JP3031397B2 - Method of molding illuminated switch parts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating switch (that is, a switch in which light is transmitted only in a character or mark portion, and other portions are shielded, and a character or mark is visible even in darkness by an internal light source). The present invention relates to a method of forming a part. Illuminated switch is used for automobile, audio, VTR
Widely used for various electric and electronic devices.

[0002]

2. Description of the Related Art As a molding method of the above-mentioned illuminating switch parts, a three-dimensional molded product is obtained by using a transparent or translucent thermoplastic resin by an injection molding method, and the molded product is painted by multilayer printing or the like. It is known to burn out only the part with leather to give illumination performance. However, if leather processing is adopted, the cost of the product is inevitably increased because the leather processing machine is expensive, and it will be work after painting. Therefore, there is a problem that productivity is reduced due to an increase in the number of steps.

In the conventional CFI technique (a method in which a sheet is mounted in a mold cavity and another thermoplastic resin is injected and further molded integrally), the sheet is inserted into a mold and the mold is closed. When the mold core hits the sheet when it is pressed, there is a defect that the printed surface of the sheet is scratched or a pressing mark remains. In such a case, a useless process of printing the damaged portion is required. In addition, a method is also conceivable in which a printing sheet is vacuum-formed and then inserted into a mold to produce the printing sheet by injection molding.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a method of forming an illuminating switch component having no damage on a sheet surface by applying the CFI technique.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies on a molding method for preventing a flaw generated on a sheet surface which occurs during the molding of an illuminated switch. It has been found that the above problem can be solved by using a sheet larger than the size and having a curvature of the corner portion equal to or more than a certain value, and mounting the sheet by mounting it on a die ejection pin, and completed the present invention. . That is, the present invention uses an injection molding machine in which a movable core is arranged on the core side of a mold, and forms a thermoplastic resin (A) sheet or film on which characters, marks, or decorations have been previously printed, painted, or hot stamped. After cutting, mounting in the mold cavity, advancing the movable core to a position corresponding to the core, and preforming, the thermoplastic molding material (B) to be welded to the thermoplastic resin (A) sheet or film is molded. Thermoplastic resin (A) used in a molding method of an illuminating switch component in which the sheet or film and the thermoplastic molding material (B) are laminated in a predetermined shape by injection injection into a cavity. Is 0.5 to 3 in the length of each side more than the corresponding dimension of the cavity side.
mm, the curvature of the corners of the sheet or film is equal to or greater than the curvature of the corners of the corresponding mold cavity, and the mounting of the sheet or film in the mold cavity is performed by using a mold ejection pin. The present invention relates to a method for forming an illuminable switch component.

Hereinafter, the present invention will be described. The thickness of the thermoplastic resin (A) sheet used in the present invention is not particularly limited, but is preferably 0.1 mm to 2.0 m.
When a sheet having a thickness of m is used, the product appearance and performance are improved. As the sheet, any ordinary thermoplastic resin can be used, and PC (polycarbonate), PET (polyethylene terephthalate), PVC (polyvinyl chloride), PMM
A (acrylic resin) and MS (methacrylate styrene) can be exemplified. The above-mentioned sheet is preliminarily printed, painted and subjected to letters, marks and decorations by hot stamping, and the sheet is previously punched into the shape of a mold cavity or cut into a shape that can be successively supplied and continuously collected. .

[0007] The sheet is mounted on one side of the mold cavity by a mold ejecting pin, and the sheet and the thermoplastic molding material (B) are injected into the thermoplastic molding material (H) by the heat and pressure of injection molding. The structure is formed into a predetermined shape integral with B). As the thermoplastic molding material (B) used in the present invention, a material having a welding property with the thermoplastic resin (A) for a sheet to be used is used. As the thermoplastic molding material (B), when a PC sheet is used, P
C, PC / polyester resin compositions, PC / ABS resin compositions, PC / polyamide resin compositions, and other polycarbonate resin compositions (PC alloys) can be exemplified. Similarly, when other thermoplastic resin sheets are used, they may be appropriately selected and used as long as the molding material forming the same resin composition has a welding property.

For the injection molding conditions, known temperature and pressure ranges of the thermoplastic resin (A) and the thermoplastic molding material (B) to be used are applied. The color tone of the thermoplastic resin (A) and the thermoplastic molding material (B) to be used is as follows.
The same color or the same color tone as the color tone of the printing ink of the sheet is preferable.

The mold used in the molding method of the present invention has a mold ejection pin for setting a sheet on the mold cavity side, and a movable core mounted on the mold core side. use. By using such a mold cavity, it is possible to prevent the sheet from being damaged when the mold is clamped after the sheet is mounted in the mold cavity. The shape of the thermoplastic resin (A) sheet or film to be used needs to be longer by 0.5 to 3 mm on each side than the corresponding dimensions on the cavity side. The dimensions are set so as to ensure the light shielding property at the end of the product and not to leave a parting line at the end of the formed sheet in the field of view (functional portion). When the length of each side of the sheet or film is less than 0.5 mm, the parting line of the sheet is conspicuous, and the light-shielding property is reduced by the edge light effect. On the other hand, when the length of each side of the sheet or film exceeds the above 3 mm, stress concentration occurs on the contact surface between the sheet and the cavity when the mold core hits the sheet printing surface, and the printing surface is damaged. In addition, there is a disadvantage that the light-shielding property is lost. As a seat mounting method, by mounting using a protruding pin,
Since post-processing is not required, the number of steps can be reduced.

Further, in the present invention, by setting the curvature of the corner of the sheet or film to be equal to or more than the curvature of the corner of the mold cavity,
Gas can be improved. We can prevent damage when seat hits core part,
The light shielding property of the product function part can be secured. By making the dimension of each side of the sheet 0.5-3mm longer than the cavity,
Scratching can be prevented to some extent, but if the sheet is square, the edge portion becomes a resistance, and in the vicinity of the portion, there is a possibility that a scratch that seems to have hit the core portion may occur. However, by setting the curvature of the corner portion to be equal to or greater than the curvature of the corresponding cavity, the material can be inserted into the cavity without resistance even when the core is hit at the time of mold clamping, and scratches can be prevented. It is possible to prevent the printing ink and the sheet from being stretched at the end of the product. As the product also needs the appearance of the edges, if the corners are square, resistance will occur at the corners during charging, and only the corners will be stretched by the heat and pressure during resin injection, and the product side corners Printing ink may be disturbed or damaged. Therefore, by setting the corner curvature to be equal to or more than the corresponding cavity curvature, the above-mentioned disadvantage is solved.

The mold used in the molding method of the present invention has a movable core having a cushioning property attached to the cavity side and / or the core side in order to prevent the sheet from being damaged during clamping. It is desirable. As the movable core having cushioning properties, a core attached to the cavity side or the core side, or both of them is used. In the present invention, it is preferable to use a spring, air, water, or hydraulic oil to operate the cavity side or core side movable core having cushioning properties. By imparting cushioning properties by such a method, it is possible to arbitrarily adjust the pressing pressure.

In the present invention, in order to prevent the surface of the sheet from being damaged, a paint or powder having a low coefficient of friction is further applied to at least one portion of a mold cavity, a sheet or film mounting portion, or a sheet or film surface to be used. It can also be applied. By applying such a paint or powder, the movable core can reduce the force applied to the sheet or film when the mold closes, and it can slide in without damaging the printed surface of the sheet in the cavity. Become. As the substance to be applied to the mold cavity or the sheet mounting portion or the sheet surface, Teflon or a compound thereof having a low coefficient of friction is generally suitable, and is applied to the mold or the mold cavity or the sheet mounting portion. Is used with Teflon processing.

In the present invention, the mold is closed in the injection molding step to prevent the sheet mounted on the fixed side from hitting the core and to prevent the sheet printing surface from being damaged or pressed. Mold cavities in which the mold cavities and / or the movable core surface are covered with elastic rubber can also be used. As the elastic rubber body, it is preferable to use silicone rubber having a certain elasticity and withstanding heat during injection molding, or an elastic body having heat resistance higher than that.

Next, in order to facilitate understanding of the present invention, an example will be described with reference to the drawings. The numbers in the figures are respectively 1: printed sheet 2: thermoplastic molding material 3: cavity side, 4: core side, 5: movable core,
6: movable core, 7: molded product, 8: illumination part. FIG.
FIG. 4 is a conceptual diagram showing a state of a cross section in which a mold is clamped after a seat is mounted. FIG. 2 is a conceptual diagram showing a cross-sectional state in which a thermoplastic molding material is injected into a mold cavity and laminated with a sheet to form an integrally molded product. FIG. 3 is a perspective view showing an illuminated switch obtained according to the present invention. FIG. 4 is a cross-sectional view of an illuminated switch obtained according to the present invention.

[0015] The die protruding pin used when mounting the sheet has a structure in which the pin retreats when the die is clamped. Such a mechanism is possible, for example, by employing a spring mechanism. In FIG. 1, the use of a movable core having a cushioning property, or the use of a mold cavity in contact with a sheet or a film and / or a mold in which the surface of the movable core is covered with elastic rubber causes damage to the sheet. It is desirable to prevent sticking. In FIG. 2, a thermoplastic resin to be fused with a sheet is injected and injected into a mold cavity, and the final molding is performed by cooling and solidifying. The range of the shaping ratio of the sheet is desirably within the proportional elastic deformation range of the sheet and within the yield elongation deformation range. As molding processing conditions, the temperature of the molding material is molded within a known temperature range of the selected molding material, and the mold temperature is preferably equal to or lower than the heat resistant temperature of the ink when using a printed sheet. . In addition, elongation that can follow the shaped shape,
It is desirable to use inks having soft properties. preferable. As described above, the manufacturing method and the mold structure of the present invention have been described.
The present invention is not naturally limited to the drawings as described above.

[0016]

The present invention will be described below in detail with reference to examples. Example 1 A 0.5 mm thick polycarbonate resin sheet (hereinafter, referred to as a polycarbonate resin sheet)
PC sheet) has a light-transmitting number and mark printing in the center, and a light-shielding topcoat printing on the other parts, and then presses the mold from the mold mounting part (cavity dimensions). The mounting sheet was punched out with the side 1 mm larger and the sheet end set at 4R. In the injection molding machine used, the movable core on the side of the cavity core has a cushioning property and the surface is covered with silicone rubber.
A mold ejection pin is provided on the cavity side. That portion has a structure in which the sheet is sandwiched between the cavities so as not to be laminated with the molding resin when the mold is opened and closed. The mold cavity is a rectangle of 20mm x 35mm,
The circumference has a curvature of 2R and its height is 3 mm. The surface of the cavity is coated with a Teflon compound to reduce the frictional force when the sheet is pushed by the core. The portion to be laminated with the resin has a thickness of 1 mm.

First, the PC sheet was mounted and fixed to the cavity side of the mold by using a mold protruding pin. Next, the mold is closed, and as shown in FIG. 1, the PC sheet attached and fixed in the step of closing the mold is placed on a core covered with silicone rubber and provided with cushioning properties, and the sheet is placed in the cavity. Pushed into. After that, a molding material (Mitsubishi Gas Chemical Co., Ltd., trade name: Iupilon S)
3000 black) at a resin temperature of 290 ° C and a mold temperature of 60
Fig. 2
A molded product having the shape shown in FIG. Since the illuminated portion obtained by the molding was completely sandwiched between the movable core and the cavity, the illuminated portion had the illuminating property without the molding material resin being laminated. In addition, since the printed portion was free from scratches, it had light-shielding properties.

Comparative Example 1 An illuminated switch was formed by a conventional method using a mold having the same product shape as in Example 1. The mold core had no cushioning property, the sheet shape was a simple square shape, and the cavity was molded without applying anything, as in normal molding. When the mold was tightened, scars were left on the print, and the sheet was not well pushed into the cavity due to the use of the square sheet. When the resin was injected, the resin partially covered the print on the sheet. In addition, there was no light-shielding property due to scars when the mold was closed.

[0019]

According to the present invention, it is possible to prevent the surface of the illuminated switch from being damaged during molding.
The degree of freedom in design is increased, and cost reduction and mass production of products can be expected by reducing the number of processes.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a state of a cross section in which a mold is closed after a seat is mounted.

FIG. 2 is a conceptual diagram showing a cross-sectional state in which a thermoplastic molding material is injected into a mold cavity and laminated with a sheet to form an integrally molded product.

FIG. 3 is a perspective view showing an illuminated switch obtained according to the present invention.

FIG. 4 is a cross-sectional view of an illuminated switch obtained according to the present invention.

[Explanation of symbols]

 1: Printed sheet 2: Thermoplastic molding material 3: Cavity side 4: Core side 5: Movable core 6: Movable core 7: Molded illuminating switch 8: Illumination section

Continuation of the front page (56) References JP-A-4-201312 (JP, A) JP-A-2-215511 (JP, A) JP-A-62-132222 (JP, A) JP-A-4-191102 (JP, A) JP-A-60-58822 (JP, A) JP-A-5-131489 (JP, A) JP-A-2-22815 (JP, U) JP-A-63-144215 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B29C 45/00-45/84

Claims (4)

(57) [Claims] 1. Using an injection molding machine having a movable core arranged on the core side of a mold, a thermoplastic resin (A) sheet or film on which characters, marks or decorations have been previously printed, painted or hot stamped. Cut it,
After being mounted in the mold cavity, the movable core is advanced to the position corresponding to the core and preformed, and then the thermoplastic molding material (B) to be welded to the thermoplastic resin (A) sheet or film is injected into the mold cavity. In a molding method of an illuminating switch component, in which the sheet or film is injected and the thermoplastic molding material (B) is integrally laminated into a predetermined shape, a cavity corresponding to the shape of the thermoplastic resin (A) sheet or film to be used. The length of each side is 0.5 to 3 mm larger than the size of the side, the curvature of the corner of the sheet or film is equal to or greater than the curvature of the corner of the mold cavity, and the metal of the sheet or film is A method for molding an illuminable switch component, wherein the component is mounted in a mold cavity by using a mold projecting pin. 2. The method according to claim 1, wherein the movable core is a movable core having a cushioning property. 3. A method for applying a paint or powder having a low coefficient of friction to the inner surface of a mold cavity to be used, a sheet or film mounting portion, or at least one portion of the sheet or film surface to close the mold. 2. The method of molding an illuminable switch component according to claim 1, further comprising sliding the printed surface of the sheet in the cavity without damaging the printed surface. 4. The method according to claim 1, wherein a mold cavity in contact with a sheet or film and / or a movable core surface is covered with an elastic rubber.
3. The method for molding an illuminable switch component according to claim 1.