KR102203326B1 - Injection mold for reducing weld-line around hole in vehicle panel - Google Patents

Abstract

An injection mold for reducing weld lines around a hole in a vehicle panel is disclosed. In order to manufacture a molded article for a vehicle panel in which a hole for bypassing the flow of the molten resin discharged from the gate and filled in the cavity is formed, the injection mold for reducing weld lines around the hole of the vehicle panel according to the present invention has a first mold and a second mold. Including a mold, and in at least one of the first mold and the second mold, the flow of the molten resin around the hole of the vehicle panel by generating a negative pressure in the cavity opposite the gate centering on the area corresponding to the hole It characterized in that it is provided with a negative pressure forming unit to improve the performance. According to the present invention, a negative pressure forming part provided in at least one of the first and second molds for manufacturing a molded article for a vehicle panel in which a hole for bypassing the flow of the molten resin discharged from the gate and filled in the cavity is formed. As a certain negative pressure is generated in the cavity opposite the gate around the area, the molten resin discharged from the gate can maintain a uniform level of flowability until it reaches the opposite side of the gate. Because of this, surface defects such as gas marks due to gas emitted from the weld line or the molten resin around the hole due to the decrease in flowability can be effectively reduced, and furthermore, there is an effect that the high-quality and high-quality injection-molded products are achieved.

Description

Injection mold for reducing weld line around the hall of vehicle panel{INJECTION MOLD FOR REDUCING WELD-LINE AROUND HOLE IN VEHICLE PANEL}

The present invention relates to an injection mold for reducing weld lines around a hole in a vehicle panel, and more particularly, to an injection mold that bypasses due to a hole formed in a molded article for a vehicle panel and improves the flowability of the molten resin filled in the cavity. About.

In recent years, the injection molding industry has focused on research and development, focusing not only on dimensional accuracy, but also on high quality that satisfies sensitivity and function for high-end products, moving away from simply emphasizing excellent moldability and mass production at low cost. .

In other words, in the recent injection molding industry, in order to enhance the appearance of the product, a predetermined pattern is engraved on the surface of the product, and functions such as high-quality matte texture and touch, and anti-slip are specifically implemented. It is increasing added value.

However, the undercut that occurs as the structure and shape of injection molded products become more and more complicated with such high quality and high quality, and the large and small holes provided in the molded product make it difficult to design the mold used to manufacture the injection molded product. Rather, it causes a problem that impairs the quality of the molded product.

In particular, the holes formed in the molded product are formed only in a closed enclosed area that does not allow penetration of the molten resin discharged from the gate of the mold closed, and the following problems arise depending on the relative position of the gate and the hole area.

For example, the hole position as shown in FIG. 6 is a position facing the gate G, so that the discharged molten resin is a cavity adjacent to the gate side based on the area HM corresponding to the hole structurally. After being filled in CG), it is bypassed and merged in the opposite cavity (COG) at a time difference, and is bound to be filled.

The parallax problem that occurred during the filling process of the molten resin in the mold is that the molten resin merges in the cavity opposite the gate (COG) based on the hole formation position, and gas marks and gas marks caused by the enveloping of the gas emitted from the molten resin It causes the same appearance quality problem.

Therefore, there is an urgent need to propose a new and efficient mold technology or process technology that can fundamentally solve this by responding to the continuous demand for high-quality and high-quality injection molded products.

It is an object of the present invention to bypass due to the positional relationship between a hole formed in a molded article for a vehicle panel and a gate for discharging the molten resin, and allow the molten resin filled in the cavity to maintain uniform flow around the hole of the vehicle panel. It is to provide an injection mold for reducing weld lines around the hole of a vehicle panel that can minimize the occurrence of weld lines or gas marks on the surface around the hole.

The object is to manufacture a molded article for a vehicle panel in which a hole is formed for bypassing the flow of the molten resin discharged from the gate and filled in the cavity, including a first mold and a second mold, and the first mold and the second mold At least one of the at least one of, characterized in that it is provided with a negative pressure forming unit for improving the flowability of the molten resin around the hole of the vehicle panel by generating a negative pressure in a cavity opposite to the gate centering on a region corresponding to the hole. This is achieved by a reduced weld line injection mold around the hole in the vehicle panel.

The negative pressure forming unit may include an exhaust hole formed through a cavity opposite to the gate so as to communicate with the outside air to induce gas discharge in the cavity; A valve core sliding and selectively opening and closing one side of the exhaust hole; And an opening/closing control unit coupled to the valve core and variably controlling an opening/closing operation of the valve core according to a pressure state in the cavity.

The opening/closing control unit may include a spring providing a predetermined elastic force to the supporting end of the valve core so that the shielding end of the valve core closes the exhaust hole; And a rotation support screw provided on the other side of the spring and moving back and forth according to the forward/reverse rotation and variably compressing the spring to adjust the elastic force.

The negative pressure forming part may include an exhaust hole formed through a cavity opposite to the gate to communicate with outside air; And a valve core provided on one side of the exhaust hole, deformed according to a pressure or temperature state in the cavity, and opening and closing the exhaust hole.

The valve core may be made of a check valve made of an elastic material that is elastically deformed in proportion to the pressure in the cavity and opened, or may be made of a check valve made of a shape memory alloy that is shape-deformed in proportion to the temperature in the cavity and opened.

The negative pressure forming part may further include a suction device installed to communicate with the outside of the exhaust hole in order to force the opening operation of the valve core.

The negative pressure forming part may further include a gap part that communicates with a cavity forming a molded article for a vehicle panel and is disposed along the circumference thereof to assist the discharge of gas in the cavity.

The gap is formed between an uneven portion formed by alternately arranging a protruding portion having the exhaust hole and a recessed portion formed along the circumference of a cavity forming a molded article for a vehicle panel, and a slide core having a complementary shape engaged with the uneven portion. I can.

A coating layer on at least one of the facing surfaces of the first mold and the second mold forming the cavity by a physical vapor deposition method (PVD) using a metal material having a property similar to that of a molten resin injected into the cavity as a deposition source Can be formed.

The molded article is formed by any one of a method of injection-molding a resin including at least one of PC, ABS, PP, PE, and PS resin as a material, or injection molding of carbon fiber reinforced plastic by overmolding. Can be.

According to the present invention, a negative pressure forming part provided in at least one of the first and second molds for manufacturing a molded article for a vehicle panel in which a hole for bypassing the flow of the molten resin discharged from the gate and filled in the cavity is formed. As a certain negative pressure is generated in the cavity opposite the gate around the area, the molten resin discharged from the gate can maintain a uniform level of flowability until it reaches the opposite side of the gate. Because of this, surface defects such as gas marks due to gas emitted from the weld line or the molten resin around the hole due to the decrease in flowability can be effectively reduced, and furthermore, there is an effect that the high-quality and high-quality injection-molded products are achieved.

1A and 1B are a perspective view showing a molded open state of a weld line reduction injection mold around a hole of a vehicle panel according to an embodiment of the present invention and a photograph of a prototype taken in practice.
2 is a plan view showing an arrangement of the negative pressure forming unit of FIG. 1.
3 is a cross-sectional view taken along line AA of FIG. 2 for showing a specific configuration and operation state of a negative pressure forming unit according to an embodiment of the present invention.
4 is a cross-sectional view taken along line AA of FIG. 2 for showing a specific configuration and operation state of a negative pressure forming unit according to a modification of the present invention.
5 is a photograph of the surface of a molded article before and after PDV coating is applied to the first and second molds.
6 is a view showing a decrease in flowability of a molten resin occurring around a hole in a vehicle panel when a molded article for a vehicle panel having a hole formed thereon is injection-molded in a conventional manner.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, in describing the present invention, a description of a function or configuration that is already known will be omitted in order to clarify the gist of the present invention.

1A and 1B are a perspective view showing a molded-open state of a weld line reduction type injection mold around a hole of a vehicle panel according to an embodiment of the present invention and a photograph of a prototype actually taken, and FIG. 2 is an arrangement of the negative pressure forming part of FIG. 3 is a cross-sectional view taken along line AA of FIG. 2 for showing a specific configuration and operation of a negative pressure forming unit according to an embodiment of the present invention, and FIG. 4 is a negative pressure forming unit according to a modified example of the present invention. It is a cross-sectional view taken along the AA cut line of FIG. 2 to show a specific configuration and operation state, FIG. 5 is a photograph of the surface of a molded product before and after PDV coating is applied to the first and second molds, and FIG. 6 is for a vehicle panel with holes It is a diagram showing a decrease in flowability of a molten resin occurring around a hole in a vehicle panel when a molded product is injection-molded in a conventional manner.

In the description and claims of the invention, the upper (upper), lower (lower), left and right (lateral or lateral), front (front, front), rear (fold, rear), etc., which refer to directions, etc. For convenience of description, it is determined based on the relative position between the drawings and the components, and this is followed unless specifically limited otherwise.

The injection mold 100 for reducing weld lines around a hole of a vehicle panel according to the present invention is an injection molding of a molded product P for a vehicle panel in which a hole H is formed, due to a decrease in the flowability of the molten resin. This invention was devised to minimize surface defects such as weld lines (WL) or gas marks that occur on the surface around the hole (H).

As above, surface defects such as weld lines (WL) and gas marks occurring on the surface around the hole (H) of the vehicle panel during injection molding are directly faced to the gate (G) that discharges the molten resin as shown in FIG. The area HM corresponding to the hole arranged so as to block the flow or filling of the molten resin, and it occurs in the process of structurally forcing the bypass so that the molten resin merges in the cavity opposite to the gate (COG).

At this time, surface defects such as weld lines (WL) and gas marks on the surface of the molded product generated during the confluence after bypass are not properly discharged to the outside after being radiated from the molten resin and are gradually accumulated at the confluence point and trapped (enclosed) of the cavity. The degree of the flow becomes worse due to the decrease in flowability due to the gas that increases the internal pressure and the temperature decrease due to heat dissipation due to the bypass.

Such surface defects change process conditions such as changing the gate (G) position or the thickness of the molded product (P), increasing the mold temperature or injection temperature, or optimizing the dimensions of a plurality of runners (R), as described above. It may be partially solved by limited temporary measures such as doing so, but it cannot be a fundamental and generalized solution.

Therefore, in order to be a fundamental and generalized solution as described above, the injection mold 100 for reducing weld lines around the hole of a vehicle panel according to an embodiment and a modified example of the present invention is a molded product for a vehicle panel (P) It may be configured to include a first mold 110 and a second mold 120 used to manufacture, and a negative pressure forming unit 130 provided in at least one of them.

Here, the cavity is the inside of the mold that forms a shape corresponding to the volume of the molded product P for a vehicle panel when the faces of the first mold 110 and the second mold 120 are in close contact, that is, when the mold is closed. As a collective term for an empty space of, it may be used by adding a name that specifically defines a location or area. (Green areas in FIGS. 1A and 2 constitute a cavity)

In addition, the gate G is a flow path manufactured in various shapes and sizes along with the runners R on the first and second molds 110 and 120 so that the above-described cavity and the injection molding machine communicate with each other. The molten resin provided through S) and the runner (R) is diffused at an appropriate discharge pressure and is uniformly supplied to the cavity.

The above-described molded article P for a vehicle panel may be an interior material for a vehicle that can be molded by an injection method such as a switch bezel on a vehicle door trim, as shown in FIG. 1A, and may be a cover panel for a home appliance. have.

As shown in the molded article P for a vehicle panel, a plurality of holes H of various shapes may be formed so that various switch modules capable of operating various convenient functions may be installed.

At this time, when a plurality of holes (H) are formed in a position facing the gate (G) described above, the flow of the molten resin discharged from the gate (G) and filled in the cavity is, as described above, the cavity opposite the gate (COG). ), thereby forming a weld line WL.

The first mold 110 and the second mold 120 are a pair of metal plates that are molded and closed to form a cavity corresponding to the volume of the vehicle panel molded article P described above, and are extruded from an injection molding machine to fill the cavity. Through cooling and solidification of the melted resin, the molded product (P) for the vehicle panel is repeatedly manufactured.

The injection molding method in which the molten resin extruded from the injection molding machine as described above is injected into the first and second molds 110 and 120 to mass-produce the molded article P for the vehicle panel is a widely known and commercialized manufacturing technology. For the basic technical contents other than the contents specifically mentioned for the purpose, detailed descriptions will be omitted.

The negative pressure forming unit 130 is applied to at least one of the first mold 110 and the second mold 120 in order to generate negative pressure in the cavity COG opposite the gate with the center of the region HM corresponding to the hole. As a component provided, the molten resin discharged from the gate side cavity (CG) maintains the discharge pressure and can flow quickly (improved flowability) to the cavity opposite the gate (COG). ) Can be minimized.

Such a negative pressure forming unit 130 has a negative pressure (負壓) in a cavity opposite to the gate (COG), that is, in a gate-side cavity (CG) from which the molten resin is discharged, centering on the region HM corresponding to the hole. As long as it is a means to generate a relatively low internal pressure (attributive force generation), the specific operation or configuration thereof is not particularly limited.

However, the negative pressure forming unit 130 according to the embodiment of the present invention is provided to form a negative pressure in the cavity COG opposite the gate compared to the cavity CG on the gate side, as shown in FIGS. 2 and 3. Likewise, it may be configured to include an exhaust hole 132, a sliding valve core 133, an opening/closing control unit 135, a suction device 136, a gap 137, and the like.

The exhaust hole 132 is formed by forming at least one through the cavity (COG) opposite the gate so that the cavity (COG) opposite the gate communicates with the outside air, that is, the atmospheric pressure on the outer side of the first and second molds 110 and 120 As a component, it may be formed through drilling processing or the like for the first and second molds 110 and 120.

Due to the formation of the exhaust hole 132, negative pressure may be naturally formed in the cavity opposite the gate (COG) compared to the cavity on the gate side (CG), which is the point at which the molten resin is discharged, and the gas emitted from the resin is smoothly discharged. Can be induced.

In this case, the number and arrangement of the exhaust holes 132 may be determined in consideration of the melt flow and temperature distribution simulation analysis as shown in FIG. 6, the shape or distribution of the weld line WL and the gas trace.

The sliding valve core 133 is a component provided to control the degree of negative pressure basically formed through the above-described exhaust hole 132 itself, together with an opening/closing control unit 135 to be described later, and the like, in the exhaust hole 132. It is sliding in operation and may be formed in a bar shape that selectively opens and closes one side of the exhaust hole 132.

One end of the sliding valve core 133 is formed with a shielding end 133a that is in close contact with the inner diameter of the exhaust hole 132 to close one side of the exhaust hole 132 as shown, and the other end A support end portion 133b may be formed that is connected to the opening/closing control unit 135 to be described later to receive a variable control force of the opening/closing control unit 135.

The opening/closing control unit 135 is a component that is coupled to the valve core 133 and variably controls the opening and closing operation of the valve core 133 according to a pressure state in the cavity, as shown in FIG. 3, a spring 135a and It may be configured to include a rotation support screw (135b) and the like.

At this time, the spring (135a) is a component that provides a predetermined elastic force to the above-described support end (133b) so that the above-described shielding end (133a) closes the exhaust hole (132), and the rotation support screw (135b), It is provided on the other side of the spring 135a, moves back and forth according to the forward and reverse rotation, and is a component that variably compresses the spring 135a to adjust the elastic force.

According to this simple mechanical control structure, basically, when the gas pressure in the cavity is smaller than the elastic force of the spring 135a described above, the sliding retreat of the valve core 133, that is, of the exhaust hole 132 by the shield end 133a. It is controlled so that no opening is allowed.

On the contrary, when the pressure in the cavity is greater than the elastic force of the spring 135a, the sliding and retracting operation of the valve core 133 is forced in proportion to the pressure level, and thus the gas in the cavity is opened through the exhaust hole 132. It can be discharged to the outside through.

At this time, when the elastic force of the spring 135a is variously adjusted through the forward and reverse rotation of the rotation support screw 135b as described above, and the opening point of the valve core 133 is appropriately optimized according to the gas pressure condition in the cavity. , The weld line WL and gas marks around the hole H of the vehicle panel can be minimized.

The suction device 136 is a component that is installed in communication with the outside of the exhaust hole 132 so that the suction force adjusted inside the exhaust hole 132 is forcibly applied, as shown in FIGS. 3 and 4. It may be a commercially known product that generates negative pressure by receiving power.

Depending on the suction force generated by the suction device 136, the valve cores 133 and 134 inside the exhaust hole 132 are freely slid or variably deformed back and forth, and the degree of opening and closing of one side of the exhaust hole 132 can be adjusted.

The gap part 137 is a component provided in addition to the negative pressure forming part 130 having the above-described configuration to assist the discharge of gas accumulated in the cavity, and communicates with the cavity forming the molded article P for a vehicle panel. It can be made of a structure that is arranged along the periphery in the state.

More specifically, the gap portion 137 may be formed of a fine gap structure formed between the uneven portion 138 and the slide core 139 (yellow block), as shown in FIGS. 1A to 2, and the like.

At this time, in the uneven portion 138, a protruding portion 138a having an exhaust hole 132 formed and a recessed portion 138b formed alternately along the circumference of the cavity (green area) forming the molded article P for the vehicle panel Can be achieved.

In addition, the slide core 139 moves in a direction different from that direction (generally a direction perpendicular to the opening and closing operation) when the first and second molds 110 and 120 (uneven portion 138) are opened and closed to form an undercut portion. As a component forming a part of the circumference of the cavity, it may be manufactured in a complementary shape that is engaged with the above-described uneven portion 138.

As described above, the uneven portion 138 and the slide core 139, which form a circumference of the cavity when combined as a divided structure of a complementary shape to each other, are cavities (green area) in the mold-closed state of the first and second molds 110 and 120. It is to form a gap portion 137 in communication with.

In addition, the gap 137 formed in this way communicates with the outside air and naturally discharges the gas accumulated in the cavity to the outside, so that the weld line WL and the gas around the hole H of the vehicle panel are separated from the exhaust hole 132. It will perform the function of secondary reduction of the country.

On the other hand, the negative pressure forming unit 130 according to a modified example of the present invention is provided to form a negative pressure in a cavity opposite to the gate (COG) compared to the cavity on the gate (CG), as shown in FIGS. 2 and 4 Likewise, it may be configured to include an exhaust hole 132, a check valve type valve core 134, a suction device 136, a gap 137, and the like.

Since the negative pressure forming unit 130 according to this modification includes the same exhaust hole 132, the suction device 136, and the gap 137, as in the above-described embodiment, the description thereof Only the check valve type valve core 134, which is a configuration that is substituted and distinguished by the above description, will be described in detail.

The check valve type valve core 134 controls the opening/closing amount of the exhaust hole 132 based on pressure or temperature among the condition conditions in the cavity of the injection mold 100 through mechanical shape modification without a control operation by a separate power supply. As a component to be controlled, it may be configured to increase the mechanical deformation rate in proportion to pressure or temperature.

This check valve type valve core 134 is formed in a plate shape as shown in FIG. 4 and is inserted into one side of the exhaust hole 132 and has a cut line that enables shape deformation in proportion to the pressure or temperature in the cavity. It can be formed in the center. In this case, the shape of the incision line may be a radial shape based on the center or various shapes such as C, T, H shape.

Specifically, the check valve type valve core 134 is elastically deformed and opened according to an increase in pressure in the cavity when the gas pressure in the cavity is a major quality factor of the molded product P, and is elastically discharging the gas in the cavity to the outside. It may be a check valve made of material.

Alternatively, the check valve type valve core 134 is of a shape memory alloy that is deformed according to the temperature in the cavity and is opened to discharge the gas in the cavity to the outside when the temperature in the cavity becomes a major quality factor of the molded product P. It may be a check valve.

The opening time or the amount of opening and closing of the check valve type valve core 134 made of the above two materials is determined by a deformation factor having a correlation with pressure or temperature, such as the thickness of the plate-shaped structure and the type of material, depending on the conditions in the cavity. It can be optimized by various changes, and through this optimization, the weld line WL and gas marks around the hole H of the vehicle panel, which is the molded product P, can be minimized.

A metal material is deposited as a deposition source on at least one of the faces of the first mold 110 and the second mold 120 to form a cavity (green area) in a structure including the configurations described above. A predetermined coating layer CL may be formed by a physical vapor deposition method (PVD).

Here, PVD coating is a coating method using physical vapor deposition, which is subdivided into thermal evaporation vacuum deposition, sputtering deposition, ion beam auxiliary deposition, etc., and in the present invention, vaporized in a vacuum chamber of approximately 400°C to 500°C. It may be a coating method in which the source source is solidified into a thin layer on the surface of the object to be deposited (faces facing the first and second molds 110 and 120).

At this time, a high purity, solid coating material (a metal such as titanium, chromium, or aluminum) is mainly used as the source source, and an active gas (nitrogen or carbon-containing gas) may be additionally introduced for the required deposition quality.

However, as the source source used in the present invention, it is preferable to use a metal material having properties or properties similar to those of the molten resin injected into the cavity, which increases the adhesion between the molten resin and the cavity so that the molten resin more easily penetrates into the cavity. To be able to.

As a result, the flowability of the molten resin can also be relatively improved as the permeability of the molten resin in the cavity is improved due to the coating layer CL deposited with such a metal material having similar properties.

For this reason, as shown in FIG. 5, when PVD coating is applied to the region forming the cavity (b), in contrast to the case where it is not made (a), the molded product is a weld line (WL) or gas marks. As surface defects are reduced and sharpness, such as a surface embossing shape, is improved, high-quality and high-quality of the molded product P can be achieved.

The molded article (P) for a vehicle panel manufactured by the injection mold 100 according to the present invention considers high strength, chemical resistance, scratch resistance, heat resistance, vibration resistance and moldability, etc., and reduces deformation due to shrinkage. In order to be able to produce products with accurate specifications, resins containing at least one of resins such as PC (Polycarbonate), ABS (Acrylonitrile-Butadiene-Styrene) PP (Polypropylene), PE (Polyethylene), PS (Polystyrene), etc. It can be injection molded from the material.

Here, PC (Polycarbonate) series resin is an amorphous thermoplastic resin, which has high mechanical strength, excellent heat resistance and insulation, is the most impact resistant among thermoplastic resins, and has physical properties that are stable against moisture and temperature changes.

ABS (acrylonitrile-butadiene-styrene)-based resins have excellent processability, moldability, impact resistance, heat resistance, chemical resistance, and secondary processability such as coloring, and have good compatibility with other resins. Polycarbonate) and the like may be mixed and used, and the defects peculiar to the resin may be compensated through this.

Polypropylene (PP)-based resins are engineering plastics with excellent chemical resistance, dimensional stability, heat resistance, insulation, and abrasion resistance, and with low bending fatigue.Also, they are mixed with other resins and can be used to compensate for defects between synthetic resins.

PE (Polyethylene)-based resins are engineering plastics that have excellent barrier properties to water and water vapor, thermal adhesion, and cold resistance, and have physical properties that are easy to process or mold because there is no significant change in viscosity even with rapid temperature changes.

The synthetic resin series mentioned above and the resin in which they are combined are injection-molded by the first and second molds 110 and 120 having a coating layer CL deposited with a metal material having a similar property corresponding thereto.

The vehicle panel molded article (P) made of a combination of resins as described above has the necessary physical properties to suit the purpose as the unique physical properties of each resin are applied complementarily, and rapid heating in the injection molding process And through rapid cooling, it is possible to be injected into a product having a clean appearance without a separate painting treatment.

In addition, the molded article P for a vehicle panel may be made of carbon fiber-reinforced plastic by injection molding of an over-molding method in order to improve physical properties such as shock resistance and sound absorption through reinforcement of impact resistance and elasticity. Here, the overmolding method refers to an injection molding method in which two or more different materials are integrated in one mold.

In the present invention, after first injection of a synthetic resin such as PC, ABS and PP as described above into the cavity of the molded injection mold 100, and then moving the injection mold 100 or the core to form a second cavity, a predetermined size The molded article for vehicle panel (P) is integrally manufactured by injecting the resin impregnated with the cut carbon fiber as a secondary injection method.

Unlike the above, the molded article for vehicle panel (P) is the injection mold 100 in which a synthetic resin such as PC, ABS and PP is molded and closed after heating the cut carbon fabric in a shape corresponding thereto and then inserting it into the injection mold 100. It can also be produced by injection into the cavity. At this time, the heating of the carbon fabric is to facilitate bonding or impregnation between the resin injected into the cavity and the inserted carbon fabric.

In the above, although specific embodiments of the present invention have been described and illustrated, the present invention is not limited to the described embodiments, and various modifications and variations can be made without departing from the spirit and scope of the present invention. It is self-evident to those who have. Therefore, such modifications or variations should not be individually understood from the technical spirit or viewpoint of the present invention, and the modified embodiments should be said to belong to the claims of the present invention.

P: Molded product for vehicle panel R: Runner
S: Sprue H: Hole
HM: Area corresponding to the hole G: Gate
CG: Gate side cavity COG: Gate side cavity
CL: coating layer
100: injection mold with reduced weld line around the hole of the vehicle panel
110: first mold 120: second mold
130: negative pressure forming unit 132: exhaust hole
133: sliding valve core 133a: shielding end
133b: support end 134: check valve type valve core
135: open/close control unit 135a: spring
135b: rotation support screw 136: suction device
137: gap portion 138: uneven portion
138a: protrusion 138b: recess
139: slide core

Claims (10)

In order to manufacture a molded article for a vehicle panel in which a hole is formed for bypassing the flow of the molten resin discharged from the gate and filled in the cavity, it includes a first mold and a second mold,
In at least one of the first mold and the second mold,
There is provided a negative pressure forming unit for improving the flowability of the molten resin around the hole of the vehicle panel by generating a negative pressure in the cavity opposite the gate centering on the area corresponding to the hole,
The negative pressure forming part,
An exhaust hole formed through the cavity opposite to the gate so as to communicate with the outside air to induce gas discharge in the cavity; And a check valve type valve core made of a shape memory alloy material provided on one side of the exhaust hole and deformed according to a temperature state in the cavity, and opening and closing the exhaust hole,
The negative pressure forming part,
Further comprising a gap portion communicating with a cavity forming a molded article for a vehicle panel and disposed along the periphery thereof to assist the discharge of gas accumulated in the cavity separately from the exhaust hole,
The gap portion,
The gas accumulated in the cavity is formed in a fine gap structure between the uneven portion formed by alternately arranged along the circumference of the cavity and the slide core having a complementary shape engaged with the uneven portion. Naturally discharged to the outside,
On at least one of the facing surfaces of the first mold and the second mold forming a cavity,
In order to increase the adhesion between the molten resin and the cavity so that the molten resin can more easily penetrate into the cavity,
A mold for reducing weld lines around a hole in a vehicle panel, characterized in that a coating layer is formed by a physical vapor deposition method (PVD) using a metal material having a property similar to that of a molten resin injected into the cavity as a deposition source. delete delete delete delete The method of claim 1,
The negative pressure forming part,
In order to force the opening operation of the valve core, a suction device installed to communicate with the outside of the exhaust hole is further provided. delete delete delete The method of claim 1,
The molded article,
It is characterized in that it is formed by any one of a method of injection molding a resin including at least one of PC, ABS, PP, PE, and PS resin as a material, and a method of injection molding into a carbon fiber reinforced plastic by overmolding. Injection mold with reduced weld line around the hole of vehicle panel.

Images