JP5907845B2 - Mold resin injection mold and runner lock pin used therefor - Google Patents

Description

The present invention relates to a mold injection mold for forming a molded product.

A high temperature molten resin is injected into the mold injection mold to perform the molding operation.
In many of the three-sheet molds, molten resin is injected from the primary sprue, and the molded portion is filled with the resin through the runner groove and the secondary sprue. In the mold opening process in one molding cycle, the molded product and the secondary sprue are cut at the gate portion. What is necessary for cutting the gate portion is a runner lock pin having an undercut shape.

  This mold injection mold is disclosed in Patent Document 1, for example.

JP2008-307807

  In order to improve the productivity of molds, a cooling circuit is conventionally provided near the cavity, runner groove, and secondary sprue of the molded part, and a cooling circuit is also provided as a standard for the primary sprue bushing parts. The cooling property of the mold is improved, and a high molding cycle has been promoted by shortening the cooling time.

  However, when the cycle is formed quickly, in the three-sheet mold in which the gate is cut by the mold opening operation, the runner lock pin for gate cutting and the resin reservoir shape portion provided on the runner plate located near the tip of the runner lock pin are highly cooled. Since it is difficult to obtain the effect, the solidification of the resin pool molten resin is delayed, the undercut effect of the runner lock pin is not effective, and pin gate cutting cannot be performed, causing a molding trouble.

  Also, by increasing the undercut angle of the runner lock pin (intensifying the undercut), the pin gate can be easily cut, but the resin tends to bite into the undercut portion of the runner lock pin, causing the following. This will affect the molding cycle and prevent high-cycle molding, so that mass productivity will not improve, sometimes sprue and runner discharge defects will cause problems such as pinching with the mold, and mold to improve these I needed technology.

  Patent Document 1 discloses a device relating to a runner lock pin that does not adversely affect the flow of injected resin in improving productivity in an injection mold.

  Patent Document 1 discloses the point of temperature control for cooling / heating the runner lock pin, but there is no detailed disclosure about the technology for cooling the runner lock pin or the structure of the runner lock pin. is there.

  An object of the present invention is to provide a technique for solving the problems that occur when the molding cycle described above is accelerated.

  In order to solve the above-mentioned problems, the present invention devised a structure having a cooling function capable of easily controlling the temperature of the runner lock pin. It is intended to provide a mold structure that can control the cooling temperature of the runner lock pin and can provide a cooling effect to the resin reservoir provided on the runner plate located near the tip of the runner lock pin when molding into the mold. .

  Moreover, in order to solve the above-mentioned problem, a rod-like member excellent in thermal conductivity is incorporated within a gap of 0.02 mm as an inner member of a runner lock pin (material: SUS-based material or SKH51, SKD61, etc.) Alternatively, the inner member is incorporated by press-fitting with respect to the outer member of the runner lock pin.

  The runner lock pin having the inner member is cooled by a cooling means using a cooling medium circulating in a cooling circuit provided in the mold, and a cooling effect is given to the resin reservoir provided in the runner plate to promote solidification of the molten resin. Devised a runner lock pin and its mold structure.

  Further, the configuration of the present invention will be described below in other expressions.

  About the present invention, a primary sprue into which molten resin from an injection molding machine, a runner groove, a secondary sprue, a gate portion, a molded portion in which the molten resin is molded, and a fixed-side mounting on which the primary sprue is supported A plate, a runner plate adjacent to the fixed-side mounting plate, a fixed-side mold plate adjacent to the runner plate and having the secondary sprue positioned therebetween, and movable relative to the fixed mold. In a mold resin injection mold having a movable mold for supporting the side and a runner lock pin for forming a runner lock portion on the runner plate to support the secondary spool, the runner lock pin is connected to the outer member and the inner member. The two-layer structure is used.

  Further, the inner member of the runner lock pin is a member having higher thermal conductivity than the outer member.

  The inner member of the runner lock pin is made of copper, copper alloy, or aluminum.

  Further, a rod-like inner member having high thermal conductivity is disposed inside the outer member of the runner lock pin, and the size of the gap between the inner wall surface of the outer member and the outer wall surface of the inner member is within 0.02 mm. And so on.

  Further, a rod-like inner member having a high thermal conductivity is incorporated into the outer member of the runner lock pin by press-fitting in the cylinder central axis direction.

  Further, a distance from the outer diameter of the cylindrical portion of the outer member of the runner lock pin to the inner member is set to 0.2 mm to 9 mm.

  Further, the runner lock pin is cooled by the cooling circuit provided on the fixed side mounting plate.

  Moreover, the convex part which the said inner member exposes from the said outer member of the said runner lock pin is provided.

  Further, the outer member that does not contact the convex portion of the inner member of the runner lock pin is provided with two or more groove shapes having a width of 0.5 mm or more passing through the center of the runner lock pin so as to be opened. To do.

  Further, a plurality of mutually intersecting grooves having a width of 0.1 mm or more are provided on the convex portion of the inner member of the runner lock pin.

  As described above, according to the present invention, it is possible to cool the molten resin filled in the resin reservoir provided in the runner plate, the cooling solidification is promoted, the mold molding cycle is shortened, the productivity is increased, and the production is performed. Efficiency can be improved, and troubles such as secondary sprue removal and pin gate uncut can be prevented.

  As a result of the above, productivity can be improved by shortening the mold cooling time during molding, and productivity can be improved, and sprue and runner can be discharged accurately, reducing problems such as mold crushing and lowering mold maintenance costs. It can be suppressed.

FIG. 3 is a diagram showing a structure of a three-die mold incorporating a runner lock pin having a temperature controllable cooling function according to an embodiment of the present invention Runner lock pin having a temperature controllable cooling function according to an embodiment of the present invention Conventional three-piece mold structure incorporating a conventional runner lock pin State diagram of pin gate cutting in three-sheet mold, state diagram when releasing sprue runner The figure explaining the pin gate uncut state caused by insufficient cooling of the resin reservoir for the runner lock The figure explaining the biting remainder of the resin reservoir part of the runner lock part produced by insufficient cooling of the resin reservoir part for runner locks

  Embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a view for explaining a mold resin injection mold according to an embodiment of the present invention, and a mold resin injection mold (100) incorporating a runner lock pin (15) having a cooling function capable of controlling temperature. The structure of is shown.

  The high-temperature molten resin injected into the mold from the injection molding machine passes through the primary sprue hole (9), the runner groove (10), the secondary sprue (11), and the gate part (12) to the molding part (13). Filled and cooled and solidified.

  FIG. 2 illustrates the runner lock pin (15) of this embodiment.

  In FIG. 2A, the runner lock pin (15) has a two-layer structure, and has an outer member (15a) outside the inner member (15d).

  The inner member (15d) is a rod-shaped member having a high thermal conductivity, and is inside the outer member (15a) of the runner lock pin (15) and has a gap (or gap, clearance) in the central axis direction. The size of is assumed to be incorporated within 0.02 mm. Alternatively, the inner member may be the central axis of the outer member so that the gap between the outer wall surface of the inner member (15d) of the runner lock pin (15) and the inner wall surface of the outer member (15a) is within 0.02 mm. It shall be incorporated in the direction.

  Alternatively, the inner member (15d) of the runner lock pin (15) is assembled by press-fitting in the central axis direction of the outer member (15a).

  The wall thickness of the outer member (15a) is 0.2 mm to 9 mm, and the distance from the cylindrical surface of the runner lock pin (15) to the rod-shaped inner member (15d) having a high thermal conductivity is 0.2 mm to 9 mm. It is said.

  The dimension of the outer diameter of the cylindrical portion of the main body of the runner lock pin (15) is φ2 to φ20 mm.

  The inner member (15d) may be a copper material, for example, as a material of the high thermal conductivity member, but is not limited thereto, and a member having high thermal conductivity such as a copper alloy or aluminum can be applied.

  Here, as illustrated in FIG. 2, the two-layer structure will be described below.

  As described above, in the mold resin injection mold (100), a molding cycle for manufacturing a molded product is repeated. In order to improve productivity, if a molding high cycle is performed by shortening the mold cooling time at the time of molding, the molding cycle is repeated at a high speed.

  In the repetition of the molding cycle, the secondary sprue (11) is held by the undercut portion (15c) of the runner lock pin (15), and the secondary sprue (11) is locked by the lock of the runner lock resin reservoir portion (14). The next sprue (11) is also released at high speed.

  Therefore, it is necessary to consider that the undercut portion (15c) of the runner lock pin (15) has durability and mechanical strength that can withstand repeated molding cycles repeated at a high speed.

  Further, in locking and holding the secondary sprue (11) of the runner lock resin reservoir portion (14) by the undercut portion (15c), the gate (12) is cut and separated from the molded product. When the gate (12) is cut and separated, a load is applied to the undercut portion (15c) that locks and holds the runner lock resin reservoir portion (14), so that it is considered to have mechanical strength. There is a need.

  In addition, in the molding cycle, since the runner lock pin (15) slides through the through hole of the runner plate, the outer surface of the outer member (15a) of the runner lock pin (15) Wear due to friction with the inner wall. Therefore, the outer surface of the outer member (15a) of the runner lock pin (15) also needs to be considered to have a large surface hardness so as to reduce wear due to the friction.

  In this respect, in this embodiment, the outer member (15a) is made of a material having a strength that can withstand the molding cycle as the two-layer structure of FIG.

  As this member, for example, a SUS-based material or SKH51, SKD61 or the like can be proposed, but it is not limited to this as long as it has a predetermined strength, hardness, and the like and can withstand repeated molding cycles.

  On the other hand, the inner member (15d) needs to be cooled satisfactorily by using a cooling medium circulating in the cooling circuit, and preferably has a high thermal conductivity and excellent thermal conductivity. For example, copper, copper alloy, aluminum and the like.

  Many of these materials, including copper, are smaller in strength and hardness than the SUS-based materials or SKH51, SKD61, etc. described as members of the outer member (15a). Therefore, if the runner lock pin (15) is composed of these members, it is expected that it is difficult to withstand the repetition of the molding cycle described above. In addition, some of these members are expensive, and it can be said that the two-layer structure illustrated in FIG. 2 is preferable considering that the price of the runner lock pin (15) is low.

  In addition, as illustrated in FIG. 2, the end surface of the inner member (15d) is formed on the outer side with the aim of cooling the inner member (15d) satisfactorily using a cooling medium circulating in the cooling circuit. The member (15a) is devised to have a convex portion (15e) that protrudes long from a part of the end surface.

  The cooling medium circulating in the cooling circuit is in direct contact with the convex portion (15e), thereby cooling the inner member (15d) through the convex portion (15e), the outer member (15a), and The undercut portion (15c) can be cooled.

  As a result, the runner lock resin reservoir (14) is well cooled, and the secondary sprue (11) is also well held by the lock. This speeds up the molding cycle and improves productivity. You can expect.

  FIG. 4 shows the pin gate cutting state by the mold opening operation of the three-sheet mold structure and the releasing state of the primary sprue (9), the runner groove (10), and the secondary sprue (11) before discharging out of the mold.

  The secondary sprue (11) is locked by the undercut shapes (15c) and (20) of the runner lock pin (15), and the gate (12) is cut and separated from the molded product.

  The inner member (15d) of the rod-shaped member having a high thermal conductivity of this embodiment is incorporated within the gap of 0.02 mm in the central axis direction of the outer member (15a), or the outer member of the runner lock pin On the other hand, the inner member is assembled by press-fitting, and the runner lock pin (15) is incorporated into the fixed side mounting plate (1) provided with the cooling circuit (16) for circulating the cooling medium.

  As for the way of assembling the stationary side mounting plate (1), the relationship between the runner lock pin (15) and the cooling circuit (16) is exemplified in the configuration of FIG. However, the present invention is not limited to the example shown in FIG. 1, and may be appropriately realized as long as the cooling medium circulating in the cooling circuit (16) can cool the runner lock pin (15). good.

  A groove shape (15b) having a width of 0.5 mm or more is provided in the flange portion of the runner lock pin (15), and the high heat conductive member incorporated in the runner lock pin is in direct contact with the cooling medium, so that the tip of the runner lock pin is The molten resin cooled to the undercut shape (15c) and accumulated in the runner lock portion resin reservoir (14) provided on the runner plate (2) is cooled and solidified.

  The groove shape (15b) provided on the runner lock pin (15) increases the area in contact with the cooling medium, and the cooling efficiency increases compared to the case where the groove shape (15b) is not provided. Can be expected.

  As described above, the portion that contacts the cooling medium with the rod member having high thermal conductivity can be expected to enhance the cooling effect by increasing the contact area as much as possible. is there.

  In the embodiment illustrated in FIG. 2B, the protrusion (15e) is provided with a plurality of intersecting grooves (15f) having a width of 0.1 mm or more to increase the contact area with the cooling medium. This is an embodiment aiming to obtain a larger cooling effect.

  The temperature of the runner lock pin itself can be controlled by controlling the temperature of the cooling medium circulated through the cooling circuit (16) provided on the fixed side mounting plate (1).

  When the cooling and solidification of the runner lock resin reservoir (14) is promoted, the lock effect of the undercut (15c) at the tip of the runner lock pin is improved, and even when the die cooling time is shortened (high cycle molding), pin gate cutting can be performed easily. I can do it.

  Therefore, the productivity can be improved by shortening the molding cycle, and the trouble of sprue and runner discharge can be reduced, so that the number of mold maintenance and its cost can be reduced.

  FIG. 3 shows a mold structure incorporating a runner lock pin (19) that does not have a conventional cooling function.

  In the structure of FIG. 3, it takes time to cool and solidify the molten resin filled in the runner lock portion resin reservoir provided on the runner plate, and when the cooling time at the time of molding is shortened, as shown in FIG. The effect of the undercut shape at the tip of the lock pin is not exhibited, which may cause “secondary sprue picking” and poor pin gate cutting, hindering continuous molding.

  In this case, it is conceivable to simply increase the undercut at the tip of the runner lock pin and shorten the cooling time without giving a cooling function to the runner lock pin as in the above-described embodiment of the present invention.

  However, by strengthening the undercut at the tip of this runner lock pin, even if it is possible to prevent “secondary sprue removal” and gate cutting failure, it is possible to prevent the resin from being collected in the undercut portion as shown in FIG. It is expected that the filled resin may be torn and easily remain.

  If the resin filled in the resin reservoir portion of the undercut portion remains, problems such as a gate cutting failure, sprue, and runner discharge failure are expected in the next molding cycle. In this respect, it is difficult to say that strengthening the undercut is necessarily the best method.

  As mentioned above, although the Example of this invention was described, according to the above-mentioned Example, it becomes possible to provide the mold resin injection mold which can aim at shortening of the molding cycle of a metal mold | die, productivity improvement, and improvement in production efficiency. .

  In addition, the runner lock pin used in the mold resin injection mold can be improved as compared with the prior art.

In particular, in the runner lock pin of the embodiment according to the present invention, the cooling performance of the runner lock pin itself is improved as compared with the prior art, and the sliding with the through hole of the runner plate is achieved by adopting a two-layer structure. The wear resistance against is also improved.

DESCRIPTION OF SYMBOLS 1 ... Fixed side mounting plate, 2 ... Runner plate, 3 ... Fixed side template,
4 ... movable side template, 5 ... spacer block, 6 ... ejector plate 1, 7 ... ejector plate 2, 8 ... movable side mounting plate, 9 ... primary sprue (part) 10 ... runner groove (runner part), 11 ... secondary sprue (part)
12 ... Pin gate (part), 13 ... Molded part (molded product),
14 ... Runner lock resin reservoir (part),
15 ... Runner lock pin,
15a: Runner lock pin body (Material: SUS steel or SKH51, SKD61, etc.)
15b ... Runner lock pin groove groove,
15c: Undercut shape of runner lock pin 15d: Rod-shaped seed member with high thermal conductivity (inner member)
15e ... Projection 15f in which end face of inner member (15d) protrudes long from a part of end face of outer member of runner lock pin ... Notch groove 16 provided in rod-shaped seed member with high thermal conductivity ... Cooling Circuit (cooling medium), 17 ... O-ring, 18 ... Biting resin 19 ... Conventional runner lock pin,
20 ... Undercut shape of runner lock pin

Claims (10)

A primary sprue, a runner groove, a secondary sprue and a gate portion into which molten resin from an injection molding machine is injected, and a molded portion in which the molten resin is molded;
A fixed-side mounting plate on which the primary sprue is supported;
A runner plate adjacent to the fixed-side mounting plate;
A stationary mold plate adjacent to the runner plate and the secondary sprue positioned therebetween;
A movable mold that is displaced with respect to the fixed- side mold plate and supports the movable side of the molding part;
In the mold resin injection mold having a runner lock pin to form a runner lock unit to the runner plate for supporting said secondary spray Lou,
The runner lock pin has a two-layer structure of an outer member and an inner member ,
A mold resin injection mold characterized in that a rod-like inner member having a high thermal conductivity is assembled into the outer member of the runner lock pin by press-fitting in the axial direction of the cylinder . In the mold resin injection mold according to claim 1,
The mold resin injection mold, wherein the inner member of the runner lock pin is a member having higher thermal conductivity than the outer member. In the mold resin injection mold according to claim 1,
The mold resin injection mold, wherein the inner member of the runner lock pin is copper, copper alloy, or aluminum. In the mold resin injection mold according to claim 1,
Arranging a rod-shaped inner member with high thermal conductivity inside the outer member of the runner lock pin,
A mold resin injection mold, wherein a size of a gap between an inner wall surface of the outer member and an outer wall surface of the inner member is 0.02 mm or less. In the mold resin injection mold according to claim 1,
A mold resin injection mold characterized in that a distance from a cylindrical portion outer diameter of the outer member of the runner lock pin to the inner member is 0.2 mm to 9 mm. In the mold resin injection mold according to claim 1,
The mold resin injection mold, wherein the runner lock pin is cooled by the cooling circuit provided on the fixed side mounting plate. A primary sprue, a runner groove, a secondary sprue and a gate portion into which molten resin from an injection molding machine is injected, and a molded portion in which the molten resin is molded;
A fixed-side mounting plate on which the primary sprue is supported;
A runner plate adjacent to the fixed-side mounting plate;
A stationary mold plate adjacent to the runner plate and the secondary sprue positioned therebetween;
A movable mold that is displaced with respect to the fixed-side mold plate and supports the movable side of the molding part;
In a mold resin injection mold having a runner lock pin that forms a runner lock portion on the runner plate and supports the secondary sprue,
The runner lock pin has a two-layer structure of an outer member and an inner member,
A mold resin injection mold characterized by providing a convex portion from which the inner member is exposed from the outer member of the runner lock pin. In the mold resin injection mold according to claim 7,
The outer member that is not in contact with the convex portion of the inner member of the runner lock pin has the run
Two or more grooves having a width of 0.5 mm or more passing through the center of the knurlock pin are provided and opened.
A mold resin injection mold characterized by that. In the mold resin injection mold according to claim 7,
The runner lock pin has a convex portion of the inner member that intersects each other with a width of 0.1 mm or more.
A mold resin injection mold having a number of grooves. A runner lock pin, wherein the runner lock pin is incorporated in the mold resin injection mold according to claim 1.

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