Method for producing overmolded part in injection molding system

Abstract

A method of producing an overmolded part may include placing a laminate between a fixed part and a movable part of an injection molding apparatus including a mold cavity. The method may include moving the movable member toward the fixed member to transform the laminate into the shape of the mold cavity to form a shaped laminate. The method may include retracting the movable component to form a first injection gap having a selected thickness between a lower surface of the movable component and a top surface of the shaped laminate. The method may include injecting a top injection of a molding material into a first injection gap on a top surface of the shaped laminate to manufacture the overmolded part. The method may include opening the movable member and the fixed member by moving the movable member away from the fixed member.

Description

Technical Field

[0001] The present invention generally relates to a method for producing overmolded parts, and more particularly to a method for overmolding a polymer material on a laminate by injection molding in one step. Background Art

[0002] Resin molded products for automobiles, household appliances, building materials, etc. can be manufactured by laminating layers or by melt-bonding a thermoplastic resin outer layer to a thermoplastic resin core layer.

[0003] Japanese Patent No. 59150740, titled "Method for Manufacturing Multilayer Molded Products", discloses a molding method in which the peripheral edge of the surface material is sandwiched between the surface material fixing plate (which is movably connected to the lower female mold) and the female mold, and the core material molten resin is supplied to the upper surface of the surface material to laminate the surface material to the core material.

[0004] U.S. Patent No. 5154872, titled "Method for Producing Multilayer Molded Products", discloses a method for producing multilayer molded products, which includes supplying a surface material between a male mold and a female mold connected to a fixture.

[0005] German Patent No. 102015221006A1 discloses a method that includes introducing a semi-finished product for producing the body of a part into a forming device, where the semi-finished product is formed of a continuous fiber-reinforced thermoplastic material; processing the semi-finished product in the forming device to complete the matrix; raising the processing tool of the molding device of the body to form a gap between the processing tool and the matrix; and supplying a coating to the gap, characterized in that in the method of the invention, the coating is introduced into the gap between the processing tool and the matrix, and preferably can compensate for the surface irregularities of the matrix.

[0006] Japanese Patent No. 2001113558A discloses a co-injection molding device having a plurality of injection devices, which includes laminating, fusing, and integrating an epidermis, an intermediate material elastomer layer, and a core material layer in this order to obtain sufficient weather resistance.

[0007] WO2017 / 051383A1 discloses a method of forming a component in an injection mold, which includes: heating a molding material to a molding temperature; injecting the molding material through a gate and into a molding cavity of an injection molding device of any one of the foregoing claims; pressing a fixed half and a movable half together to form the molding cavity between a resin mold surface and an insert molding surface; moving a movable mold insert, thereby moving the insert molding surface and adjusting the shape, depth, volume of the molding cavity, or a combination including at least one of the foregoing along at least a part of the molding cavity; cooling the surface of the molding cavity with a cooling system; separating the resin mold surface and the movable mold half surface; and blanking the component from the injection molding device.

[0008] Existing solutions have different drawbacks. Summary of the Invention

[0009] In different cases where the geometry is complex and the required inserts are not flat but form a three-dimensional structure, due to inaccurate laminate positioning (which can cause the laminate to remain visible when the material flows to the wrong side of the molded article), it is not possible to effectively manufacture overmolded articles with desired tactile touch characteristics and aesthetics. The potential causes leading to inaccurate laminate positioning can be the cavity size, which leaves room for the molten resin to flow to the wrong side, and the driving force of the molten resin flowing over the heated and softened laminate, which guides the softened laminate to the wrong side.

[0010] Injection molded components with structural ribs often suffer from sink marks caused by non-uniform temperature distribution in the component. Non-uniform temperature distribution causes hot spots at the joints where the ribs are connected to the component. Due to the larger mass of material at the joints, a longer cooling time is required, which causes this part to shrink more than the surrounding parts. The presence of such sink marks deteriorates the surface of the component.

[0011] Due to the complex shape, overmolding the insert causes the material to flow towards the other side of the component, which forms an unsightly product with surface defects, and the sunken part causes pits and wrinkles.

[0012] The prior art is not suitable for solving these drawbacks, which also include producing components with complex shapes or large-area curvatures or complex components with structural ribs without compromising the aesthetics of the components.

[0013] In view of the above, the present invention provides a method for producing overmolded parts in one step, in particular a method for overmolding a polymer material on a laminate in an injection molding device that can operate independently. The present invention also relates to an overmolded part produced by the method. An object of the present invention is to provide an overmolded part that does not damage the aesthetic part and the surface properties of the laminate, while maintaining the predetermined shape and position of the laminate. Using the method disclosed in the present invention, the formation of the overmolded part can be carried out in one device, and it will result in cost and time savings, which eliminates the need for separate tools.

[0014] The present invention provides a method for producing an overmolded part having structural ribs that can be free of dimples. The present invention provides a method for producing an overmolded part using an injection molding device that includes movable mold inserts present in a movable part, and these movable mold inserts keep the laminate intact at critical locations where the laminate may deviate from the desired shape.

[0015] These and other features and characteristics are described in more detail below. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The following is a brief description of the drawings, in which like elements are numbered alike and which are presented for the purpose of illustrating the different steps of the method for producing an overmolded part and the exemplary embodiments disclosed herein, and not for the purpose of limiting them.

[0017] FIG. 1(a) is a cross-sectional view of an injection molding device in an open position.

[0018] FIG. 1(b) is a cross-sectional view of a laminate located in the injection molding device.

[0019] FIG. 1(c) is a cross-sectional view of the movable and fixed parts of the injection molding device in a closed position.

[0020] FIG. 1(d) is a cross-sectional view of an injection gap formed in the injection molding device.

[0021] FIG. 1(e) is a cross-sectional view of injecting a top charge of molding material into the injection gap formed as in FIG. 1(d).

[0022] FIG. 1(f) is a cross-sectional view of the overmolded part.

[0023] FIG. 1(g) is a cross-sectional view of a multi-layer overmolded part.

[0024] FIG. 2(a) is a cross-sectional view of an injection molding device having a movable part that includes movable mold inserts.

[0025] Figure 2(b) is a cross-sectional view of the plasticizing device of Figure 2(a), and the laminate is located therein.

[0026] Figure 2(c) is a cross-sectional view of the injection molding device of Figure 2(b), and the movable part and the fixed part are in the closed position.

[0027] Figure 2(d) is a cross-sectional view of the injection molding device of Figure 2(c), and the top injection of the molding material is injected therein.

[0028] Figure 2(e) is a cross-sectional view of the injection molding device of Figure 2(d), and the remaining movable mold inserts are retracted.

[0029] Figure 3(a) is a cross-sectional view of an injection molding device including an injection system located in a fixed part.

[0030] Figure 3(b) is a cross-sectional view of the laminate located in the device of Figure 3.

[0031] Figure 3(c) is a cross-sectional view of the device of Figure 3(b), wherein the movable part and the fixed part of the injection molding device are in the closed position.

[0032] Figure 3(d) is a cross-sectional view of the device of Figure 3(c), wherein the bottom injection of the molding material is injected into the injection system located in the fixed part.

[0033] Figure 3(e) is a cross-sectional view of the device of Figure 3(d), wherein the top injection of the molding material is injected into the device.

[0034] Figure 3(f) is a cross-sectional view of the overmolded part.

[0035] Figure 3(g) is a cross-sectional view of the multi-layer overmolded part.

[0036] Figure 4(a) is a cross-sectional view of an injection molding device including a movable part (which includes movable mold inserts).

[0037] Figure 4(b) is a cross-sectional view of the device of Figure 4(a), which includes a laminate located in the injection molding device.

[0038] Figure 4(c) is a cross-sectional view of the device of Figure 4(b), which shows the first movable mold insert of the movable part and the fixed part in the closed position.

[0039] Figure 4(d) is a cross-sectional view of the device of Figure 4(c), which shows the bottom injection of the molding material and the top injection of the molding material injected into the device.

[0040] Figure 4(e) is a cross-sectional view of Figure 4(d), which shows the retracted movable mold inserts and the top injection of the molding material injected into the injection molding device.

[0041] These drawings (also referred to herein as "figures") are only schematic representations for the convenience and ease of showing the present invention, and are not intended to indicate the relative sizes and dimensions of the device or its components and / or to define or limit the scope of the exemplary embodiments. Detailed Description

[0042] The method of the present invention will be described in detail by referring to the accompanying drawings.

[0043] Figure 1(a) is a cross-sectional view of an injection molding apparatus 10 in an open position. The injection molding apparatus 10 may have a stationary part 2 and a movable part 1. In the present invention, the injection molding apparatus 10 may include a movable part 1 and a stationary part 2 operatively connected together. In the open position, the molding cavity 3 may be located between the movable part 1 and the stationary part 2. The molding cavity 3 may have any shape, depending on the desired shape of the overmolded part.

[0044] Figure 1(b) is a cross-sectional view of the injection molding apparatus 10 in the open position, and the laminate 5 is located between the stationary part 2 and the movable part 1 of the injection molding apparatus 10. The laminate 5 may be in contact with the top surface 6 of the stationary part 2 of the injection molding apparatus 10.

[0045] The laminate may be a fiber-reinforced composite material, whereby high rigidity can be easily obtained. The laminate may comprise different fibers such as glass fibers, carbon fibers or aramid fibers or combinations thereof. Before the laminate 5 is located between the stationary part 2 and the movable part 1 of the injection molding apparatus 10, the laminate 5 may be preheated to a softening temperature, i.e., a temperature greater than or equal to the glass transition temperature of the material of the laminate 5 or at least one of the temperatures close to its melting point temperature. The laminate may be preheated to a softening temperature such that the laminate does not become too soft and lose its integrity. The thickness of the laminate may be 0.1 mm - 6 mm, preferably 0.1 mm - 5 mm, or more preferably 0.1 mm - 4 mm.

[0046] Figure 1(c) is a cross-sectional view of the movable part 1 and the stationary part 2 of the injection molding apparatus 10 of Figure 1 in a closed position. In the closed position, the movable part 1 may be lowered towards the stationary part 1 until it presses against the laminate 5 to transform it into the specified shape of the mold cavity 3 to form a shaped laminate 7. In the closed position, the lower surface 50 of the shaped laminate 7 may be in contact with the top surface 6 of the stationary part 2 of the injection molding apparatus 10.

[0047] FIG. 1(d) is a cross-sectional view of an injection gap 8 formed between a lower movable member 1 and a fixed member 2 of an injection molding apparatus 10. The movable member 1 can be retracted in a direction opposite to the fixed member 2 to form a first injection gap 8 between the top surface 60 of the formed laminate 7 and the lower surfaces 70, 201 of the movable member 1. The movable member 1 can be configured to move toward the fixed member, thereby adjusting the molding cavity shape, molding cavity depth, molding cavity volume, or a combination thereof.

[0048] FIG. 1(e) is a cross-sectional view of the injection molding apparatus 10, which includes injecting a top charge 9 of molding material into the first injection gap 8. The top charge 9 of the injection molding material can be in a molten state when injected into the first injection gap 8 of the injection molding apparatus 10 formed between the top surface 60 of the formed laminate 7 and the lower surfaces 70, 201 of the movable member 1. The top charge 9 of the molding material can be injected into the first injection gap 8 until the first injection gap 8 is filled with the top charge 9 of the molding material.

[0049] After injecting the top charge 9 of the injection molding material, the injection molding apparatus 10 can maintain the final shape of the top charge 9 of the molding material, and the mold can be cooled to solidify the overmolded part 110. Once cooling is completed within a selected time period, the overmolded part 110 can be ejected.

[0050] The steps of FIG. 1(d) can be repeated again to retract the movable member 1 in a direction opposite to the fixed member 2, thereby forming another injection gap between the top surfaces 180, 271 of the top charge of the molding material and the lower surfaces 70, 201 of the movable member 1, to further inject a top charge of the molding material or a molding material 130 different from the top charge of the molding material onto the top surfaces 180, 271 of the top charge of the molding material, thereby forming a multi-layer overmolded part 120.

[0051] After injecting the top charge of the molding material or a molding material 130 different from the top charge of the molding material onto the top surfaces 180, 271 of the top charge of the molding material, the injection molding apparatus 10 can maintain the final shape of the multi-layer overmolded part 120. The mold can be cooled to solidify the multi-layer overmolded part 120. Once cooling is completed within a selected time period, the overmolded part 120 can be ejected.

[0052] According to the number of layers of the molding material required to manufacture a multi-layer overmolding part, the movable part is retracted to create a channel for injecting new molding material onto the previously injected molding material, and then the step of injecting the molding material onto the previously injected molding material can be repeated multiple times. The multi-layer overmolding part can comprise at least 2 layers. The multi-layer overmolding part can comprise 5 layers, or preferably 4 layers, or preferably 3 layers, or more preferably 2 layers. To manufacture a multi-layer overmolding part, the top feed of the molding material or a molding material different from the top feed of the molding material can be injected onto the top surface of the top feed of the molding material.

[0053] Figure 1(f) is a cross-sectional view of the overmolding part 110. The overmolding part 110 comprises a formed laminate 7 that is bonded to a layer comprising the top feed 9 of the molding material.

[0054] Figure 1(g) is a cross-sectional view of the multi-layer overmolding part 120. The multi-layer overmolding part 120 comprises a formed laminate 7 that is bonded to a layer comprising the top feed 9 of the molding material, and the layer of the top feed 9 of the molding material is further bonded to a layer comprising a molding material 130 different from the top feed 9 of the molding material.

[0055] Figure 2(a) is a cross-sectional view of an injection molding device (20) in an open position, which is adapted to perform the injection molding method of the present invention. The injection molding device 20 comprises a fixed part 12 and a movable part 11. The injection molding device 20 comprises a movable part 11 and a fixed part 12 that are operably connected or joined together. The movable part 11 can include a movable insert 111. The movable insert can include a first movable mold insert 11(a) and a second movable insert 11(b) or more movable inserts. The movable insert 111 can be located within the movable part 11, the fixed part 12, or within both of these parts. The movable part can comprise one or more movable mold inserts, wherein the movable mold insert is configured to move towards the fixed part or away from the fixed part. The movable part or the movable mold insert is configured to move towards the fixed part so as to adjust the cavity depth, the cavity volume, or a combination thereof.

[0056] Figure 2(b) - 2(e) The injection molding device 20 is shown as having three movable mold inserts in cross-section, but the injection molding device 20 can include any number of movable mold inserts. For simplicity and ease of understanding, when referring to the movable mold insert 111 in the following description, it can refer to any one or any combination of the movable mold inserts 111.

[0057] Figure 2(b) is a cross-sectional view of the injection molding apparatus 20 in the open position, and the movable member 11 has a movable mold insert 111. In the open position, the laminate 15 can be located between the stationary member 12 and the movable member 11 of the injection molding apparatus 20. The laminate 15 can be a fiber-reinforced composite material, whereby high stiffness can be easily obtained. The laminate can comprise different fibers, such as glass fibers, carbon fibers or aramid fibers or combinations thereof. Before being placed between the stationary member 12 and the movable member 11 of the injection molding apparatus 20, the laminate 15 can be preheated to a softening temperature, i.e., a temperature greater than or equal to at least one of the glass transition temperature or the temperature close to the melting point temperature of the material of the laminate 15. The laminate can be preheated to a softening temperature such that the laminate does not become too soft so that the laminate loses its integrity. The thickness of the laminate can be 0.1 mm - 6 mm, preferably 0.1 mm - 5 mm, or more preferably 0.1 mm - 4 mm.

[0058] Figure 2(c) is a cross-sectional view of the injection molding apparatus 20 of Figure 2(b) with the movable member 11 having the movable mold insert 111 and the stationary member 12 in the closed position. In the closed position, the movable member 11 comprising the movable insert 111 can be lowered towards the stationary member 12 until it presses against the laminate 15 of Figure 2(b) to transform it into the defined shape of the mold cavity 13 to form the formed laminate 17. In the closed position, the lower surface 150 of the formed laminate 17 can contact the top surface 16 of the stationary member 12.

[0059] Figure 2(d) is a cross-sectional view of the injection molding apparatus 20 of Figure 2(a) with the movable part 11 having the movable mold inserts 111 and the fixed part 12 in a partially open position, and a first injection gap 18 is formed between the lower surface 160 of the second movable insert 11(a) and the top surface 170 of the formed laminate 17. The movable mold inserts 111 can be in mechanical communication with each other, such as hydraulic elements (e.g., pistons or plungers), pneumatic, electromechanical, mechanical mechanisms (e.g., hydraulic, pneumatic, screw), electromechanical mechanisms (e.g., induction), etc., which can move the movable mold inserts 111 toward and away from the formed laminate 17. When the injection molding apparatus 20 is in the partially open position shown in Figure 2(d), the mold cavity 13 of Figure 2(a) located between the second movable mold insert 11(b) and the formed laminate 17 is correspondingly opened to form the first injection gap 18. The first injection gap 18 can be located between the lower surface 160 of the second movable mold insert 11(b) and the top surface 170 of the formed laminate 17 and can be further defined by a first mold cavity edge 18(a) and a second mold cavity edge 18(b). When in the partially open position, as shown in Figure 2(d), the top charge 19 of the molding material can be injected through the first injection gap 18. The top charge 19 of the molding material can be injected simultaneously or sequentially from the first mold cavity edge 18(a) and the second mold cavity edge 18(b), or sequentially from the second mold cavity edge 18(b) and the first mold cavity edge 18(a).

[0060] Figure 2(e) is a cross-sectional view of the injection molding apparatus 20 of Figure 2(d) in the open position, where the first injection gap 18 is formed by retracting the first movable mold insert 11(a) of the movable part 11. In this open position, the first movable mold insert 11(a) can be retracted or moved away or withdrawn relative to the top surface 170 of the formed laminate 17 to form a fully open first injection gap 18 between the top surface 170 of the formed laminate 17 and the lower surface 160 of the movable part 11. The first movable mold insert 11(a) can be retracted to align with the second movable mold insert 11(b). The retraction of the first movable mold insert 11(a) can be achieved by using computer numerical control, which measures the mold cavity thickness and uses this thickness to retract the movable mold insert so that the mold cavity thickness remains constant during the movement of the movable mold insert. In this way, the top charge 19 of the molding material can start to spread into the remaining volume (e.g., unoccupied volume) of the first injection gap 18. The first movable mold insert 11(a) can be held in place so that the thickness of the first injection gap 18 is always maintained to manufacture the overmolded part 210.

[0061] After the top injection 19 of the injection molding material, the injection molding equipment 20 can maintain the final shape of the top injection 19 of the molding material because the mold can be cooled to solidify the overmolded part. Once the cooling is completed within a selected time period, the overmolded part can be ejected.

[0062] The steps of FIGS. 2(d) and 2(e) can be repeated to form a multi-layer overmolded part. After injecting the top injection 19 of the molding material or a molding material different from the top injection of the molding material onto the top surface of the top injection of the molding material, the injection molding equipment 20 can maintain the final shape of the multi-layer overmolded part. The mold can be cooled to solidify the multi-layer overmolded part. Once the cooling is completed within a selected time period, the multi-layer overmolded part can be ejected.

[0063] The movement of each movable mold insert can overlap with each other. For example, the first movable mold insert can still move while the subsequent movable mold insert starts to move. In other words, the movement of the movable mold inserts can be simultaneous. In addition, although the case where the first movable mold insert moves first is described herein, it should be understood that the movement of the movable mold inserts can start at any one of the inserts and is not limited to the first or second movable mold insert moving first. The top injection of the molding material can be injected into the first injection gap until the first injection gap is filled with the top injection of the molding material. After injecting the first polymer material, the injection molding equipment can maintain the final shape of the top injection of the molding material because the mold is cooled to solidify the overmolded part. Once the cooling is completed within a selected time period, the overmolded part can be ejected. The thickness of the top injection of the molding material of the overmolded part is 0.2 mm - 10 mm, 0.2 mm - 7 mm, 0.2 mm - 5 mm, 0.2 mm - 4 mm, or 0.2 mm - 3 mm.

[0064] According to the number of layers of the molding material required to manufacture the multi-layer overmolded part, the step of retracting the movable mold inserts to create a channel for injecting a new molding material onto the previously injected molding material and then injecting the molding material onto the previously injected molding material can be repeated multiple times. The multi-layer overmolded part can include at least 2 layers. The multi-layer overmolded part can preferably include 5 layers, or preferably 4 layers, or preferably 3 layers, or more preferably 2 layers. To manufacture the multi-layer overmolded part, the top injection of the molding material or a molding material different from the top injection of the molding material can be injected onto the top surface of the top injection of the molding material.

[0065] Figure 3(a) - Figure 3(e)Disclosed are different steps for producing overmolded parts including ribbed structures and cross-sectional views of injection molding equipment. Figure 3(a) is a cross-sectional view of an injection molding apparatus 30 suitable for performing the injection molding method of the present invention. The injection molding apparatus 30 may include a stationary part 22 and a movable part 21. The injection molding apparatus 30 includes a movable part 21 and a stationary part 22 operatively connected together. In addition, as shown in Figure 3(a), the stationary part 22 of the injection molding apparatus 30 may further include an injection system 24. The injection system 24 may be located on any face or any side of the stationary part.

[0066] Figure 3(b) - 3(e) The injection molding apparatus 30 is shown having three ribs 270 along the cross-section. However, the injection molding apparatus 30 may include any number of ribs 270. For simplicity and ease of understanding, when referring to the ribs 270 in the following description, it may refer to any one or any combination of the ribs 270.

[0067] Figure 3(b) provides a cross-sectional view of the injection molding apparatus of Figure 3(a). A laminate 25 may be located between the stationary part 22 and the movable part 21 of the injection molding apparatus 30. The laminate 25 may be located on the stationary part 21, i.e., the lower surface 250 of the laminate 25 may contact the top surface 26 of the stationary part. The stationary part 22 includes an injection system 24 which may be configured to inject a bottom feed 290 of the molding material of the apparatus 30. The laminate 25 may be a fiber-reinforced composite material, whereby high rigidity can be easily obtained. The laminate may include different fibers, such as glass fibers, carbon fibers, or aramid fibers or combinations thereof. Before the laminate 25 is located between the stationary part 22 and the movable part 22 of the injection molding apparatus 30, the laminate 25 may be preheated to a softening temperature, i.e., a temperature greater than or equal to at least one of the glass transition temperature or the temperature close to the melting point temperature of the material of the laminate 25. The laminate may be preheated to a softening temperature such that the laminate does not become too soft so that the laminate loses its integrity. The thickness of the laminate may be 0.1 mm - 6 mm, preferably 0.1 mm - 5 mm, or more preferably 0.1 mm - 4 mm.

[0068] Figure 3(c) is a cross-sectional view of the movable part 21 and the stationary part 21 of the injection molding apparatus 30 of Figure 3(b) when in the closed position. In the closed position, the movable part 21 may be lowered towards the stationary part 22 until it presses against the laminate 25 to transform it into a specified shape of the mold cavity 23 to form a formed laminate 27. In the closed position, the lower surface 260 of the formed laminate 27 may contact the top surface 260 of the stationary part 22, and the stationary part 22 includes an injection system 24 configured to inject a bottom feed 290 of the molding material.

[0069] Figure 3(d) is a cross-sectional view of the injection molding apparatus 30 of FIG. 3(c) in the closed position. The bottom feed 290 of the molding material can be injected through the injection system 24, which includes a void 280 in the stationary member 22, to form a formed laminate 27 that includes ribs 270. The bottom feed 290 of the molding material can be well-bonded to the lower surface 260 of the laminate 27 on the top surface 26 of the stationary member 22. The bond between the formed laminate 27 and the ribs 270 formed on the surface 260 of the formed laminate 27 can be the result of polymer interactions caused by heating of the polymeric material.

[0070] The ribs can have any structural variations, including but not limited to honeycomb, network, vertical, diagonal, etc. There is no limit to the number of ribs present, and any number of ribs can be used, which provides the desired structural integrity to the article made of the ribs.

[0071] Figure 3(e) is a cross-sectional view of the first injection gap 28 formed between the movable member 21 and the stationary member 22 of the injection molding apparatus 30. The movable member 21 can be retracted in a direction opposite to the stationary member 22 to form the first injection gap 28 between the top surfaces 180, 271 of the formed laminate 27 and the lower surface 70, 201 of the movable member 21. The top feed 29 of the molding material can be injected in a molten form into the first injection gap 28. The movable member 21 can be configured to be movable so as to adjust the molding cavity shape, molding cavity depth, molding cavity volume, or a combination thereof. The retraction of the movable member 21 can be controlled by using computer numerical control, which measures the thickness of the molding cavity 23 and uses this thickness to retract the movable member 21 so that the cavity thickness can be kept constant during the movement of the movable member 21. In this way, the top feed 29 of the molding material can start to spread into the first injection gap 28 formed between the movable member 21 and the formed laminate 27.

[0072] After injecting the top feed 29 of the molding material, the injection molding apparatus 30 can hold the final shape of the top feed 29 of the molding material and the bottom feed 290 of the molding material, since the mold can be cooled to solidify the overmolded part that includes the rib structure. Once cooling is completed within a selected time period, the overmolded part that includes the rib structure can be ejected. The thickness of the top feed of the molding material of the overmolded part is 0.2 mm - 10 mm, 0.2 mm - 7 mm, 0.2 mm - 5 mm, 0.2 mm - 4 mm, 0.2 mm - 3 mm.

[0073] The steps of FIG. 3(d) can be repeated again to retract the movable member 21 in a direction opposite to the fixed member 22 to form another injection gap between the top surface 240 of the top injection of the molding material and the lower surfaces 70, 201 of the movable member 21, so as to inject the over-injection 230 of the molding material different from the top injection 29 of the molding material onto the top surfaces 180, 271 of the top injection 230 of the molding material, thereby forming the multi-layer overmolded part 220.

[0074] After injecting the over-injection 230 of the molding material, the injection molding device 30 can maintain the final shape of the multi-layer overmolded part 220, and the device 30 can be cooled to solidify the multi-layer overmolded part 220. Once the cooling is completed within the selected time period, the multi-layer overmolded part 220 can be ejected.

[0075] According to the number of layers of the molding material required to manufacture the multi-layer overmolded part, the step of retracting the movable member to create a channel for injecting new molding material onto the previously injected molding material and then injecting the molding material onto the previously injected molding material can be repeated multiple times. The multi-layer overmolded part can include at least 2 layers. The multi-layer overmolded part can preferably include 5 layers, or preferably 4 layers, or preferably 3 layers, or more preferably 2 layers. To manufacture the multi-layer overmolded part, the top injection of the molding material or the bottom injection of the molding material or a molding material different from the top injection and the bottom injection of the molding material can be injected onto the top surface of the top injection of the molding material.

[0076] FIG. 3(f) is a cross-sectional view of the overmolded part 210. The overmolded part 210 includes the formed laminate 27 combined with the top injection 29 of the molding material. The top surfaces 180, 271 of the formed laminate 27 can be combined with the layer of the top injection 29 of the molding material. The lower surface 260 of the formed laminate can be combined with the rib 270.

[0077] FIG. 3(g) is a cross-sectional view of the multi-layer overmolded part 220. The multi-layer overmolded part 220 can include the top surfaces 180, 271 of the formed laminate 27 combined with the top injection 29 of the molding material, and the top injection 29 of the molding material can be further combined with the layer of the bottom injection 290 of the molding material or a layer of the molding material 230 different from the top injection 29 or the bottom injection 290 of the molding material. The lower surface 260 of the formed laminate can be combined with the bottom injection 290 of the molding material for injecting to manufacture the rib 270.

[0078] Figure 4(a) is a cross-sectional view of an injection molding apparatus 40 suitable for performing the injection molding method of the present invention. The injection molding apparatus 40 may have a stationary member 32 and a movable member 31. The injection molding apparatus 40 may include a movable member 31 and a stationary member 32 operatively connected together. The movable member 31 may include a movable mold insert 311. The movable mold insert 311 may be located in the movable member 31, the stationary member 32, or the movable mold insert 311 may be located in two halves. The movable insert may include a first movable mold insert 31(a) and a second movable insert 31(b) or more movable inserts. The movable member 31 may include a plurality of movable mold inserts 311, wherein the movable mold inserts may be configured to move towards or away from the stationary member. The movable member or the movable mold insert is configured to move towards the stationary member so as to adjust the cavity depth, cavity volume, or a combination thereof.

[0079] Figure 4(a) provides an illustration, wherein the stationary member 32 of the injection molding apparatus 40 may further include an injection system 34 located in the stationary member 32. The bottom injection 390 of the molding material may be injected through the injection system 34 located in the stationary member 32 of the injection molding apparatus 40. The injection system 34 located in the stationary member 32 may be located on any face or any side of the stationary member 32.

[0080] Figure 4(a) - 4(e) The molding apparatus 40 is shown as having three movable mold inserts 311 along the cross-section, but the molding apparatus 40 may include any number of movable mold inserts 311. For simplicity and ease of understanding, reference to the movable mold insert 311 in the following description may refer to any one or any combination of the movable mold inserts 311.

[0081] Figure 4(a) - 4(e) The molding apparatus 40 is shown as having three ribs 370 along the cross-section, but the molding apparatus 40 may include any number of ribs 370. For simplicity and ease of understanding, reference to the rib 370 in the following description may refer to any one or any combination of the ribs 370.

[0082] Figure 4(b) provides a cross-sectional view of the injection molding apparatus of Figure 4(a). The laminate 35 can be located between the stationary part 32 and the movable part 31 of the apparatus 40. The laminate 35 can be located on the stationary part 32, i.e., the lower surface 350 of the laminate 35 can be in contact with the top surface 36 of the stationary part 32, and the stationary part 32 includes an injection system 34 with a bottom sprue 390 configured to inject molding material. The laminate 35 can be a fiber-reinforced composite material, whereby high stiffness can be easily obtained. The laminate can include different fibers, such as glass fibers, carbon fibers, or aramid fibers, or combinations thereof. Before being located between the stationary part 32 and the movable part 31 of the injection molding apparatus 40, the laminate 35 can be preheated to a softening temperature, i.e., preheated to a temperature greater than or equal to at least one of the glass transition temperature or a temperature close to the melting point temperature of the material of the laminate 35. The laminate can be preheated to a softening temperature such that the laminate does not become too soft so that the laminate loses its integrity. The thickness of the laminate can be 0.1 mm - 6 mm, preferably 0.1 mm - 5 mm, or more preferably 0.1 mm - 4 mm.

[0083] Figure 4(c) is a cross-sectional view of the injection molding apparatus 40 of Figure 4(b) with the movable part 31 having a movable mold insert 311 and the stationary part 32 in a partially open position, wherein a first injection gap 38 is formed between the second movable insert 31(b) and the formed laminate 37 when in the open position. The movable mold inserts 311 can be in mechanical communication with each other, such as hydraulic elements (e.g., pistons or plungers), pneumatic, electromechanical, mechanical mechanisms (e.g., hydraulic, pneumatic, screw), electromechanical mechanisms (e.g., induction), etc., which can move the movable mold inserts 311 towards and away from the formed laminate 37. When the injection molding apparatus 40 is in the partially open position shown in Figure 4(c), the mold cavity 33 located between the second movable mold insert 31(b) and the formed laminate 37 can be opened accordingly to form the first injection gap 38. In the partially open position, the second movable mold insert 31(b) can retract from the formed laminate 37 to form the first injection gap 38. The first injection gap 38 located between the lower surface 301 of the second movable mold insert 31(b) and the top surface 371 of the formed laminate 37 can be further defined by a first mold cavity edge 38(a) and a second mold cavity edge 38(b).

[0084] FIG. 4(d) is a cross-sectional view of the movable part 31 and the fixed part 32 of the injection molding apparatus 40 of FIG. 4(c) with the movable mold insert 311. The top feed 39 of the molding material can be injected simultaneously from the first cavity edge 38(a) and the second cavity edge 38(b). The top feed 39 of the molding material can be injected sequentially from the second cavity edge 38(b) and the first cavity edge 38(a), or from the first cavity edge 38(a) and the second cavity edge 38(b). When injected into the first injection gap 38, the top feed 39 of the molding material can be in a molten state. The bottom feed 390 of the molding material can also be injected into the top feed 39 of the molding material simultaneously or sequentially from the second injection system 34 including the void 380 located in the fixed part 32 to form the rib 370 on the formed laminate surface 360 in contact with the top surface 36 of the fixed part 32. When injected in the injection system 34, the bottom feed 39 of the molding material can be in a molten state.

[0085] The ribs can have any structural variations, including but not limited to honeycomb, mesh, vertical, diagonal, etc. There is no limit to the number of ribs present, and any number of ribs can be provided to give the desired structural integrity to the article made of the ribs.

[0086] FIG. 4(e) is a cross-sectional view of the injection molding apparatus 40 of FIG. 4(d), which has a fully opened injection gap 38 formed by moving the first movable mold insert 31(a) of the movable part 31 of the injection molding apparatus 40. In this position, the first movable mold insert 31(a) can be retracted or removed or withdrawn from the formed laminate 37 to form a fully opened injection gap 38 between the top surface 371 of the formed laminate 37 and the lower surface 301 of the first movable mold insert 31(a). The first movable mold insert 31(a) can be moved backward to align with the second movable mold insert 31(b). The backward movement of the first movable mold insert 31(a) can be carried out by using computer numerical control, which measures the cavity thickness and uses this thickness to retract the movable mold insert so that the cavity thickness remains constant during the movement of the movable mold insert. In this way, the top feed 39 of the molding material can start to spread into the remaining volume (e.g., the unoccupied volume) of the first injection gap 38. The first movable mold insert 31(a) can be held in place so that the thickness of the first injection gap 38 can always be maintained.

[0087] According to the number of layers of the molding material required to manufacture a multi-layer overmolded part, the movable mold insert is retracted to create a channel for injecting new molding material onto the previously injected molding material, and then the step of injecting the molding material onto the previously injected molding material can be repeated multiple times. The multi-layer overmolded part can comprise at least 2 layers. The multi-layer overmolded part can preferably comprise 5 layers, or preferably 4 layers, or preferably 3 layers, or more preferably 2 layers. To manufacture a multi-layer overmolded part, the top feed of the molding material or the bottom feed of the molding material or a molding material different from the top feed or the bottom feed of the molding material can be injected onto the top surface of the top feed of the molding material.

[0088] It should be understood that in all embodiments disclosed herein, the movement of each movable mold insert can overlap with each other. For example, while the first movable mold insert is still moving, the subsequent movable mold insert can start to move simultaneously. In other words, the movement of the movable mold inserts can be simultaneous. Additionally, although the case where the first movable mold insert moves first is described herein, it should be understood that the movement of the movable mold inserts can start from any one of the inserts and is not limited to the first or second movable mold insert moving first. The top feed of the molding material can be injected in the first injection gap until the first injection gap is filled with the top feed of the molding material. After injecting the top feed of the molding material, the injection molding equipment can maintain the final shape of the top feed of the molding material as the mold is cooled to solidify the overmolded part comprising ribs. Once cooling is completed within a selected time period, the overmolded part can be ejected.

[0089] In all of the above methods, the surface of the overmolded part can comprise Class A surfaces (e.g., at least such surfaces can be smooth, glossy, and weather-resistant). As used herein, the term "Class A surface" is given its general meaning known in the art and refers to a surface that is substantially free of visible defects such as hairline cracks, pinholes, etc. For example, a Class A surface can include a glossiness greater than 100 units at 20° or 60°, a wave scan of less than 5 units (both long and short), and an image definition (DOI) greater than 95 units.

[0090] The above process sequence ( Figure 1(a) - Figure 1(e) ; Figure 2(a) - Figure 2(e) ; FIGS. 3(a)-(e) and Figure 4(a) - Figure 4(e) ) can also allow for the manufacture of large-sized (e.g., having a size greater than or equal to 1.2 m 2 , e.g., greater than or equal to 2 m 2 , e.g., greater than or equal to 3 m 2components with a projected area). The components can be blanked using a blanking rod. The thickness of the top feed of the molding material for overmolding the components is 0.2 mm - 10 mm, 0.2 mm - 7 mm, 0.2 mm - 5 mm, preferably 0.2 mm - 4 mm, or more preferably 0.2 mm - 3 mm.

[0091] As shown in the above-mentioned drawings ( Figure 1(a) - Figure 1(e) ; Figure 2(a) - Figure 2(e) ; Figures 3(a) - 3(e) and Figure 4(a) - Figure 4(e) ), the injection molding method may include cooling a part of the overmolded component until a cooling standard is met, cooling the overmolded component until the surface temperature of the component drops below the glass transition temperature of the molding material, holding the injection molding equipment in the closed position for a specified duration, holding the injection molding equipment in the closed position until the mold wall temperature reaches the required temperature, or a combination thereof.

[0092] The rapid temperature change injection molding process ("heating and cooling") can be used in any of the processes disclosed herein. Using such a rapid temperature change injection molding process can increase the melt flowability in the filling stage of the injection molding cycle and can further improve the component quality. The heating and cooling process generally includes raising the mold wall temperature above the glass transition temperature or melting temperature of the thermoplastic polymer in the filling stage and then rapidly cooling. Rapid cooling means cooling at a rate of 5 - 50 degrees per second. Using the heating and cooling process will reduce the total cycle time for manufacturing the components by 20% - 25%. The heating and cooling process will help to more easily mold larger components (e.g., greater than or equal to 1 m 2 ), and will reduce the occurrence and number of insert seams. The benefits of processing can include longer and more uniform holding pressure, even in areas far from the gate, which will reduce the injection pressure and clamping requirements; improved flow length; reduced internal component stress; and reduced or eliminated weld lines, jets, silver streaks, or dimples. Other benefits can include improved replication of fine mold surface details and improved component surface finish. The thermal cycle of the mold can eliminate downstream operations after the mold, such as sanding, annealing, priming, and painting, to hide surface defects.

[0093] The top injection of the molding material and the bottom injection of the molding material used in all of the above methods can be any material. The top injection of the molding material, the bottom injection of the molding material, the laminate, and the molding material different from the top injection of the molding material or the bottom injection of the molding material contain the same or different polymer materials. The top injection of the molding material, the bottom injection of the molding material, the laminate, and the molding material different from the top injection of the molding material or the bottom injection of the molding material can be the same or different based on the final requirements and the compatibility of the materials with each other. The top injection of the molding material or the bottom injection of the molding material can include a polymer material (e.g., including oligomers), a metal material, glass, or a combination including at least one of the foregoing.

[0094] The top injection of the molding material or the bottom injection of the molding material or the molding material different from the top injection of the molding material or the bottom injection of the molding material, or the laminate contains a polymer material selected from the following: polycarbonate, blends of polycarbonates, polystyrene, copolymers of polycarbonate and styrene, polyphenylene ether-polystyrene blends, polyimide, acrylonitrile-butadiene-styrene (ABS), alkyl poly(meth)acrylates, polyesters, polyolefins, polyamides, polyarylates, polysulfones, polyphenylene sulfides, polytetrafluoroethylene, polyethers, polyacrylic acids, polyacetals, polybenzoxazoles, polybenzothiazoles, polyoxadiazoles, poly(pyrazinoquinoxalines), poly(pyromellitimides), polyquinoxalines, polybenzimidazoles, polyhydroxyindoles, polyoxoisoindolines, polyazines, poly(pyridazines), poly(piperazines), poly(pyridines), poly(piperidines), poly(triazoles), poly(pyrazoles), poly(pyrrolidines), poly(carboranes), poly(oxabicyclononanes), poly(dibenzofurans), polystyphnates, polyacetals, polyanhydrides, polyethylenes, poly(sulfonates), polysulfides, polyureas, poly(phosphazenes), poly(silazanes), poly(siloxanes) and combinations thereof, as well as blends or recycled products thereof. The polymer material can have any microstructure including branched units.

[0095] Possible polymer resins that can be used include, but are not limited to, oligomers, polymers, ionomers, dendrimers, copolymers such as graft copolymers, block copolymers (e.g., star block copolymers, random copolymers, etc.), and combinations comprising at least one of the foregoing. Examples of such polymer resins include, but are not limited to, polycarbonates (e.g., blends of polycarbonates (e.g., polycarbonate - polybutadiene blends, copolyester polycarbonates)), polystyrenes (e.g., copolymers of polycarbonate and styrene, polyphenylene ether - polystyrene blends), polyimides (e.g., polyetherimides), acrylonitrile - styrene - butadiene (ABS), alkyl poly(meth)acrylates (e.g., poly(methyl methacrylate)), polyesters (e.g., copolyesters, polythioesters), polyolefins (e.g., polypropylene and polyethylene, high - density polyethylene, low - density polyethylene, linear low - density polyethylene), polyamides (e.g., polyamideimides), polyarylates, polysulfones (e.g., polyarylsulfones, polysulfonamides), polyphenylene sulfides, polytetrafluoroethylene, polyethers (e.g., polyether ketones, polyether ether ketones, polyether sulfones), polyacrylics, polyacetals, polybenzoxazoles (e.g., polybenzothiazine - based phenothiazines, polybenzothiazoles), polyoxadiazoles, polypyrazinyl quinoxalines, polyisophthalimides, polyquinoxalines, polybenzimidazoles, polyhydroxyindoles, polyoxoisoindolines (e.g., poly(dioxoisoindoline)), polytriazines, polypyridazines, polypiperazines, polypyridines, polypiperidines, polytriazoles, polypyrazoles, polypyrrolidines, polycarboranes, polyoxabicyclononanes, polydibenzofurans, polystyphnates, polyacetals, polyanhydrides, polyethylenes (e.g., polyethylene ethers, polyethylene sulfides, polyvinyl alcohols, polyvinyl ketones, polyvinyl halides, polyvinyl nitriles, polyvinyl esters, polyvinyl chlorides), polysulfonates, polysulfides, polyureas, polyphosphazenes, polysilazanes, polysiloxanes, and combinations comprising at least one of the foregoing.

[0096] More specifically, the polymer can include, but is not limited to, polycarbonate resins (e.g., LEXAN TM resin, commercially available from SABIC's Innovative Plastics business, e.g., LEXAN TM XHT, LEXAN TM HFD, etc.), polyphenylene ether - polystyrene blends (e.g., NORYL TM resin, commercially available from SABIC's Innovative Plastics business), polyetherimide resins (e.g., ULTEM TM resin, commercially available from SABIC's Innovative Plastics business), polybutylene terephthalate - polycarbonate blends (e.g., XENOY TM resin, commercially available from SABIC's Innovative Plastics business), copolyester carbonate resins (e.g., LEXAN TMSLX or LEXAN TM FST resin, commercially available from SABIC's Innovative Plastics business), acrylonitrile butadiene styrene resin (such as CYCOLOY TM resin, commercially available from SABIC's Innovative Plastics business), polyetherimide / siloxane resin (such as SILTEM TM , commercially available from SABIC's Innovative Plastics business), polypropylene resin, such as long glass fiber filled polypropylene resin (such as STAMAX TM resin, commercially available from SABIC's Innovative Plastics business), and combinations comprising at least one of the foregoing resins.

[0097] The polymeric material may include additives typically incorporated into polymer compositions of this type, provided that the additives are selected so as not to have a significant adverse effect on the desired properties of the injection molded part. Exemplary additives include impact modifiers, fillers, reinforcing agents, antioxidants, heat stabilizers, light stabilizers, ultraviolet (UV) light stabilizers, plasticizers, lubricants, mold release agents, antistatic agents, colorants (such as carbon black and organic dyes), surface effect additives, anti-ozonants, heat stabilizers, anti-corrosion additives, flow promoters, pigments, dye radiation stabilizers (such as infrared absorbers), flame retardants, and anti-drip agents. Combinations of additives may be used, such as a combination of heat stabilizer, mold release agent, and UV light stabilizer. Generally, the additives are used in amounts that are typically known to be effective. The total amount of additives (other than any impact modifier, filler, or reinforcing agent) is typically 0.001 wt% - 5 wt% based on the total weight of the polymeric material composition. The molding material may include reinforcing materials such as glass, carbon, basalt, aramid, or combinations comprising at least one of the foregoing. The reinforcing materials may include chopped, short chopped, strand fibers, or combinations comprising at least one of the foregoing. For example, the reinforcing materials may include chopped glass fibers, rovings, or combinations comprising at least one of the foregoing.

[0098] As used herein, the term "vehicle" or "vehicular" or other similar terms generally include motor vehicles such as passenger vehicles including sport utility vehicles (SUVs), buses, trucks, various commercial vehicles, vessels including various boats and ships, aircraft, etc., and include hybrid vehicles, electric vehicles, plug-in hybrid vehicles, hydrogen-powered vehicles and other alternative fuel vehicles (e.g., fuels derived from resources other than petroleum). As described herein, a hybrid vehicle is a vehicle having two or more power sources, such as a vehicle having both gasoline power and electric power.

[0099] The terms "a" and "an" are defined as one or more, unless the present invention clearly requires otherwise. For example, "an element" has the same meaning as "at least one element" unless the context clearly indicates otherwise. The term "combination" includes blends, mixtures, alloys, reaction products, etc. In addition, "at least one" means that the list individually includes each element, as well as combinations of two or more elements of the list, and combinations of at least one element of the list with similar elements not mentioned. "Or" means "and / or". As used herein, the suffix "(s)" is intended to include both the singular and plural of the term it modifies, thereby including one or more of that term (e.g., membranes(s) includes one or more membranes).

Claims

1. A method of manufacturing an overmolded part using an injection molding apparatus that includes operatively connected movable and stationary parts, the method comprising: a) preheating a laminate to a softening temperature; b) placing the laminate between a mold cavity of the stationary part and the movable part; c) forming the laminate by moving the movable part toward the stationary part, wherein the laminate is formed into a shape defined by the mold cavity to form a formed laminate, and a lower surface of the formed laminate contacts a top surface of the stationary part; d) retracting the movable part and forming a first injection gap of a selected thickness between a lower surface of the movable part and a top surface of the formed laminate; e) injecting a top charge of molding material into the first injection gap on the top surface of the formed laminate and forming the overmolded part; f) using a cooling system to cool the overmolded part; g) opening the movable part and the stationary part by moving the movable part away from the overmolded part; and h) ejecting the overmolded part from the injection molding apparatus.

2. The method according to claim 1, wherein a gap is defined between the formed laminate and the stationary part, and the method includes injecting a bottom charge of molding material into the gap and forming a ribbed structure on a lower surface of the formed laminate.

3. The method according to any one of claims 1-2, comprising reacting the bottom charge of molding material with the formed laminate to form a polymer bond between the bottom charge of molding material and the formed laminate.

4. The method according to any one of claims 1-3, comprising injecting the bottom charge of molding material simultaneously or sequentially with the injection of the top charge of molding material to form the overmolded part that includes the ribbed structure.

5. The method according to any one of claims 1-4, wherein after step e) and before step f), the method includes retracting the movable part to create another injection gap of a selected thickness to inject an overcharge of molding material onto a top surface of the top charge of molding material to form a multi-layer overmolded part.

6. The method according to any one of claims 1-5, wherein injecting the top charge, the bottom charge, and the overcharge includes injecting different polymers.

7. The method according to any one of claims 1-5, wherein injecting two of the top charge, the bottom charge, and the overcharge includes injecting the same polymer.

8. The method according to any one of claims 1-7, wherein the movable part includes one or more movable mold inserts, and the method includes moving the one or more movable mold inserts toward or away from the stationary part to form one or more of the formed laminate, the top charge of molding material, and the bottom charge of molding material.

9. The method according to any one of claims 1-8, wherein the movable mold inserts are configured to move toward or away from the stationary part simultaneously or sequentially with each other.

10. The method according to any one of claims 1-9, wherein the movable member or the movable mold insert is configured to move towards the fixed member to adjust the cavity depth, cavity volume or a combination thereof.

11. A overmolded part formed by the method according to any one of claims 1-10.

12. The overmolded component according to claim 11, wherein the overmolded component comprises: An overmolded part comprising a ribbed structure, or a multi-layer overmolded part, or a multi-layer overmolded part comprising a ribbed structure.

13. The overmolded part according to any one of claims 11-12, wherein the top feed of the molding material comprises a polymeric material selected from the following: polycarbonate, blends of polycarbonates, polystyrene, copolymers of polycarbonate and styrene, polyphenylene ether-polystyrene blends, polyimides, acrylonitrile-butadiene-styrene (ABS), alkyl polyacrylates, polyesters, polyolefins, polyamides, polyarylate, polysulfone, polyphenylene sulfide, polytetrafluoroethylene, polyethers, polyacrylics, polyacetals, polybenzoxazoles, polybenzothiazoles, polyoxadiazoles, pyrazinoquinoxalines, pyromellitimides, quinoxalines, polybenzimidazoles, polyhydroxyindoles, oxoisoindolines, triazines, pyridazines, piperazines, pyridines, piperidines, triazoles, pyrazoles, pyrrolidines, polycarboranes, oxabicyclononanes, dibenzofurans, phthalides, polyacetals, polyanhydrides, polyethylenes, polysulfonates, polysulfides, polyureas, polyphosphazenes, polysilazanes, polysiloxanes and combinations thereof, as well as blends or recycled products thereof.

14. The overmolded part according to any one of claims 12-13, wherein the laminate comprises a fiber-reinforced composite material.

15. The overmolded part according to any one of claims 13-14, wherein the thickness of the laminate is 0.1 mm - 6 mm, preferably 0.1 mm - 5 mm, or more preferably 0.1 mm - 4 mm.

Images