CN201264364Y - Mould - Google Patents

Abstract

A mould comprises a female mould and a male mould that is matched with the female mould, wherein, the female mould is provided with a mould cavity and at least an exhausting groove that exhausts the air inside the mould cavity; the male mould is provided with a medium passage, and the medium passage can be communicated with one medium source so as to convey the medium into the mould. Through the double effects of vacuum pumping of the exhausting groove at the side of the female mould and the medium pressurizing at the side of the male mould, the tensile elongation of the film between the male and the female moulds is greatly prolonged, and the film can be perfectly matched with the mould cavity of the female mould even under the conditions of small angle and large depth.

Description

mold

technical field

The utility model relates to an in-mold decoration device, in particular to a mold for in-mold decoration.

Background technique

In-mold decoration (IMD, In Mold Decoration) is a surface decoration technology widely used in information and home appliances. It is commonly used in notebook computer casings, mobile phone window lenses and casings, washing machine control panels, refrigerator control panels, air conditioner control panels, and automotive instruments. Appearance parts such as panels and signs in various fields such as plates and rice cooker control panels.

IMD is divided into IML (In Mold Label) and IMR (In Mold Roller). The biggest difference between these two processes is whether there is a transparent protective film on the surface of the product.

The Chinese name of IML is In-Mold Insert Injection Molding. Its process is very remarkable: the surface is a layer of hardened transparent film, the middle is a printed pattern layer, and the back is a plastic layer. Because the ink is sandwiched in the middle, the product can prevent surface It is scratch-resistant and abrasion-resistant, and can maintain the bright color for a long time and is not easy to fade.

The Chinese name of IMR is in-mold transfer printing. This process is to print the pattern on the film, and then attach the film to the cavity of the mold through a film feeding machine. After injection molding, the patterned ink layer is separated from the film, and the ink layer remains on the plastic part to obtain a plastic part with a decorative pattern on the surface. There is no transparent protective film on the surface of the final product, and the film is just A carrier in the production process. The advantage of IMR lies in the high degree of automation in production and the low cost of mass production.

In the existing IMR process, the film is adsorbed and positioned in the cavity of the master mold only by vacuuming the master mold side at room temperature. Therefore, the depth of film drawing is limited by the tensile limit of the film matrix layer itself at room temperature. For example, when the film It may be damaged or broken when it is stretched more than 20% of its natural state; moreover, when the mother mold cavity is designed with a small angle (especially at an acute angle) structure, due to the size of the negative pressure generated by vacuuming and the Due to the restriction of room temperature deformation of the film base layer material, it is not easy for the film to completely conform to the shape of the mold cavity.

Based on the lack of the above existing technology, the industry has appeared a process for pre-heating the film. For example, the prior art discloses an independent heating device for heating the film before closing the mold. The heating device is independent of the outside of the mold. When heating is required, another conveying device is needed to send the heating device between the male and female molds to heat the film, and after heating, the conveying device removes the heating device from between the male and female molds. Therefore, the prior art not only needs to design the heating device and the conveying device used in conjunction with it, resulting in a bulky structure of the entire equipment and high cost; it also increases the entire process time and lowers the efficiency. In addition, this technology also has the limitation of film drawing depth and small-angle structure.

Utility model content

Based on the above, it is necessary to provide a mold that can increase the depth and angle range of film drawing.

A mold, comprising a female mold and a male mold matched with the female mold, the female mold is provided with a mold cavity and at least one exhaust groove for discharging the gas in the mold cavity, and the male mold is provided with a medium channel , the medium channel can communicate with a medium source to pass the medium into the mould.

This mold can greatly extend the stretching length of the film itself between the male and female dies through the dual functions of vacuuming through the exhaust groove on the female die side and pressurizing the medium on the male die side, and can achieve the film even in a small It can also perfectly fit the mold cavity of the master mold under the condition of angle and large depth.

Description of drawings

Fig. 1 is a cross-sectional view of a preferred embodiment of the mold of the present invention.

Fig. 2 is a cross-sectional view of the master mold of the preferred embodiment of the mold of the present invention.

Fig. 3 and Fig. 4 are cross-sectional views of the medium passage part of the male mold of the preferred embodiment of the mold of the present invention, respectively showing two different states thereof.

Fig. 5 is a cross-sectional view of a master mold and a film in a preferred embodiment of the mold of the present invention.

Fig. 6 is a cross-sectional view of a preferred embodiment of the mold of the present invention after the mold is clamped and inflated into the mold cavity.

Fig. 7 is a cross-sectional view of the injection molded state of the preferred embodiment of the mold of the utility model after the mold is closed.

Detailed ways

Please refer to Fig. 1, a kind of mold is used for transferring the pattern on the film 100 on the workpiece while injection molding, and it comprises film feeding device 10, male mold 20, female mold 30, pressing frame 40 and heat medium Source 90.

Please also refer to Fig. 2, this master mold 30 offers a mold cavity 31, and mold cavity 31 comprises a first surface A1, a second surface A2 and a third surface A3, the first surface A1 and the first surface A1 of mold cavity 31 opening positions The length of the longest connecting line between the second surfaces A2 is L. The female mold 30 is provided with a plurality of exhaust grooves 32 in and around the mold cavity 31 , and one end of the exhaust grooves 32 is connected to a vacuum device. A sealing ring 33 is disposed between the peripheral edge of a side of the female mold 30 facing the male mold 20 and the exhaust groove 32 .

Please continue to refer to Fig. 1, the male mold 20 includes a matching portion 21 corresponding to the mold cavity 31 of the female mold 30, and the male mold 20 is adjacent to the matching portion 21 and offers some exhaust grooves 23, and each exhaust groove 23 is connected to a Adjust the pressure relief valve 80, and the pressure relief threshold value of the pressure relief valve 80 can be adjusted according to the pressure change required by the molding conditions. Between the peripheral edge of the male mold 20 facing the female mold 30 and the exhaust groove 23 is defined a receiving groove 25 for accommodating the corresponding pressing frame 40 , and a sealing ring 27 is installed in the receiving groove 25 .

Please refer to Fig. 3 and Fig. 4 together, this male die 20 passes through this fitting part 21 and offers several media passages 29, and each media passage 29 comprises a bell-mouth-shaped opening 291 offered at the fitting part 21 and from the opening 291. The channel body 295 whose thinner end extends into the male mold 20 . The channel body 295 of the medium channel 29 defines a channel 296 away from the opening 291 , and the end of the channel 296 is connected to the heat medium source 90 through a pipeline 91 . A fixing body 298 is provided at an end of the channel body 295 of the medium channel 29 away from the opening 291 , and a through hole is defined in the fixing body 298 . It can be understood that the number of the medium channels 29 should be determined according to the actual demand of the product. A switch device is installed in the medium channel 29. In this embodiment, the switch device is a plunger 70. The plunger 70 includes a conical plunger head 71 that matches the shape of the medium channel 29, and a small end with the plunger head 71. Connected rod portion 73 and a fixing piece 75 that can be fixed on the other end of the rod portion 73, the plunger head 71 is used to close the opening 291 of the medium channel 29, and the rod portion 73 of the plunger 70 is away from the center of the plunger head 71. One end passes through the through hole of the fixing body 298 and passes through an elastic element, the elastic element is a coil spring 79 in this embodiment, the fixing element 75 is fixed on the end of the rod 73 to limit the spring 79 Between the fixing body 298 and the fixing member 75 .

The heat medium source 90 can be gas, and the gas can be heated by a resistance wire or an infrared heater (IR Heater) and then communicated with the pipeline 91 through a pressure regulating valve, wherein the resistance wire can be a variable resistance, so it can be heated according to the molding conditions. Adjust the gas temperature. In addition, the gas can also be heated by the heat generated by the mold water channel. The pressure regulating valve can adjust the pressure of the output gas according to the molding pressure.

The film feeding device 10 includes two film delivery wheels 13 arranged upstream and downstream of the mold and two guide wheels 15 guiding the direction of film delivery.

The film 100 includes a base layer and a transfer layer printed on the base layer. The base layer is generally made of polymer materials such as PC/PBT, and the transfer layer is generally patterns or characters printed on the base layer with ink or paint.

Please refer to Fig. 5 together. Before the mold is closed, the film feeding device 10 sends the film 100 vertically between the male and female molds 20 and 30 through the transmission of the transmission wheel 13 and the guidance of the guide wheel 15. And positioning, the film 100 is covered on the side of the female mold 30 facing the male mold 20, and then the pressing frame 40 presses the film 100 on the surface of the female mold 30, and at the same time cooperates with the sealing ring 33 to form a gap between the film 100 and the mold cavity 31. The first airtight space. The vacuum device draws out part of the air in the first airtight space through the exhaust groove 32 , and sucks a part of the film 100 into the mold cavity 31 .

Please also refer to FIG. 6 , when the mold is closed, the pressing frame 40 is accommodated in the receiving groove 25 of the male mold 20 and pressed against the sealing ring 27 of the male mold 20, so that a second gas is formed between the film 100 and the male mold 20. dense space. At this time, the exhaust groove 23 communicates with the second airtight space. Close the pressure relief valve 80, and set a pressure relief threshold for the pressure relief valve 80. The heat medium source 90 feeds a certain pressure of heat medium (hot air in this embodiment) into the medium passage 29 through the pipeline 91, and the heat medium pushes the plunger 70 to move toward the master mold 30, exposing the opening 291 of the medium passage 29 (As shown in Figure 4), hot air blows and pressurizes to film 100 through medium channel 29, and the substrate layer of film 100 is softened, and is evacuated by exhaust groove 32 on mother mold 30 side and passes through to male mold 20 medium The film 100 is completely attached to the inner wall of the mold cavity 31 of the master mold 30 under the action of heating and pressurizing the hot air injected into the channel 29 . The heat medium source 90 stops supplying air, and the plunger 70 reversely moves under the restoring force of the spring 79 to close the medium channel 29 .

Please also refer to Fig. 7 to inject glue into the mold cavity 31 of the master mold 30. When the air pressure in the mold cavity 31 of the master mold 30 is greater than the threshold value of the pressure relief valve, the pressure relief valve 80 is automatically opened, and the glue in the mold cavity 31 of the master mold 30 is automatically opened. The gas escapes, and glue injection is continued until the mold cavity 31 of the master mold 30 is filled. Cooling under pressure, finally opening the mold, taking out the molded product, the transfer layer of the film 100 is attached to the surface of the molded product, and the base layer will be peeled off from the transfer layer due to the pressing of the pressing frame 40 . Afterwards, the pressing frame 40 is released, and the film feeding device 10 is continued to be activated, and the base layer of the film 100 located in the previous molding cycle is removed from the male and female molds 30, and the next molding cycle is started.

In the technical solution of the utility model, the double action of heating the film after mold closing and vacuuming on the side of the female mold 30 and blowing air on the side of the male mold 20 can greatly extend the stretching length of the film itself, and can achieve The effect that the film 100 can fit perfectly with the mold cavity 31 of the master mold 30 even at a small angle and a large depth. For example, when the dimensional relationship of the first surface A1, the second surface A2 and the third surface A3 of the mold cavity 31 of the master mold 30 conforms to the relationship a1+a2+a3>=(1+20%)*L, wherein the first The length of the surface A1 from the bottom wall of the mold cavity 31 to the opening is a1, the length of the second surface A2 from the bottom wall of the mold cavity 31 to the opening is a2, and the length of the third surface A3 from the bottom wall of the mold cavity 31 to the opening is a3, the effect that the film 100 fits perfectly with the mold cavity 31 of the master mold 30 can be achieved.

As another embodiment of the present invention, the switch device of the medium channel 29 may also be an openable and automatically closed valve installed at the opening 291 of the medium channel 29 . In addition, the medium in the medium source 90 can also be a liquid (such as water), and the male mold 20 is correspondingly provided with a channel for discharging the liquid medium.

Claims (10)

1. [claim 1] a kind of mould, comprise a master mold and a male model that matches with described master mold, described master mold is offered a die cavity and at least one air discharge duct that gas in the die cavity is discharged, it is characterized in that: described male model is offered a medium channel, and medium channel can be communicated with to feed medium in described mould with a medium source.
2. [claim 2] mould as claimed in claim 1 is characterized in that: the medium of described medium source is a gas, and correspondingly described male model also offers at least one air discharge duct, and described air discharge duct is communicated with a relief valve.
3. [claim 3] mould as claimed in claim 1 is characterized in that: described mould comprises that also one is used for the pressing frame of pressing film, and described male model is offered an accepting groove of accommodating described pressing frame.
4. [claim 4] mould as claimed in claim 3 is characterized in that: be provided with one of at least the sealing ring that compresses mutually with described pressing frame in described male model and the master mold.
5. [claim 5] is as each described mould in the claim 1 to 4, it is characterized in that: described medium channel comprises an opening towards master mold, be provided with the switching device of an elastic restraint in the described medium channel, described medium can promote described switching device and move to the master mold direction, and described opening is opened.
6. [claim 6] mould as claimed in claim 5 is characterized in that: described switching device is a plunger.
7. [claim 7] mould as claimed in claim 6 is characterized in that: the opening of described medium channel is bell mouth shape, and described plunger comprises a stopper head, and the shape of described stopper head and the opening of described medium channel are complementary.
8. [claim 8] mould as claimed in claim 7, it is characterized in that: described plunger also comprises a bar portion that links to each other with the small end of stopper head, described bar portion connects a flexible member away from an end of stopper head, and described flexible member resets after being used to make described plunger to move.
9. [claim 9] mould as claimed in claim 8 is characterized in that: described flexible member is a helical spring.
10. [claim 10] mould as claimed in claim 5 is characterized in that: described switching device is the valve that can open and cut out automatically.

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