Molding tool for injection molding

Abstract

An injection molding tool for mounting on an injection molding machine for the automated molding of plastic workpieces forms at least one main runner channel (9) extending between a runner channel branch that branches into two or more branch runner channels leading to the molding cavity and the gate channel, the at least one main runner channel (9) downstream of the gate channel having two flow channels (12) that are joined to each other at a junction of the main runners downstream of the gate channel, the two flow channels (12) up to the junction of the main runners being straight and extending parallel to each other and separated in part or in whole by a straight separating wall (13).

Description

Technical Field

[0001] The present invention relates to an injection mold for attachment to an injection molding apparatus for the automatic molding of plastic workpieces. The injection mold includes at least two separable molding components that form a set of molding cavities, and the separable molding components include a sprue molding component having a molding inlet, a runner channel for the injection of liquid plastic from the injection molding apparatus, and a second molding component. The separable molding components have abutting side surfaces that face a common molding separation surface, and the abutting side surfaces form a set of runner channels that extend between the molding inlet and the molding cavities. The runner channels are two flow channels that include two flow channels that are connected to each other at a confluence point at the downstream ends of the two flow channels.

Background Art

[0002] Patent Document 1 discloses an injection mold of the above type. Here, channels that are spaced apart intersect at an angle with each other to generate a cross-sectional flow, thereby promoting the mixing of the material flow in the intersecting flow channels.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Based on this, the object of the present invention is to provide a cold runner for an injection molding tool that enables a certain aspect where the cold runner channel or the injection runner channel can quickly transfer all the molten material to all the molding cavities without an unnecessary increase in the injection pressure or temperature of the molten material, or without an unnecessary long cooling time for cooling the material in the injection runner before demolding.

Means for Solving the Problems

[0005] What can be achieved by the present invention defined in claim 1 is that the two flow channels up to the confluence point are straight, extend parallel to each other, and are partially or entirely separated by a straight separation wall.

[0006] According to a preferred embodiment, the molding tool further comprises a closing component, the second molding component is arranged between the injection port molding component and the closing component, the closing component and the second molding component are provided with a second abutting side surface facing the second common molding separation surface, and the second abutting side surface forms the molding cavity.

[0007] The two flow channels may have a cross-section in a circular, semi-circular, elliptical, semi-elliptical, polygonal, or other shape in a direction perpendicular to the direction of the flow in the flow channel for efficiently transferring the molten material through the flow channel.

[0008] Advantageously, two parallel flow channels and, optionally, a separation wall extend from the molding injection port and all the paths to the runner branches.

[0009] Furthermore, it is advantageous if the separation wall and the two flow channels open into each other laterally at the flow channels closest to each other. Thereby, the demolded distribution part is harder and easier to demold.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

DETAILED DESCRIPTION OF THE INVENTION

[0011] FIG. 1 is a basic diagram showing the basic structure of an injection molding tool 1 having three separate molded part groups 2, 3, 4. The three separate molded part groups 2, 3, 4 include an inlet molding part 2, an intermediate / second molding part 3, and a closing molding part 4.

[0012] The inlet molding part 2 has a sprue channel 6 that extends between a molding inlet 5 and a set of main runner channels 11. Each of the set of main runner channels 11 extends from each of the sprue channels 6 and joins downstream to a set of branched runner channels 11 via runner branches 10. The set of branched runner channels 11 are in turn connected to a plurality of molding cavities (not shown) either directly or via many additional runner branches and branched runner channels (not shown).

[0013] In this embodiment, the injection molding tool 1 includes the above-described three molding parts, and the injection port molding part 2 and the intermediate / second molding part 3 have abutting side surfaces that form a molding separation surface 7 in which a runner channel (cold runner) is formed. Similarly, the intermediate molding part 3 and the closing molding part 4 have abutting side surfaces that form a second molding separation surface 8 in which a molding cavity (not shown) for forming a molded product is disposed. However, it is obvious to those skilled in the art that the present invention is used in relation to an injection molding tool having only two separated molded products, namely, the injection port molding part 2 and the intermediate / second molding part 3. In the last-mentioned embodiment, the molding cavity (not shown) is disposed on the same molding separation surface 7 as the runner channels 9, 11 (cold runners).

[0014] To ensure an efficient distribution of the molten plastic into the molding cavity, and as shown in FIG. 1, the main runner channel 9 has a larger cross-section than the cross-section of the branched runner channel 11.

[0015] FIGS. 2, 3, and 4 show different embodiments of the main runner channel perpendicular to the flow direction of the molten plastic in the main runner channel 9 shown in FIG. 1. Each embodiment has two straight flow channels 12 separated by a straight separating wall 13, and the molten plastic material flowing through the main runner channel 9 is mainly divided into two separated continuous flows.

[0016] In the embodiments shown in FIGS. 2, 3, and 4, the straight separating wall 13 is not completely separated into the two flow channels 12, whereby the runner formed by the main runner channel 9 is more stable and the release of the runner from the main runner channel 9 is more reliable. However, it is obvious to those skilled in the art that all the straight separating walls extend in a path across the cross-section of the main runner channel 9, whereby the flow channels 12 and the runner formed by the main runner channel 9 are completely separated.

Claims

1. An injection molding tool for attachment to an injection molding apparatus for the automatic molding of plastic workpieces, said injection molding tool comprising at least two separable molding parts which, in the closed position of the injection molding tool, form a set of molding cavities, said separable molding parts comprising a sprue molding part having a molding inlet, a runner channel for the injection of liquid plastic from the injection molding apparatus, and a second molding part, said separable molding parts having abutment side surfaces facing a common molding separation surface, said abutment side surfaces forming at least one main runner channel which extends between a runner branch which branches into two or more runner channels leading to the molding cavities and the sprue channel, the at least one main runner channel downstream of the sprue channel comprising two flow channels which are joined together at a runner confluence point downstream of the sprue channel, the two flow channels up to the runner confluence point being straight and extending parallel to each other, and the cross-sections of the two flow channels being partially separated by a separating wall, an injection molding tool.

2. The injection molding tool according to claim 1, further comprising a closing part, said second molding part being arranged between the sprue molding part and the closing part, said closing part and said second molding part having second abutment side surfaces facing a second common molding separation surface, said second abutment side surfaces forming the injection molding tool for forming the molding cavities.

3. The injection molding tool according to claim 1 or 2, wherein the cross-sections of the two flow channels are at least partially circular, semi-circular, elliptical, semi-elliptical or polygonal in a direction perpendicular to the direction of flow in the two flow channels, an injection molding tool.

4. The injection molding tool according to claim 3, wherein the two flow channels extend from the sprue channel, and the runner confluence point is formed by the runner branch.

5. The injection molding tool according to claim 3 or 4, wherein the separation wall is beside the flow channels closest to each other and the two flow channels open to each other.

6. The injection molding tool according to any one of claims 1 to 5, wherein the runner channel forms a cold runner.

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