INJECTION MOLD FOR PRODUCING INJECTION-MOLDED COMPONENTS, AND METHOD FOR PRODUCING INJECTION-MOLDED COMPONENTS

Abstract

An injection mold includes a first mold half with a first mold surface and a second mold half with a second mold surface. The first and second mold surfaces together delimit a cavity when the injection mold is closed. An electrically conductive reinforcing element is arranged on at least one of the first and second mold surfaces and is configured for an electrical voltage to be applied such that the electrically conductive reinforcing element increases in temperature and a viscosity of an injection-molding compound flowing past the electrically conductive reinforcing element decreases. A method for producing injection-mold components using the injection mold includes applying an electrical voltage to the electrically conductive reinforcing element and thereby increasing its temperature such that the viscosity of the injection-molding compound flowing past the electrically conductive reinforcing element decreases as it flows and fills the cavity.

Claims

1. An injection mold for producing injection-molded components, the injection mold comprising: a first mold half with a first mold surface and a second mold half with a second mold surface, wherein the first mold surface and the second mold surface together delimit a cavity when the injection mold is closed; and at least one electrically conductive reinforcing element arranged on at least one of the first mold surface and the second mold surface, wherein the at least one electrically conductive reinforcing element is configured to receive an electrical voltage during injection molding such that the at least one electrically conductive reinforcing element increases in temperature.

2. The injection mold according to claim 1, wherein the at least one conductive reinforcing element is a fiber-reinforced tape comprising a plastic matrix and fibers embedded in the plastic matrix.

3. The injection mold according to claim 2, wherein the fibers are selected from the group consisting of carbon fibers, metal fibers, glass fibers, plastic fibers, and combinations thereof.

4. The injection mold according to claim 2, wherein the fibers are electrically conductive.

5. The injection mold according to claim 2, wherein the fiber-reinforced tape comprises electrically conductive fillers.

6. The injection mold according to claim 1, wherein the least one electrically conductive reinforcing element comprises unidirectionally oriented continuous fibers.

7. The injection mold according to claim 1, wherein the at least one electrically conductive reinforcing element is connected to at least one of the first mold surface and the second mold surface with an adhesive bond.

8. The injection mold according to claim 1, wherein the least one electrically conductive reinforcing element arranged on at least one of the first mold surface and the second mold surface is a fiber-reinforced tape arranged on at least one of the first mold surface and the second mold surface with a laser-assisted tape-laying process.

9. The injection mold according to claim 1, wherein the least one electrically conductive reinforcing element is connected to an electrical voltage source configured to apply the electrical voltage to the least one electrically conductive reinforcing element.

10. The injection mold according to claim 1, wherein the first mold half and the second mold half are printing products of a 3D printer.

11. An injection mold for producing injection-molded components, the injection mold comprising: a first mold half with a first mold surface and a second mold half with a second mold surface, wherein the first mold surface and the second mold surface together delimit a cavity when the injection mold is closed; and an electrically conductive fiber-reinforced tape arranged on at least one of the first mold surface and the second mold surface, wherein the electrically conductive fiber-reinforced tape is configured to receive an electrical voltage during injection molding such that the electrically conductive fiber-reinforced tape increases in temperature, thereby decreasing a viscosity of a polymer flowing past the electrically conductive fiber-reinforced tape.

12. The injection mold according to claim 11, wherein the electrically conductive fiber-reinforced tape comprises a plastic matrix and fibers embedded in the plastic matrix.

13. The injection mold according to claim 12, wherein the fibers are selected from the group consisting of carbon fibers, metal fibers, glass fibers, plastic fibers, and combinations thereof.

13. The injection mold according to claim 11, wherein the electrically conductive fiber-reinforced tape is attached to at least one of the first mold surface and the second mold surface with an adhesive bond.

14. The injection mold according to claim 11, wherein the electrically conductive fiber-reinforced tape is arranged on at least one of the first mold surface and the second mold surface with a laser-assisted tape-laying process.

15. The injection mold according to claim 11, wherein the electrically conductive fiber-reinforced tape is connected to an electrical voltage source configured to apply the electrical voltage to the electrically conductive fiber-reinforced tape.

16. A method for producing injection-molded components with an injection mold, the method comprising: closing a first mold half with a first mold surface and a second mold half with a second mold surface such that a cavity is delimited by the first mold surface and the second mold surface, wherein at least one electrically conductive reinforcing element is arranged on at least one of the first mold surface and the second mold surface; applying an electrical voltage to the at least one electrically conductive reinforcing element during injecting injection-molding compound into the cavity and forming an injection-molded component, wherein the injection molding compound flows past the at least one electrically conductive reinforcing element when the electrical voltage is applied.

17. The method according to claim 16, wherein applying the electrical voltage to the at least one electrically conductive reinforcing element during injection of the injection-molding compound into the cavity reduces a viscosity of the injection-molding compound flowing past the at least one electrically conductive reinforcing element such that mold impressions or interspaces arranged between mold cores are filled with the injection-molding compound.

18. The method according to claim 16, wherein the at least one electrically conductive reinforcing element is a fiber-reinforced tape that is arranged on at least one of the first mold surface and the second mold surface with a laser-assisted tape-laying process.

19. The method according to claim 16, wherein the least one electrically conductive reinforcing element is attached on at least one of the first mold surface and the second mold surface with an adhesive bond.

20. The method according to claim 16, wherein the at least one electrically conductive reinforcing element is a fiber-reinforced tape comprising a plastic matrix and fibers embedded in the plastic matrix.

Description

DRAWINGS

[0031] In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which:

[0032] FIG. 1 shows a schematic representation of two mold halves of an injection mold (dispensing with the representation of further components of the injection mold) according to the prior art;

[0033] FIG. 2 shows a schematic representation of a mold half for an injection mold and/or a method according to the teachings of the present disclosure; and

[0034] FIG. 3 shows a schematic representation of a unidirectional tape, as used as a reinforcing element for the injection mold and/or the method according to the teachings of the present disclosure.

[0035] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

DETAILED DESCRIPTION

[0036] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

[0037] Referring now to FIG. 1, a highly schematized representation of a first mold half 1 and a second mold half 2 of an injection mold according to the prior art is shown. The first mold half 1 has a first mold surface 3 and the second mold half 2 has a second mold surface 4. The mold surfaces 3, 4 form a cavity 5 or the interior space of the injection mold. A softened injection-molding compound, for example a plastics compound, is injected into the cavity 5. The shape of the injection-molded component is defined by shaping elements or the shape of the mold surfaces 3, 4. Shaping elements may be formed for example as mold impressions 6 or cores 7.

[0038] The injection-molding compound passes through a gating system (not represented) into the interior space or the cavity 5 of the injection mold. As already stated at the beginning, one of the mold halves 1, 2 is arranged in a fixed position, in particular a nozzle-side mold half. The other of the mold halves 1, 2, in particular the mold half 1, 2 assigned to an ejector side, is arranged movably in relation to the nozzle-side mold half 1, 2. Before the actual injection molding, the mold halves 1, 2 are moved toward one another, in order to close the cavity 5 or the interior space of the casting mold. Then, the injection-molding compound, for example a plastics compound, passes through the gating system and a nozzle-side mold half 1, 2 into the cavity or the interior space. After completion of the injection-molding process, the ejector-side mold half 1, 2 is moved away from the nozzle-side mold half 1, 2 and the injection-molded component is removed by ejector elements (not shown) provided on the nozzle-side mold half 1, 2, for example an ejector plate or ejector bolt, i.e. it is ejected.

[0039] Referring to FIG. 2, the mold surfaces 3, 4 of the respective mold halves 1, 2 may be provided with a reinforcing element 8 (only mold surface 4 of mold halve 2 shown). In one aspect of the present disclosure, the reinforcing element 8 is a UD tape, that is to say a tape made up of a plastic matrix 9 and electrically conductive fibers 10 embedded therein (as shown in FIG. 3). The reinforcing element 8 or UD tape may be provided over the full surface area on one of the mold surfaces 3, 4 or on both mold surfaces 3, 4. As represented, it is also possible however for only certain regions of the mold surfaces 3, 4 to be provided with the UD tape, for example the portions defining the cores 7 of the mold halves 1, 2. The UD tape may be adhesively attached on the mold surfaces 3, 4 with a suitable adhesive. The UD tape may also be self-adhesive. Alternatively, the UD tape may be arranged on the mold surfaces 3, 4 by way of a laser-assisted tape laying process. The arrangement of UD tapes or portions of UD tape leads to a structural strengthening of the portions of the mold halves 1, 2 covered with them. As used herein, the term strengthening refers to an increase of the mechanical stability or stiffness. Also, the arrangement of the UD tape leads to a structural stabilization of the components to which it is applied in the sense of a fiber-reinforced composite material.

[0040] Referring to FIG. 3, fibers 10 embedded in a plastic matrix 9 of the UD tape may be electrically conductive and electrically contacted by way of a suitable electrical contact 11 (also referred to herein simply as contact). The contact 11 may, as schematically represented in FIG. 3, be formed like a clamp, in order to electrically contact the UD tape. For this, part of the tape may be led out or extend from the cavity 5, in order to be electrically contacted outside the cavity 5. Nevertheless, contact 11 may be provided within the cavity 5, or be integrated in the mold surfaces 3, 4. When arranging the UD tape, it may be contacted by way of the contact 11 integrated in the mold surfaces 3, 4. The contact 11 may be brought into connection with the UD tape by way of an electrically conductive medium, for example by way of an electrically conductive adhesive or contact wire. The contacting of the reinforcing element 8 by way of the contact 11, as represented by way of example in FIG. 3, shows contacting by way of tooth-shaped contact pins 13, which extend from a base 14 in the form of teeth, tapering to a point in the direction of the reinforcing element 8. Individual contact pins 13 are separated by tooth bases 15. The tooth-shaped contact pins 13 are delimited by tooth flanks 16. The contact pins 13 may protrude into the plastic matrix 9 of the reinforcing element 8 and contact electrically conductive fillers contained in the plastic matrix 9. Nevertheless, the contact pins 13 may directly contact the electrically conductive fibers 10.

[0041] Via the electrical contacting, an electrical voltage V can be applied to the reinforcing element 8. It should be understood that applying the electrical voltage V to the reinforcing element 8 can provide particular advantages, in particular during the injection of the injection-molding compound into the cavity 5. For example, the UD tape heats up as a consequence of the applied electrical voltage V and the heat generated thereby increases the temperature of the injection-molding compound flowing in the cavity 5. If the injection-molding compound is a plastics compound, for example a polymer melt, the temperature increase can lead to a reduction in the viscosity of the polymer. This in turn leads to a reduction of the melt pressure and makes it easier for the polymer melt to adapt itself even to the shape of finely formed structures on the first or second mold surface 3, 4. Consequently, even extremely small structures, for example mold impressions 6 or interspaces arranged between mold cores 7, can be filled with the polymer melt. The electrical contacting together with the accompanying increase in temperature in the cavity 5 of the injection mold ultimately makes possible even the formation of finely structured injection-molded components.

[0042] Unless otherwise expressly indicated herein, all numerical values indicating mechanical/thermal properties, compositional percentages, dimensions and/or tolerances, or other characteristics are to be understood as modified by the word about or approximately in describing the scope of the present disclosure. This modification is desired for various reasons including industrial practice; material, manufacturing, and assembly tolerances; and testing capability.

[0043] As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean at least one of A, at least one of B, and at least one of C.

[0044] The description of the disclosure is merely exemplary in nature and, thus, variations that do not depart from the substance of the disclosure are intended to be within the scope of the disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure.