JPH0351563B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a multi-stage molding die that effectively connects solidified gate scrap, runner scrap, and sprue scrap into one body for molding.

[Conventional technology]

A feature of multi-stage molding molds is that even if the shapes of the molding cavities are different between the left and right stage molds, multiple molded products can be molded at once within a limited projected area, and it has high molding efficiency. On the other hand, however, in this type of molding die, since the gates, runners, etc. are also multistaged in accordance with the multistage arrangement, there is a problem in peeling off of the solidified material in these parts. This problem is especially serious when a large number of molded cavities are formed on the same parting line. That is,
For multi-stage molding molds, it is desirable to remove mold gate scraps, runner scraps, etc. easily. However, until now, nothing has been proposed that satisfies this point.

[Problem that the invention seeks to solve]

The purpose of the present invention is to ensure that gate scraps, runner scraps, and sprue scraps from the mold can be easily stripped even when molding cavities are molded in large numbers on the same parting line, and that this can be done for the desired purpose. The objective is to achieve the following and establish further enhancement of the usefulness of multi-stage molding molds.

[Means for solving problems]

That is, the multistage molding mold of the present invention has a hot runner manifold with branch hot runners branching from the main hot runner to the left and right, and the tips of the branch hot runners forming small nozzles. In a multi-stage molding mold in which the molding molds are arranged on the side, the synthetic resin can fit into the mold on the opposite side of the hot runner manifold at the parting line of each set of left and right molding molds. (b) a gate with a narrowly narrowed tip leading from the runner to the molding cavity; The sprue is continuous, and the starting end is narrowly constricted so that the starting end can come into contact with a small nozzle.

In the present invention, the mold structure is such that molding molds are placed on the left and right sides of a hot runner manifold block having a predetermined hot runner manifold, so that the synthetic resin of the molding material in the hot runner manifold of the block is kept constant. The block is heated to a constant temperature to keep it in a molten state, but the molding material flow path after the small nozzle tip of the branch hot runner that branches left and right from the main hot runner of the hot runner manifold, that is, the hot After molding, the sprue formed in the mold on the side of the runner manifold block, the runner at the parting line, and the molding material in the gate between the runner and the molding cavity are removed from the hot runner manifold block, and the mold is removed from the hot runner manifold block.
It can be solidified by cooling the mold. The solidified sprue scum, runner scum and gate scum in the sprues, runners and gates that are connected together are narrowed at the starting end of the sprue and the tip of the gate, and the runner scum is hot on the opposite side of the runner manifold. Since it is designed to fit into the mold, it is separated from the molded product and the small nozzle by opening the mold, and at the same time, as the runner debris is peeled off by the stripper installed on the runner of the parting line, the entire mold is removed. Concise and easily exfoliated.

〔Example〕

The present invention will be described in more detail below with reference to drawings of embodiments. The same symbols indicate the same parts throughout the figures.

In the figure, reference numeral 1 indicates a multistage molding die, 2 indicates a forming die in each set, and each set of molds 2 has a male die 2a and a female die 2b. 3 is a hot runner manifold block, and this block 3 has hot runners 5 that branch from the main hot runner 4 to the left and right.
The hot runner manifold 7 has a branched hot runner manifold 7 with a small nozzle 6 at the end of the branched hot runner. The molds 2, 2 are arranged on the left and right sides of the hot runner manifold block 3, and the molds 2, 2 and the hot runner manifold block 3 are opened, closed, and clamped by known appropriate means. The hot runner manifold block 3 and its left and right forming molds 2, 2 may be installed as a single set, or multiple sets may be installed side by side (see Figure 2). In the latter type, the hot runner manifold block 3 may be a divided communicating type that separates and contacts as the mold opens and closes. In the divided and communicating type block, the hot runner at a portion corresponding to a predetermined parting line becomes a nozzle 8, and can be separated there. The base end (right end in FIG. 1) of the nozzle 8 is slidably fitted into the block 3, and is biased toward the distal end (leftward in FIG. 1) by a spring 24.

At the parting line of each set of molding molds 2, 2, there is a runner 9 and a molding cavity 1 from this.
A gate 11 leading to 0 is provided, and a sprue 12 whose distal end is connected to the runner 9 is formed in the mold on the side of the hot runner manifold block 3. The starting end of the sprue 12 is narrowly constricted, and the small nozzle 6 of the hot runner manifold block 3 contacts there. It is better to form multiple molded cavities 10 on the same parting line, and this type is shown in the figure. The gate 11 has a narrow end.

Reference numeral 13 denotes a plate that holds the hot runner manifold block 3 from the left and right sides. The injection nozzle 14 may be touched in the mold clamping direction (see Figures 1 and 2), or may be touched in a direction perpendicular to the mold clamping direction (3. , 4).

The runner 9 in the parting line is provided with a suitable stripper, for example a pin-shaped stripper 15 (see FIG. 5). This stripper 15 is arranged on the runner 9. The stripper 15 forms an undercut 16 on a part of the circumference,
A solidified integrated product of sprue scrap 17, runner scrap 18 and gate scrap 19 (see FIG. 6) is hooked onto it and peeled off.

Reference numeral 20 denotes an air stripper for the molded product 21 installed at the bottom of the molding cavity 10. The air stripper is a shallow (usually 0.3 mm or less) air jet groove extending along the length on the circumference. 22 as shown in Fig. 7, or a pin or bush type made of sintered alloy as shown in Fig. 8 with fine (usually 0.2 mmφ or less) open cells. things can be used. Pressurized air is forced into the air stripper 20 through the guide holes 23 when the molded product 21 is released from the mold, and the molded product 21 is released from the mold by the pressurized air that is ejected from the air stripper 20 . Note that the air stripper 20 can also vent gas from the molding cavity 10 through the guide hole 23 by utilizing its air permeability during injection of the molding material.

〔Effect of the invention〕

In the multi-stage molding mold of the present invention, the molding molds are arranged on the left and right sides of the hot runner manifold block, so only the mold can be cooled efficiently. Sprue scum, runner scum, and gate scum solidify quickly, as do sprue scum, runner scum, and gate scum, which move along with the mold opening movement of runner scum mated to the mold on the opposite side of the hot runner manifold. Then, the sprue scum is neatly separated from the small nozzle and the gate scum is neatly separated from the molded product at a narrow constriction point, and finally the runner scum is peeled off by a stripper. As a result, the finishing work of the molded product is omitted, and the next molding can be started smoothly.

[Brief explanation of drawings]

FIG. 1 is a partially longitudinal front view showing one embodiment of the present invention, FIG. 2 is a front view of the molding cavity arrangement on the mold parting line of FIG. 1, and FIGS.
The figure is a partial sectional view showing a modified example of the nozzle touch of the injection nozzle, Figure 5 is a partially enlarged detailed view of Figure 1, and Figure 6 is solidification of sprue scrap, runner scrap, and gate scrap in the embodiment of Figure 1. FIGS. 7 and 8 are perspective views showing different types of air strippers for molded products. 1 is a multi-stage mold, 2 is a molding mold, 3 is a hot runner manifold block, 4 is a main hot runner, 5 is a branched hot runner, 6 is a small nozzle, 7 is a hot runner manifold, 9 is a mold parting Line runner, 10 is the molding cavity, 11 is the gate, 12 is the sprue, 14 is the injection nozzle, 15 is the runner stripper, 16 is the undercut, 17 is the sprue waste, 18 is the runner waste, 19 is the gate waste, 20 is the This is a molded air stripper.

Claims (1)

[Claims] 1 A multi-stage molding mold in which molding molds are arranged on the left and right sides of a hot runner manifold block, which has a hot runner manifold in which branch hot runners branch from the main hot runner to the left and right, and the tips of the branched hot runners become small nozzles. In the mold, on the parting line of each set of left and right molding molds, (a) a runner having a shape that allows the synthetic resin to fit into the mold on the opposite side of the hot runner manifold and equipped with a stripper; (b) Form a gate with a narrowly constricted tip leading from the runner to the molding cavity, and (c) Form a gate with the end connected to the runner in the mold on the hot runner manifold block side.
A multi-stage mold with a sprue whose starting end is narrowly constricted so that the starting end of the sprue can come into contact with a small nozzle.