DE2341589A1 - Temp. control of mould sprues - using externally thermostatically regulated heating medium - Google Patents

Abstract

A heated sprues distributor, partic. for injection moulding presses etc., controls the feeder sprues by a system of passages through which a heated liq. flows and this liq. is heated thermostatically outside the distributor. The system provides much simpler temp. control than usual electric heating element rods or cartridges and avoids the problem of their fitting and removal.

Description

The invention "relates to a hot runner manifold, in particular" for injection molding, die casting and press works eye, "where the one or the other Distribution channels "are heated.

The multi-point gate is "preferred" for large, rectangular and relatively thin-walled parts in particular the plastic is pressed into the actual hollow form at several points in the injection molding tool. Included the center of the molded part remains free from casting. With these multi-point or multiple sprues, the plastic arrives Plastic material to the individual injection points via a distribution channel system. To freeze the material To prevent on the distribution path, so-called hot runner manifolds are used in the injection molding tool the electric heating rods or around the distribution kai ducts

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Cartridges are arranged. The Compensated for heat loss. The temperature level "with polypropylene "moves, for example, between .25O and 300.degree.

The known hot runner manifolds with electrical heating have some specialist parts, especially because of the relatively short ones Lifetime of the highly stressed heating rods, which have to give off large amounts of heat with a relatively small surface. To the In addition, multiple thermocouples must be used for temperature control. The installation of the heating rods requires more Bores and feed channels that make the tool or the hot runner manifold expensive and its cross-section weaknesses. It is also common to remove the defective heating element difficult, as these jam or burn in their bores.

The object of the invention is therefore to provide a tool for injection molding or die casting or a pressing tool with a • to equip simpler, controllably heated hot runner vertexers.

A hot runner vertexer is therefore used to solve the task of the invention proposed of the type mentioned, which is characterized by a system of channels, which of a hot fluid is flowed through, its heating and Temperature control takes place outside the distributor.

According to a preferred embodiment, such a plate

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'Like hot runner manifold equipped with a central sprue bushing and arms corresponding to the number of nozzle needles in which channels are arranged. The channels in the hot runner manifold are connected to channels in the nozzle needles. Conveniently, the channel system is created for the heating fluid so &&> the liquid entering sequentially passes through the channels and the Düsennadelii.

The heating of the hot runner manifold according to the invention proves to be significantly less expensive and less prone to failure and better controllable than the known distributors with electrical heating. The heating fluid runs in one closed system. Based on the measured and adjustable inlet and outlet temperatures of the liquid the heat emission can be controlled in a simple Veise. the complex bores and channels for the heating rods and the electrical leads to the rods and the thermocouples can be omitted.

The goal of the invention also belongs to the goal, in the hollow To form nozzle needles through an inserted partition plate, two channels through which the heating fluid enters or. exit. The hot runner manifold is expediently formed from two plates connected to one another in a liquid-tight manner, the heating fluid and the plastic distribution channels partially lying in the parting plane. Leave that way avoid costly drilling with blind holes and corresponding dead zones.

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The heating channels can have any course and spacing be arranged by the plastic channels. Suitable cross-sections of any kind can be realized.

Based on an illustrated embodiment, the Invention explained below.

Show it:

Figure 1 is a plan view of the hot runner manifold of an injection molding tool,

FIG. 2 shows a section along the line I - I through a hot runner manifold according to FIG. 1 in a tool

and

FIG. 3 shows a section along the line II-II Figure 1 also in a tool.

The hot runner manifold shown for the multiple sprue consists of a cross-like horizontally divided plate 1. Upper plate part 1a and lower plate part 1b are liquid-tight connected with each other. In the center of the hot runner manifold 1, the sprue bushing 2 is used, through which the plasticized plastic material got into the tool. Four arms 3 extend symmetrically from the middle part at the ends of which the individual nozzle inserts 4- are arranged.

At the point marked 11 in Figure 1, the heated outside the tool and at a certain temperature occurs.

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Heating fluid maintained at the level of rotation in the hot runner distributor 1 ■ a. In circulation it reaches the nozzle needle via the channels 13, 14 and 15 6, as shown in FIG. In this hollow nozzle needle 6, a partition plate 17 is arranged so that two Channels 16 and 18 are formed through which the heating fluid enters and exits again and via the channels 19, 20, 21 to the next Jet needle flows.

The plastic material comes from the sprue bushing 2 via the distribution channels 22 and 23 to an annular channel 8, the is formed in each case between a nozzle needle 6 and the tool part 7. Through the lower opening 5 of this channel 8 is the plastic material in the hollow mold »wipe the" two tool parts 7 and 10 injected and forms the designated 9 Fuel.

The plastic plastic material is on its entire distribution route by the arrangement of the heating channels kept at the necessary temperature level until the final injection in the hollow form. The channel system for the heating fluid is laid out in such a way that the fluid entering at 11 follows one another runs through the channels and the nozzle needles and exits the hot runner manifold 1 again at 12.

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Claims (1)

- 6 claims Hot runner manifold, especially for injection molding, die casting and pressing tools, in which the distribution channel or channels are controllably behest, characterized by a system of Channels (13, 14, 15, 16, 18, 19, 20, 21) which from a heating fluid flows through, the heating and temperature control of which takes place outside the distributor (1). Hot runner manifold according to Claim 1, characterized by a plate-like structure with a central sprue bushing (2) and corresponding to the number of nozzle needles (6) Arms (3) »in which heating channels are arranged. 3 · Hot runner distributor according to claim 2, characterized in that the heating channels (15 ₅ 19) are connected to corresponding channels (16, 18) in the nozzle needles (6). 4. Hot runner manifold according to claims 1 - 3> characterized in that in the hollow nozzle needles (6) through a inserted separating plate (17) two channels (16,18) are formed through which the heating fluid.ein-bsw. exit. 5 · Hot runner manifold according to claims 1-4, characterized in that that the channel system for the heating fluid is designed so that the incoming fluid is sequential passes through the channels and the nozzle needles. 5 09810/0439 6. Hot runner manifold after. Claim. 1, characterized by two liquid-tight interconnected plates (1a, 1b), in the parting plane partially the heating (13 »21) and the Plastic distribution channels (2p) lie. 509810/0439 Blank