KR20020078685A - injection method and molding device for printing on rear side - Google Patents

Abstract

PURPOSE: A melting injection molding method for fabricating a solid workpiece and a mold for fabricating the same are provided to prevent a printing surface of a printing sheet from being corrugated by closely attaching the printing sheet to an upper mold when the upper mold moves down. CONSTITUTION: An inlet(11) is formed at an upper portion of a body(10) to feed liquid phase synthetic material in the body(10). In addition, a passage(12) for transferring the liquid phase synthetic material into a mold is formed at a side of the body(10). The liquid phase synthetic material is conveyed towards a lower mold(20) through the passage(12). The lower mold(20) is formed at an upper portion thereof with the first division part(21). An engraving(22) is formed at a recess formed in the first division part(21). An injection passage(23) is formed at a lower surface of the engraving(22). The second division part(31) is formed in an upper mold(30).

Description

Melt injection method and mold apparatus for producing a three-dimensional molded object in which the printing sheet is attached to the back and the external projection is made {injection method and molding device for printing on rear side}

The present invention relates to a melt injection method and a mold apparatus for producing a three-dimensional molded article is bonded to the back of the printing sheet is formed external projection, more specifically, the printing sheet between the lower mold and the upper mold to the lower mold side printing sheet Position and the injection molding of the liquid synthetic resin material from the injection passage provided in the lower mold to make a molded article and at the same time the printing sheet is attached to the back of the molded article, the pattern is displayed through the transparent or translucent molded article and mold Relates to a device.

Many products are manufactured using synthetic resin materials, and injection molding methods are used a lot in the production of synthetic resin materials. Initially, only synthetic resin was injected by molding between molds, but then, a technique of printing on the surface of the injection molded product was needed.

Currently, various techniques are known as a method of printing a pattern by placing a printing sheet between a lower mold and an upper mold, bonding a printing sheet to a surface of a molded article simultaneously with injection molding.

When using a technique for printing a pattern simultaneously with such injection molding, a general method is injection molding with the printing surface 3 'of the printing sheet 3 toward the upper mold 2 as shown in FIG. As shown in 2a, the printing sheet 3 is attached to the surface of the product. In this case, the printing sheet 3 is directly exposed to the outside, and the printing sheet 3 is gradually damaged by external friction. In order to prevent damage to the printing sheet 3, there is a method of attaching a printing surface protection coating film to the printing sheet 3. However, when the coating film is attached, there is a problem in that the cost is increased by adding a process.

In addition, when the printing sheet 3 is attached to the molded article 4, the printed sheet 3 should be evenly spread on the surface of the molded article 4.

However, according to the prior art, the upper mold 2 is engraved as shown in Fig. 1A. In this case, as shown in FIG. 1B, when the upper mold 2 is vertically lowered to apply pressure to the printing sheet 3, the printing sheet 3 is an engraved portion of the upper mold 2. It will not be in close contact with. When the upper mold 2 and the lower mold 1 are completely combined, the printing sheet 3 is rather in close contact with the lower mold 1 side. When the liquid synthetic resin material is injected from the bottom surface of the lower mold 1 after bonding, the pressure in the mold increases, and the printing sheet 3 is pushed toward the upper mold 2 by the pressure of the liquid synthetic resin material. In this process, wrinkles occur in the print sheet 3, which causes a problem that print quality is lowered.

Accordingly, the present invention is designed to solve the above problems, the upper mold is produced in the form provided with a protrusion, when the upper mold when the printing sheet is in close contact with the upper mold side, the occurrence of wrinkles on the printing surface is reduced It is an object of the present invention to provide a melt injection method and a mold apparatus used therein.

Further, another object of the present invention is to provide a molten injection method for protecting a printing surface without a separate coating layer by attaching and attaching a printing sheet to a rear surface of a transparent or translucent synthetic resin material projected inside.

Figure 1a: cross-sectional view of the pre-injection molding step of the melt injection mold apparatus according to the prior art

Figure 1a: cross-sectional view of a step immediately before the injection of the liquid synthetic resin material of the melt injection molding apparatus according to the prior art

Figure 2a: cross-sectional view of an injection molded and printed three-dimensional molded article according to the prior art

Figure 2b: cross-sectional view of a three-dimensional molded injection molded and printed according to the prior art

Figure 3 is a cross-sectional view of the pre-injection molding step of the melt injection mold apparatus according to the present invention

Figure 4 is a cross-sectional view of the injection molding step of the melt injection molding apparatus according to the present invention

<Description of the reference numerals for the main parts of the drawings>

10: main body 11: inlet

12: transmission passage 20: lower mold

21: first partition 22: engraving

23: injection passage 30: upper mold

31: 2nd partition 32: Sculpture pattern

40: printing sheet 41: printing unit

50: three-dimensional molded article 51: surface of the three-dimensional molded article

52: back of the three-dimensional molded article

In order to achieve the above object, the present invention is a liquid synthetic resin material for forming a transparent or semi-transparent injection molding is projected inside is formed by the main body and the intaglio engraving for injection molding is formed into the receiving groove, An injection passage of the liquid synthetic resin material transmitted from the main body is provided with a lower mold and an embossed protrusion corresponding to the receiving groove, and an upper mold provided with a patterned piece corresponding to the engraved piece on the bottom of the embossed protrusion. Located between the upper mold and the lower mold, and comprises a printing sheet is installed so that the printed printing portion is directed to the lower mold side by the movement of the upper mold glyph carving and lower portion of the print sheet in the embossed projection of the upper mold Upper and lower molds are combined to be located between the intaglio pieces of the mold Injection molding and at the same time, printing of sheet material a liquid synthetic resin which is passed through the combination and that is attached to the back surface of the three-dimensional shaped article with a base of technology.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention. Figure 3 is a cross-sectional view of the injection molding step of the melt injection molding apparatus according to the present invention. 4 is a cross-sectional view of the injection molding step of the melt injection mold apparatus according to the present invention.

The present invention can be seen that the main purpose to provide a melt injection method for reducing the wrinkles generated in the printing sheet affects the print quality when printing at the same time injection molding of the three-dimensional molded article. To this end, as shown in Figure 3 in the present invention, the mold apparatus is made of a fixed lower mold having a receiving groove formed therein and a moving upper mold having a protrusion corresponding to the receiving groove. The reason why the lower mold is engraved and the protrusion is provided on the upper mold is to reduce the occurrence of wrinkles due to pressure during injection molding because the printing sheet is in close contact with the upper mold.

When the upper mold is intaglio, a space is generated between the printing sheet and the upper mold when the upper mold is lowered, and the printing sheet is pushed into the space during the injection molding due to the pressure of the liquid synthetic resin material inside the mold generated during the injection molding. Wrinkles occur as you enter.

However, the upper mold has an embossed protrusion, and when the upper mold is lowered, the printing sheet and the upper mold are in close contact with each other so that there is no space between the upper mold and the printing sheet, and the printing is caused by the pressure of the liquid synthetic resin inside the mold where the injection molding occurs. The movement of the sheet is suppressed and wrinkles of the printed sheet are reduced.

Hereinafter, such a mold apparatus will be described in detail.

As shown in Figure 3, the main body 10 is provided with an injection port 11 for replenishing the liquid synthetic resin raw material on the upper side, the delivery passage 12 for delivering the liquid synthetic resin raw material into the mold on the side Is formed. The synthetic resin material is injected through the injection hole 11 inside the main body 10, the synthetic resin material is heated to change the liquid state, and the liquid synthetic resin material is lowered through the transfer passage 12. It is transferred to 20) side and injected. Since the technology related to the main body 10 is well known in the art, a detailed description thereof will be omitted.

The lower mold 20 has a flat first divided surface 21 formed thereon, and an intaglio corresponding to the shape of the surface 51 of the three-dimensional molded product 50 in a receiving groove formed inside the first divided surface 21. Piece 22 is formed, the bottom surface of the engraving 22 is provided with an injection passage 23 through which the liquid synthetic resin material is delivered from the main body 10.

In addition, the upper mold 30 is formed with a flat second divided surface 31 corresponding to the first divided surface 21 of the lower mold 20, the lower mold 31 on the lower mold An embossed protrusion corresponding to the receiving groove 20 is provided, and a patterned piece 32 corresponding to the shape of the back surface 52 of the three-dimensional molded article 50 is formed on the bottom of the embossed protrusion. The upper mold 30 is moved vertically, and is coupled to the lower mold 20 when descending.

The upper mold 30 pressurizes the printing sheet 40 positioned below when the lower mold 30 is lowered, and the printing sheet 40 is in close contact with the surface of the upper mold 30 by the pressure.

Here, the printing sheet 40 is a synthetic resin film attached to one side of the printing portion 41 printed with the color pattern to be formed on the three-dimensional molded article 50. The printing sheet 40 is located between the lower mold 20 and the upper mold 30, and is installed with the printing portion 41 facing the lower mold 20 side. The printing sheet 40 needs to be in close contact with the upper mold in order to be attached to the three-dimensional molded article (50). Therefore, the printing sheet 40 should be flexibly stretched when subjected to pressure. In addition, the film portion of the printing sheet 40 is attached to the rear surface of the three-dimensional molding portion 50 serves to protect the printed portion 41 is printed pattern.

In addition, another object of the present invention is to provide a melt injection method for protecting a printing surface without a separate coating film when printing on a three-dimensional molded article of the projected material. To this end, in the present invention, the printed portion of the printing sheet is attached to the back of the three-dimensional molded article so that the printed pattern is projected through the three-dimensional molded article. The reason why the printing sheet is attached to the back side as described above is that the three-dimensional molded article is placed on the front side and the printing surface is installed on the rear surface, so that the printing surface is not exposed to the outside, so that the printing surface printed on the rear surface is damaged due to wear or the like. To prevent this.

Hereinafter, the melt injection method will be described in detail.

As shown in FIG. 3, the printing sheet 40, which is heated on the upper mold 30 and has a high elasticity, is installed with the printing unit 41 facing the lower mold 20.

When the upper mold 30 is lowered as shown in FIG. 4, the upper mold 20 exerts a pressure on the printing sheet 40 to cause deformation of the printing sheet 40. The printing sheet 40 is extended according to the surface shape of the embossed projection and the pattern piece 32 of the upper mold 30, and is in close contact with the embossed projection and the pattern piece 32 of the upper mold 30.

The upper mold 30 continues to descend so that the upper mold 30 and the lower mold 20 are combined. After the upper mold 30 and the lower mold 20 are completely combined, and the liquid synthetic resin material is injected through the injection passage 23 provided on the lower surface of the lower mold 20, the pressure of the liquid synthetic resin material The printing sheet 40 is completely in close contact with the upper mold (30). When the liquid synthetic resin material is cooled, it solidifies to form a shape of a three-dimensional molded product 50 capable of transparent or translucent projection, and the printing sheet 40 is attached and bonded to the rear surface of the three-dimensional molded product 50.

After cooling, the upper mold 30 rises vertically, and the upper mold 30 and the lower mold 20 are separated, and the three-dimensional molded article 50 formed in the mold is taken out.

Herein, the present invention is not limited to printing by bonding the printing sheet 40 to the back surface of the three-dimensional molded product 50. Ink may be printed on the transfer film instead of the print sheet 40 to pressurize the transfer film to bond the ink to the back surface of the three-dimensional object 50 and to remove the transfer film.

As described above, using the melt injection method and the mold apparatus for producing a three-dimensional molded object in which the printing sheet is bonded to the back of the present invention to the external projection is formed, the upper mold is produced in the form having an embossed protrusion, When the upper mold is lowered, the printing sheet is in close contact with the upper mold side, so that the occurrence of wrinkles in the printing sheet is reduced, thereby improving printing quality.

In addition, since the printing sheet printed with the pattern is attached to the back of the three-dimensional molding, the three-dimensional molded object acts as a protective film without forming a separate printing surface protective film, there is an effect of protecting the printed pattern.

Claims (4)

A main body 10 into which a liquid synthetic resin raw material for forming a transparent or translucent injection molded product projected inside is supplied by melt injection; The intaglio engraving 22 for injection molding is formed into the receiving groove, and the lower mold 20 provided with the injection passage 23 of the liquid synthetic resin material transferred from the main body 10 through the bottom of the intaglio engraving 22. ; An upper mold 30 having an embossed protrusion corresponding to the receiving groove, and having a patterned piece 32 corresponding to the engraved piece 22 on the bottom of the embossed protrusion; And And a printing sheet 40 positioned between the upper mold 30 and the lower mold 20 and installed such that the printed printing portion 41 faces the lower mold 20 side. The upper and lower molds are positioned such that the printing sheet 40 is located between the pattern sculpture 32 in the relief portion of the upper mold 30 and the intaglio engraving 22 of the lower mold 20 by the movement of the upper mold 30. This combination is combined with the injection molding of the liquid synthetic resin material that is delivered through the bottom of the lower mold 20, the engraving 22, at the same time the print sheet 40 is attached to the back 52 of the three-dimensional molding 50 attached to the back Melt injection mold apparatus for producing a three-dimensional molded article is bonded to the printing sheet to the external projection. According to claim 1, wherein the printing sheet 40 is a molten injection mold apparatus for producing a three-dimensional molded object is a projection sheet is attached to the back is characterized in that the colored pattern is formed on the surface of the synthetic resin film In the melt injection molding method of the three-dimensional molded article 50 made of transparent or translucent projected inside, The intaglio engraving 22 for injection molding is formed into the receiving groove, and the lower mold 20 provided with the injection passage 23 of the liquid synthetic resin material transferred from the main body 10 through the bottom of the intaglio engraving 22. The printing part 41 is provided between the upper mold 30 having an embossed projection corresponding to the receiving groove, and the upper mold 30 having a patterned piece 32 corresponding to the intaglio engraving 22 on the bottom of the embossed protrusion. The printing sheet 40 is installed to face toward the 20) side, the print sheet 40 by the movement of the upper mold 30, the pattern piece 32 in the embossed projection of the upper mold 30 and the lower mold The upper and lower molds are coupled to be positioned between the intaglio pieces 22 of the 20 and the printing sheet 40 is a three-dimensionally molded article 50 at the same time as the injection molding of the liquid synthetic resin material transferred through the bottom of the intaglio pieces 22. Attached to the back 52 of the) is characterized in that the external projection of the printing surface Method of producing a melt injection molding three-dimensional molded article is attached to the back of the printing sheet is attached to the external projection. 4. The method of claim 3, wherein the printing sheet (40) has a colored pattern on the surface of the synthetic resin film.