JPS59232809A - Mold assembly for molding synthetic resin products - Google Patents

Abstract

PURPOSE:To obtain a mold assembly capable of producing a remarkable temperature difference partially on the cavity surface by a method wherein a plurality of mutually independent fluid passages are provided on the backside of a cavity surface and mold temperature controlling fluid with different temperatures is supplied into the respective fluid passage. CONSTITUTION:A vortex groove 28 is provided on the backside of an area sticking fixedly to a lens 2 on the liner 16 of a bottom force 10 and winding grooves 30, 31 are provided around the grooves 28. These grooves 28, 30, 31 form disk- type heat exchange fins 32, 34. Regarding the liner 24 on a top force 12 side a vortex groove 38, winding grooves 40, 41, heat exchange fins 42, 44 are formed in the same manner. When a goggle is formed by a mold assembly constituted in such a manner, cold air is supplied into the vortex grooves 28, 38 of the liners 16, 24 and steam is supplied to the winding grooves 30, 31, 40, 41 to cool the central portions of the liners 16, 24 and to heat the outer circumfernce.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mold apparatus for molding synthetic resin products, and in particular to temperature control thereof.

Controlling the temperature of a mold has been conventionally practiced in order to shorten the molding cycle time of synthetic resin products or increase the molding thickness. As a typical means for this purpose, it is widely practiced to form a fluid passage inside the mold and to flow a temperature control fluid through it. In addition, fluid passages are densely provided in areas where salinity control is particularly required to partially enhance the cooling or heating effect.

However, conventional control of this type has focused on making the mold temperature uniform throughout the cavity.

In contrast, the present invention has been made with the purpose of providing a mold that can generate a significant temperature difference locally on the cavity surface, and its gist is to provide a mold for molding synthetic resin products. A fluid supply system that forms a plurality of independent fluid passages along the cavity surface on the back side of the cavity surface that surrounds the mold cavity, and supplies mold temperature control fluid with a different temperature to each fluid passage. The problem is that the device is connected.

In this way, it is possible to proactively provide high-temperature areas and low-temperature areas on one cavity surface. In particular, heating fluid is supplied to the - fluid passage, and cooling fluid is supplied to the other fluid passage. It is also possible to supply a cooling fluid, and in this way particularly significant temperature differences can be created.

If such a mold device is used, it is possible to perform multi-stage molding of thermoplastic resins with relatively similar melting temperatures, for example, by molding a part of the 1111i1 product with a certain thermoplastic resin and molding the remaining By molding different parts with different thermoplastic resins, it is possible to mold an integrated product in stages using multiple types of thermoplastic resins with different colors and materials.

Moreover, according to the molding apparatus according to the present invention, even products having extreme differences in wall thickness can be molded without causing sink marks or distortion. Furthermore, if the present invention is applied to a mold for multistage molding of thermosetting resin, thermal distortion of the previously molded portion can be prevented.

Hereinafter, some embodiments of the present invention will be described in detail based on the drawings.

What is shown in FIG. 1 is goggles (underwater goggles) as an example of a product that can be suitably molded by the mold apparatus according to the present invention. In this goggle, the lens 2 is made of hygroscopic resin, and the frame 4 is made of polycarbonate resin. A hygroscopic resin is one with excellent hygroscopic properties, such as cellulose propionate resin, which is commercially available from West Germany's Bayer AG under the trade name Ceridore, and lenses made with such a hygroscopic resin cannot be used. It does not sometimes cause cloudiness. However, since this hygroscopic resin and polycarbonate resin are both thermoplastic resins and have relatively similar melting temperatures, it is difficult to mold the frame 4 around the lens 2 to form an integral goggle. was difficult.

However, according to the mold apparatus according to the present invention shown in FIGS. 2 to 4, goggles as described above can be easily molded. In FIG. 2, 10 is a fixed type and 12 is a movable type. The fixed mold 10 consists of a mold body 14 and a nest 16. A bottomed nesting hole 18 is formed in the center of the parting surface of the mold body 14, and the nesting hole 16 is hermetically fitted and fixed therein. The movable mold 12 similarly includes a mold body 20, and a nest 24 is hermetically fitted into a nest hole 22 of the mold body 20.

The surfaces of the nests 16 and 24 are the fixed mold 10 and the movable mold 12.
and a cavity 2 for sandwiching and fixing the lens 2 in a predetermined position in a closed state, and for molding the frame body 4.
The cavity surface 26.27 is machined into a shape that forms 5.
It becomes. A thinly wound groove 28 is formed on the back side of the portion of the nest 16 that comes into close contact with the lens 2, as shown in FIG. Although this groove 28 is narrow, it is formed deep, and its bottom reaches close to the surface of the nest 16. Also, as can be seen from FIG. These grooves 30.31 are also formed with a narrow width and depth.
By forming 30 and 31, the remaining flesh of nest 16 serves as temporary heat exchange fins 32 and 34 and cavity wall 36. Nest 2 on the movable mold 12 side
4, similarly, a thinly wound groove 38 and a zigzag groove 40, 41 are formed, and as a result, heat exchange fins 42 and 44 and a cavity wall 46 are formed.

In addition, the mold body 14 has two inflow ports 48.5 each.
0 and outflow boats 52 and 54 are formed. As is clear from FIG. 3, the inflow boat 48 has a thin spiral groove 2
The inflow boat 4 is connected to the outer peripheral end of the boat 8.
8 is communicated with the branching part between the zigzag grooves 30 and 31. In addition, the outflow boat 52 has a spiral groove 2
The outflow boat 54 is connected to the other branch of the grooves 30 and 31. Similarly, the inflow ball 1 is placed on the mold body 20 on the movable mold 12 side.
56.58 and an outflow bow 1-60.62 are provided.

The fixed mold 10 is provided with a sprue for press-fitting the resin into the cavity 25, and other items such as a kite bin, positioning pin, ejector, etc. that are installed in a regular injection mold are included in the fixed mold 10 or the movable mold. 12, but illustration is omitted.

As shown in FIG. 4, a steam generator 64 as a heating fluid supply device and a cooling device 66, 67 as a cooling fluid supply device are connected to the mold. Steam generator 6
4 is equipped with a boiler that generates steam using a heavy oil burner or the like, and a heat exchanger that preheats the water supplied to the boiler with the steam returned from the mold. Connected to inlet boats 50 and 58 and outlet boats I 54 and 62. The cooling device 66 also includes a refrigerant compressor, a condenser, an evaporator,
It is equipped with a heat exchanger and the like to cool the air, and is connected to the inflow boats 48 and 56 and the outflow boats 52 and 60 via an electromagnetic on-off valve 70. The cooling device 67 has a similar configuration, and the electromagnetic switching valve 68
and 69 to the steam generator 64 and alternatively to the inlet boats 50 and 58 and the outlet boats 54 and 62.

When molding goggles using the mold device configured as described above, the fixed mold 10 is mounted on the fixed plate of the injection molding machine (q), and the movable mold 12 is attached to the movable plate. and 69 to the right side, and opens the electromagnetic on-off valve 70 to supply cold air to the spiral grooves 28 and 38 of the nests 16 and 24. Steam is supplied to cool the centers of the nests 16 and 24 and heat the outer peripheries. At this time, the cold air and water vapor flow through the narrow grooves at a fairly high speed, and the plate-shaped heat exchange fins 32. The cavity walls 36 and 46 are efficiently cooled and heated through the s4°42.44, etc.

When the cavity walls 36 and 46 reach a predetermined temperature, the fixed mold IO and the movable mold 12 are removed with the lens 2, which has been molded in advance from a hygroscopic resin, placed in a predetermined position as shown in FIG. close. And cavity 25
is filled with molten polycarbonate resin and allowed to solidify. At this time, a large molding pressure acts on the cavity walls 36 and 46, and this pressure and force is transmitted to the mold bodies 14 and 20 by the heat exchange fins 32, 34, 42, 44, etc. These heat exchange fins serve as reinforcing ribs for the cavity walls 36 and 46 as well as supporting walls. Further, when the molten polycarbonate resin filled in the cavity 25 comes into contact with the outer periphery of the lens 2, a part of the outer periphery melts, but the lens 2 is sandwiched between the low-temperature central part of the nests 16 and 24. Since the lens 2 is cooled, only the portion that will be covered by the lens frame 4 after formation is melted, and the lens 2 will not be distorted or its appearance will be deteriorated. Rather, by melting a portion of the lens 2, the welding between the lens 2 and the frame 4 becomes stronger, which is advantageous. Further, even though the center portions of the nests 16 and 24 are cooled, the outer peripheral portions to be filled with the polycarbonate resin are heated to a sufficient temperature, so there is no risk of defective products due to insufficient filling of the polycarbonate resin.

When the filling of the filled polycarbonate resin is completed, the electromagnetic switching valve 68, 69 is switched to the left state G to supply cold air to the hollow grooves 30, 31, 40, 41, and close the nests 16 and 24. If the temperature at the outer periphery is lowered, the polycarbonate resin will solidify quickly.Therefore, when the mold is opened after this, the lens 2 will be formed as shown in Figure 1.
A goggle for one eye in which the frame body 4 and the frame body 4 are firmly integrated is obtained.

According to the mold apparatus according to the present invention, a product as shown in FIG. 5 can be easily molded. This includes both the center part 72 and the outer peripheral part 74.
are made of the same thermoplastic resin material, but have different colors, for example, the center portion 72 is red and the outer peripheral portion 74 is cream colored.

A mold device for molding such a product is shown in FIGS. 6 and 7, and since this is basically the same as the mold device in the previous embodiment, corresponding parts are The same reference numerals are used to omit detailed explanation.

In the mold apparatus of this embodiment, the grooves 30 and 40 formed on the outer periphery of the nests 16 and 24 are also spirally shaped. Furthermore, in the above embodiment, the lens 2 at the center was molded first, and the frame 4 at the outer periphery was molded later, whereas in this embodiment, the outer periphery 74 was molded first. Since the center portion 72 is molded later, the center portions of the nests 16 and 24 are heated and the outer periphery portions are cooled.

As shown in the molded product shown in Figure 5, a product made of the same +4 quality thermoplastic resin is molded in two or more parts,
Moreover, it is almost impossible to maintain a beautiful boundary line between the first and second molded parts and to connect them with sufficient strength using normal mold equipment. According to the mold according to the present invention, the purpose can be easily achieved.

Additionally, similar mold equipment may be used to mold products such as those shown in FIGS. 8 and 9. What is shown in FIG. 8 is a flexible duct ttr+hand, in which a tube 78 is integrally molded at both ends of a cylindrical bellows 76 made of thermoplastic resin with excellent elasticity. Moreover, FIG. 9 shows the side surface of a basket with a colander weave pattern, which is a DJ molded product with unevenness on the surface as if it were knitted with strings. Such molded products have been manufactured in the past, but by performing multi-stage molding using the mold according to the present invention, the colors of the warp part 80 and the width part 82 can be made different, or even the width parts can be made different. Since the color of the bar parts 82 can also be made different, it is possible to obtain a molded product with an appearance similar to a real basket by -1 m. Furthermore, although not shown in the drawings, it is also possible to integrally mold a vertically long transparent part into the container made of opaque resin so that the inside can be seen through.

According to the mold apparatus according to the present invention, a dial plate 83 as shown in FIG. 10 can also be easily molded. Conventionally, such dials have been manufactured by manual processes such as engraving, hot stamping, two-color engraving, etc., or by impossible machine operations. This makes it possible to easily manufacture dials of excellent quality.

An example of the mold apparatus is shown in FIGS. 11 to 13.

11 and 12 are a front view and a rear view of the nest, and the front surface of the nest 84 has a plurality of bottomed rectangular holes 86.
A character shape 88 is fitted into this hole 86 and fixed by seven screws 1 to 90. There are two types of character shapes 88, one with a protruding character part and one with a recessed character part, and these can be used interchangeably. Grooves 92 and 94 as shown in FIG. 12 are formed on the back side of the nest 84. The groove 92 is formed behind the bottomed rectangular hole 86, and the groove 94 is formed to surround the periphery thereof.

As shown in FIG. 13, the nest 84 is fluid-tightly fitted and fixed into a nest 98 formed in a mold body 96. The mold body 96 is provided with an inlet boat 100 communicating with one end of each of the grooves 92 and an outlet boat 1-102 communicating with the other end, and furthermore? An inflow boat 104 communicating with one end of the 1Ii94 and an outflow boat 106 communicating with the other end are provided. The movable mold 10, which forms the product cavity in cooperation with the fixed mold 108 consisting of the insert 84 and the mold body 96, similarly includes a mold body 112 and the insert 114, and the mold body 112 has an inflow. A bow I~116 and an outflow boat 118 are provided, while a groove 120 in the shape of a flute is provided on the back side of the nest 114.

A heating fluid supply device that supplies high-temperature oil and a cooling fluid supply device that supplies low-temperature oil are connected to each of the above-mentioned outflow and inbound boats via electromagnetic directional valves, but the illustration is not Omitted.

In order to mold the dial plate shown in FIG. 10 using the mold device configured as described above, first, the character mold 88 with the character part protruding is fixed to the nest 84, and the inflow boats 100, 104 are and 116, while supplying high-temperature oil, a dial main body with concave character portions is formed. After molding the desired amount of the dial main body, the character mold 88 of the nest 84 is replaced with a recessed character shape, and
Character parts are formed while low temperature oil is supplied to the inflow ports 116 and 104, and high temperature oil is supplied to the inflow port 100. At this time, the dial body that was previously formed is cooled, and the parts where the characters are to be formed are locally heated, so it is possible that distortion may occur in the dial body. The characters can be formed without excessive melting of the boundary between the dial main body and the characters, and a dial 83 of excellent quality can be easily obtained.

In the above embodiment, the dial main body was molded first, but the various characters were molded first, and after positioning them at predetermined positions in the mold, the characters were molded. It is also possible to mold the plate body to form an integral dial plate. In this case, it is necessary to cool the area between the nested characters, but a heat pipe is suitable for cooling only such a narrow area. A heat pipe is a sealed tube with a lining that transports liquid through capillary action.When the liquid transported by this lining evaporates in a high temperature area, it absorbs heat from the surrounding area and releases heat in a low temperature area. It transports heat from a high-temperature area to a low-temperature area by releasing and liquefying it, and it appears to have extremely high thermal conductivity. Therefore, if such a heat pipe is placed in close proximity to the surface on which the hanging type letters are to be sandwiched, that area can be locally cooled, and when the dial body is molded, the letters will be cooled down. This can prevent the circular surface from melting excessively and making the boundary between the letters and the dial body look unsightly. In this case, the heat pipe serves as a fluid passage for guiding the cooling fluid.

In the above examples, either the entire previously molded part of the product was accommodated in the mold cavity before the next stage of molding was performed, or the next stage of the previously molded part It is also possible to firmly sandwich only the part adjacent to the molding part between the molds, and perform the next molding with the other parts exposed to the outside.

Furthermore, if a temperature sensor is embedded inside the mold, particularly inside the nest, and temperature management is performed while measuring the temperature of each part, the mold temperature can be controlled more accurately.

Furthermore, the heat exchange fins formed on the back side of the nest are rectangular w.
The fins are not limited to those having an i-plane; for example, a fin having a trapezoidal cross section that is thinner at the distal end and thicker at the proximal end is also possible. Furthermore, thermal efficiency can be improved by interposing a cross-sectional material such as a high-strength ceramic plate material between the bottom surface or inner surface of the nest hole and the nest. Similarly, in order to improve the heat exchange efficiency, it is particularly desirable that the height of the heat exchange fins be at least twice the thickness.

Several embodiments of the present invention have been described in detail above, but the present invention can be modified and improved in various ways based on the knowledge of those skilled in the art without departing from the scope of the claims. Of course, it is important to implement the following.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of goggles as an example of a product that can be suitably molded by the mold apparatus according to the present invention. Second
The figure is a front cross-sectional view schematically showing a mold for molding the goggles, and FIG. 3 is a cross-sectional view taken along the line 1--2 in FIG. 2. FIG. 4 is a system diagram showing a state in which a temperature control fluid supply device is connected to the mold shown in FIGS. 2 and 3. FIG. Fig. 5 is a front view showing another example of a molded product, Fig. 6 is a front sectional view schematically showing a mold for molding the molded product, and Fig. 7 is a - ■It is a sectional view. FIG. 8 is a front sectional view of another molded product, and FIG. 9 is a diagram showing a part of the side surface of another molded product. FIG. 10 is a perspective view of yet another molded product, FIG. 11 is a front view showing only the mold insert used for molding the molded product, and FIG. 12 is a rear view. FIG. 13 is a front sectional view schematically showing the mold device including the nest shown in FIGS. 11 and 12. FIG. 10.1・08: Fixed type 12,110: Movable type 14.
20, 96, 112: Mold body 16.24, 84. ．． 114: Nesting 18. 22. 98: Nesting hole 25: Gavity 26, 27: Cavity surface 28.
30, 31, 38, 40, 41, 92, 94.12 (l
Groove 32.34.42.44: Heat exchange fin 36.46: Cavity wall 48.50.56, 58, 100, 104.116 = Inflow boat 52.54, 60.62, 102, 106, 118: Outflow boat 64: Steam generator (heating fluid supply device) 66.67
: Cooling device (cooling fluid supply device) 68. 69: Solenoid switching valve 70: Solenoid switching valve 86: Bottomed rectangular hole
88: Character type applicant Shigeru Ikemoto Figure 2 27 16 J(J(:jυ Figure 6:;, :l, 12 (-8) Figure 13

Claims (4)

[Claims] (1) On the back side of the cavity surface surrounding the cavity of a mold for molding synthetic resin products, a plurality of mutually independent fluid passages are formed along the cavity surface, and each fluid passage has a different mold temperature. A mold device for molding synthetic resin products, characterized in that a fluid supply device for supplying control fluid is connected. (2) The mold includes a mold body having a bottomed nesting hole and a nest fitted into the nesting hole, and the fluid passage is formed on the back side of the nest. 2. The mold device according to claim 1, wherein the groove is covered by the bottom surface of the nesting hole. (3) The groove is formed in such a state that two portions separated in the longitudinal direction of the groove are adjacent to each other substantially parallel to each other, so that the meat of the nest remaining between the adjacent portions becomes a plate-shaped heat exchange fin. and the heat exchange fins are adapted to act as a support wall that abuts the bottom surface of the nesting hole at the tip and transmits the molding pressure acting on the cavity surface to the mold body. A mold device according to claim 2. (4) Claims 1 to 3, wherein at least one of the plurality of fluid supply devices is a device that supplies mold cooling fluid, and at least one is a device that supplies mold heating fluid. A mold device according to any of paragraphs.