JPH07214620A - Mold assembly, and molding method of resin product using the mold assembly - Google Patents

Abstract

PURPOSE:To mold a thin-wall part without occurrence of molding failures, such as underfill, void, and weld, and mold an opening-free resin product and a resin product with an opening without requiring postforming. CONSTITUTION:A movable member 15 is driven to a retracting position where the top surface is flush with a molding surface 11. A required amount of resin in a melt state is injected into a product part 23. In this manner, a resin 26 in a melt state is charged into the product part 23. Next, the movable member 15 is projected into the product part 23. In this state, the resin is cooled to be set under a dwell pressure. In this manner, the molten resin 26 is set, and a resin product 27 is molded in the product part 23. The molded resin product 27 is provided with a recessed part 28 at a position which has been occupied by the movable member 15 and a thin-wall part 29 corresponding to the recessed part 28.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold device used for molding a resin product having a partial thin portion or an opening, and a method for molding a resin product using the mold device.

[0002]

2. Description of the Related Art Conventionally, for example, in a resin bumper mounted on an automobile, a structure in which a fog lamp is mounted is different from a structure in which the fog lamp is not mounted. That is, the resin bumper used for the specification vehicle with the fog lamp installed has an opening for mounting the fog lamp, whereas the resin bumper used for the specification vehicle without the fog lamp has no opening. Has been formed.

When manufacturing these two types of resin bumpers, only the non-open resin bumper is molded, and the non-open resin bumper is installed as it is in a vehicle without a fog lamp. In addition, a vehicle equipped with a fog lamp is equipped with a resin bumper in which an opening for assembling the fog lamp is formed by cutting a predetermined portion with a trimming jig or a water jet. That is, in the case of manufacturing two types of resin products having the same overall shape and differing only in whether or not there is an opening in a part thereof, only an unopened product is molded,
Two types of resin products are obtained by forming the openings by post-processing. As a result, a single mold is shared by two types of resin products, and the cost required for the mold is reduced.

[0004]

However, if only a non-open product is molded using a single mold, post-processing is indispensable as described above when a resin product having an opening is obtained. Become. Therefore, although the cost required for the mold can be reduced, post-processing requires time and cost when obtaining a resin product having an opening. Therefore, in order to facilitate the post-processing, it has been considered to form a partial convex portion on the product part of the mold and preliminarily form a thin portion of the opening for post-processing. However, if a part of the product is extremely thinly molded, molding defects such as lack of thickness, voids, and welds will occur. The reality is that they are molded.

The present invention has been made in view of the above-mentioned conventional circumstances, and makes it possible to form a thin-walled portion without causing molding defects such as lack of wall thickness, voids, and welds, and to perform post-processing. It is an object of the present invention to provide a mold device capable of molding a resin product having no opening and a resin product having an opening, and a method for molding a resin product using the mold device without needing to do so. is there.

[0006]

In order to solve the above-mentioned problems, in a mold apparatus according to the present invention, a movable member capable of advancing into and retracting from the product section formed in the mold. And driving means for driving the movable member forward and backward. Further, in the method of molding a resin product according to the present invention, using a mold device having a movable member capable of advancing into and retracting from the product section,
A method of molding a resin product having a partially thin portion or an opening, comprising: an injection step of injecting a molten resin into the product portion in a state where the movable member is retracted from the inside of the product portion; After the start or after the end, a movable member driving step of advancing the movable member into the product portion by a predetermined amount, and a mold pressure holding step of cooling and solidifying the resin while holding the pressure while the movable member has advanced into the product portion. After the die pressure-holding step, the die device is opened to release the resin product from the product section.

[0007]

When performing the molding method using the mold apparatus, the injection step is performed with the movable member retracted from the inside of the product section, and the molten resin is filled into the product section. Next, after the start or end of this injection step, the movable member driving step is executed to advance the movable member by a predetermined amount into the product section. After that, in a state where the movable member is advanced into the product part, the resin in the product part is cooled and solidified while the pressure is maintained in the mold pressure maintaining step. Then, in the final step, the demolding step, the mold device is opened to separate the solidified resin product from the product section.

In the resin product separated from the product part, a thin portion or an opening is formed in a corresponding part in accordance with the amount of the movable member driven in the movable member driving step into the product part. Has been done. That is, when the movable member is advanced from one of the wall surfaces forming the product portion to the intermediate position of the product portion, the thin portion is formed by the concave portion having a shape corresponding to the movable member. Further, the thickness of the thin portion differs depending on the amount of advancement of the movable member into the product portion. On the other hand, when the movable member is advanced from one wall surface of the product portion facing each other to a position where it abuts on the other wall surface, an opening having a shape corresponding to the movable member is formed in the resin product.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. That is, as shown in FIG.
It is composed of a fixed mold 2 and a movable mold 3. The fixed mold 2 has a lower mounting plate 4 at its lower end and is fixed at a predetermined position by the lower mounting plate 4. A lower block 5 is fixed on the lower mounting plate 4. A spool bush 7 is vertically fitted in the central portion of the lower block 5, and a through resin passage 6 is provided in the axial center portion of the spool bush 7. Further, a concave receiving portion 8 is formed on the upper surface of the lower block 5, which is a side portion of the spool bush 7.

An upper block 9 is fixedly arranged on the lower block 5. A ridge 10 is provided in the center of the upper block 9, and fixed side guide blocks 20, 20 are fixed to the periphery of the ridge 10. A molding surface 11 for molding the lower surface side of a predetermined resin product is provided on the upper end surface of the raised portion 10.
A gate 12 that communicates with the resin passage 6 is provided at the center of the. The side surface of the molding surface 11 has a through passage 1
3 is provided in the vertical direction, and the through passage 13 communicates with the receiving portion 8 via a large diameter portion 14 having a step portion 14a, as shown in FIG.

A support member 18 is fixedly arranged in the receiving portion 8, and a hydraulic cylinder 25 as a driving means is fixed to the support member 18. The hydraulic cylinder 2
5 has a piston rod 16 that can move back and forth, and a first port 25a and a second port 25b. Both ports 25a, 25b are connected to a hydraulic power source (not shown),
The piston rod 16 is driven forward by the hydraulic pressure supplied from the first port 25a, and the piston rod 16 is driven backward by the hydraulic pressure supplied from the second port 25b. The piston rod 16 is surrounded by a space 13
In the state of having a, it is loosely inserted in the through passage 13, and the movable member 15 is fixed to the tip portion thereof. The movable member 15 is slidably arranged with its peripheral surface in close contact with the peripheral wall of the through passage 13.

On the other hand, the movable mold 3 has an upper mounting plate 19 at the upper end, and is mounted on a vertical drive mechanism (not shown) via the upper mounting plate 19. Also,
The movable side mold 3 includes the fixed side guide block 2
Movable-side guide blocks 21 and 21 which are in sliding contact with 0 and 20 are provided. This movable guide block 21, 21
In the middle of the lower surface of the movable side mold 3, the molding surface 22
Is provided, and the molding surface 22 of the movable mold 3 and
A product part 23 is formed by the molding surface 11 of the fixed side mold 3.

In this embodiment having the above-mentioned structure, at the time of molding, as shown in FIG. 1, the fixed side mold 2 and the movable side mold 3 are matched with each other to form the product portion 23. At this time, the amount of hydraulic pressure supplied from both the ports 25a and 25b is adjusted to a predetermined amount to control the amount of advance / retreat of the piston rod 16, and as shown in FIG. It is driven to a retracted position where it is flush with the molding surface 11.

Subsequently, the "injection process" is executed, through the resin passage 6 of the spool bush 7 and the gate 12,
A predetermined amount of molten resin is injected into the product portion 23. As a result of this injection step, as shown in FIG.
The resin 26 in a molten state is filled inside. At this time, since the movable member 15 is driven to the retracted position, the molten resin 26 reaches the end of the product portion 23 without being hindered by the movable member 15.

After the injection process is started or completed, a predetermined amount of hydraulic pressure is supplied to the hydraulic cylinder 25 from the first port 25a side. As a result, the “movable member driving step” is executed, the piston rod 16 is driven forward, and the movable member 15 is moved to the product section 2 as shown in FIG.
Advance to the prescribed position within 3. Next, a "mold pressure holding step" is executed to cool and solidify the resin while holding the pressure while the movable member 15 has advanced into the product portion 23. By this mold pressure-holding step, the molten resin 26 is solidified, and a resin product 27 is molded in the product portion 23 as shown in FIG.

Further, after the pressure-holding process is completed, the movable mold 3 is raised to open the mold device 1 to execute a "demolding process" to separate the resin product 27 from the product section 23. As a result, as shown in FIG. 3 (E), the movable member 1
5 has a recess 28 at the position where
Accordingly, the resin product 27 having the thin portion 29 can be obtained. In the resin product 27, as described above, with the movable member 15 retracted from the product unit 23,
By performing the injection process, the molten resin 26 reaches the end of the product portion 23 without being blocked by the movable member 15. Therefore, the thin portion 29 can be formed without causing molding defects such as lack of wall, void, and weld.
It is possible to form a resin product 27 having

After the completion of this demolding process, the hydraulic pressure is supplied to the piston rod 1 from the second port 25b in a predetermined amount.
By moving the movable member 15 backward, the movable member 15 is driven to the retracted position where the top surface thereof is flush with the molding surface 11.
As a result, when the movable side mold 3 is lowered during the molding of the next product, the state of FIG. 3A is set, and the molding of the next product can be performed by the same steps as described above. In the movable member driving step shown in FIG. 7C, the amount of hydraulic pressure supplied to the first port 25a is controlled to change the amount of advancement of the movable member 15 to the product portion 23, thereby reducing the thin portion 29. It is also possible to mold resin products 27 having different wall thicknesses.

FIG. 4 is a process diagram showing a method for molding a resin product according to another embodiment of the present invention. In FIG. 4, the mold matching in (A) and the injection process in (B) are shown in FIG. It is similar to the embodiment shown. However, in the "movable member driving step" shown in FIG. 7C, the movable member 15 is advanced to a position where the top surface of the movable member 15 contacts the molding surface 22 of the movable mold 3. Then, as shown in FIG. 6D, the mold pressure holding step is performed in this state, and then the demolding step is performed, so that the opening 30 is provided as shown in FIG. The resin product 27 can be molded. Also,
After the injection process of (B) is completed, if the mold pressure holding process and the mold releasing process are executed as they are without driving the movable member 15, as shown in FIG. It is also possible to obtain a resin product that does not.

If the amount of resin to be filled in the product portion 23 is set in advance in accordance with the amount of the movable member 15 entering the product portion 23, molding can be performed without overfilling. That is, the filling amount of the resin when the movable member 15 is retracted from the inside of the product unit 23 is 100%, and the product unit 2
Assuming that the volume occupied by the movable member 15 that advances into the inside 3 is 5%, by filling 95% of the resin, the resin product 27 having the thin portion 29 or the opening 30 can be molded without overfilling. .

[0020]

As described above, according to the present invention, a movable member capable of advancing into and retracting from the product section,
A mold device having drive means for driving the movable member is configured, and the molten member is injected into the product portion in a state where the movable member is retracted from the inside of the product portion, and then the movable member is advanced into the product portion. I did it. Therefore, it is possible to spread the molten resin to the end of the product section without being hindered by the movable member, and thereby locally forming a thin wall without causing molding defects such as lack of wall, void, and weld. A resin product having parts can be formed.

Further, it is possible to freely mold a resin product having thin-walled portions having different wall thicknesses according to the amount of advance of the movable member into the product portion. Furthermore, by advancing the movable member from one wall surface of the product portion facing each other to a position where it abuts on the other wall surface, a resin product having an opening can be molded, and the movable member is attached to the product portion. By molding without advancing, it is also possible to mold an open-ended resin product. Therefore, an unopened product and a product having an opening can be selectively formed using only a single mold device. As a result, the thin portion can be easily and surely formed, and the molded product can be easily post-processed. Furthermore, it is possible to efficiently form a non-open resin product and a resin product having an opening selectively without the need for post-processing to perform cutting using an instrument such as a trimming jig or a water jet. Is possible.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a mold device according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a main part of the mold device.

FIG. 3 is a process drawing of a molding method according to an embodiment of the present invention.

FIG. 4 is a process drawing of a molding method according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mold device 2 Fixed side mold 3 Movable side mold 13 Through passage 15 Movable member 25 Hydraulic cylinder (driving means)

Claims (2)

[Claims] 1. A mold which is provided with a movable member capable of advancing into and retracting from the product part formed in the mold, and a drive means for driving the movable member forward and backward. apparatus. 2. A method for molding a resin product having a partially thin portion or an opening by using a mold device having a movable member capable of advancing into and retracting from the product portion. An injection step of injecting a molten resin into the product section with the movable member retracted from the inside of the product section, and a movable member driving step of injecting the movable member into the product section by a predetermined amount after starting the injection step. And a mold pressure step of cooling and solidifying the resin while pressure is maintained in a state where the movable member has advanced into the product part, and after completion of the mold pressure step, the mold device is opened to release the resin product from the product part. A molding method for a resin product, comprising: