Device and method for producing at least partially fiber-reinforced injection-molded parts

Abstract

The invention relates to a device for producing at least partially fiber-reinforced injection-molded parts, comprising an injection-mold half, a receiving chamber which is configured to be partially open to a cavity portion of the injection-mold half, a supply channel which opens into the receiving chamber and through which the receiving chamber is communicatively connected to the surroundings of the injection-mold half, a supply device which supplies a strip portion of a fiber-reinforced plastic strip into the receiving chamber through the supply channel, first and second clamping devices which are respectively arranged in an initial region and an end region of the receiving chamber, through which clamping devices the strip portion supplied into the receiving chamber can be clamped, and first and second cutting devices which are respectively arranged in the initial region and the end region, the cutting devices being arranged between the clamping devices and through which cutting devices an intermediate portion of the strip portion located between the clamping devices can be separated from the remaining portion.

Description

Technical Field

[0001] This invention relates to an apparatus for producing injection-molded parts (particularly vehicle parts) that are at least partially fiber-reinforced, the apparatus comprising at least one injection mold half. The invention further relates to a method for producing injection-molded parts (particularly vehicle parts) that are at least partially fiber-reinforced using at least a two-piece injection mold. Background Technology

[0002] Injection-molded parts have wide applications in various technical fields. For example, they are used in vehicle construction because these parts are typically lighter than their corresponding metal counterparts. However, it may be necessary to reinforce injection-molded parts so that they can withstand mechanical loads during their intended use. For this purpose, it is known to produce injection-molded parts from injection molding compounds containing reinforcing fibers. It is also known to locally reinforce injection-molded parts using reinforcing elements, such as those made of fiber composite materials themselves. These reinforcing elements can be configured, for example, as fiber-reinforced plastic strips. Applications are known where this type of reinforcing element is overmolded or at least partially overmolded using injection molding compounds during the production of the injection-molded part.

[0003] When using reinforcing elements in the form of fiber-reinforced plastic strips (also known as tapes) in mass production applications, the biggest challenge arises in the production process of injection-molded parts. Arranging the strip in the injection mold can be extremely time-consuming. A robot or worker must arrange the thin strip in the mold before the injection molding process begins. This results in an inefficient production process (especially due to manual process actions) and the risk of not achieving the required positioning tolerances. Using robots instead of workers is more efficient in terms of time and accuracy, but it is more expensive and requires more space.

[0004] WO 2014 / 076061 A1 discloses a mold tool for injection molding an injection-molded part with the aid of at least one fiberless, foamed, or short-fiber-reinforced or long-fiber-reinforced plastic. The mold tool has at least two mold tool components that are movable relative to each other from a closed position of a molding cavity defining the injection-molded part to an open position for removing the injection-molded part. A negative profile of the injection-molded part is formed on the boundary surface of the mold cavity in the closed position. A molding compound container is also provided, movable in the direction of the mold cavity from the closed positions of the at least two mold tool components, and the molding compound container has a receiving surface facing the mold cavity, the mold cavity forming a notch for receiving continuous fiber-reinforced thermoplastic material in a first position of the molding compound container, and forming a portion of the boundary surface of the mold cavity in a second position of the molding compound container. The molding compound container is independently heatable from the at least two mold components.

[0005] DE 42 27 729 A1 discloses an injection molding process for producing plastic molded parts, wherein a stamped part, for example, made of metal partially overmolded with plastic, is introduced into an injection mold. To produce the stamping, a strip of material is supplied through the injection mold. The stamping operation in the injection mold is achieved by a stamping punch disposed therein. Using this stamping punch, the stamped part is held in the correct position within the hollow mold.

[0006] US 2005 / 0258559 A1 discloses a thermoforming process and an apparatus for an injection molding machine that simultaneously performs various functions such as forming, cutting, and shaping of deep-drawn injection molded parts. The thermoforming apparatus has a forming tool with a forming assembly on one side and a heating assembly for thermoforming an imprinted substrate on the opposite side. The forming assembly includes a forming die connected to a vacuum source and housed in a pressurized container. The heating assembly includes a heating element for rapidly turning heating of the substrate on and off, a temperature sensor for continuously monitoring the substrate temperature during heating, a pressurized container coupled to a pressure source, and a cooling container. The forming assembly and the heating assembly are combined to join the substrates between them.

[0007] US 8,128,358 B2 discloses an engine cooling fan shroud structure for a vehicle. The structure has a housing defining a frame. The frame has a defined wall thickness and defines an opening designed and configured to allow air to pass through a skirt. The housing has an engine mounting structure supported within the opening and designed and configured to mount a fan motor thereto. The frame defines channels to reduce the amount of material in the housing. A layered material has a wall thickness substantially less than the defined wall thickness and covers the channels so that air can primarily flow through the opening.

[0008] US 6,207,090 B1 discloses a method for producing a film-covered article. A movable press having first and second mold surfaces moves to an open position. The first mold surface has a sealing surface, and the second mold surface has a cutting surface. A thin, flexible film having a waste portion is disposed between the first and second mold surfaces. The waste portion is positioned between the sealing and cutting surfaces and acts as a seal between the mold halves. The press moves to a closed position. The cutting surface contacts the film and partially cuts the waste portion along the periphery of the film. The waste portion remains between the cutting surface and the sealing surface and seals the space between the first and second mold surfaces.

[0009] The publication available for download at http: / / www.cs.odu.edu / ~mln / ltrs-pdfs / NASA-97-iccm-njj.pdf discloses the automated production of high-performance composites. Summary of the Invention

[0010] The object of this invention is to optimize the production of injection-molded parts that are at least partially fiber-reinforced, particularly in terms of reducing their production costs.

[0011] According to the present invention, this objective is achieved by a device having the features of claim 1. The device comprises:

[0012] At least one receiving chamber is disposed on the injection mold half and configured to partially open to the cavity portion of the injection mold half;

[0013] At least one supply channel is provided on the injection mold half and leads to a receiving chamber, and through the supply channel, the receiving chamber is communicatively connected to the periphery of the injection mold half;

[0014] At least one supply device for supplying a portion of the fiber-reinforced plastic tape into a receiving chamber from the outside of the injection mold half via a supply channel;

[0015] At least one first clamping device is disposed in the initial region of the receiving chamber, which, viewed longitudinally, is positioned closer to the supply channel.

[0016] At least one second clamping device is disposed in the end region of the receiving chamber, which, viewed longitudinally, is positioned further away from the initial region from the supply channel.

[0017] The belt portion supplied to the receiving chamber can be clamped in certain areas using a clamping device; and

[0018] At least one first cutting device and at least one second cutting device, the first cutting device being disposed in the initial region and the second cutting device being disposed in the end region, the cutting devices being disposed in front of and behind the clamping devices and, through the cutting devices, the middle portion of the belt portion located between the clamping devices can be separated from the rest of the belt portion.

[0019] It should be noted that the features and measures individually referenced in the following description can be combined with each other in any technically reasonable manner, and can illustrate other embodiments of the invention. Furthermore, this description is particularly characterized and illustrated in conjunction with the accompanying drawings.

[0020] According to the present invention, the middle portion of the fiber-reinforced plastic tape (which forms part of the injection-molded component) is automatically and precisely supplied to a receiving chamber on the injection mold half by a supply device before injection molding. Therefore, manual operation of the plastic tape is eliminated, which improves the accuracy, speed, and reproducibility of the positioning of the middle portion in the receiving chamber.

[0021] After the belt portion is automatically fed into the receiving chamber by the supply device, the belt portion is clamped in a given end region relative to the receiving chamber by a clamping device and thus held in a fixed position. Furthermore, the clamping of the belt portion ensures that the closed injection mold is sealed, including in the region of the injection mold half according to the invention, so that subsequent injection molding can be performed. After the belt portion is clamped, the injection mold can be closed and injection molding can begin.

[0022] Before injection molding, a cutting device can separate the middle section from the belt section. After injection molding, the clamping device can be opened or the clamps on the remaining ends of the belt section can be released, allowing the injection-molded part with the middle section to be removed from the open injection mold without delay. Once the injection-molded part has been removed from the open injection mold, another production process can begin, which starts again by automatically feeding another section of the fiber-reinforced plastic belt into the receiving chamber.

[0023] According to the present invention, a supply device, a clamping device, and a cutting device are combined with an injection mold half to form a sub-assembly, wherein the supply channel, receiving chamber, clamping device, and cutting device can be structurally integrated into the injection mold half. This sub-assembly can be used in new injection molding machines and can also be used in upgrades of existing injection molding machines. Therefore, no additional machines or robots are required, and no additional manual operation steps are needed to introduce fiber-reinforced elements into the injection mold half.

[0024] Fiber-reinforced plastic tapes can be configured as flat tapes having reinforcing fibers oriented unidirectionally, bidirectionally, or multidirectionally in the longitudinal direction of the tape. The plastic tape can consist of two or more layers with different fiber orientations. The plastic tape can have a polymer material in which the reinforcing fibers are at least partially embedded. The polymer material can be similar to or the same as the plastic component of the injection molding compound, particularly in terms of its melt temperature, so that the polymer material can be integrally bonded to the plastic component of the injection molding compound during injection molding. Therefore, separation of the middle portion of the tape from the rest of the injection-molded part can be reliably prevented. For example, the reinforcing fibers of the plastic tape can be glass fibers, carbon fibers, aramid fibers, or some other artificial or natural fibers.

[0025] The receiving chamber, for example, has an elongated shape in the longitudinal direction of the strip and is arranged on the injection mold half in such a way that it is partially open to the cavity portion of the injection mold half, so that the middle portion of the strip can be arranged at the desired position of the injection molded part. The receiving chamber may be, for example, a cuboid configuration, and partially or completely receives the clamping and cutting devices.

[0026] The supply channel, located on the injection mold half and leading to the receiving chamber, is preferably adapted to the cross-sectional surface of the plastic strip or accordingly configured to be flat, so as to securely supply the plastic strip or its end strip portion to the receiving chamber without dislocation.

[0027] The supply device may have a replenishable storage unit for storing fiber-reinforced plastic strip, enabling the continuous supply of desired strip portions to the receiving chamber during the continuous production of identical injection-molded parts. The supply device further includes at least one electrically controllable drive mechanism, by which the plastic strip can be moved segmentally from the storage unit to the receiving chamber. The storage unit or supply device may be designed to signal when the amount of plastic strip still available in the storage unit drops below a given limit.

[0028] Each clamping device may have at least one clamping element by which a portion of the belt supplied to the receiving chamber can be pressed against and thus clamped against another part of the clamping device or the inner wall of the receiving chamber. Each clamping device may further have an electrically controllable driver for driving the respective clamping element. Alternatively, the clamping elements of the clamping devices may be actuated by a common driver.

[0029] Each cutting device may have at least one cutting element, such as a blade, which can be used to separate portions of the belt supplied to the receiving chamber. Each cutting device may further have an electrically controllable driver for driving the respective cutting element. Alternatively, the cutting elements of the cutting devices may be actuated by a common driver. The cutting devices are positioned in front of and behind the clamping device relative to the longitudinal direction of the belt.

[0030] The clamping and cutting devices in the initial area of ​​the receiving chamber can be implemented using a single clamping and cutting device. The clamping and cutting devices in the end area of ​​the receiving chamber can also be implemented using a single clamping and cutting device. The corresponding clamping elements of the respective clamping and cutting devices can also be used as cutting elements of the clamping and cutting devices. Alternatively, the clamping elements and cutting elements of the respective clamping and cutting devices can be separate components.

[0031] The apparatus according to the invention can be used particularly for producing at least partially fiber-reinforced injection-molded parts in the form of vehicle components. For this purpose, the apparatus can have an additional injection mold half, conventionally configured, and which can be connected to the injection mold according to the invention for the purpose of closing the injection mold. Alternatively, two injection mold halves can be designed according to the invention. In the context of the invention, the term "injection mold half" should not be construed as meaning that the injection mold half actually precisely or approximately represents a physical half of the injection mold. Rather, the injection mold half can be significantly different in size from the precise physical half of the injection mold.

[0032] According to an advantageous embodiment, the supply device has at least one mounting member disposed on the exterior of the injection mold half and at least one detachable plastic strip roll interchangeably disposed on the mounting member. The plastic strip roll serves as a storage unit for the plastic strip. The plastic strip roll is disposed on the mounting member by a portion of the mounting member supplied through a central axial opening in the plastic strip. If a new plastic strip roll is disposed on the mounting member, the free portion of the plastic strip can first be manually supplied into the supply channel. This step is only required when a new plastic strip roll is disposed on the mounting member. Thereafter, the strip portion can be continuously and automatically supplied into the receiving chamber.

[0033] According to another advantageous embodiment, the supply device has at least one electrically controllable actuator for unwinding the plastic strip roll. To control this actuator, separately controlled electronics of the injection molding machine or appropriately programmed electronics can be used. The actuator is preferably an electric motor, by which the plastic strip roll can be rotated about its longitudinal central axis.

[0034] The aforementioned objective is further achieved by a method having the features of claim 4, according to which: before the injection molding plastic is injected into the cavity of a closed injection mold, a portion of a fiber-reinforced plastic tape is automatically supplied from outside the injection mold to a receiving chamber on a half of the injection mold, wherein the receiving chamber is configured to be partially open to the cavity portion of the injection mold half; the portion of tape supplied to the receiving chamber is automatically clamped at at least two clamping points spaced apart in the longitudinal direction of the portion of tape; and during the injection molding plastic is injected into the closed injection mold, the middle portion of the portion of tape located between the clamping points is automatically separated from the remainder of the portion of tape.

[0035] The aforementioned advantages of the device are also relevant to the method. In particular, the method can be implemented using a device according to one of the above embodiments or a combination of at least two of these embodiments.

[0036] Materials containing or without reinforcing fibers, or containing or without any other filler materials (such as talc), can be used as injection molding compounds. Examples of materials that can be used include polypropylene, polyamide, polyoxymethylene, polycarbonate, or acrylonitrile-butadiene-styrene copolymer. For fiber reinforcement, short or long fibers can be used. For example, glass fiber, carbon fiber, aramid fiber, or other artificial or natural fibers can be used for fiber reinforcement. Furthermore, injection molding compounds can be foamed using physical or chemical foaming processes to reduce the weight of the injection-molded parts.

[0037] According to an advantageous embodiment, the plastic strip for supplying to the receiving chamber is automatically unwound from a plastic strip roll disposed outside the injection mold. Therefore, this embodiment should be associated with the aforementioned advantages of corresponding embodiments of the apparatus. Attached Figure Description

[0038] Other advantageous embodiments of the invention are disclosed in the description of the dependent claims and the following drawings, wherein...

[0039] Figure 1 A schematic diagram illustrating an embodiment of the device according to the present invention is shown;

[0040] Figure 2 It shows Figure 1 A schematic cross-sectional view of the device shown; and

[0041] Figure 3 A flowchart illustrating an illustrative embodiment of the method according to the present invention is shown. Detailed Implementation

[0042] In different accompanying drawings, the same parts are always given the same reference numerals, and thus they are usually described only once.

[0043] Figure 1 A schematic diagram of an illustrative embodiment of an apparatus 1 according to the invention for producing at least partially fiber-reinforced injection-molded parts (not shown) is shown. The apparatus 1 has at least one injection mold half 2.

[0044] The device 1 has a receiving chamber 4, which is disposed on the injection mold half 2 and configured to partially open to the cavity portion 3 of the injection mold half 2. Figure 1 The open side of the receiving chamber 4 is shown in the figure. The receiving chamber 4 is, for example, configured as a cuboid and extends within the longitudinal range shown in the injection mold half 2.

[0045] The device 1 further has a supply channel ( Figure 2(Not shown in the image) The supply channel is provided on the injection mold half 2 and leads to the receiving chamber 4, and the receiving chamber 4 is connected in communication with the periphery of the injection mold half 2 through the supply channel.

[0046] Furthermore, the device 1 includes a supply device 5 for supplying a portion 6 of the fiber-reinforced plastic tape 7 from the outside of the injection mold half 2 to the receiving chamber 4 via a supply channel. The supply device 5 has a mounting member 8 disposed on the outside of the injection mold half 2 and an unwrapable plastic tape roll 9 interchangeably disposed on the mounting member 8. Additionally, the supply device 5 includes an electrically controlled actuator (not shown) for unwrapping the plastic tape roll 9. Figure 1 In the process, a portion of the plastic belt 7 is unwound from the plastic belt roll 9 so that the belt portion 6 is supplied to the receiving chamber 4.

[0047] The device 1 has a first clamping device 12 and a second clamping device 13. The first clamping device 12 is disposed in the initial region of the receiving chamber 4, which, viewed longitudinally, is positioned closer to the supply channel of the supply device 5. Figure 2 The second clamping device 13 is located in the end region of the receiving chamber 4, which is set further away from the supply channel relative to the initial region. The belt portion 6 supplied to the receiving chamber 4 can be clamped in certain areas by means of the clamping device.

[0048] Furthermore, the device 1 has a first cutting device 10 disposed in the initial region and a second cutting device 11 disposed in the end region. The cutting devices are respectively disposed in front of and behind the clamping devices 12 and 13, and the middle portion 14 of the belt portion 6 located between the clamping devices can be separated from the rest of the belt portion 6 by means of the cutting devices. The clamping device 12 and the cutting device 10 can be combined with each other to form a single clamping and cutting device (not shown). The clamping device 13 and the cutting device 11 can be combined with each other to form a single clamping and cutting device (not shown).

[0049] Figure 2 It shows Figure 1 A schematic cross-sectional view of the device 1 shown. Specifically, a supply channel 15 is shown disposed on the injection mold half 2, through which the plastic strip 7 extends, and the supply channel leads to the receiving chamber 4. The supply channel 15 is positioned at an angle relative to the horizontal plane, and... Figure 2 It extends at a certain angle from top to bottom in the drawing plane.

[0050] Figure 3 A flowchart illustrating an illustrative embodiment of a method according to the invention for producing at least partially fiber-reinforced injection-molded parts using at least a two-piece injection mold is shown.

[0051] In method step 100, before the injection molding plastic is injected into the cavity of the closed injection mold, a portion of the fiber-reinforced plastic tape is automatically supplied from the outside of the open injection mold to a receiving chamber on the mold half, wherein the receiving chamber is configured to be partially open to the cavity portion of the mold half. Here, the plastic tape can be automatically unwound from a plastic tape roll disposed outside the injection mold for supply to the receiving chamber.

[0052] In method step 200, the belt portion supplied to the receiving chamber is automatically clamped at at least two clamping points, which are spaced apart in the longitudinal direction of the belt portion.

[0053] In method step 300, the injection mold is first closed, and thereafter, before the injection molding plastic is injected into the closed injection mold, the middle portion of the belt portion located between the clamping points is automatically separated from the rest of the belt portion.

[0054] List of reference numerals

[0055] 1 device

[0056] 2 Injection mold half

[0057] 3. Hollow section

[0058] 4 Receiving Room

[0059] 5. Supply device

[0060] 6 with part

[0061] 7 Plastic belts

[0062] 8 Installation components

[0063] 9 Plastic tape rolls

[0064] 10 Cutting device

[0065] 11 Cutting device

[0066] 12 Clamping device

[0067] 13 Clamping device

[0068] 14. Middle section

[0069] 15 Supply Channels

[0070] 100 Methods and Procedures (Supply)

[0071] 200 Method and Steps (Clamping)

[0072] 300 Methods and Steps (Separation)

Claims

1. An apparatus (1) for producing at least partially fiber-reinforced injection-molded parts, said injection-molded parts being vehicle parts, said apparatus (1) comprising at least one injection mold half (2). Its features are, The device (1) comprises: - At least one receiving chamber (4) is disposed on the injection mold half (2) and configured to partially open to the cavity portion (3) of the injection mold half (2). - At least one supply channel (15) is provided on the injection mold half (2) and leads to the receiving chamber (4), and the receiving chamber (4) is communicatively connected to the periphery of the injection mold half (2) through the supply channel (15). - At least one supply device (5) for supplying the belt portion (6) of the fiber-reinforced plastic belt (7) from the outside of the injection mold half (2) into the receiving chamber (4) through the supply channel (15). - At least one first clamping device (12) and at least one second clamping device (13), the first clamping device (12) being disposed in the initial region of the receiving chamber (4), the initial region being disposed closer to the supply channel (15), and the second clamping device (13) being disposed in the end region of the receiving chamber (4), the end region being disposed further away from the supply channel (15), wherein the belt portion (6) supplied to the receiving chamber (4) can be clamped in certain regions by means of the clamping devices, and At least one first cutting device (10) and at least one second cutting device (11), the first cutting device (10) being disposed in the initial region and the second cutting device (11) being disposed in the end region, the cutting devices being disposed in front of and behind the clamping devices (12, 13) respectively, and through the cutting devices, the middle portion (14) of the belt portion (6) located between the clamping devices can be separated from the rest of the belt portion (6).

2. The apparatus (1) as described in claim 1. Its features are, The supply device (5) has at least one mounting member (8) disposed outside the injection mold half (2) and at least one detachable plastic strip roll (9) interchangeably disposed on the mounting member (8).

3. The apparatus (1) as described in claim 2. Its features are, The supply device (5) has at least one electrically controllable driver for unwinding the plastic tape roll (9).

4. A method for producing at least partially fiber-reinforced injection-molded parts using at least a two-piece injection mold, said injection-molded parts being vehicle parts. Its features are, Before the injection molding plastic is injected into the cavity of the closed injection mold, a portion (6) of a fiber-reinforced plastic strip (7) is automatically supplied from outside the injection mold to a receiving chamber (4) on the injection mold half (2), wherein the receiving chamber (4) is configured to partially open to the cavity portion (3) of the injection mold half (2). - The belt portion (6) supplied to the receiving chamber (4) is automatically clamped at at least two clamping points, the clamping points being spaced apart in the longitudinal direction of the belt portion (6), and - During the injection molding of the injection molding compound into the closed injection mold, the middle portion (14) of the belt portion (6) located between the clamping points automatically separates from the rest of the belt portion (6).

5. The method as described in claim 4, Its features are, The plastic strip (7) used to supply the receiving chamber (4) is automatically unwound from the plastic strip roll (9) located outside the injection mold.

Images