JPH0820047A - Method and mold for press molding - Google Patents

Abstract

PURPOSE:To prevent molding deficiency such as a short shot and to easily perform mold processing and mold planning, in a method and mold for press molding, by devising the shape of the sprue formed to a lower mold by drilling processing. CONSTITUTION:In order to distribute and supply a semi-molten resin material to a lower mold 30 through an injection molding machine 50 and a manifold 33, the sprues 34 formed to the lower mold 30 by drilling processing are set so as to be inclined at a predetermined angle with respect to a vertical axis direction to make the center position of the block-shaped resin material distributed and supplied to the lower mold 30 from the sprues 34 eccentric in the inclined direction. By this constitution, even when the distance between the respective sprues 34 is too far, a short shot or the like can be prevented and a cooling pipe 35 or an ejector pin 36 can be arranged to the optimum position of the lower mold and the degree of freedom of shaping can be also enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold press molding method suitable for molding automobile interior parts and a mold press molding die used for the molding.

[0002]

2. Description of the Related Art For example, a mold press molding method can be mentioned as a method for molding automobile interior parts.

According to this mold press molding method, a semi-molten block-shaped resin material is distributed and supplied into the upper and lower molds for mold press molding, and the upper and lower molds are clamped to reduce the material loss, and the interior is excellent in moldability. It is possible to get the parts.

In order to carry out this mold press forming method, as shown in FIG.
The resin molding is molded between the upper and lower mold press molding dies 1 and 2 having a desired cavity shape. The method of supplying the resin material is performed through the injection molding machine 3 connected to the lower mold 1. .

That is, the resin material is supplied from the nozzle of the injection molding machine 3 to the manifold 4 arranged in the lower mold 1, and further communicates with the manifold 4.
A sprue 5 is perforated at a predetermined location on the lower die 1, and a semi-molten resin material is distributed and supplied to a predetermined location on the die surface of the lower die 1 through the sprue 5.

The order of designing the molds is as follows. First, when a slide piece is set in the lower die 1 at a position corresponding to the undercut portion of the molded product, a slide piece and a tilt knock are set, and then the lower die 1 is set. A manifold 4 for supplying a resin material from the injection molding machine 3 is housed and installed therein.

After that, the sprue 5 is drilled in the lower mold 1 so as to communicate with the manifold 4, and then the cooling pipe 6 is piped and the ejector pin 7 is installed in the lower mold 1. This is the general order of design.

[0008]

However, in the conventional mold for press-molding, since the sprue 5 is drilled in the order after the tilt knock is set, the setting position is restricted so as not to interfere with the tilt knock. Therefore, if the molding is defective such as a short shot or the distance between the sprues 5 is large, problems such as skin wrinkles due to welds and reduction in strength occur.

This means that the setting position of the sprue 5 should be given the highest priority in consideration of L / T (L; distance, T; resin flow), but as described above, the setting position of the tilt knock should be avoided. This is because the sprue 5 must be set at the position.

Further, since the cooling pipe 6 and the ejector pin 7 must be set at a position where they do not interfere with the sprue 5 and cannot be provided at the optimum proper position, deformation of the molded product due to insufficient cooling and the ejector. This causes defective molding such as deformation at the time of demolding due to imbalance of the pins 7.

Further, the sprue 5 formed by punching the lower mold 1
11 schematically shows the state in which the resin material is distributed and supplied through the sprue 5.
a, 5b, 5c, 5d, the sprue 5 is the mounting plate 1a.
Since it is usually installed in the vertical direction orthogonal to
Are supplied in a shape close to a perfect circle, and the supply amount of the resin material M is adjusted by the sprue 5 as shown in the time chart of FIG.
a, 5b, 2 seconds for sprue 5c, 3 seconds for sprue 5d, 1 second for sprue 5d, so that each sprue is controlled so that molding defects such as short shots and weld lines do not occur. There is.

Therefore, it has been pointed out that the molding cycle is prolonged.

The present invention has been made in view of the above circumstances, and by adding a device to the sprue formed in the lower die for mold press molding, molding defects such as short shots and formation of weld lines can be prevented. It can be prevented as much as possible, and it is possible to install cooling pipes and ejector pins at appropriate positions. In addition, it is possible to save the labor of adjusting the supply amount of resin material for each sprue and shorten the molding cycle. An object of the present invention is to provide a mold press molding method and a mold press molding die used for the molding.

[0014]

In order to achieve the above-mentioned object, the present invention has a cavity formed between upper and lower molds for mold press molding, and a lower mold is bored from an injection molding machine through a manifold. In the mold press molding method in which a block-shaped semi-molten resin material is distributed and supplied from the sprue onto the mold surface of the lower mold, and the upper and lower molds are clamped to mold-mold a molded product of the required shape, the sprue is vertically It is characterized in that the semi-molten resin material is eccentrically supplied in the inclination direction through the sprue by setting the inclination with respect to the shaft.

Further, the mold for molding according to the present invention has a sprue which is connected to the injection molding machine and the manifold, and is provided with a cavity of a desired shape. In a mold for mold press molding, which comprises an upper mold for mold press molding configured to be movable up and down so as to be lowered to a predetermined clearance, the sprue is set to be inclined at a predetermined angle with respect to a vertical axis. It is characterized by

[0016]

As apparent from the above construction, since the sprue to be drilled in the lower die is set in a state of being inclined at a predetermined angle with respect to the vertical axis, the sprue is distributed and supplied onto the lower die surface. The resin material to be supplied can be supplied in a state of being eccentric in the direction of inclination rather than in a perfect circle with the sprue outlet (supply port) as the middle point, so even if the distance between sprues is too long, By adjusting the tilt angle, it is distributed and supplied to appropriate places, and short shots etc. do not occur.

Further, in designing the mold, the position of the sprue outlet (supply port) is first determined, and then the inclined knock, the manifold, the cooling pipe, and the ejector pin are laid out to avoid these layout members. Since the sprue can be drilled as described above, the cooling pipe and the ejector pin can be set at an ideal position, and there is no problem of deformation due to insufficient cooling and imbalance of the ejector pin.

[0018]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

1 and 2 are a front view and a sectional view showing an automobile door trim manufactured by applying the method of the present invention, and FIG. 3 shows a structure of an embodiment of a mold for press molding according to the present invention. FIG. 6 is a cross-sectional view, FIG. 4 is a plan view showing a configuration of a lower mold in the mold for press molding, and FIG. 5 is an explanatory view showing a supply state of a resin material in the mold for press molding according to the present invention. 8 shows a mold press molding method according to the present invention, FIG. 6 is a sectional view showing a material setting step, FIG. 7 is a sectional view showing a resin material supplying step, and FIG. 8 is a sectional view showing a mold press molding step. It is a figure. FIG. 9 is a sectional view showing another embodiment of the mold for press molding according to the present invention.

First, referring to FIGS. 1 and 2, the structure of an automobile door trim manufactured by applying the method of the present invention will be described.
Briefly explained.

The automobile door trim 10 has a resin core material 11 having a proper shape retention property and a mounting rigidity to a vehicle body panel, and is integrally attached to the surface of the resin core material 11 to provide cushioning property and decorative property. And a skin material 12.

In this embodiment, as the resin core material 11,
Molded into a curved shape as shown by molding press molding a composite resin material in which 10 parts by weight of a filler such as talc is mixed with 90 parts by weight of a polypropylene resin. , Skin material 1
2 is attached integrally.

Next, the automobile door trim 10 described above.
The mold press molding die 20 used for the mold press molding will be described with reference to FIGS. 3 and 4.

This mold press molding die 20 comprises a mold press molding lower mold 30 and a mold press molding upper mold 40 which is paired therewith and is configured to be movable up and down.
As a resin material supply mechanism for distributing and supplying a semi-molten resin material to a predetermined portion of the lower mold 30 for mold press molding,
The injection molding machine 50 is connected to the lower mold 30.

More specifically, the lower die 30 for mold press molding is attached to a mounting plate 31 so that the cavity 32 forming the product shape of the door trim 10 has a desired curved surface shape, as shown in FIG. Is set,
A manifold 33 is housed and installed in the lower mold 30 so as to communicate with the nozzle 51 of the injection molding machine 50. Sprues 34 are drilled at four positions of the lower mold 30 so as to communicate with the manifold 33. Has been formed.

A cooling pipe 35 for cooling the molded product is provided in the lower mold 30, and an ejector pin 36 for pushing the molded product upward is installed at a predetermined position when the molded product is released from the mold. There is.

On the other hand, the upper die 40 has a die surface having the same shape as the cavity 32 of the lower die 30, and is attached to a mounting plate 41, which is connected to an elevating mechanism (not shown). The upper die 40 is configured to be vertically movable by a predetermined stroke.

By the way, the feature of the present invention is that the sprue 34 punched in the lower mold 30 for mold press molding is installed in the form shown in FIG.
As shown in, the feature is that it is set in an inclined shape.

That is, the sprue 34 is conventionally set in a direction orthogonal to the mounting plate 31 (vertical axis direction).
In the present invention, the tilt angle is set to 30 ° in this embodiment with respect to the vertical axis.

This will be described in detail with reference to FIGS. 4 and 5. The sprues 34 formed at four locations on the lower die 30 will be described as 34a, 34b, 34c and 34d, respectively. , For example, sprues 34a, 34
When the sprue 34c is set at an extremely distant position with respect to b and 34d (the cooling pipe 35 and the ejector pin 3).
6), the vertical sprue 34 has a short shot or a weld line formation as in the conventional case, but as in the present invention, it is inclined about 30 ° toward the center. Since the sprue 34c is set, the semi-molten resin material M distributed and supplied from each sprue 34 is schematically represented in FIG. 4 by the locus shown by each imaginary line. The resin material M supplied from is distributed and supplied from the outlet P of the sprue 34c in a state where the midpoint P1 of the resin material is eccentric to the center side.

As described above, even when the distance between the sprues 34 is too long, if the sprues 34 are inclined at a predetermined angle in the supply direction as in the present invention, there is no defective molding such as short shot or weld line formation. The semi-molten resin material can be appropriately distributed and supplied.

Therefore, as in the conventional case, each sprue 34
Since it is not necessary to control the injection of the resin material through the gate for each time a, 34b, 34c, 34d (between 1 second and 3 seconds), there is also an advantage that the molding cycle can be shortened.

Further, also in the mold design of the lower mold 30 for mold press molding, the outlet of the sprue 34 is first determined, and then the inclined knock pin is arranged and the manifold 33 is formed.
Mounting of the cooling pipe 35, installation of the ejector pin 36, and then the sprue 34 may be drilled in the lower mold 30 so as to connect the manifold 33 and the outlet of the sprue 34. The degree of freedom in design is improved, and the cooling pipe 35 and the ejector pin 36 are provided.
Can be installed in an ideal place, and the defects such as deformation of the molded product due to insufficient cooling and deformation due to improper balance of the ejector pin 36 do not occur, and defective molding can be prevented as much as possible. There is.

FIGS. 6 to 8 show an embodiment applied to the method of molding the automobile door trim 10 shown in FIGS. 1 and 2. As shown in FIG. 6, upper and lower molds 30 and 40 for mold press molding are shown. When the mold is in the mold open state, the upper and lower molds 30, 4
The skin material 12 is set between 0s with the peripheral edge held by the clamp device 60.

After that, as shown in FIG. 7, when the upper die 40 for mold press molding moves down by a predetermined stroke and the clearance between the upper and lower dies 30, 40 reaches 10 to 30 mm, the injection molding machine 50, the manifold. Through the 33 and the sprue 34, the semi-molten resin material M is distributed and supplied onto the mold surface of the lower mold 30.

At this time, as shown in FIG.
Is inclined, even if the distance between the sprues 34 is too long, the resin material can be supplied in an eccentric state, which does not cause a short shot or the like.

After that, as shown in FIG. 8, the upper die 40 for mold press molding descends to the bottom dead center, and the semi-molten resin material M is molded along the shape of the cavity 32 by a predetermined press pressure. Press forming and skin material 12
Are integrated into a vehicle door trim 1 shown in FIGS.
0 molding is completed. The press pressure at this time is 80k
It is set to g / cm ² and the pressing time is 30 seconds.

Thus, according to the method of the present invention, the lower mold 3
By setting the sprue 34 provided at 0 in an inclined shape, it is possible to properly supply the resin material M that is distributed and supplied to a predetermined position on the mold surface of the lower mold 30, and to prevent molding defects such as short shots. This is advantageous in that it can be prevented in advance, and that the installation location of the sprue 34 can be set arbitrarily, so that the degree of freedom in forming the molded product can be dramatically improved.

Further, since the sprue 34 is set in an inclined shape, the cooling pipe 35 and the ejector pin 36 can be set at optimum proper positions, and the conventional problems such as insufficient cooling and improper balance of the ejector pin can be effectively solved. .

Next, FIG. 9 shows another embodiment of the mold for press molding according to the present invention, in which the sprue 34 is
The sprue 34 is set in the concave portion 32a of the cavity 32, and is slanted toward the vertical wall portion 32b of the cavity 32.

According to this embodiment, the semi-molten resin material M that is distributed and supplied through the sprue 34 is sufficiently spread even in the vertical wall portion 32b, which is apt to be defectively filled, and the portion contacting the skin material 12 is not present. Since the resin temperature is slightly lowered, the adverse effect of the resin heat on the skin material 12 can be minimized.

As described above, by installing the sprue 34 of the present invention set in an inclined shape according to the shape of the product, it is possible to effectively solve the defective molding and the defective appearance of the skin material 12, and the method of the present invention is applicable. It is a wide invention.

[0043]

As described above, the present invention has the following special operational effects.

(1) In the method of the present invention, in order to distribute and supply the semi-molten resin material onto the mold surface of the lower mold for mold press molding, the sprue to be drilled in the lower mold is set in an inclined shape. By doing so, the center position of the block-shaped resin material supplied onto the lower mold is eccentric in the tilt direction, so that even if the relative distance between the sprues is extremely large, the Further, there is an effect that molding accuracy such as a short shot does not occur and molding accuracy can be significantly improved.

(2) According to the method of the present invention, by setting the sprue in an inclined shape, the central position of the block-shaped resin material distributed and supplied onto the lower mold is decentered in the inclination direction. Therefore, in the mold design, after installing the ejector pin, the cooling pipe can be drilled with sprue so as to communicate with the manifold, so that the cooling pipe and the ejector pin can be installed in the appropriate positions of the lower mold.
The conventional problems such as distortion deformation of the molded product due to insufficient cooling and deformation at the time of demolding due to improper balance of the ejector pins can be effectively solved, and distortion deformation and deformation at the time of demolding can be reliably prevented.

(3) According to the method of the present invention, the center position of the resin material distributed and supplied onto the lower mold is eccentric in the tilt direction by setting the sprue to be drilled in the lower mold in an inclined shape. Therefore, unlike the conventional method, it is not necessary to control the amount of resin material input for each sprue, and by setting the inclination angle of each sprue, the amount of resin material supplied from each sprue can be adjusted. It has the effect that it can be set uniformly and the molding cycle can be shortened.

(4) According to the method of the present invention, the center position of the block-shaped resin material distributed and supplied onto the lower die is set in the inclination direction by setting the sprue to be drilled in the lower die in an inclined shape. Since the eccentricity of the sprue can be set arbitrarily, the sprue can be set at any position, which has the effect of significantly improving the molding flexibility of the molded product.

[Brief description of drawings]

FIG. 1 is a front view showing an automobile door trim manufactured by using the method of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a first part of a mold for press molding according to the present invention.
Sectional drawing which shows an Example.

4 is a plan view showing a configuration of a lower die for mold press molding, which is a view taken in the direction of arrow A in FIG. 3. FIG.

FIG. 5 is a first part of a mold for press molding according to the present invention.
Sectional drawing which shows the principal part in an Example.

FIG. 6 is a cross-sectional view showing how materials are set in a mold for molding according to the present invention.

FIG. 7 is a cross-sectional view showing a state of distribution and supply of a resin material in the mold for mold press molding according to the present invention.

FIG. 8 is a cross-sectional view showing a state during mold press molding in the mold press molding die according to the present invention.

FIG. 9 is a cross-sectional view showing the main parts of another embodiment of the mold for press molding according to the present invention.

FIG. 10 is a cross-sectional view showing the overall configuration of a conventional mold for press molding.

FIG. 11 is a plan view showing the configuration of a lower die in a conventional mold for press molding.

FIG. 12 is a time chart diagram for supplying a resin material when a conventional mold for press molding is used.

[Explanation of symbols]

 10 Automotive Door Trim 11 Resin Core Material 12 Skin Material 20 Mold Press Molding Mold 30 Mold Press Molding Lower Mold 32 Cavity 33 Manifold 34 Sprue 35 Cooling Pipe 36 Ejector Pin 40 Mold Press Molding Upper Mold 50 Injection Molding Machine M Resin material

Claims (4)

[Claims] 1. Upper and lower molds (30, 4) for mold press molding
0) in the cavity formed between the injection molding machine (5
0) through the manifold (33) to the lower mold (30)
After the block-shaped semi-molten resin material (M) is distributed and supplied to the mold surface of the lower mold (30) from the sprue (34) perforated in the lower mold (30), the upper and lower molds (30, 40) are clamped. In a mold press molding method for molding a shaped molded article, the semi-molten resin material (M) is tilted through the sprue (34) by setting the sprue (34) in an inclined shape with respect to a vertical axis. A mold press-molding method, which comprises eccentrically supplying in a direction. 2. An injection molding machine (50), a manifold (3)
3) A sprue (34) connected to the lower mold (30) for forming a mold is provided with a cavity (32) having a desired shape, and a sprue (34) connected to the lower mold (30) can be lowered to a predetermined clearance. A mold press molding die comprising a mold press molding upper die (40) configured to be movable up and down, wherein the sprue (34) is inclined at a predetermined angle with respect to a vertical axis. Mold for press molding. 3. The sprue (34) drilled into the lower mold (30) has a lower mold (30) with a semi-molten resin material supply port.
Is set in the concave (32a) surface of the cavity (32) of
The mold for mold press molding according to claim 2, wherein the mold is inclined toward the vertical wall portion (32b). 4. The mold press according to claim 2, wherein the sprue (34) formed in the lower mold (30) is inclined at an inclination angle of 10 to 40 ° with respect to the vertical axis. Mold for molding.