CN114763009A - Injection molding apparatus and method for ejecting molded product obtained by injection molding apparatus - Google Patents

Abstract

The utility model provides an injection molding apparatus and a method for ejecting a molded product obtained by the injection molding apparatus. The injection molding device (10) has a 1 st ejector pin (44) and a 2 nd ejector pin (46). The 1 st ejector pin (44) presses a product portion (50) of the molded product (S). The 2 nd ejector pin (46) presses a runner (28) of the molded article (S). The molded article (S) has a notch (58) at the boundary between the product portion (50) and the gate portion (54). The 1 st ejector pin (44) is disposed at a position offset in a predetermined direction from the center of the horizontal direction of the runner (28) (runner portion 52). Accordingly, the product portion and the waste portion can be easily and reliably cut and taken out from the mold.

Description

Injection molding device and method for ejecting molded product obtained by injection molding device

Technical Field

The present invention relates to an injection molding apparatus and a method of ejecting a molded product obtained by the injection molding apparatus.

Background

Conventionally, resin molded articles have been generally used as exterior parts or interior parts of automobile bodies. In the injection molding apparatus, a molten resin is filled into a cavity and cooled to solidify. Then, the mold is opened in the injection molding apparatus. After the mold is opened, the ejector pin is advanced and retreated to push the resin molded product out of the mold. As a result, the resin molded article having a shape corresponding to the shape of the cavity can be taken out from the cavity.

A resin molded article obtained by injection molding has a plurality of product portions molded simultaneously. Adjacent product portions of the resin molded product are connected to each other by a runner portion. The runner portion is a passage of molten resin (resin material) to the cavity. After the resin molded product is taken out from the cavity, a runner portion, which is a waste portion other than the product, is cut out.

For example, in an injection molding apparatus disclosed in japanese patent application laid-open No. hei 1-115521, when opening of a mold is performed, a product push-out pin pushes out a product. At this time, the runner connected to the product is not pushed out by the runner push-out pin. The runner is kept in close contact with the inside of the mold. Therefore, when the product is demolded from the mold, the runner is cut off from the product by a shear force generated when the product is demolded.

Disclosure of Invention

The manufacturing process performed by the injection molding apparatus of japanese patent application laid-open No. hei 1-115521 includes a product push-out process by a product push-out pin and a runner push-out process by a runner push-out pin. In the injection molding apparatus, these two ejection processes are provided with a time difference. Thereby, the product and the runner are cut. However, in the resin molded article, depending on the positional relationship or the shape of the product and the runner, it may be difficult to reliably cut and separate the two.

The present invention aims to solve the above problems.

The scheme of the utility model is as follows: an injection molding apparatus for cutting a waste portion of a molded article molded by an injection molding die in the die,

having a 1 st pin and a 2 nd pin, wherein,

the 1 st pin presses a 1 st portion of the molded article, the 1 st portion being one of a product portion and the disposal portion other than the product portion;

the 2 nd pin presses a 2 nd portion, the 2 nd portion being the other of the product portion and the disposal portion which is not pressed by the 1 st pin,

the molded article has a notch portion at a boundary between the product portion and the disposal portion adjacent to each other in the width direction,

the 1 st pin is disposed at a position shifted from a center of the discarding portion in a direction from the center of the discarding portion in the orthogonal direction to the width direction toward the cutout portion,

the 1 st portion is pressed by the 1 st pin, and the molded article is twisted with the notch portion as a fulcrum, thereby cutting the disposal portion and the product portion at the boundary.

According to the injection molding apparatus described above, the 1 st pin is disposed at a position offset from the center of the disposal portion in the direction from the center of the disposal portion toward the cutout portion along the orthogonal direction. The 1 st pin is driven to press the 1 st portion, which is either a product portion or a disposal portion, of the molded product. Thereby, the product portion or the disposal portion pressed by the 1 st pin is pressed in the moment direction with the notch portion as a fulcrum. The molded product is twisted from the notch portion, and the product portion and the disposal portion can be cut at the boundary.

Thus, the injection molding apparatus can easily and reliably cut and take out the product portion and the waste portion from the mold while the molded product is released from the mold.

The above objects, features and advantages can be easily understood from the following description of the embodiments with reference to the accompanying drawings.

Drawings

Fig. 1 is a main part sectional view of an injection molding apparatus according to an embodiment of the present invention.

Fig. 2 is an enlarged plan view showing the vicinity of the ejection mechanism and the molded article in the injection molding apparatus of fig. 1.

Fig. 3 is a perspective view of a single body constituting the ejector mechanism of the injection molding apparatus of fig. 1.

Fig. 4 is a plan view of a molded article obtained by the injection molding apparatus of fig. 1.

Fig. 5 is a sectional view of a main part showing a state after a stationary mold and a movable mold of the injection molding apparatus of fig. 1 are opened.

Fig. 6A is a main part cross-sectional view of the molded article and the ejector mechanism shown in fig. 4 as viewed in the width direction, and fig. 6B is a main part cross-sectional view showing a state in which the molded article of fig. 6A is pushed downward by the 1 st ejector pin.

Fig. 7A and 7B are explanatory views of the operation of the ejection process for taking out the molded article from the injection molding apparatus after the mold opening of fig. 5.

Fig. 8A to 8C are explanatory views of the operation of the ejection step of taking out the molded article from the injection molding apparatus by the ejection method different from that of fig. 7A and 7B.

Detailed Description

As shown in fig. 1, the injection molding apparatus 10 has an injection mold (mold) 17 and an ejection mechanism 16. The injection molding die 17 has a stationary die 12 and a movable die 14. The movable mold 14 is disposed above the fixed mold 12 (in the direction of arrow a). The movable mold 14 can be displaced in a manner approaching or departing from the stationary mold 12. The ejector mechanism 16 is attached to the movable mold 14 and is used to strip the molded product S. The movable mold 14 is displaced in a direction (direction of arrow A, B) toward and away from the fixed mold 12 by a displacement mechanism (e.g., a hydraulic cylinder, etc.), not shown.

The fixed mold 12 is fixed to, for example, a work table not shown through a fixed platen 18. The fixed platen 18 is plate-shaped. The fixed mold 12 has a convex portion 20. The fixed mold 12 has a split surface 12a facing the movable mold 14. The convex portion 20 is disposed on the dividing surface 12 a. The convex portion 20 protrudes toward the movable mold 14. The cross-sectional shape of the projection 20 is, for example, a trapezoid. The protruding portion 20 is formed in a shape that is narrowed toward the movable mold 14. The projection 20 has a shape corresponding to the shape of the product portion 50 of the molded article S. The fixed mold 12 has a number of the convex portions 20 corresponding to the number of the product portions 50. The injection molding apparatus 10 according to the present embodiment has two convex portions 20 that are away from each other by a predetermined distance in the width direction (the direction of arrow C).

The movable mold 14 is connected to a displacement mechanism, not shown, via a movable platen 22. The movable platen 22 is plate-shaped. The movable die 14 has a recess 24. The movable mold 14 has a split surface 14a facing the fixed mold 12. The concave portion 24 is disposed on the dividing surface 14 a. The concave portion 24 is recessed in a direction (arrow a direction) away from the fixed mold 12. The concave portion 24 is arranged at a position facing the convex portion 20 of the fixed mold 12. The recess 24 has a shape corresponding to the shape of the product portion 50 of the molded product S. The movable die 14 has the number of recesses 24 (i.e., two) corresponding to the product portion 50. When the movable mold 14 approaches the fixed mold 12 (when the movable mold 14 moves in the arrow B direction), the convex portion 20 enters the concave portion 24. When the movable mold 14 abuts against the fixed mold 12, a cavity 26 is formed between the convex portion 20 and the concave portion 24.

The movable mold 14 has a sprue 28, a pair of gates 30, and a sprue 32. The runner 28, the pair of gates 30, and the sprue 32 are disposed on the dividing surface 14a of the movable mold 14. The runner 28 is disposed between two adjacent recesses 24. One gate 30 (the left gate 30 in fig. 1) connects one end of the runner 28 in the width direction and one recess 24. The other gate 30 (the right gate 30 in fig. 1) connects the other end of the runner 28 in the width direction and the other recess 24. The sprue 32 extends from the runner 28 in a direction (the direction of arrow a) away from the dividing surface 14 a. The sprue 32 is connected to a resin material supply path 34. The resin material supply path 34 extends up to the surface of the movable mold 14 connected to the movable platen 22 (the upper surface of the movable mold 14). The sprue 32 is connected to an injection machine, not shown, via a resin material supply path 34. The runner 28 may not be disposed between two adjacent recesses 24. For example, the runners 28 may be disposed in the plurality of recesses 24, respectively, and the plurality of runners 28 may be connected to the injection machine.

The runner 28 and the gate 30 are arranged along the dividing surface 14a of the movable mold 14 in the width direction (the arrow C direction). The runners 28 and gates 30 are arranged on a straight line in the width direction. The resin material injected from an injection machine, not shown, is supplied to the cavity 26 through the sprue 32, the runner 28, and the gate 30. In other words, the sprue 32, the runner 28, and the gate 30 are resin injection paths for supplying the resin material to the cavity 26.

As shown in fig. 1 and 2, the movable mold 14 has a protrusion 36. The protrusion 36 is disposed at the end in the width direction of the gate 30 (the boundary between the recess 24 and the gate 30). The protrusion 36 protrudes from one end (an end in the direction of arrow D1 in fig. 2) in the horizontal direction orthogonal to the width direction (the direction of arrow C) of the gate 30 to the other end (an end in the direction of arrow D2). For example, the cross-sectional shape of the protrusion 36 is triangular when viewed in the moving direction of the movable mold 14 shown in fig. 2. The protrusion 36 is formed in a shape tapered toward the horizontal center of the gate 30. The projection 36 is provided for molding the notch 58 during molding. Specifically, the protrusion 36 forms a notch 58 at the end of the gate 54 of the molded product S in the width direction. The size of the projection 36 is preferably such that the resin material (molten resin) does not obstruct the flow from the gate 30 to the cavity 26.

An ejector mechanism 16 is mounted on the movable mold 14. The movable mold 14 has a housing portion 48 that opens on the upper surface of the movable mold 14. The movable die 14 has a pair of 1 st through holes 38 and a pair of 2 nd through holes 40. The 1 st through hole 38 extends from the receiving portion 48 to the recess 24. The 2 nd through holes 40 extend from the receiving portions 48 to the runners 28, respectively. The 1 st through hole 38 and the 2 nd through hole 40 extend respectively in the moving direction (the direction of the arrow A, B) of the movable die 14. The 1 st through hole 38 and the 2 nd through hole 40 are substantially parallel to each other.

As shown in fig. 1 to 3, the ejector mechanism 16 includes a base 42, a 1 st ejector pin 44, and a 2 nd ejector pin 46. The base 42 is, for example, substantially rectangular and is housed in the housing portion 48. A drive source (not shown) is housed inside the base 42. The driving source retracts the 1 st and 2 nd ejector pins 44 and 46 in the axial direction.

The 1 st knockout pin 44 and the 2 nd knockout pin 46 are disposed on the base 42 so as to be able to advance and retreat, respectively. The 1 st and 2 nd knockout pins 44 and 46 each have a circular cross-sectional shape, for example. The 1 st and 2 nd ejector pins 44 and 46 are shafts extending in the axial direction (the direction of arrow A, B) with constant diameters, respectively. The 1 st ejector pin (1 st pin, pin) 44 has a smaller diameter than the 2 nd ejector pin 46. The 1 st knock-out pin 44 is inserted through the 1 st through hole 38 of the movable mold 14. The 2 nd knockout pin (2 nd pin, pin) 46 is inserted through the 2 nd through hole 40.

The 1 st ejector pin 44 and the 2 nd ejector pin 46 are arranged substantially in parallel with each other so as to be apart from each other by a predetermined interval in the width direction (the arrow C direction) of the ejector mechanism 16. The 1 st and 2 nd knockout pins 44 and 46 are offset from each other by a predetermined distance L in a horizontal direction (in fig. 2, the direction of arrows D1 and D2) orthogonal to the width direction.

The 1 st eject pin 44 is driven by a drive source not shown to move toward the fixed mold 12. The tip of the 1 st knock-out pin 44 protrudes into the recess 24 from the 1 st through hole 38 and is exposed. The 2 nd ejector pin 46 is driven by a drive source (not shown) to move toward the fixed mold 12 (in the direction of arrow B in fig. 1). The tip of the 2 nd ejector pin 46 protrudes and is exposed from the 2 nd through hole 40 into the runner 28. The 1 st knockout pin 44 and the 2 nd knockout pin 46 are driven by a drive source, not shown, and are independently movable in the axial direction.

As shown in fig. 2 and 6A, the 1 st knock-out pin 44 is disposed in the recess 24 at a position shifted by a predetermined distance L from the center in the horizontal direction toward one side in the horizontal direction (the direction of arrow D1). The 2 nd ejector pin 46 is disposed in the recess 24 at the horizontal center of the runner 28. In other words, the 1 st ejector pin 44 is disposed offset in the horizontal direction (the direction of arrow D1) with respect to the 2 nd ejector pin 46. Therefore, the 1 st ejector pin 44 is offset in one direction (the direction of arrow D1) from the horizontal direction center of the recess 24 in the injection mold 17.

In other words, the 1 st knock-out pin 44 is disposed offset from the 2 nd knock-out pin 46 in the direction from the 2 nd knock-out pin 46 toward the protrusion 36 along the horizontal direction (the direction of arrows D1, D2) of the injection molding apparatus 10.

Next, the molded article S molded by the injection molding apparatus 10 will be described.

As shown in fig. 1 and 4, the molded article S has a plurality of product portions 50. The product portion 50 is used as a product. The molded product S has, for example, two product portions 50, a runner portion 52, a pair of gate portions 54, and a sprue portion 56. The two product portions 50 are spaced apart from each other by a predetermined distance in the width direction (arrow C direction) of the molded product S. The runner portion 52 is disposed between two adjacent product portions 50. The one gate portion 54 connects the one product portion 50 and the runner portion 52. The other gate portion 54 connects the other product portion 50 and the runner portion 52. The gate portion 54 is smaller in vertical dimension than the runner portion 52, for example (see fig. 1). The sprue portion 56 supplies a molten resin material (molten resin) to the runner portion 52.

The molded product S has a notch 58. The notch 58 is disposed at the boundary between the product portion 50 and the gate portion 54 adjacent to each other. As shown in fig. 4, the notch portion 58 is recessed from the center in the horizontal direction (the direction of arrow D2) in the horizontal direction, which is the horizontal direction orthogonal to the width direction. The notch 58 is formed by the protrusion 36 (see fig. 2) of the movable mold 14 when the molded article S is molded. Similarly to the projection 36, the cross-sectional shape of the notch 58 is a triangle tapered toward the horizontal center (the direction of arrow D2).

In the manufacturing process of the molded product S, a molten resin material (hereinafter, referred to as a molten resin) is filled into the cavity 26 from the resin material supply path 34. The molten resin is cooled and solidified in the cavity 26, thereby forming the molded article S. A portion of the molten resin filled into the cavity 26, which is filled between the concave portion 24 and the convex portion 20, becomes a product portion 50. The portions of the molten resin filled into the cavity 26 that fill the runner 28 and the gate 30 become the runner portion 52 and the gate portion 54. The portion of the molten resin filled in the cavity 26 that is supplied to the sprue 32 becomes the sprue portion 56. The runner portion 52, the gate portion 54, and the sprue portion 56, which are portions other than the product portion 50, of the molded product S are discarded portions. The waste portion is a portion that is not used as a product.

Next, the operation and operational effects of the injection molding apparatus 10 will be described. In the following description, an open state (see fig. 5) in which the movable mold 14 is lifted away from the fixed mold 12 is set as an initial state of the injection mold 17.

First, from the initial state described above, the movable mold 14 of the injection mold 17 is lowered by driving a displacement mechanism, not shown. The movable mold 14 moves in such a manner as to approach the stationary mold 12. Then, as shown in fig. 1, the split surface 12a of the fixed mold 12 is brought into contact with the split surface 14a of the movable mold 14. Thereby, the injection mold 17 is clamped. In the injection mold 17, the convex portion 20 enters the concave portion 24 to form a cavity 26.

After that, the molten resin is injected from an unillustrated injection machine into the resin material supply path 34 of the movable mold 14. The molten resin is supplied to the cavity 26 through the resin material supply path 34, the sprue 32, the runner 28, and the gate 30, and is filled in the cavity 26. At this time, the inflow rate of the molten resin into the cavity 26 is controlled by a pair of gates 30.

The 1 st and 2 nd knockout pins 44, 46 of the knockout mechanism 16 both stand by in the retreated position. The tip (lower end) of the 1 st knock-out pin 44 is housed in the 1 st through hole 38. The tip (lower end) of the 2 nd ejector pin 46 is housed in the 2 nd through hole 40. The tips of the 1 st and 2 nd ejector pins 44 and 46 do not protrude into the cavity 26 (see fig. 1).

The molten resin is cooled for a predetermined time while filling the cavity 26. When the molten resin is solidified in the cavity 26, a molded article S having a shape corresponding to the shape of the cavity 26 is obtained. The molded product S has a sprue portion 56, a runner portion 52, a pair of gate portions 54, and two product portions 50. The sprue portion 56 is connected to a lower end of the resin material supply path 34. The runner portion 52 extends in the width direction (the direction of arrow C) so as to be substantially orthogonal to the sprue portion 56. The pair of gate portions 54 are connected to both ends of the runner portion 52 in the width direction. The one product portion 50 is connected to the one gate portion 54. The other product portion 50 is connected to the other gate portion 54. The molded product S has a notch 58 at the boundary between the gate portion 54 and the product portion 50. The notch portion 58 is disposed at one end portion (end portion in the direction of arrow D1) of the gate portion 54 in the horizontal direction. The notch portion 58 is formed as a notch from one end portion in the horizontal direction of the gate portion 54 toward the other end portion in the horizontal direction.

Next, an ejection step of taking out the molded product S from the injection mold 17 is performed. In the push-out step, first, as shown in fig. 5, the movable mold 14 is raised by a displacement mechanism, not shown. As the movable mold 14 is lifted, the movable mold 14 is moved upward away from the fixed mold 12 by a predetermined distance. Thereby, the injection mold 17 is opened. At this time, the molded article S is kept in close contact with the concave portion 24 of the movable mold 14. Therefore, the molded article S moves upward (in the direction of arrow a) so as to be separated from the fixed mold 12 together with the movable mold 14.

Next, a drive source (not shown) of the ejection mechanism 16 is driven in accordance with a control signal from a controller (not shown). The 1 st eject pin 44 advances toward the fixed mold 12 (in the arrow B direction) by the driving force of the driving source. Before the 1 st knockout pin 44 advances, the tip of the 1 st knockout pin 44 abuts on the upper surface of the product portion 50 in the molded product S and does not protrude into the recess 24. As the 1 st ejector pin 44 advances, the tip of the 1 st ejector pin 44 protrudes into the recess 24. As a result, the tip of the 1 st ejector pin 44 presses the product portion 50 (see fig. 6B).

On the other hand, the 2 nd ejector pin 46 is not advanced toward the fixed mold 12 (arrow B direction). The tip of the 2 nd ejector pin 46 is kept housed in the 2 nd through hole 40. Therefore, the runner portion 52 of the molded article S is not pressed against the fixed mold 12 (in the direction of arrow B) by the 2 nd knockout pin 46. Therefore, the runner portion 52 is kept in close contact with the recess 24 of the movable mold 14.

As the 1 st knock-out pin 44 advances, the product portion 50 is pushed out downward from the recess 24 by the 1 st knock-out pin 44 as shown in fig. 7A. The product portion 50 begins to peel from the recess 24.

At this time, as shown in fig. 6B, the pressing force F of the 1 st knock-out pin 44 is applied to the product portion 50 at a position shifted in one horizontal direction (the direction of the arrow D1) from the runner portion 52 and the gate portion 54. Therefore, a moment M is generated in the product portion 50 with the boundary between the gate portion 54 and the product portion 50 as a fulcrum. The product portion 50 starts to break from the notch portion 58 disposed at the boundary. Then, the boundary of the product portion 50 is broken in the other horizontal direction (the direction of the arrow D2). As shown in fig. 7A, the molded article S is cut and separated at the boundary between the gate portion 54 and the product portion 50.

Finally, the product portion 50 of the molded product S is separated from the gate portion 54, and as a result, the product portion 50 is separated from the recess 24 of the movable mold 14. Then, by driving the driving source (not shown), the 2 nd ejector pin 46 of the ejector mechanism 16 is advanced along the 2 nd through hole 40 as shown in fig. 7B. The tip of the 2 nd ejector pin 46 is projected from the 2 nd through hole 40 into the recess 24. As the 2 nd ejection pin 46 advances, the tip of the 2 nd ejection pin 46 presses the runner portion 52. Thereby, the runner portion 52 is pressed against the fixed mold 12 (in the direction of arrow B) by the 2 nd ejector pin 46, and the driven mold 14 is released. With the demolding of the runner portion 52, the gate portion 54 and the sprue portion 56 are integrally demolded from the movable mold 14. As a result, in the molded product S, the runner portion 52, the gate portion 54, and the sprue portion 56, which are the waste portions, are removed integrally from the movable mold 14.

As described above, the present embodiment is an injection molding apparatus 10 that obtains a molded product S by injecting a molten resin into a cavity 26. The injection molding apparatus 10 has an ejector mechanism 16. The ejector mechanism 16 separates the molded product S from the mold 14 that is opened after molding. The ejector mechanism 16 has a 1 st ejector pin 44 and a 2 nd ejector pin 46. The 1 st knock-out pin 44 presses the product portion 50 of the molded product S against the fixed mold 12 (in the direction of arrow B). The 2 nd knockout pin 46 presses a waste portion such as the runner portion 52 of the molded product S against the fixed mold 12. The molded product S has a notch portion 58 at the boundary between the product portion 50 and the gate portion 54 connected to the runner portion 52. The 1 st knockout pin 44 is disposed offset from the horizontal center of the runner portion 52 toward the notch portion 58.

Then, when the molded product S is taken out from the cavity 26, only the 1 st eject pin 44 of the 1 st eject pins 44 and the 2 nd eject pins 46 is driven. The 1 st knock-out pin 44 pushes the product part 50 out of the movable mold 14 toward the fixed mold 12. Thereby, the product portion 50 of the molded product S is pressed in the moment direction (downward) toward the runner portion 52 with the notch portion 58 as a fulcrum. Accordingly, in the molded article S, the product portion 50 and the runner portion 52 are gradually broken from the notch portion 58 by being twisted about the notch portion 58 as a fulcrum. The product portion 50 and the runner portion 52 are finally cut.

As a result, the 1 st eject pin 44 of the eject mechanism 16 presses the product portion 50 of the molded product S. The 1 st ejector pin 44 is offset to one side in the horizontal direction from the runner portion 52 that is a part of the discard portion. The molded product S has a notch 58 at the boundary between the product portion 50 and the gate portion 54. With these simple configurations, in the ejection step of opening the injection mold 17 and taking out the molded article S, the runner portion 52 and the like of the molded article S can be easily and reliably cut off from the product portion 50 and taken out.

The product portion 50 of the molded product S is pressed by the 1 st knock-out pin 44, and a waste portion such as a runner portion 52 and the product portion 50 are cut at a boundary. Then, the runner portion 52 and the like are pressed by the 2 nd ejector pin 46. Thereby, the runner portion 52 is pushed out from the recess 24 of the movable mold 14. After the injection mold 17 is opened, the product portion 50 and the runner portion 52 of the molded product S can be simultaneously separated and the product portion 50 and the runner portion 52 can be simultaneously taken out from the recess 24. Therefore, the manufacturing time for manufacturing the molded product S using the injection molding apparatus 10 can be shortened.

In another embodiment of the injection molding apparatus 10, the 2 nd ejector pin 46 may be advanced prior to the 1 st ejector pin 44 to press and release the runner portion 52. In this case, the 2 nd ejector pin 46 cuts the runner portion 52 at the boundary with the product portion 50 via the cutaway portion 58. Then, the 1 st ejector pin 44 is advanced, and the product portion 50 is stripped from the recess 24.

On the other hand, in the ejection step, after the injection mold 17 is opened as described above, the 1 st ejection pin 44 and the 2 nd ejection pin 46 are driven by the time difference, not limited to this. For example, in the ejection step shown in fig. 8A to 8C, the 1 st ejection pin 44 is advanced while the injection mold 17 is opened.

Specifically, fig. 8A shows the injection mold 17 which completes the molding of the molded article S and the mold clamping. In the injection mold 17, as shown in fig. 8B, the movable mold 14 is raised by a displacement mechanism, not shown. The movable mold 14 is separated from the fixed mold 12 by a predetermined distance to open the mold. At the same time, the 2 nd ejector pin 46 of the ejector mechanism 16 is driven by a control signal from a controller not shown. The 2 nd ejector pin 46 advances toward the fixed mold 12 (arrow B direction). The 2 nd ejector pin 46 is made to follow the movement of the movable mold 14 so that the runner portion 52 is held in contact with the divided surface 12a of the fixed mold 12.

That is, the 2 nd knockout pin 46 advances toward the fixed mold 12 (in the arrow B direction) by an amount corresponding to the displacement amount by which the movable mold 14 is displaced upward (in the arrow a direction). In other words, the 2 nd ejection pin 46 is advanced and presses the runner section 52. Thus, the runner portion 52 and the fixed mold 12 (the divided surface 12a) do not move relative to each other in a state where the runner portion 52 is held in contact with the divided surface 12a of the fixed mold 12.

On the other hand, the 1 st knock-out pin 44 is not advanced toward the fixed mold 12. The tip end of the 1 st knock-out pin 44 is held in the 1 st through hole 38. Thus, the product portion 50 of the molded product S is not pressed against the fixed mold 12 (in the direction of arrow B) by the 1 st knock-out pin 44. The product portion 50 rises together with the movable mold 14 in a state of being closely attached to the concave portion 24 of the movable mold 14.

The product portion 50 of the molded product S rises together with the movable mold 14. As described above, the runner portion 52 is retained to the fixed mold 12 by the 2 nd ejector pin 46. This generates a moment M about the boundary between the runner portion 52 and the product portion 50 in the molded product S. The molded article S starts to fracture the product portion 50 and the gate portion 54 from the notch portion 58 at the boundary. By the molded article S being fractured in the horizontal direction along the notch portion 58, the gate portion 54 and the product portion 50 are cut and separated at the boundary.

As described above, after the product portion 50 of the molded product S is separated from the gate portion 54 and the runner portion 52, the movable mold 14 is further lifted without driving the 2 nd knockout pin 46 as shown in fig. 8C. Thereby, the runner portion 52 is separated from the split surface 12a of the fixed mold 12. As the movable die 14 is raised, the driving source (not shown) is driven to advance the 1 st ejector pin 44 along the 1 st through hole 38. The leading end of the 1 st ejector pin 44 presses the product portion 50 against the fixed mold 12 (in the direction of arrow B). Thereby, the product portion 50 is separated from the gate portion 54, and the product portion 50 is taken out from the recess 24 by the 1 st eject pin 44.

In the above-described ejection step, when the injection molding apparatus 10 is opened, the 2 nd ejection pin 46 presses the waste portion such as the runner portion 52 against the divided surface 12a of the fixed mold 12 to make contact with the divided surface 12 a. Thus, by moving the movable mold 14, the product portion 50 held in close contact with the recess 24 and the runner portion 52 held in the fixed mold 12 can be cut from the notch portion 58.

Therefore, after the injection molding apparatus 10 is opened, the runner portion 52 and the product portion 50 can be separated simultaneously with the opening, unlike the case where the molded product S is taken out by the ejector mechanism 16. Therefore, the time can be shortened in the ejection process of the injection molding apparatus 10. The product portion 50 and the gate portion 54 can be cut off before the temperature of the molded product S is lowered. The molded product S can be cut more easily and reliably than when the molded product S is cut after curing.

In the molded product S, a waste portion such as the runner portion 52 is pushed out prior to the product portion 50. This can avoid the product portion 50 as a product from having a poor appearance.

The ejector mechanisms 16 including the 1 st ejector pin 44 and the 2 nd ejector pin 46 are both provided on the movable mold 14. Therefore, for example, the injection molding apparatus 10 can be made smaller than in the case where the 1 st knockout pin 44 is disposed on the movable mold 14 and the 2 nd knockout pin 46 is disposed on the fixed mold 12.

The injection molding apparatus 10 includes a runner portion 52, a gate portion 54, and a sprue portion 56, which function as a resin injection path, for each product portion 50. The product portion 50 may have a plurality of runner portions 52, a plurality of gate portions 54, and a plurality of sprue portions 56 depending on the shape or size thereof. In this configuration, the same effect can be obtained by providing the ejector mechanism 16 in accordance with the number of the disposal portions.

The ejector mechanisms 16 of the injection molding apparatus 10 each have a 1 st ejector pin 44 and a 2 nd ejector pin 46. The utility model is not limited thereto. The number of the 1 st and 2 nd knockout pins 44 and 46 may be a plurality of the 1 st and 2 nd knockout pins 44 and 46 in the knockout mechanism 16 depending on the size or shape of the molded product S and the number of the discarded parts.

The present invention is not limited to the above-described embodiments, and various configurations can be adopted without departing from the scope of the present invention.

Claims (5)

1. An injection molding die (10) for cutting a waste portion (52, 54, 56) of a molded article (S) molded by an injection molding die (17) in the die,

having a 1 st pin (44) and a 2 nd pin (46), wherein,

the 1 st pin presses a 1 st portion of the molded article, the 1 st portion being one of a product portion (50) and the disposal portion other than the product portion;

the 2 nd pin (46) presses a 2 nd portion, which is the other of the product portion and the disposal portion not pressed by the 1 st pin,

the molded article has a notch (58) at the boundary between the product portion and the disposal portion adjacent to each other in the width direction,

the 1 st pin is disposed at a position offset from a center of the disposal portion in a direction from the center of the disposal portion in the orthogonal direction to the width direction toward the cutout portion,

the 1 st portion is pressed by the 1 st pin, and the molded article is twisted with the notch portion as a fulcrum, thereby cutting the waste portion and the product portion at the boundary.

2. A method of ejecting a molded article obtained by the injection molding apparatus according to claim 1,

the 1 st part is pressed by the 1 st pin, the waste part and the product part are cut at the boundary, and thereafter,

the 2 nd portion is pushed by the 2 nd pin, and the 2 nd portion is ejected from the inside of the injection molding die.

3. A method of ejecting a molded article obtained by the injection molding apparatus according to claim 1,

the injection molding die has a stationary die (12) and a movable die (14), the movable die (14) approaching and separating with respect to the stationary die,

opening the die with the 1 st pin pressing the 1 st portion against either the fixed die or the movable die to cut the waste portion and the product portion,

and after the movable mold is opened relative to the fixed mold, ejecting the 2 nd part from the injection molding mold through the 2 nd pin.

4. The method of ejecting a molded article according to claim 2 or 3,

the 1 st pin presses the disposal portion, and the 2 nd pin presses the product portion.

5. The method of ejecting a molded article according to claim 3,

the 1 st pin and the 2 nd pin are disposed on the movable mold, respectively, and the 1 st pin presses the 1 st portion against the fixed mold.

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