otherwise rendered inoperable, the opening and closing movement of the affected valve pin stops. To address this challenge, hot runner manufacturers have created valve pin seats that disengage the valve pin from the valve pin plate when the release force acting on the valve pin exceeds the connecting force (e.g., friction, lateral force, magnetic force, etc.) holding the valve pin on the plate. While the theoretical connecting force of the valve pin seat can be calculated, factors such as accumulated manufacturing tolerances, material variations, assembly errors, and wear can cause the actual connecting force of the valve pin seat to be less than its theoretical connecting force. Furthermore, the release force acting on the valve pin seat varies depending on various parameters, including the viscosity of the molding material, actuator speed, and tooling design. In some cases, the actual connection force and the actual release force can differ at different locations within the mold. Given the uncertainty of the actual connection force and the actual release force, situations may arise where the valve pin seat disengages from the valve pin operating the mold cavity. Summary of the Invention

[0003] Embodiments of the present invention relate to an injection molding apparatus, comprising: a manifold having a manifold passage extending between a manifold inlet and a manifold outlet; a nozzle having a nozzle passage extending through the nozzle and in fluid communication with the manifold passage via a manifold outlet; and a valve pin plate coupled to an actuator, the actuator causing the valve pin plate to move axially between a closed position and an open position during operation. A mold plate is spaced apart from the manifold and disposed between the manifold and the valve pin plate. The mold plate includes a valve pin passage through which a valve pin extends. The valve pin is releasably coupled to the valve pin plate via a valve pin seat, wherein when the valve pin plate is in the closed position, a biasing member is pressed against a support surface by the valve pin seat.

[0004] One aspect of this application relates to an injection molding apparatus comprising: a manifold having a manifold channel extending between a manifold inlet and a manifold outlet; a nozzle having a nozzle channel extending through the nozzle and in fluid communication with the manifold channel via the manifold outlet; a valve pin plate coupled to an actuator that, during operation, causes the valve pin plate to move axially between a closed position and an open position; a mold plate spaced apart from the manifold and disposed between the manifold and the valve pin plate, the mold plate including a valve pin passage extending through the mold plate; a valve pin extending through the valve pin passage; a valve pin seat releasably coupling the valve pin to the valve pin plate; and a biasing member pressed against a support surface by the valve pin seat when the valve pin plate is in the closed position.

[0005] When the valve pin plate is in the open position, the biasing member can be compressed by the valve pin seat.

[0006] When the valve pin plate is in the closed position, the biasing member can be pressed against the mold plate.

[0007] The valve pin can extend through the biasing member.

[0008] The mold plate may include a countersunk hole defining a step in the valve pin passage, and the biasing member is seated on the step.

[0009] The injection molding apparatus may further include a spacer, wherein the mold plate is spaced apart from the manifold by the spacer, and the biasing member is pressed against the spacer when the valve pin plate is in the closed position.

[0010] The injection molding apparatus may further include a sleeve through which the valve pin extends, the sleeve surrounding the valve pin and forming a circumferential barrier between the valve pin and the biasing member.

[0011] The downstream end of the sleeve may include a flange, on which the biasing member is pressed when the actuator is in the closed position.

[0012] The injection molding apparatus may further include a scraper fixed within the valve pin passage between the bias member and the manifold, the valve pin extending through the scraper and slidably engaging the scraper.

[0013] The injection molding apparatus may further include: another mold plate, wherein the valve pin plate is disposed between the mold plate and the other mold plate; and another biasing member, which presses against the other mold plate when the valve pin plate is in the open position.

[0014] The other mold plate may include a recess defining a base, wherein the other biasing member is pressed against the base when the valve pin plate is in the open position.

[0015] The valve pin seat may include a first connecting component and a second connecting component, the first connecting component being attached to the valve pin plate, and the second connecting component being fixed to the valve pin and releasably connected to the first connecting component.

[0016] The second coupling component can be releasably coupled to the first coupling component by either friction or magnetism.

[0017] The biasing component can be a helical spring. Attached Figure Description

[0018] The attached diagram is not to scale.

[0019] Figure 1 This is a cross-sectional view of an injection molding apparatus according to an embodiment of this application.

[0020] Figure 2 yes Figure 1 An enlarged view of a portion shows the valve pin plate in the closed position and the actuator in the closed configuration.

[0021] Figure 3 yes Figure 2 The enlarged view shows the valve pin plate in the open position and the actuator in the open configuration.

[0022] Figure 4 yes Figure 1 An enlarged view of a portion shows the valve pin plate in the open position, the actuator in the open configuration, and the valve pin seat in the disengaged configuration.

[0023] Figure 5 This is an enlarged view of a portion of an injection molding apparatus according to another embodiment of this application.

[0024] Figure 6 This is an enlarged view of a portion of an injection molding apparatus according to yet another embodiment of this application.

[0025] Figure 7 This is an enlarged view of a portion of an injection molding apparatus according to yet another embodiment of this application.

[0026] Figure 8 This is an enlarged view of a portion of an injection molding apparatus according to yet another embodiment of this application, showing the valve pin plate in the closed position and the actuator in the closed configuration.

[0027] Figure 9 It is based on Figure 8 An enlarged view of a portion of the injection molding apparatus of an embodiment shows the valve pin plate in the open position and the actuator in the open configuration. Detailed Implementation

[0028] Specific embodiments of this application will now be described with reference to the accompanying drawings. The following detailed description is exemplary in nature only and is not intended to limit the scope of this application. In the following description, "downstream" refers to the direction in which molding material flows from the injection unit of the injection molding machine to the mold cavity of the mold of the injection molding apparatus, and also refers to the sequence in which the molding material flows from the injection unit through it to its components or parts in the mold cavity, while "upstream" refers to the opposite direction. In the following description, reference numerals following the letter "s" indicate schematic diagrams of components or parts associated with that reference numeral. Furthermore, there is no intention to be bound by any express or implied theory presented in the foregoing technical field, background art, summary of the invention, or the following detailed description.

[0029] Figure 1 This is a cross-sectional view of an injection molding apparatus 100 according to an embodiment of this application. The injection molding apparatus 100 delivers molding material received from a source (not shown) to a plurality of mold cavities 101. The injection molding apparatus 100 includes a plurality of mold plates, such as a first mold plate 104, a second mold plate 106, a third mold plate 108, and a fourth mold plate 109, in which and between these mold plates a hot runner system 110 is received. It is well known that the mold plates 104, 106, 108, and 109 are held together by fasteners (not shown) and may also include additional fastening and / or alignment components, such as guide pins, guide bushings, etc., which will be understood by those skilled in the art. Although four mold plates 104, 106, 108, and 109 are shown, the injection molding apparatus 100 may include mold plates other than the four mold plates.

[0030] The injection molding apparatus 100 includes a hot runner system 110 that distributes an inflow of molding material (not shown) to mold cavities 101s. The hot runner system 110 includes: a manifold 112; a plurality of nozzles 114, each nozzle having a corresponding heater; and a plurality of valve pins 115, which are translated between open and closed positions by an actuator 116 to control the flow rate of molding material into the mold cavities 101. For brevity, valve pins 115 and nozzles 114 are generally referred to in the singular. The manifold 112 divides the inflow of melt into a plurality of outflowing melt flows, each melt flow being delivered to a corresponding mold cavity 101 via a corresponding nozzle 114. The manifold 112 is received within a housing 118 defined by a second mold plate 106 and a third mold plate 108, and is spaced apart from the second mold plate 106 and the third mold plate 108 to form an insulating air gap between them. The manifold 112 includes a manifold inlet (in... Figure 1A manifold passage 120 extends between the manifold outlet 122 (not visible in the cross-sectional view). A nozzle 114 is received in a nozzle well 124 extending downstream from the housing 118. The nozzle 114 includes a nozzle passage 125 extending therethrough. The nozzle passage 125 is in fluid communication with the manifold passage 120 via the manifold outlet 122. At its downstream end, the nozzle passage 125 is in fluid communication with an end passage 126 of a nozzle tip 127 that delivers molding material to the mold cavity 101 via a mold gate 128.

[0031] Valve pin 115 is connected to valve pin plate 130, and valve pin plate 130 is connected to actuator 116. Actuator 116 is in the closed configuration (see...). Figure 1 and Figure 2 ) and open construction (see Figure 3 The valve pin plate 130 is located between the third mold plate 108 and the fourth mold plate 109. The valve pin plate 130 is separated from the manifold 110 by the third mold plate 108, which includes a valve pin passage 132 through which the valve pin 115 extends. Downstream of the third mold plate 108, the valve pin 114 extends through the manifold 110 and the nozzle 114 toward the mold gate 128.

[0032] During operation, as the actuator 116 moves between the closed and open configurations, the valve pin plate 130 moves accordingly, and the valve pin 115, connected to the valve pin plate 130, moves synchronously with the valve pin plate 130. When the actuator 116 is in the open configuration, the valve pin 115 is in the open position, separated from the mold gate 128s, to allow molding material to pass through the mold gate 128s into the mold cavity 101s. Conversely, when the actuator 116 is in the closed configuration, the valve pin 115 is in the closed position, thereby blocking the mold gate 128s to prevent molding material from entering the mold cavity 101s. Figure 1 In this configuration, actuator 116 is in a closed position, and valve pin plate 130 and valve pin 115 are in the closed position. As shown, actuator 116 is a dual-position, fluid-driven actuator. Alternatively (not shown), actuator 116 can be configured to synchronously move valve pin plate 130 and its coupled valve pin 115 to one or more positions other than the open and closed positions. Actuator 116 and fourth mold plate 109 can also be servo-driven actuators, such as those available from Master Molds Ltd. in Georgetown, Ontario, Canada. E-drive obtained TM .

[0033] refer to Figure 2 and Figure 3 ,in, Figure 2 yes Figure 1An enlarged view of part P1, showing the valve pin plate 130 in the closed position and the actuator 116 in the closed configuration. Figure 3 yes Figure 1 A magnified view of part P1, showing valve pin plate 130 in the open position and actuator 116 in the open configuration. Valve pin 115 is connected to valve pin plate 130 via valve pin seat 133. Valve pin seat 133 is configured to allow valve pin 115 to disengage from synchronous movement with valve pin plate 130 when valve pin plate 130 moves from the closed position to the open position. Figures 1 to 3 In the illustrated embodiment, the valve pin seat 133 includes a first coupling assembly 134 and a second coupling assembly 135. The first coupling assembly 134 is fixed to the valve pin plate 130, for example, by complementary threads, and the second coupling assembly 135 is coupled to the valve pin 115 and releasably coupled to the first coupling assembly 134 by a coupling force FC.

[0034] exist Figures 1 to 3 In the illustrated embodiment, the coupling force FC is a magnetic force achieved through a first coupling assembly 134 and a second coupling assembly 135, wherein the first coupling assembly 134 includes a magnet 136 or is magnetic, and the second coupling assembly 135 is made of or includes an ferrous material and is magnetically attracted to the first coupling assembly 134. In operation, as the valve pin plate 130 moves from the open position to the closed position, the first coupling assembly 134 pushes against the second coupling assembly 135 to move the valve pin 115 to the closed position. Conversely, as the valve pin plate 130 moves from the closed position to the open position, the magnetic attraction, the coupling force FC, pulls the second coupling assembly 135 through the first coupling assembly 134 to move the second coupling assembly 135 and the valve pin 115 coupled thereto to the open position. According to an embodiment of the invention, the injection molding apparatus includes a biasing member 138 that provides a supplementary coupling force FS to the valve pin seat 130, as will be discussed in further detail below.

[0035] refer to Figure 4 , Figure 4 This shows the absence of bias member 138. Figure 1 A magnified view of part P1. Figure 4In this configuration, valve pin 115 is in the open position, actuator 116 is in the open configuration, and valve pin seat 133 is in the disengaged configuration, wherein the second connecting assembly 135 is separated from the first connecting assembly 134. As valve pin plate 130 moves from the closed position to the open position, and the disengagement force FD experienced by valve pin 115 is greater than the connecting force FC, the second connecting assembly 135 disengages from the first connecting assembly 134. If disengagement occurs immediately when actuator 116 moves from the closed configuration to the open configuration, valve pin 115 may remain in the closed position, preventing molding material from entering the mold cavity 101s and rendering the mold cavity 101s inoperable, i.e., not producing functional molded articles. If disengagement occurs when valve pin plate 130 moves from the closed position to the open position, valve pin 115 may remain in an intermediate position between the closed and open positions, potentially hindering molding material from entering the mold cavity 101s and rendering the mold cavity 101s inoperable. The release force FD can be generated by a variety of factors, including, for example, friction or jamming between the valve pin 115 and another hot runner assembly that slides into the valve pin 115, friction between the valve pin 115 and the molding material in the nozzle channel 125, and too fast actuator speed when the valve pin plate 130 moves to the open position.

[0036] Re-reference Figure 2 and Figure 3 And refer to Figure 1 If it is determined that the injection molding apparatus 100 is operational, i.e., capable of producing molded articles except for the disengagement of valve pin 115 from valve pin plate 130, then a biasing member 138 is mounted on valve pin seat 133 to supplement the coupling force FC between the first coupling assembly 134 and the second coupling assembly 135 by pushing the second coupling assembly 135 against the first coupling assembly 135, at least when valve pin plate 130 is in the closed position. With the biasing member 138 mounted in the injection molding apparatus 100 and compressed by valve pin seat 133, as valve pin plate 130 moves from the closed position to the open position, the biasing member 138 expands and abuts against the second coupling assembly 135, which increases the supplementary coupling force SF to the coupling force FC between the first and second coupling assemblies 134, 135. The supplementary coupling force SF increases the disengagement force FD required to disengage valve pin 115 from valve pin plate 130. When valve pin plate 130 is in the closed position, the biasing member 138 is compressed to the maximum extent. In some applications where an additional connecting force SF is required throughout the entire travel distance of the valve pin plate 130, i.e. between the closed and open positions, the biasing member 138 is partially compressed by the valve pin seat 133 when the valve pin plate 130 is in the open position.

[0037] exist Figures 1 to 3In the illustrated embodiment, valve pin 115 extends through biasing member 138. Alternatively, (not shown), biasing member includes a plurality of biasing members arranged parallel to and uniformly spaced around valve pin 115.

[0038] exist Figures 1 to 3 In the illustrated embodiment, the third mold plate 108 includes a countersunk hole 139 in which a biasing member 138 is received. The countersunk hole 139 defines a step 140 on which the biasing member 138 is pressed. This is contrasted with a recess 144 in which the countersunk hole 139 is omitted and the biasing member 138 is pressed against, receiving a valve pin plate 130 (see [reference]). Figure 1 Compared to an embodiment with an injection molding device (not shown) on the bottom 142 of the injection molding unit 100, the countersunk hole 139 and step 140 reduce the stacking height of the injection molding unit 100. The countersunk hole 139 also allows the injection molding unit 100 to be provided to the user without the biasing member 138 being installed therein. In this configuration, when operating the injection molding unit 100, if it is determined that some valve pin seats 133 do not need to disengage, the biasing member 138 is installed in the countersunk hole 139 associated with the valve pin seats 133 that do not need to disengage, to add a supplementary coupling force FS to the main coupling force FC that holds the first and second coupling members 134, 135 together. If the stacking height of the injection molding unit 100 allows, the countersunk hole 138 can be omitted, such that the biasing member 138 is pressed against the bottom 142 of the recess 144.

[0039] Figure 5 This is an enlarged view of a portion of an injection molding apparatus 100a according to another embodiment of this application. Figure 5 The injection molding apparatus 100a shown in the figure is part of the same as Figure 1 Part of P2 is similar. Features and aspects of the current embodiment may be used in other embodiments. Injection molding apparatus 100a and Figures 1 to 3 The injection molding apparatus 100a differs in that it includes a sleeve 145a received in a countersunk bore 139a. The sleeve 145a surrounds a valve pin 115a, thereby forming a physical barrier between the valve pin 115a and a biasing member 138a. The downstream end of the sleeve 145a includes a flange 146a seated on a step 140a. The biasing member 138a presses against the flange 146a to secure the sleeve 145a within the valve pin passage 132a. In the event of molding material or molding material byproducts being discharged from the hot runner system 110a into the valve pin passage 132a, the sleeve 145a prevents or reduces the possibility of the biasing member 138a being compressed and losing its functional compression by the discharged molding material or molding material byproducts. Figure 5In the illustrated embodiment, the sleeve 145a and the biasing member 138a are closely sized to help the biasing member 138a be centered within the countersunk hole 139a and to limit or prevent the biasing member 138a from bending when it is compressed.

[0040] Figure 6 This is an enlarged view of a portion of the injection molding apparatus 100b according to another embodiment of this application. Figure 6 The injection molding apparatus 100b shown in the figure is part of the same as Figure 1 Part of P2 is similar. Features and aspects of the current embodiment may be used in other embodiments. Injection molding apparatus 100b and Figure 5 The difference between the injection molding apparatus 100a and the injection molding apparatus 100b is that the injection molding apparatus 100b includes a scraper 148b, which is axially fixed to the biasing member 138b and the manifold. Figure 6 Within the valve pin passage 132b (not visible in the manifold). The scraper 148b is annular and includes an inner bore 149b, which is sized to slidably receive the valve pin 115b. The peripheral surface 150b of the scraper 148b is sized to allow lateral displacement of the scraper 148b within the valve pin passage 132b, for example, when the manifold (not visible in the manifold) is in the valve pin passage 132b. Figure 6 When heated to the operating temperature (not visible in the image), scraper 148b is allowed to move laterally together with valve pin 115b. If molding material or molding material byproducts are discharged from the hot runner system 110b and move along valve pin 115b towards valve pin seat 133b, scraper 148b will separate the discharged material from valve pin 115b as valve pin 115b retracts from the closed position to the open position. Figure 6 In the illustrated embodiment, the scraper 148b is received in a countersunk hole 151b at the downstream end of the sleeve 145b and held therein by a retaining clip 152b. Alternatively (not shown), the sleeve 145b is omitted, the scraper 148b is sized to sit on the step 140b, and is fixed in a countersunk hole 139b in the third mold plate 108b by, for example, a retaining ring.

[0041] Figure 7 This is an enlarged view of a portion of an injection molding apparatus 100c according to another embodiment of this application. Figure 7 The injection molding apparatus 100c shown in the figure is part of the same as Figure 1 Part of P1 is similar. Features and aspects of the current embodiment may be used in other embodiments. Injection molding apparatus 100c and Figure 1The difference in the injection molding apparatus 100a is that the valve pin passage 132c and the biasing member 138c are sized such that the biasing member 138c extends through the valve pin passage 132c and presses against the spacer 154c, wherein the spacer 154c separates the third mold plate 108c from the manifold 110c. This configuration reduces the thickness T of the third mold plate 108c between the manifold 110c and the valve pin plate 130c.

[0042] Figure 8 and Figure 9 This is an enlarged view of a portion of an injection molding apparatus 100d according to another embodiment of this application. Figure 8 In the middle, the valve pin plate 130d is in the closed position, and the actuator 116d is in the closed configuration. Figure 9 In the middle, the valve pin plate 130d is in the open position, and the actuator 116d is in the open configuration. Figure 8 and Figure 9 The injection molding apparatus 100d shown in the figure is part of the same Figure 1 Part of P1 is similar. Features and aspects of the current embodiment may be used in other embodiments. Injection molding apparatus 100d and Figure 1 The injection molding apparatus 100a differs in that it includes another biasing member 155d, which counteracts the force generated by the biasing member 138d. The biasing member 155d is located between the valve pin plate 130d and the fourth mold plate 109d, and is compressed by the valve pin plate 130d when it is in the open position. Depending on the compressive strength of the biasing member 155d, the biasing member 155d buffers the opening speed of the valve pin plate 130d, and / or reduces the actuator closing force CF required to move the valve pin plate 130d to the closed position by supplementing the actuator closing force CF with the supplementary closing force FCS.

[0043] exist Figure 8 and Figure 9 In the illustrated embodiment, the biasing member 155d is laterally offset from the biasing member 138d, and the fourth template 109d includes a recess 156d that defines a base 157d, wherein the biasing member 155d is pressed against the base 157d when the valve pin plate 130d is in the open position.

[0044] In addition, Figure 8 and Figure 9 In the illustrated embodiment, the biasing member 155d is aligned with the recess 156d via a guide pin 158d extending from the valve pin plate 130d. In addition to aligning the biasing member 155d, the guide pin 158d also restricts or prevents the biasing member 155d from bending when it is compressed.

[0045] As disclosed herein, valve pin seat 133 is configured such that the coupling force FC is a magnetic force between the first coupling assembly 134 and the second coupling assembly 135. It should be understood that valve pin seat 133 can also be configured such that the coupling force FC is a frictional force between the first coupling assembly, which is in the form of a conical socket, and the second coupling assembly, which is in the form of a complementary conical plug. In this configuration, biasing member 138 is arranged to push the conical plug into the conical socket.

Claims

1. An injection molding apparatus, comprising: A manifold having a manifold passage extending between a manifold inlet and a manifold outlet; The nozzle has a nozzle passage extending through the nozzle and the nozzle passage is in fluid communication with the manifold passage via the manifold outlet; A valve pin plate, which is connected to an actuator, which, during operation, causes the valve pin plate to move axially between a closed position and an open position; A mold plate, spaced apart from the manifold and disposed between the manifold and the valve pin plate, the mold plate including a valve pin passage extending through the mold plate; A valve pin that extends through the valve pin passage; A valve pin seat, wherein the valve pin seat releasably connects the valve pin to the valve pin plate; and The biasing member is pressed against the mold plate by the valve pin seat when the valve pin plate is in the closed position.

2. The injection molding apparatus according to claim 1, wherein, When the valve pin plate is in the open position, the biasing member is compressed by the valve pin seat.

3. The injection molding apparatus according to claim 1, wherein, The valve pin extends through the biasing member.

4. The injection molding apparatus according to claim 3, wherein, The mold plate includes a countersunk hole that defines a step in the valve pin passage, and the biasing member is seated on the step.

5. The injection molding apparatus according to claim 1, further comprising a spacer, wherein, The mold plate is spaced apart from the manifold by the spacer, and the biasing member is pressed against the spacer when the valve pin plate is in the closed position.

6. The injection molding apparatus of claim 1, further comprising a sleeve through which the valve pin extends, the sleeve surrounding the valve pin and forming a circumferential barrier between the valve pin and the biasing member.

7. The injection molding apparatus according to claim 6, wherein, The downstream end of the sleeve includes a flange, and when the actuator is in the closed position, the biasing member is pressed against the flange.

8. The injection molding apparatus of claim 1, further comprising a scraper fixed within the valve pin passage between the biasing member and the manifold, the valve pin extending through the scraper and slidably engaging the scraper.

9. The injection molding apparatus according to claim 1, further comprising: Another mold plate, wherein the valve pin plate is arranged between the mold plate and the other mold plate; and Another biasing member presses against the other mold plate when the valve pin plate is in the open position.

10. The injection molding apparatus according to claim 9, wherein, The other mold plate includes a recess that defines a base, and when the valve pin plate is in the open position, the other biasing member is pressed against the base.

11. The injection molding apparatus according to claim 1, wherein, The valve pin seat includes a first connecting component and a second connecting component. The first connecting component is attached to the valve pin plate, and the second connecting component is fixed to the valve pin and releasably connected to the first connecting component.

12. The injection molding apparatus according to claim 11, wherein, The second coupling component is releasably coupled to the first coupling component by one of frictional force and magnetic force.

13. The injection molding apparatus according to claim 1, wherein, The biasing component is a helical spring.

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