CN217622124U

CN217622124U - Thermal forming die

Info

Publication number: CN217622124U
Application number: CN202220699487.7U
Authority: CN
Inventors: 翁桂源; 卢泓斌
Original assignee: Shantou Dacheng Environmental Protection Precision Machinery Technology Co ltd
Current assignee: Shantou Dacheng Environmental Protection Precision Machinery Technology Co ltd
Priority date: 2022-03-29
Filing date: 2022-03-29
Publication date: 2022-10-21
Anticipated expiration: 2032-03-29

Abstract

The utility model relates to a thermal forming die, which comprises a lower die and an upper die; the lower die comprises a lower die base, a lower die body and a lower die, and a plurality of molding die cavities are arranged on the top surface of the lower die; the upper die comprises an upper die base, an upper die body and a plurality of forming cup cover dies, the upper die body is arranged on the upper die base, and each forming cup cover die is arranged on the upper die body and is respectively matched with a corresponding forming die cavity; the hot forming die further comprises a pressure plate and a pressure plate lifting mechanism used for driving the pressure plate to lift, the pressure plate is located on the lower side of the upper die body and matched with the top surface of the lower die, a plurality of through holes which run up and down and are matched with the openings of the forming die cavities are formed in the pressure plate, and each forming cup cover die is located on the inner side of the corresponding through hole and can move up and down relative to the pressure plate. The hot forming die can prevent the occurrence of mutual sheet robbing among forming die cavities in the die closing process, so that the thickness of the peripheral sheets of the formed plastic product is uniform, and the yield of the plastic product can be improved.

Description

Thermal forming die

Technical Field

The utility model relates to a mould, concretely relates to thermoforming mould.

Background

A thermoforming mold for manufacturing disposable plastic products (such as plastic cup covers) generally comprises a lower mold and an upper mold, wherein the upper mold is arranged right above the lower mold; the lower die comprises a lower die base, a lower die body and a forming die, the lower die body is arranged on the lower die base, the forming die is arranged on the lower die body, and a plurality of forming die cavities with upper end openings are arranged on the top surface of the forming die; the upper die comprises an upper die base, an upper die body and a plurality of forming cup cover dies, the upper die body is installed on the upper die base, each forming cup cover die is installed on the upper die base, and the forming cup cover dies are the same in number with the forming die cavities and are matched in a one-to-one correspondence mode. In the process of forming the thermoforming mold, the plastic sheet is heated to make the temperature of the plastic sheet reach the forming temperature. After the heated plastic sheet enters a forming station, the upper die and the lower die of the thermal forming die are matched, and after the plastic product is stretched and formed by matching of each forming cup cover die and each forming die cavity, the upper die and the lower die are separated; then sending the plastic product into a shearing station to complete the shearing process by a punching and shearing die, and obtaining the plastic product (such as a plastic cup cover) after demoulding. Wherein, whether the plastic product is molded in place directly influences the yield, so the molding station is very important.

However, in the prior art, in the forming process of some plastic products (such as plastic cup lids), an upper die and a lower die are directly clamped, mutual material robbing between cavities occurs in the clamping and stretching process of plastic sheets, so that the peripheral sheets of the plastic products are uneven after forming, the integral strength of the plastic products is reduced, and the final yield is affected. Although the spring action is adopted for pressing the sheet in advance in the prior art, the spring is easy to fatigue and damage, and is troublesome to replace frequently, time and labor are wasted, the working efficiency is reduced, and the production cost is increased.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the technical problem that a thermoforming mould is provided, this kind of thermoforming mould can prevent to rob the condition of piece mutually between the shaping die cavity in the compound die in-process and appear, and the plastic products sheet thickness is even all around after making the shaping, can improve plastic products's yield. The technical scheme is as follows:

a hot forming die comprises a lower die and an upper die; the lower die comprises a lower die base, a lower die body and a lower die, the lower die body is arranged on the lower die base, the lower die is arranged on the lower die body, and a plurality of molding die cavities are arranged on the top surface of the lower die; the upper die comprises an upper die base, an upper die body and a plurality of forming cup cover dies, the upper die body is arranged on the upper die base, and each forming cup cover die is arranged on the upper die body and is matched with the corresponding forming die cavity; the method is characterized in that: the hot forming die further comprises a material pressing plate and a material pressing plate lifting mechanism used for driving the material pressing plate to lift, the material pressing plate lifting mechanism is installed on the upper die body or the upper die base, the material pressing plate is located on the lower side of the upper die body and matched with the top surface of the lower die, a plurality of through holes which are vertically arranged and matched with the openings of the forming die cavities are formed in the material pressing plate, and the forming cup cover dies are respectively located on the inner sides of the corresponding through holes and can move up and down relative to the material pressing plate.

When the device works, after a heated plastic sheet enters a forming station, the pressure plate is driven by the pressure plate lifting mechanism to descend to a low position, the plastic sheet is pre-pressed, and the corresponding parts of the plastic sheet are pressed together through the upper end opening edge of each forming die cavity of the lower die and the bottom surface of the pressure plate, so that the plastic sheet is in a flat state; then, the upper die and the lower die are closed, and meanwhile, the pressure plate lifting mechanism drives the pressure plate to slowly rise to be matched with the lower die to synchronously act, so that the pressing force on each corresponding part of the plastic sheet is kept, the phenomenon that the adjacent forming die cavities grab the sheet mutually is avoided, and the thickness of the sheet between the pressure plate and the lower die is basically consistent; and (4) after the upper die and the lower die are closed, the forming cup cover die enters a forming die cavity to stretch the plastic sheet and assist positive pressure or negative pressure to complete the stretch forming of the plastic product. The hot forming die can be matched with a lower die in advance to perform sheet pressing on a plastic sheet, so that the situation that the sheets are caught between adjacent forming die cavities in the die closing process is prevented, the thickness of the peripheral sheets of the formed plastic product is uniform, and the yield of the plastic product can be improved; compared with the prior art that adopts the mode of spring preforming, can make the preforming effect even controllable to need not to shut down and change the spring, use labour saving and time saving, can improve work efficiency and practice thrift manufacturing cost.

In a preferred scheme, the pressure plate lifting mechanism comprises a lifting cylinder and a plurality of cooling sleeves, a cylinder body of the lifting cylinder is installed on the upper die body or the upper die base, a piston rod of the lifting cylinder faces downwards and is connected with the pressure plate, and the cooling sleeves are respectively installed on the inner sides of the corresponding through holes of the pressure plate and are in the vertical direction; the forming cup cover die comprises a cup cover die body and a cup cover die ring, the cup cover die body is installed on the upper die body, the lower portion of the cup cover die body is matched with the forming die cavity correspondingly, the cup cover die ring is sleeved on the outer side of the cup cover die body, the cup cover die ring is located on the inner side of the cooling sleeve, and the outer side wall of the cup cover die ring is in sliding fit with the inner side wall of the cooling sleeve. When the device works, the piston rod of the lifting cylinder can stretch to drive the pressure plate to ascend or descend by a certain height; the forming cup cover die can move up and down relative to the material pressing plate through the sliding fit between the cup cover die ring and the cooling sleeve; when the upper die and the lower die are closed, the lower parts of the cup cover die bodies push the corresponding parts of the plastic sheets to enter a forming die cavity, the plastic sheets are stretched, and positive pressure or negative pressure is assisted to complete stretching forming of the plastic products.

In a more preferable scheme, a cooling pipe is arranged in an inner cavity of the cup cover die body. The cooling pipe can be used for cooling water or cooling liquid to pass through, so that the heat of the cup cover forming die body is taken away, and a cooling effect is achieved.

In a further more preferred scheme, a circulating cooling water path is arranged in the upper die body, and each cooling pipe is communicated with the circulating cooling water path. When the cup cover mold works, cooling water can be supplied to each cooling pipe through the circulating cooling water channel, and each cup cover mold body can be cooled; under the condition that the pressure plate lifting mechanism adopts the lifting cylinder, the cooling plate is provided with a guide hole for a piston rod of the lifting cylinder to pass through, and the piston rod of the lifting cylinder can be guided.

In a still further more preferred scheme, the upper die body comprises a negative pressure plate and a cooling plate, the negative pressure plate is installed on the upper die base, and the cooling plate is installed on the lower side of the negative pressure plate and is located on the upper side of the material pressing plate; the circulating cooling water path is arranged in the cooling plate; the bottom surface of the negative pressure plate is provided with a negative pressure groove, and the negative pressure groove and the top surface of the cooling plate form a negative pressure cavity; the cooling plate is provided with a plurality of vent holes in the vertical direction, the cup cover die bodies are arranged on the cooling plate, and the inner cavities of the cup cover die bodies are communicated with the negative pressure cavity through the corresponding vent holes. Typically, the negative pressure chamber is in communication with a negative pressure generating device. When the vacuum cup cover mold works, the negative pressure generating device forms negative pressure in the inner cavity of each cup cover mold body through the negative pressure cavity and each vent hole, and the plastic products are stretched and molded by the aid of the negative pressure.

Compared with the prior art, the utility model, have following advantage:

the thermal forming die can be matched with a lower die in advance to perform sheet pressing on a plastic sheet, so that the condition that sheets are mutually caught between adjacent forming die cavities in the die closing process is prevented, the thickness of the peripheral sheets of the formed plastic product is uniform, and the yield of the plastic product can be improved; compared with the prior art which adopts a spring tabletting mode, the tabletting effect is uniform and controllable, the spring does not need to be replaced after shutdown, the time and the labor are saved, the working efficiency is improved, and the production cost is saved.

Drawings

Fig. 1 is a schematic structural diagram of a preferred embodiment of the present invention.

Detailed Description

As shown in fig. 1, this thermoforming mold includes a lower mold 1 and an upper mold 2; the lower die 1 comprises a lower die base 11, a lower die body 12 and a lower die 13, wherein the lower die body 12 is arranged on the lower die base 11, the lower die 13 is arranged on the lower die body 12, and a plurality of molding die cavities 131 are arranged on the top surface of the lower die 13; the upper die 2 comprises an upper die base 21, an upper die body 22, a plurality of forming cup cover dies 23, a pressure plate 24 and a pressure plate lifting mechanism 25 for driving the pressure plate 24 to lift, wherein the upper die body 22 is arranged on the upper die base 21, and each forming cup cover die 23 is arranged on the upper die body 22 and is respectively matched with a corresponding forming die cavity 131; the pressure plate lifting mechanism 25 is installed on the upper die body 22, the pressure plate 24 is located at the lower side of the upper die body 22 and is matched with the top surface of the lower die 13, a plurality of through holes 241 which run up and down and are matched with the opening of the forming die cavity 131 are arranged on the pressure plate 24, and each forming cup cover die 23 is located at the inner side of the corresponding through hole 241 and can move up and down relative to the pressure plate 24.

In this embodiment, the material pressing plate lifting mechanism 25 includes a lifting cylinder 251 and a plurality of cooling sleeves 252, the lifting cylinder 251 is installed on the upper die body 22, a piston rod of the lifting cylinder 251 faces downward and is connected with the material pressing plate 24, and each cooling sleeve 252 is installed inside a corresponding through hole 241 of the material pressing plate 24 and is in a vertical direction; the forming cup cover die 23 comprises a cup cover die body 231 and a cup cover die ring 232, the cup cover die body 231 is arranged on the upper die body 22, the lower part of the cup cover die body 231 is matched with the corresponding forming die cavity 131, the cup cover die ring 232 is sleeved on the outer side of the cup cover die body 231, the cup cover die ring 232 is positioned on the inner side of the cooling sleeve 252, and the outer side wall of the cup cover die ring 232 is in sliding fit with the inner side wall of the cooling sleeve 252; a cooling pipe 233 is arranged in the inner cavity of the cup cover die body 231. When the device works, the piston rod of the lifting cylinder 251 can stretch to drive the material pressing plate 24 to ascend or descend for a certain height; the forming cup cover die 23 can move up and down relative to the material pressing plate 24 through the sliding fit between the cup cover die ring 232 and the cooling sleeve 252; when the upper die 2 and the lower die 1 are closed, the lower part of each cup cover die body 231 pushes the corresponding part of the plastic sheet to enter the forming die cavity 131, so that the plastic sheet is stretched and the positive pressure or negative pressure is assisted to complete the stretch forming of the plastic product. The cooling pipe 233 can be used for cooling water to pass through and take away the heat of the cup forming cover mold body 231, so as to play a cooling role.

In the present embodiment, the upper die body 22 includes a negative pressure plate 221 and a cooling plate 222, the negative pressure plate 221 is mounted on the upper die base 21, and the cooling plate 222 is mounted on the lower side of the negative pressure plate 221 and on the upper side of the pressure plate 24; cooling plate 222 is provided with a circulating cooling water path 2221; a negative pressure groove 2211 is arranged on the bottom surface of the negative pressure plate 221, and the negative pressure groove 2211 and the top surface of the cooling plate 222 form a negative pressure cavity 201 (the negative pressure cavity 201 is communicated with a negative pressure generating device); a plurality of vent holes 2222 extending up and down are formed in the cooling plate 222, each cup cover mold body 231 is mounted on the cooling plate 222, and an inner cavity of each cup cover mold body 231 is communicated with the negative pressure cavity 201 through the corresponding vent holes 2222. The cooling plate 222 is further provided with a guide hole 2223 through which a piston rod of the lifting cylinder 251 can pass, so as to guide the piston rod of the lifting cylinder 251.

The working principle of the thermoforming mold is briefly described as follows:

during operation, after the heated plastic sheet enters the forming station, the lifting cylinder 251 drives the pressure plate 24 to descend to a low position (the pressure plate 24 can descend stably through the sliding fit between each cup cover mold ring 232 and each cooling sleeve 252), the plastic sheet is pre-pressed, and the opening edges of each forming mold cavity 131 of the lower mold 13 and the bottom surface of the pressure plate 24 compress each corresponding part of the plastic sheet together, so that the plastic sheet is in a flat state; subsequently, the upper die 2 and the lower die 1 are closed, and simultaneously the lifting cylinder 251 drives the pressure plate 24 to slowly rise (the pressure plate 24 can stably rise through the sliding fit between each cup cover die ring 232 and each cooling sleeve 252) to cooperate with the lower die 13 to synchronously act to keep the pressing force on each corresponding part of the plastic sheet, so that the phenomenon that the adjacent forming die cavities 131 mutually grab the sheet is avoided, and the thickness of the sheet between the pressure plate 24 and the lower die 13 is basically consistent; until the upper die 2 and the lower die 1 complete die assembly, the lower part of the cup cover die body 231 of each forming cup cover die 23 pushes the corresponding part of the plastic sheet to enter the corresponding forming die cavity 131, so that the plastic sheet is stretched, meanwhile, the negative pressure generating device forms negative pressure in the inner cavity of each cup cover die body 231 through the negative pressure cavity 201 and each vent hole 2222, and the plastic product is stretched and formed by auxiliary negative pressure. In the working process, cooling water can be supplied to each cooling pipe 233 through the circulating cooling water path 2221, and the heat of each cup cover mold body 231 can be taken away to realize cooling.

In addition, it should be noted that the names of the various parts of the embodiments described in the present specification may be different, and all the equivalent or simple changes made according to the structures, characteristics and principles of the present invention are included in the protection scope of the present invention. Various modifications, additions and substitutions may be made by those skilled in the art without departing from the scope of the invention as defined in the accompanying claims.

Claims

1. A thermal forming die comprises a lower die and an upper die; the lower die comprises a lower die base, a lower die body and a lower die, the lower die body is arranged on the lower die base, the lower die is arranged on the lower die body, and a plurality of molding die cavities are formed in the top surface of the lower die; the upper die comprises an upper die base, an upper die body and a plurality of forming cup cover dies, the upper die body is arranged on the upper die base, and each forming cup cover die is arranged on the upper die body and is matched with the corresponding forming die cavity; the method is characterized in that: the hot forming die further comprises a pressure plate and a pressure plate lifting mechanism used for driving the pressure plate to lift, the pressure plate lifting mechanism is installed on the upper die body or the upper die base, the pressure plate is located on the lower side of the upper die body and matched with the top surface of the lower die, a plurality of through holes which run up and down and are matched with the openings of the forming die cavities are formed in the pressure plate, and the forming cup cover dies are respectively located on the inner sides of the corresponding through holes and can move up and down relative to the pressure plate.

2. A thermoforming mould as claimed in claim 1, characterised in that: the material pressing plate lifting mechanism comprises a lifting cylinder and a plurality of cooling sleeves, the lifting cylinder is installed on the upper die body or the upper die base, a piston rod of the lifting cylinder faces downwards and is connected with the material pressing plate, and the cooling sleeves are respectively installed on the inner sides of the corresponding through holes of the material pressing plate and are in the vertical direction; the forming cup cover die comprises a cup cover die body and a cup cover die ring, the cup cover die body is installed on the upper die body, the lower portion of the cup cover die body is matched with the forming die cavity correspondingly, the cup cover die ring is sleeved on the outer side of the cup cover die body, the cup cover die ring is located on the inner side of the cooling sleeve, and the outer side wall of the cup cover die ring is in sliding fit with the inner side wall of the cooling sleeve.

3. A thermoforming mould as claimed in claim 2, characterised in that: and a cooling pipe is arranged in the inner cavity of the cup cover die body.

4. A thermoforming mould as claimed in claim 3, characterised in that: and a circulating cooling water path is arranged in the upper die body, and each cooling pipe is communicated with the circulating cooling water path.

5. A thermoforming mould as claimed in claim 4, characterised in that: the upper die body comprises a negative pressure plate and a cooling plate, the negative pressure plate is arranged on the upper die base, and the cooling plate is arranged on the lower side of the negative pressure plate and is positioned on the upper side of the material pressing plate; the circulating cooling water path is arranged in the cooling plate; the bottom surface of the negative pressure plate is provided with a negative pressure groove, and the negative pressure groove and the top surface of the cooling plate form a negative pressure cavity; the cooling plate is provided with a plurality of vent holes in the vertical direction, the cup cover die bodies are arranged on the cooling plate, and the inner cavities of the cup cover die bodies are communicated with the negative pressure cavity through the corresponding vent holes.