JPH0588925U - Automatic centering mechanism for injection mold - Google Patents

Abstract

(57) [Abstract] [Purpose] A die that can be accurately and easily aligned and can prevent uneven thickness of injection-molded products. Even if multiple dies are used, the dies should be compatible with each other. (EN) Provided is an automatic centering mechanism for an injection molding die which facilitates die replacement and has a long life. [Structure] The core mold 2 and the stripper member 3 are fixed so as to be movable with respect to the respective plates 5 and 4, and the cavity mold 1, the stripper member 3 and the core mold 2 have tapered surfaces 12, respectively. Since 13, 14, 15 are formed, the stripper member 3 can be formed by fitting the respective dies with their respective tapered surfaces during injection molding.
Also, the core molds 2 are moved by a minute distance so that their respective axes coincide with the axes of the cavity mold 1, and the respective mold members are automatically aligned.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an alignment mechanism for an injection molding die having a core die, a cavity die and a stripper member for ejecting a molded product.

[0002]

[Prior Art]

 Generally, in injection molding, in order to prevent uneven thickness of a molded product, these dies are centered so that the cavity mold and the core mold have the same axis. The uneven thickness that occurs in a molded product during injection molding becomes particularly noticeable when a thin molded product is molded.

On the other hand, conventionally, in the multi-cavity injection molding, there is a molding method in which a molded product is projected by a stripper member when the mold is opened. This injection molding die is composed of a cavity die, a core die, and a stripper member for projecting a molded product. For fixing and positioning of these respective dies, for example, the following method 1 or 2 is used. It is used.

1. Positioning method using plates The cavity mold and core mold used in this method are fitted and fixed to the cavity plate and core plate that hold these molds, and each plate has a positioning mechanism such as the tapered surface. There is. The stripper member is fitted and fixed to the stripper plate, and the stripper plate has a positioning mechanism such as a cavity plate and a tapered surface corresponding to the core plate. At the time of mold clamping, the cavity plate, the stripper plate, and the core plate are aligned with each other by the mutual positioning mechanism, so that the respective molding dies fitted to the respective plates are aligned.

2. Positioning method by individual mold The cavity mold, stripper member, and core mold used in this method have a positioning mechanism by taper fitting for each mold. This alignment method will be described. First, the cavity mold is fixedly fixed to the cavity plate, and the stripper member and the core mold are temporarily fixed to the stripper plate and the core plate, respectively. At this point, the stripper member and the core mold can move within a range in which the core misalignment is allowed for each core misalignment. By performing the blanking a few times, the stripper member and the core die are aligned with the cavity die as a reference by the positioning mechanism of each component. After that, the stripper member and the core mold are fastened and fixed to the respective plates.

[0006]

[Problems to be solved by the device]

 However, the above 1. The method of aligning the injection mold by the positioning method using the plate has the following problems. The precision of the mating axis of each mold, in other words, the precision of the uneven thickness of the injection-molded product, is greatly influenced by the precision of the tapered mating surface of each plate, so precise machining is required for each plate. Need. Further, when a large number of molded products are taken, it becomes difficult to accurately position the molds for each cavity mold as the number of molds increases. In addition, misalignment between molds may occur due to different molding conditions such as mold temperature, so make a trial shot and perform accurate centering by considering the molding conditions before molding. There is a need. Also, because each mold is fitted and fixed to each plate, it is difficult to attach and detach each mold, and if uneven thickness due to misalignment occurs, large-scale correction work is required. .. Also, in the case of multi-cavity production, it is necessary to perform adjustment work for centering each cavity mold, so it is difficult to make each cavity mold compatible with each other. The mold cannot be replaced. In addition, the life of each plate is short because stress is applied to the tapered fitting surface of each plate during injection molding.

Next, the above 2. The centering method of the injection mold by the positioning method of each mold has the following problems. After aligning the molds with each other, when the molds are fastened to the respective plates, misalignment may occur again during the fastening work. In addition, since each die is fixedly fixed to each plate during injection molding, one-sided contact is likely to occur on the tapered fitting surface of each die, which causes wear of the die, This will shorten the life of the mold. For this reason, it is necessary to periodically interrupt the molding work and readjust it to perform centering.

In view of the above, the present invention solves the above-mentioned problems and prevents the uneven thickness of the injection-molded product by performing the centering accurately and easily, and in the case of multi-cavity molding, each die is molded. As an interchangeable object, it is an object to provide an automatic centering mechanism for an injection molding die, which can reduce the cost by facilitating the die replacement and extending the die life cycle. And

[0009]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention provides an automatic centering mechanism for an injection molding die having a core die, a cavity die and a stripper member for ejecting a molded product. The stripper member is movably held by the core plate, the stripper member is movably held by the stripper plate, and the cavity die is fixedly held by the cavity plate, and is formed on the taper surface formed on the core die and the stripper member. The first taper surface aligns the stripper member and the core die, and the second taper surface formed on the stripper member and the taper surface formed on the cavity die form the stripper member and the core die. The automatic centering mechanism of the injection molding die is characterized by being aligned with the axis of the cavity die fixed at the reference position.

[0010]

[Action]

 According to the present invention, the core mold and the stripper member are fixed to the respective plates in a movable state, and the cavity mold, the stripper member, and the core mold are each formed with a tapered surface. At the time of injection molding, by fitting each die with its respective tapered surface, the stripper member and the core die are separated by a minute distance so that their respective axes coincide with the axes of the cavity die. After moving, each mold member is automatically aligned.

[0011]

[Embodiment 1] FIG. 1 shows a sectional view of an automatic centering mechanism of an injection molding die of the present invention. Reference numeral 1 denotes a cavity mold, which is fixed to the cavity plate 4 by a bolt 7 so as not to move and to be screwed. Reference numeral 2 denotes a core mold that forms a cavity space with the cavity mold 1, and is fixed to the core plate 5 by bolts 9 and bushings 10 so as to be movable by a minute distance. The core plate 5 is provided with a fitting hole for receiving and supporting the base of the core mold 2, and the base of the core mold 2 is fitted therein. When the flange surface for fixing 5 is wide, it is not necessary to provide the fitting hole and the base of the core mold 2.

Reference numeral 3 denotes a stripper member for ejecting a molded body molded by injection molding from the core mold 2, and is arranged so as to be fitted around the core mold 2 during mold clamping. The cavity mold 1 and the stripper member 3 are fitted with each other by the tapered surface 12 formed on the cavity mold 1 and the second tapered surface 13 formed on the stripper member 3, and the axial centers of the mold and the stripper member 3 are locked by the mold clamping operation. They are formed to be the same. Further, the stripper member 3 and the core mold 2 are fitted by the first tapered surface 14 formed on the stripper member 3 and the tapered surface 15 formed on the core mold 2, and are mutually engaged by the mold clamping operation. The axes are formed to be the same.

FIG. 2 is an enlarged sectional view showing a fixed portion of the core mold 2 fixed to the core plate 5 so as to be movable by a minute distance. A gap A is provided between the core mold 2 and the core plate 5 that holds the core mold 2 in the direction perpendicular to the axis. This gap A allows the misalignment of the axial center between the cavity mold 1 and the core mold 2 due to the temperature difference between the cavity mold 1 and the core mold 2 that occurs during injection molding and an unavoidable error in processing. It is provided for. The gap A is within the range that does not hinder the automatic alignment mechanism. A bolt hole for fixing the core mold 2 is bored in the core plate 5, and a bolt 9 is inserted into the bolt hole via a bushing 10 having a flange portion at the tip, so that the core mold 2 is It is fastened and fixed to the core plate 5 in a movable state within the range of the gap A.

The height E of the collar portion of the bushing 10 that covers the bolt 9 is slightly larger than the thickness D of the collar portion of the core mold 2. That is, when the core die 2 is fixed to the core plate 5, a gap C is formed in the axial direction of the bolt 9 between the collar portion of the bushing 10 and the collar portion of the core die 2. Is. Further, between the peripheral surface of the bushing 10 and the core mold 2, there is a gap B having a size substantially the same as the gap A. Therefore, the core mold 2 is clamped and fixed to the core plate 5 while keeping the movable state freely within the gaps A, B, and C. In order to fix the core mold 2 to the core plate 5, a clamp member 16 may be used instead of the bushing 10 as shown in FIG.

A minute gap is formed between the stripper member 3 and the stripper plate 6 and between the ring member 11 and the stripper plate 6, and the stripper member 3 is movable with respect to the stripper plate 6 by a minute gap. It is fixed to. Since the ring member 11 has a function similar to that of the bushing 10 or the clamp member 16 described above, the stripper member 3 is moved by a minute distance while the stripper plate 6 is held in a sandwich shape by the ring member 11 and the bolt 8. It is fixed as possible.

Next, the operation of the mold of the present invention will be described. FIG. 4 to FIG. 6 are views showing the mold position of each step at the time of injection molding. FIG. 4 shows a state in which the mold is opened, and the molded product is ejected and removed by the stripper member 3 at the same time as the mold is opened. FIG. 5 shows a state in which the stripper plate 6 has returned closest to the core plate 5 by the ejector mechanism of the injection molding machine. At this time, the stripper member 3 and the tapered surfaces 14 and 15 of the core mold 2 are slidably fitted to each other, so that the self-centering operation works and the axes of the two are substantially coincident with each other.

FIG. 6 shows a mold clamping state at the time of injection molding, in which the cavity plate 4 and the stripper plate 6 are closest to each other, and the cavity mold 1 and the taper surfaces 12, 13 of the stripper member 3 slide against each other. The self-aligning action works by the dynamic fitting. This self-centering action is because the cavity mold 1 is immovably fitted and fixed to the cavity plate 4, so that the space between the stripper member 3 and the core mold 2 that have already been fitted is the cavity mold 4. 1, the center axes of the respective mold members are completely aligned by moving in the direction in which the central axes are aligned and the respective tapered surfaces of the respective mold members are completely fitted together during mold clamping.

The self-centering mechanism of the injection molding die of the present invention can be effectively applied to stripper projecting type injection molding dies of a multi-cavity type, and in particular, runner-less dies that easily cause a temperature difference between plates. Can be effectively applied. In addition, the injection molding device with the automatic centering mechanism of the injection mold of the present invention makes it easy to disassemble and replace parts such as molds around the molded product, and integrate the injection molding machine and the mold base part. It can be effectively applied to molds of the type in which only parts around molded products are replaced.

[0019]

[Effect of the device]

 As described above, in the automatic centering mechanism for the injection mold of the present invention, the fixing of the core mold and the stripper member is movably fixed to each plate, and the cavity mold, the stripper member, and Since each core die has a taper surface, even if the molding conditions change or the fixing state changes, self-alignment is performed for each shot of injection molding, so uneven thickness does not occur in the obtained molded product. ..

Furthermore, since there is no wear such as uneven contact on each taper surface of each die provided for centering during automatic alignment, the life cycle of each die can be lengthened and the cost of the cost can be reduced. It can be reduced. In the case of multi-cavity injection molding, even if the molding conditions and fixed state of individual molds change, automatic centering is performed, so compatibility is lost even if each mold is replaced. I will never be told.

Since a gap is provided between the core mold and the stripper member other than the cavity mold and each plate for fixing each, the core mold and the stripper member are loosely fitted, Each mold can be easily replaced.

[Brief description of drawings]

FIG. 1 shows a sectional view of an automatic centering mechanism of an injection molding die of the present invention.

FIG. 2 is an enlarged cross-sectional view of a fixed portion of a core mold fixed to a core plate so as to be movable by a minute distance.

FIG. 3 is an enlarged sectional view of a fixed portion of a core die fixed to a core plate by a clamp member.

FIG. 4 is a view showing a state of mold opening at the time of injection molding.

FIG. 5 shows a state where the stripper plate comes closest to the core plate and returns by the ejector mechanism of the injection molding machine.

FIG. 6 is a view showing a mold clamping state at the time of injection molding.

[Explanation of symbols]

 1 Cavity Mold 2 Core Mold 3 Stripper Member 4 Cavity Plate 5 Core Plate 6 Stripper Plate 7, 8, 9 Bolt 10 Bushing 11 Ring Member 12, 15 Tapered Surface 13 Second Tapered Surface 14 First Tapered Surface 16 Clamping Member

Claims (1)

[Scope of utility model registration request] 1. A self-aligning mechanism for an injection molding die having a core die, a cavity die and a stripper member for ejecting a molded product, wherein (1) the core die is movably held by a core plate. (2) The stripper member is movably held by the stripper plate, (3) the cavity mold is fixedly held by the cavity plate, and (4) the tapered surface formed on the core mold and the stripper member are formed. The first taper surface aligns the stripper member and the core die, and (5) the second taper surface formed on the stripper member and the taper surface formed on the cavity die form the stripper member and the core die. An automatic centering mechanism for an injection molding die, wherein the die is centered on the axis of a cavity die fixed at a reference position.