JPH04288210A - Method and apparatus for molding of resin - Google Patents

Abstract

PURPOSE:To provide a method and an apparatus for the molding of resin, wherein a uniform IMC layer can be formed on the surface of a primary molded article made of an SMC by preventing the occurrence of such a state that an IMC material connot be distributed uniformly onto the surface of the primary molded article made of the SMC at the time of repressing due to displacement of a top mold caused by pressure reduction in a high-pressure IMC process. CONSTITUTION:The position of a top force 4 is controlled by a control unit 9 so that the lower face of the top force 4 is made parallel to the upper face of a primary molded article made of an SMC, on the basis that which of turns are taken when a plurality of pressure sensors 8 provided in a bottom force 5 detect changes in pressure, or that which of turns are taken when a plurality of IMC material sensors provided in the top force 4 detect an IMC material, before repressing is finished after pressure reduction; alternatively, on the basis of displacement of the top force caused by pressure reduction and detected by a plurality of displacement sensors.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a resin molding method and apparatus, and more particularly to a sheet molding method and an apparatus for the same.
After pressure molding the molding compound, in-mold coating material is injected into the mold, and an in-mold coating layer is applied to the surface of the primary molded product of the sheet molding compound to form a resin molded product. The present invention relates to a method and an apparatus for doing so.

0002

[Prior art] Thermosetting resin such as unsaturated polyester,
Sheet molding compound consisting of glass fiber and fillers such as calcium carbonate
Molding Compound: Hereinafter "SMC"
It is abbreviated as. ) in a mold heated to a predetermined temperature, the obtained primary molded product is held in the mold, and a thermosetting resin such as unsaturated polyester is injected into the mold,
In-mold coating (I) is applied to the surface of the primary molded product.
n-Mold Coating: Hereinafter abbreviated as "IMC". ) A resin molding method called the in-mold coating method is known, in which a resin molded product is obtained by applying a layer.

[0003] Generally, when a molded product made of SMC is pressure-molded, a large number of small porosity are often formed inside the product, filled with air or gas from volatile components in the SMC. If such porosity exists, when baking or painting a molded product made of SMC, the gas in the porosity expands or pushes up the formed coating film due to baking after the coating film is formed. It is also known that the IMC layer breaks through the formed coating film and causes defects in the coating film, and the IMC layer is
By covering the surface of a molded product made of porosity, the gas within the porosity is contained, thereby preventing defects in the coating film from occurring.

However, in the conventional IMC method, after pressure forming a molded product made of SMC, the upper mold is lifted and a gap is created between the lower surface of the upper mold and the upper surface of the molded product made of SMC. After forming the IMC material, an IMC material made of a thermosetting resin such as unsaturated polyester is injected into the gap and pressurized again. Therefore, when the IMC material is injected, the air in the gap is There is a problem in that it may penetrate into the interior and form a large number of small porosity, making it impossible to effectively prevent the defects in the coating film described above.

[0005] Therefore, in order to prevent the formation of porosity during injection of such IMC materials, in recent years, after pressure molding of molded products made of SMC, the upper mold is held as it is without lifting it. A method called a high-pressure in-mold coating method has been proposed in which high-pressure IMC material is injected into a mold to prevent the formation of porosity during injection of the IMC material. According to this high-pressure in-mold coating method, the IMC material is injected while compressing the SMC to form the IMC.
No porosity is formed inside the MC layer, and S
The gas in the porosity inside the molded product made of MC is
The MC layer can completely confine the gas inside the porosity, and even when baking paint is applied, a coating film is formed on the surface of the IMC layer and baked, so the gas inside the porosity is cured. The IMC layer makes it possible to completely encapsulate and prevent defects from forming in the coating.

[0006]

[Problems to be Solved by the Invention] In this high-pressure in-mold coating method, the primary molded product made of SMC is
The IMC material is injected into the mold without lifting the mold, so in order to prevent the injection pressure from becoming excessive, the press pressure is For example, 0 to 5 kgf
/cm2, and then IMC
Generally, the material is injected, but by this reduced pressure,
If the upper die is displaced and the IMC material is injected from the center of the upper die, when the IMC material is injected and re-pressurized, the IMC material will form the desired SMC primary molding. There was a problem in that the IMC layer was not distributed over the surface of the product, and as a result, the IMC layer could not be uniformly formed.

[0007]

OBJECTS OF THE INVENTION The first object of the present invention is to inject an IMC material onto the surface of a primary molded product made of SMC from the center of an upper mold to form a resin molded product by a high-pressure in-mold coating method. An object of the present invention is to provide a resin molding method that can form a uniform IMC layer.

A second object of the present invention is to provide an I.
A uniform IMC layer is formed in a resin molding device that is equipped with an MC material injection section and injects an IMC material onto the surface of a primary molded product made of SMC to mold a resin molded product using a high-pressure in-mold coating method. The object of the present invention is to provide a resin molding device that can perform the following steps.

[0009]

[Structure of the Invention] A first object of the present invention is that, according to the first invention, after reducing the pressure for molding the primary molded product,
By the end of repressing the IMC material, the bottom surface of the upper mold is SM
This is achieved by controlling the upper mold so that it is parallel to the upper surface of the primary molded product made of C.

[0010] A second object of the present invention is that, according to the second invention, two or more pressure sensors for detecting the pressure of the IMC material are placed between the upper mold and the upper mold so as to sandwich the part corresponding to the IMC material injection part. Upper mold control means is provided on at least one of the lower molds and controls the upper mold so that the lower surface of the upper mold is parallel to the upper surface of the primary molded product made of SMC based on the pressure detected by the pressure sensor. By or on the upper mold, I
An IMC material sensor that detects two or more IMC materials is installed across the MC material injection part, and based on the IMC detection signal detected by the IMC material sensor, the lower surface of the upper mold is parallel to the upper surface of the primary molded product made of SMC. By providing an upper die control means for controlling the upper die, or by providing an upper die displacement detection means for detecting displacement of the upper die after forming the primary molded product, the detection of the upper die displacement detection means may be performed. This is achieved by providing an upper mold control means for controlling the upper mold so that the lower surface of the upper mold becomes parallel to the upper surface of the primary molded product made of SMC based on the displacement of the upper mold.

[0011]

[Operation of the Invention] According to the first invention, the upper mold is controlled so that the lower surface of the upper mold becomes parallel to the upper surface of the primary molded product made of SMC after depressurization and before the end of repressurization. Since repressurization is performed during the repressurization process, it is possible to distribute the IMC material on the surface of the SMC primary molded product as desired, thereby forming a uniform IMC layer. becomes possible.

According to the second invention, the lower surface of the upper mold and the S
Using the fact that the flow distribution of the injected IMC material on the top surface of the primary molded product made of SMC changes depending on the relative positional relationship with the top surface of the primary molded product made of MC, the pressure of the IMC material is measured by a pressure sensor. The relative positional relationship between the lower surface of the upper mold and the upper surface of the primary molded product made of SMC is detected by detecting the S
An upper mold control means is provided to control the upper mold so that the upper mold is parallel to the upper surface of the primary molded product made of MC, or
An IMC material sensor that detects two or more IMC materials is provided across the IMC material injection part, and based on the IMC material detection signal detected by the IMC material sensor, the lower surface of the upper mold is
An upper mold control means is provided to control the upper mold so that the upper mold is parallel to the upper surface of the primary molded product, or an upper mold displacement detection means is provided to detect displacement of the upper mold after the primary molded product is formed. An upper mold control means is provided for controlling the upper mold so that the lower surface of the upper mold becomes parallel to the upper surface of the primary molded product made of SMC based on the displacement of the upper mold detected by the upper mold displacement detection means. During the repressurization process, the IMC material is
It becomes possible to distribute the resin on the surface of the SMC primary molded product, and it becomes possible to provide a resin molding apparatus that can form a uniform IMC layer.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a schematic diagram of a resin molding apparatus according to an embodiment of the present invention, FIG. 2 is a schematic plan view of a molded resin product, and FIG. 3 is a schematic side view thereof. The resin molding apparatus according to the embodiment of the present invention can perform molding once,
The structure is such that two products can be molded, and as shown in FIGS. 2 and 3, the molded resin molded product 1 has product parts 2, 2 that will become the final resin molded product, and a product part 1. Part 2
, 2, and is provided with a gate portion 3 which is removed after molding.

In FIG. 1, the resin molding apparatus according to the embodiment of the present invention includes an upper mold 4 and a lower mold 5, and the IMC material supplied from the IMC material supply device 6 is placed in the center of the upper mold 4. , an IMC material injector unit 7 is provided between the upper mold 4 and the lower mold 5. The IMC material injector unit 7 is placed at a position corresponding to the center of the gate part 3 of the resin molded product 1 so that no injection marks are left on the product parts 2, 2 when the IMC material is injected. It is located. In the lower mold 5, in the horizontal direction in FIG.
Four pressure sensors 8 are provided to detect the pressure of the IMC material injected from the material injector unit 7 between the upper die 4 and the lower die 5, and pressure detection signals are input to the control unit 9. The control unit 9 is
Based on the pressure detection signal input from the pressure sensor 8, the leveling cylinders 10 provided at the four corners of the upper mold 4 are driven, and the upper mold 4 is leveled after the start of injection of IMC material and before the end of repressurization. The lower surface is controlled to be parallel to the upper surface of the primary molded product made of SMC (not shown), and the IMC
An IMC material supply signal is output to the material supply device 6, and a pressure control signal is output to the pressure control means 11, respectively. When the pressure control means 11 receives a pressure control signal from the control unit 9, the pressure control means 11 controls the oil pressure of the upper mold drive means 12 that drives the upper mold 4 to a predetermined pressure using oil pressure, and controls the upper mold 4 to a predetermined pressure. While moving mold 4 up and down,
Create a predetermined pressing pressure.

FIGS. 4 to 6 are process diagrams showing the steps of molding the resin molded product 1 using the resin molding apparatus according to the embodiment of the present invention configured as described above. Figure 4 shows the S.M.
C13 is shown set on the lower mold 5, and the upper mold 4 is retracted to a raised position. In this state, a pressure control signal is output from the control unit 9 to the pressure control means 11, and the pressure control means 11 controls the oil pressure of the upper mold drive means 12 to a predetermined value. 12, the upper die 4 is lowered.

FIG. 5 shows that after the upper die 4 has completed its descent, the control unit 9 sends the pressure to the pressure control means 11.
A pressure control signal is output, and the pressure control means 11 controls the press pressure to, for example, 70 to 120 kgf/cm.
2, the hydraulic pressure of the upper die driving means 12 is controlled so that the primary molded product 14 made of the SMC 13 is molded. When the molding of the primary molded product 14 made of the SMC 13 is completed in this way, a pressure control signal is output from the control unit 9 to the pressure control means 11, and the pressure control means 11 adjusts the press pressure, for example, from 0 to 5 kgf/ The press pressure applied from the upper die driving means 12 is reduced so that the pressure becomes .cm2.

FIG. 6 shows that after depressurization, the IMC material 15 is
The state is shown in which C material is injected from the material supply device 6 through the IMC material injector unit 7 between the upper mold 4 and the lower mold 5, and is then repressurized. By repressurizing, IMC
The IMC material 15 injected from the material injector unit 7 flows toward both ends between the primary molded product 14 made of SMC 13 and the upper mold 4, but it flows toward both ends of the primary molded product 14 made of SMC 13. If the lower surface of the upper mold 4 is not parallel, the distance between the upper surface of the primary molded product 14 made of SMC 13 and the lower surface of the upper mold 4 is not uniform, and in such a case, a larger gap is better. , since the flow resistance is small, the IMC material 15 is suitable for the primary molded product 1 made of SMC13.
In FIG. 1, among the four pressure sensors 8 disposed laterally, the pressure sensor 8 disposed in the one with the largest gap between the upper surface of the mold 4 and the lower surface of the upper mold 4 Then, the upper part of the pressure sensor 8 near the part facing the IMC material injector unit 7 is first reached. As a result, the pressure detection value of the pressure sensor 8 increases. The pressure detection signal detected in this way is transmitted to the control unit 9
The control unit 9 determines the relative positional relationship between the lower surface of the upper die 4 and the upper surface of the primary molded product 14 made of the SMC 13, depending on which pressure sensor 8's pressure detection value increases first. Since the gap between the upper mold 4 and the upper surface of the primary molded product 14 made of the SMC 13 on the pressure sensor 8 side where the pressure detection value first rose is larger than on the other side, In order to correct this, the control unit 9 sets a pair of leveling cylinders 10 on the side opposite to the side where the gap was determined to be large, that is, on the side where the gap was determined to be small, based on a pre-stored map or the like. The position of the upper mold 4 is controlled so that the upper mold 4 is moved upwardly, and the gap on that side becomes larger.

As a result, the flow of the IMC material 15 changes, and the pressure sensor 8, whose detected pressure value has increased, and the IMC
For the part facing the material injector unit 7,
The pressure detection value of the pressure sensor 8 arranged at the symmetrical position then increases. Then, when the pressure detection values of the remaining two pressure sensors 8 rise simultaneously, the upper mold 4
Since it can be determined that the correction has been made so that the lower surface of the SMC 13 and the upper surface of the primary molded product 14 made of the SMC 13 are parallel to each other, the control unit 9 can determine which leveling cylinder 10
I continued repressurizing without operating it, but
If the pressure detection value of one of the remaining two pressure sensors 8 rises first, it is determined that the gap on the side where that pressure sensor 8 is arranged is larger than the other gap. Therefore, the control unit 9 operates the pair of leveling cylinders 10 on the side opposite to the side where the pressure sensor 8 is arranged, and controls the position of the upper die 4 so that the gap on that side becomes larger.

When the repressurization is thus completed, the resin molded product 1 is taken out from the upper mold 4 and the lower mold 5, the gate portion 3 is cut, and two final products 2, 2 are obtained. As described above, according to this embodiment, based on the pressure detection signals input from the four pressure sensors 8 arranged laterally in FIG. 1, in which order the pressure detection value increases? is detected, i.e. IMC
By first detecting which pressure sensor 8 the material 15 has reached and controlling the position of the upper mold 4 by feedback, the lower surface of the upper mold 4 and the SMC 1 are
Since the IMC material 15 is controlled to be parallel to the upper surface of the primary molded product 14 made of
Therefore, it becomes possible to form a uniform IMC layer on the surface of the primary molded product 14 made of SMC. Furthermore, according to this embodiment, two products are molded in one molding process, so it is possible to significantly reduce manufacturing costs.

FIG. 7 is a schematic diagram of a resin molding apparatus according to another embodiment of the present invention, showing a state corresponding to FIG. 4. In FIG. 7, a resin molding apparatus according to another embodiment of the present invention is equipped with four displacement sensors 16 for detecting vertical displacements of the four corners of the upper mold 4 instead of the pressure sensor 8. These four displacement sensors 16 are SM
The vertical displacement of the upper mold 4 caused by the reduced pressure after molding the primary molded product 14 made of C13 is expressed as follows:
It detects and outputs a displacement detection signal to the control unit 9 (omitted in FIG. 7). The control unit 9 controls these four displacement sensors 1
Based on the displacement detection signal input from 6, the displacement of the upper mold 4 caused by the depressurization is detected, and one or more leveling cylinders 10 are operated based on a pre-stored map etc. 4 and the upper surface of the primary molded product 14 made of SMC 13 are controlled so that they are parallel to each other, and then a pressure control signal is output to the pressure control means 11 to control the hydraulic pressure of the upper mold drive means 12 to a predetermined pressure. control and repressurize.

[0021] When the repressurization is thus completed, the resin molded product 1 is taken out from the upper mold 4 and the lower mold 5, the gate portion 3 is cut, and two final products 2, 2 are obtained. According to this embodiment, the displacement of the upper die 4 caused by the reduced pressure is
The four displacement sensors 16 detect the vertical displacement of the four corners of the upper mold 4, and the lower surface of the upper mold 4 and the upper surface of the primary molded product 14 made of SMC 13 are made parallel to each other prior to repressurization. Therefore, during repressurization, the IMC material 15 can be reliably distributed uniformly on the surface of the primary molded product 14 made of SMC 13. Therefore, a uniform IMC layer can be formed. It becomes possible to form it on the surface of the primary molded product 14 made of SMC13.

FIG. 8 is a schematic diagram of a resin molding apparatus according to another embodiment of the present invention, showing a state corresponding to FIG. 4. In FIG. 8, in a resin molding apparatus according to another embodiment of the present invention, in place of the pressure sensor 8 and displacement sensor 15 in the previous embodiment, the gate part 3 of the upper die 4 is placed at a position corresponding to the position where the gate part 3 is molded. , four IMC material sensors 1 arranged laterally in FIG. 8 along the center line of the gate section.
It has 7.

In this embodiment, when repressurizing,
In the same manner as in the above embodiment, the pressure sensor 8 detected the IMC material 15 by the change in the detected pressure value,
These four IMC material sensors 16
The leveling cylinder 10 is selectively operated by the control unit 9 according to the order of detection, so that the lower surface of the upper die 4 and the upper surface of the primary molded product 14 made of the SMC 13 are parallel to each other by the end of repressurization. is controlled by feedback. Therefore, as in the case of using the pressure sensor 8, the IMC material 15 is uniformly spread over the SMC 13.
Therefore, it is possible to form a uniform IMC layer on the surface of the primary molded product 14 made of SMC 13.

[0024] The present invention is not limited to the above-mentioned embodiments, but various modifications can be made within the scope of the invention described in the claims, and these are also included within the scope of the present invention. Needless to say, this is something that will be done. for example,
In the embodiment shown in FIG. 7, the control unit 9 selectively operates the leveling cylinder 10 based on the displacement of the upper mold 4 due to depressurization detected by the four displacement sensors 16, The bottom surface of type 4 is SMC13
However, during repressurization, the leveling cylinder 10 is selectively operated so that the lower surface of the upper mold 4 is parallel to the upper surface of the primary molded product 14. may be controlled so that it is parallel to the upper surface of the primary molded product 14 made of the SMC 13.

Furthermore, in the embodiments shown in FIGS. 1, 4 to 6, the pair of leveling cylinders 10 on the side determined to have a smaller gap are raised based on the pressure detection signal from the pressure sensor 8. However, conversely, the pair of leveling cylinders 10 on the side determined to have a larger gap may be operated in a lowered manner. moreover,
In the above embodiment, four pressure sensors 8 and four IMC material sensors 16 are arranged linearly in the horizontal direction in FIG. 1 or FIG.
Of course, the arrangement is not limited to IM
Depending on whether the C material 15 is detected, one of the four leveling cylinders 10 may be selectively operated. Further, the pressure sensor 8 and the IMC material sensor 16 may be used together, and in that case, the pressure sensor 8 and the IMC material sensor 16 may be used together.
The C material sensor 16 may be placed at a corresponding position or may be placed at a different position.

[0026] In the above embodiment, an explanation was added regarding the case where two products are molded in one molding process, but in the case of a resin molded product where the injection marks of the IMC material 15 are not a problem, or In the case of post-processing the injection marks, the present invention can also be applied to the case of resin molding one product by one molding. Further, in the embodiments shown in FIGS. 1, 4 to 6, the pressure sensor 8 is provided on the lower mold 5, but the pressure sensor 8 may be provided on the upper mold.

Furthermore, in the embodiment shown in FIG.
IM at a position corresponding to the position where the gate part 3 is molded.
Although the C material sensor 17 is provided, when post-processing the traces on the surface of the resin molded product 1 caused by providing the IMC material sensor 17 on the upper mold 4, the product parts 2, 2 of the upper mold 4 are molded. An IMC material sensor 17 can also be provided at a position corresponding to the position.

[0028]

Effects of the Invention According to the first invention, an IMC material is injected from the center of the upper mold onto the surface of a primary molded product made of SMC, and a resin molded product is molded by a high-pressure in-mold coating method. In the resin molding method, it is possible to provide a resin molding method that can form a uniform IMC.

According to the second invention of the present invention, the I
A method for forming uniform IMC in a resin molding device that is equipped with an MC injection section and injects IMC material onto the surface of a primary molded product made of SMC and molds a resin molded product using a high-pressure in-mold coating method. It becomes possible to provide a resin molding device that can

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a resin molding apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic plan view of a molded resin product.

FIG. 3 is a schematic side view of a molded resin product.

FIG. 4 is a process diagram showing a process of molding a resin molded product 1 using a resin molding apparatus according to an embodiment of the present invention.

FIG. 5 is a process diagram showing a process of molding a resin molded product 1 using a resin molding apparatus according to an embodiment of the present invention.

FIG. 6 is a process diagram showing a process of molding a resin molded product 1 using a resin molding apparatus according to an embodiment of the present invention.

FIG. 7 is a schematic diagram of a resin molding apparatus according to another embodiment of the present invention.

FIG. 8 is a schematic diagram of a resin molding apparatus according to another embodiment of the present invention.

[Explanation of symbols]

1 Resin molded product 2 Product Department 3 Gate part 4 Upper mold 5 Lower mold 6 IMC material supply device 7 IMC injector unit 8 Pressure sensor 9 Control unit 10 Leveling cylinder 11 Pressure control means 12 Upper mold drive means 13 SMC 14 Primary molded products 15 IMC materials 16 Displacement sensor 17 IMC material sensor

Claims (6)

[Claims] 1. A resin molding method in which an IMC material is injected onto the surface of a primary molded product made of SMC from the center of an upper mold to form a resin molded product by a high-pressure in-mold coating method. After reducing the pressure for molding the molded product, the upper mold is controlled so that the lower surface of the upper mold is parallel to the upper surface of the primary molded product made of SMC by the end of repressurization of the IMC material. A resin molding method characterized by: 2. The upper mold is controlled so that after the pressure reduction and before the repressurization, the lower surface of the upper mold is parallel to the upper surface of the primary molded product made of SMC. 1
The resin molding method described in . 3. At the time of repressurization, the lower surface of the upper mold is SM
2. The resin molding method according to claim 1, wherein the upper mold is controlled so as to be parallel to the upper surface of the primary molded product made of C. 4. A resin molded product having an IMC material injection part in the center of the upper mold, injecting the IMC material onto the surface of the primary molded product made of SMC, and molding the resin molded product using a high-pressure in-mold coating method. In the molding equipment, IMC
The IM includes two or more pressure sensors that detect the pressure of the material.
It is provided on at least one of the upper mold and the lower mold so as to sandwich a portion corresponding to the C material injection part, and based on the pressure detected by the pressure sensor, the lower surface of the upper mold becomes the upper surface of the primary molded product made of the SMC. A resin molding apparatus characterized in that an upper mold control means is provided for controlling the upper mold so that the upper mold is parallel to the upper mold. 5. A resin molded product having an IMC material injection part in the center of the upper mold, injecting the IMC material onto the surface of a primary molded product made of SMC, and molding the resin molded product by a high-pressure in-mold coating method. In the molding apparatus, two or more IMCs are placed in the upper mold with the IMC material injection part sandwiched therebetween.
An IMC material sensor is provided to detect the material, and based on the IMC detection signal detected by the IMC material sensor, the upper mold is moved so that the lower surface of the upper mold is parallel to the upper surface of the primary molded product made of the SMC. A resin molding apparatus characterized in that it is provided with an upper mold control means for controlling. 6. A resin molded product having an IMC material injection part in the center of the upper mold, and injecting the IMC material onto the surface of a primary molded product made of SMC to form a resin molded product by a high-pressure in-mold coating method. The molding apparatus is provided with an upper mold displacement detection means for detecting displacement of the upper mold after molding of the primary molded product, and based on the displacement of the upper mold detected by the upper mold displacement detection means, the lower surface of the upper mold is A resin molding apparatus characterized in that an upper mold control means is provided for controlling the upper mold so that the upper mold is parallel to the upper surface of the primary molded product made of SMC.