Plastic uptake forming device with pneumatic ejection function and forming method of plastic uptake forming device

Abstract

The invention discloses a plastic uptake forming device with a pneumatic ejection function and a forming method.The plastic uptake forming device comprises an upper die set, a lower die set and a sheet fixing frame, the upper die set comprises an upper die assembly and a lower die assembly, and the sheet fixing frame is located between the upper die assembly and the lower die assembly; the sheet fixing frame is used for fixing a sheet, and the upper mold assembly and the lower mold assembly move to the sheet through downward movement and upward movement correspondingly to conduct plastic uptake shaping and demolding treatment after shaping on the sheet. The lower mold assembly comprises a lower mold and a pneumatic control system, and the pneumatic control system is used for controlling the lower mold assembly to carry out vacuum plastic uptake on the sheet and carrying out pneumatic ejection demolding after plastic uptake shaping; the upper mold assembly comprises an upper mold body and a pressure difference control system, the pressure difference control system is used for controlling the upper mold assembly to provide air pressure so as to balance stress of a sheet during pneumatic ejection demolding, and non-contact efficient demolding of plastic uptake is achieved through cooperative control of pneumatic ejection and dynamic pressure difference.

Description

Technical Field

[0001] The present invention relates to the technical field of plastic blister forming, in particular to a plastic blister forming device with a pneumatic ejection function and a forming method thereof. Background Art

[0002] Traditional blister packaging processes typically rely on mechanical ejection structures, such as cylinder ejectors or push plates, to physically remove the molded product from the mold surface during demoulding. However, mechanical ejection has the following drawbacks: Risk of product damage: Direct contact between the ejector pin or push plate and the product can easily cause scratches on the high-gloss surface or deformation of thin-walled parts; Rapid mold wear: Long-term friction of the mechanical structure leads to a decrease in mold surface accuracy, and frequent mold repairs increase production costs; Poor adaptability: Sheets of different materials or thicknesses require readjustment of ejection force and stroke, making production changeover and debugging time-consuming; Efficiency bottleneck: The long reciprocating motion cycle of the ejector restricts the demand for high-speed production.

[0003] Although the existing technology attempts to alleviate the above problems by optimizing the ejector pin layout or using a silicone buffer layer, it does not fundamentally solve the inherent defects of contact demoulding. Summary of the Invention

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide a blister molding device with a pneumatic ejection function and a molding method thereof, which adopts a contactless demoulding design for blister molding and realizes efficient demoulding through the coordinated control of pneumatic ejection and dynamic pressure difference.

[0005] In order to achieve the above-mentioned purpose, the present invention provides a vacuum forming device on one hand. In the technical solution of the present invention, the vacuum forming device includes upper and lower modules and a sheet fixing frame, the upper and lower modules include an upper module assembly and a lower module assembly, the sheet fixing frame is located between the upper module assembly and the lower module assembly, the sheet fixing frame is used to fix the sheet, the sheet fixing frame has a double-layer annular structure, and when fixing the sheet, the sheet edge is evenly clamped to ensure that the sheet is flat and without deformation during the heating and forming process, the upper module assembly and the lower module assembly move toward the sheet by moving downward and upward respectively to perform vacuum forming and demolding on the sheet after shaping.

[0006] Furthermore, the lower mold assembly includes a lower mold and a pneumatic control system, and the pneumatic control system is used to control the lower mold assembly to vacuum form the sheet and pneumatically eject the sheet after the sheet is formed; The upper mold assembly includes an upper mold and a pressure difference control system, and the pressure difference control system is used to control the upper mold assembly to provide air pressure to balance the force applied to the sheet during pneumatic ejection and demoulding.

[0007] Furthermore, in the technical solution of the present invention, the vacuum forming device also includes a heating plate, a vacuum pump and a high-pressure gas tank. The heating plate is used to heat the sheet material to raise the temperature of the sheet material to a softening temperature. The vacuum pump and the high-pressure gas tank provide negative pressure and positive pressure for the pneumatic control system and the pressure difference control system.

[0008] Furthermore, the surfaces of the lower mold and the upper mold are provided with evenly distributed air holes, and the air holes are connected to the vacuum pump and the high-pressure gas tank when the upper and lower mold assemblies are installed. The pneumatic control system controls the vacuum pump and the high-pressure gas tank to provide the vacuum forming air pressure and the ejection air pressure for pneumatic ejection and demolding through the air holes on the surface of the lower mold. The pressure difference control system controls the vacuum pump and the high-pressure gas tank to provide the balancing air pressure through the air holes on the surface of the upper mold to balance the force on the sheet during pneumatic ejection and demolding.

[0009] Furthermore, the pneumatic control system controls the vacuum blister pressure to be: Sheet thickness : ; Sheet thickness : ; in, Expressed as vacuum blister pressure; The pneumatic control system controls the ejection pressure of the pneumatic ejection demoulding to be: ; in, Indicates the ejection pressure of pneumatic ejection. Expressed as the adhesion of the sheet, Expressed as the sheet projected area, Expressed as safety margin, Expressed as a safety factor.

[0010] Furthermore, the pressure differential control system controls the upper mold assembly to provide a balanced air pressure to balance the force on the sheet during pneumatic ejection and demolding, specifically including: The pressure difference control system controls the ejection pressure of the pneumatic ejection according to the pneumatic control system And the size of the equilibrium air pressure provided by the real-time calculation of the sheet's gravity: ; in, Expressed as equilibrium pressure, Expressed as the weight of the sheet, Expressed as ejection pressure and balance air pressure The pressure difference between Expressed as the balance coefficient.

[0011] Another aspect of the present invention provides a blister forming method, which is implemented using the blister forming device as described above and specifically comprises the following steps: Step S1: Install the corresponding upper mold and lower mold according to the blister product, fix the sheet on the sheet fixing frame between the upper mold and the lower mold, and heat the sheet through the heating plate. After the sheet is heated to the softening temperature, remove the heating plate; Step S2: Control the lower mold to move upward to contact the sheet and start the vacuum pump through the pneumatic control system to absorb and adhere the softened sheet to the surface of the lower mold for vacuum forming; Step S3: After vacuum forming and holding pressure for 5-30 seconds, the upper mold is controlled to move down to a position 0.5 mm above the sheet, and a cavity environment is formed between the upper mold and the sheet; Step S4: Control the lower mold to switch to the high-pressure gas tank through the pneumatic control system to reversely pressurize the high-pressure gas, so that the sheet attached to the surface of the lower mold is separated from the surface of the lower mold and moved toward the upper mold; Step S5: The pressure differential control system synchronously controls the upper mold to start the vacuum pump and the high-pressure gas tank to provide balanced air pressure to balance the force on the sheet during pneumatic ejection and prevent the sheet from deforming and further adhering to the surface of the upper mold; Step S6: After demoulding is completed, the upper and lower molds are reset, and the sheet fixing frame is opened to take out the molded product.

[0012] The beneficial effects of the present invention are as follows: In summary, the present invention provides a blister molding device with a pneumatic ejection function and a molding method thereof, adopts a contactless demolding design for blister molding, and realizes efficient demolding through the coordinated control of pneumatic ejection and dynamic pressure difference. Compared with traditional blister molding devices, the present invention realizes zero-contact demolding through air pressure ejection and suspended pressure difference control, avoids scratches and deformation of products caused by mechanical ejection, and avoids friction loss of the mold. At the same time, the response time of air pressure ejection is faster than that of the traditional ejector structure, further saving demolding time. In addition, by dynamically adjusting the ejection air pressure and pressure difference, it can be compatible with sheets of different types and thicknesses, effectively reducing the time for production change and debugging.

[0013] Other features and advantages of the present invention will be set forth in the description that follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0015] Figure 1 is a flow chart of a blister forming method according to this embodiment; Figure 2 Schematic diagram of the structure of a vacuum forming device according to this embodiment; Figure 3 This is a schematic diagram of the use of a vacuum forming device according to this embodiment. Figure 1 ; Figure 4 This is a schematic diagram of the use of a vacuum forming device according to this embodiment. Figure 2 ; Figure 5 This is a schematic diagram of the use of a vacuum forming device according to this embodiment. Figure 3 ; Figure 6 This is a schematic diagram of the use of a vacuum forming device according to this embodiment. Figure 4 ; Figure 7 This is a schematic diagram of the use of a vacuum forming device according to this embodiment. Figure 5 ; In the figure: A, sheet fixing frame; B, lower mold; C, upper mold; D, heating plate; E, sheet. DETAILED DESCRIPTION

[0016] In order to make the purpose, features, and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0017] The core of the embodiment of the present invention is to provide a vacuum forming device and a forming method with a pneumatic ejection function, adopt a contactless demoulding design for vacuum forming, and achieve efficient demoulding through the coordinated control of pneumatic ejection and dynamic pressure difference.

[0018] On the one hand, this embodiment provides a blister forming device. Figure 2 FIG. 1 is a structural diagram of a blister forming device according to this embodiment, as shown in FIG. Figure 2 As shown, in this embodiment, it includes upper and lower modules and a sheet fixing frame A. Figure 3 and Figure 4 FIG. 1 is a schematic diagram of the use process of a blister forming device according to this embodiment, as shown in FIG. Figure 3 and Figure 4As shown, the sheet fixing frame A is used to fix the sheet E. The sheet fixing frame A has a double-layer ring structure. When fixing the sheet E, the sheet E is clamped in the middle of the double layers of the sheet fixing frame A. When fixing the sheet E, the sheet fixing frame A evenly clamps the edge of the sheet E to ensure that the sheet E is flat and without deformation during the heating and forming process. The upper and lower mold assemblies include an upper mold assembly and a lower mold assembly. The sheet fixing frame A is located in the middle of the upper mold assembly and the lower mold assembly. The upper mold assembly and the lower mold assembly move toward the sheet E by moving downward and upward respectively to perform vacuum forming and demolding on the sheet E after forming.

[0019] Specifically, in this embodiment, the lower mold assembly includes a lower mold B and a pneumatic control system, which is used to control the lower mold assembly to perform vacuum molding on the sheet E and pneumatic ejection and demolding after molding; the upper mold assembly includes an upper mold C and a pressure difference control system, which is used to control the upper mold assembly to provide air pressure to balance the force on the sheet E during pneumatic ejection and demolding.

[0020] In this embodiment, Figure 5 FIG. 1 is a schematic diagram of the use process of a blister forming device according to this embodiment, as shown in FIG. Figure 5 As shown, the blister molding device also includes a heating plate D, a vacuum pump and a high-pressure gas tank (not shown in the figure). The heating plate D is used to heat the sheet E to raise the temperature of the sheet E to a softening temperature. The vacuum pump and the high-pressure gas tank provide negative pressure and positive pressure for the pneumatic control system and the pressure difference control system.

[0021] Specifically, evenly distributed air holes are opened on the surfaces of the lower mold B and the upper mold C. The air holes are connected to the vacuum pump and the high-pressure gas tank (not shown in the figure) when the upper and lower mold assemblies are installed. The pneumatic control system controls the vacuum pump and the high-pressure gas tank to provide the vacuum forming air pressure and the ejection air pressure of the pneumatic ejection through the air holes on the surface of the lower mold B. The pressure difference control system controls the vacuum pump and the high-pressure gas tank to provide the balance air pressure through the air holes on the surface of the upper mold C to balance the force on the sheet E during the pneumatic ejection.

[0022] Specifically, in this embodiment, the pneumatic control system controls the vacuum blister pressure to be: Sheet thickness : ; Sheet thickness : ; in, Expressed as vacuum blister pressure; The pneumatic control system controls the ejection pressure of the pneumatic ejection demoulding to: ; in, Indicates the ejection pressure of pneumatic ejection. Expressed as the adhesion of sheet E, Expressed as the projected area of ​​sheet E, Expressed as safety margin, Expressed as a safety factor, i.e., ejection pressure The adhesion of the sheet E needs to be overcome, and the adhesion of the sheet E is affected by the material of the sheet.

[0023] Specifically, the pressure differential control system controls the upper mold assembly to provide a balanced air pressure to balance the force on the sheet E during pneumatic ejection and demolding, specifically including: The pressure differential control system controls the ejection pressure of the pneumatic ejection mold according to the pneumatic control system And the equilibrium air pressure provided by the real-time calculation of the gravity of sheet E: ; in, Expressed as equilibrium pressure, Expressed as the weight of the sheet, Expressed as ejection pressure and balance air pressure The pressure difference between Expressed as the balance coefficient, it should be noted that, The value of is in the range of 0-1, that is, the sheet holder A has a certain gravity support effect on the sheet E, and the pressure difference The function of is to balance the residual weight of sheet E not supported by sheet holder A, so The value of is within the gravity range of sheet E.

[0024] On the other hand, this embodiment also provides a vacuum forming method, which is implemented using a vacuum forming device as described above. Figure 1 FIG. 1 is a flow chart of a blister forming method according to this embodiment, as shown in FIG. Figure 1 As shown, the blister forming method specifically includes the following steps: Step S1: Install the corresponding upper mold C and lower mold B according to the blister product, fix the sheet E on the sheet fixing frame A between the upper mold C and the lower mold B, and heat the sheet E through the heating plate D. After the sheet E is heated to the softening temperature, the heating plate D is removed; Step S2: Control the lower mold B to move upward to contact the sheet E and start the vacuum pump through the pneumatic control system to absorb and adhere the softened sheet E to the surface of the lower mold B for vacuum forming. Figure 6 FIG. 1 is a schematic diagram of the use process of a blister forming device according to this embodiment, as shown in FIG. Figure 6 As shown; Step S3: After vacuum forming and holding pressure for 5-30 seconds, control the upper mold B to move down to a position 0.5mm above the sheet E. Figure 7FIG. 1 is a schematic diagram of the use process of a blister forming device according to this embodiment, as shown in FIG. Figure 7 As shown, a cavity environment is formed between the upper mold C and the sheet E. It should be noted that when the upper mold C and the lower mold B move toward the sheet E, the external dimensions of the upper mold C and the lower mold B are equal to the annular dimensions of the sheet fixing frame A, that is, the upper and lower end surfaces of the sheet E and the annular inner wall of the sheet fixing frame A respectively form a cavity with the mold surfaces of the upper mold C and the lower mold B; so that the air pressure acting on the sheet E can be adjusted through the air holes on the upper mold C and the lower mold B.

[0025] Step S4: Control the lower mold to switch to the high-pressure gas tank through the pneumatic control system to reversely pressurize the high-pressure gas, so that the sheet E attached to the surface of the lower mold B is separated from the surface of the lower mold and moves toward the upper mold C; Step S5: The pressure differential control system synchronously controls the upper mold to start the vacuum pump and the high-pressure gas tank to provide balanced air pressure to balance the force on the sheet E during pneumatic ejection and prevent the sheet from deforming and further adhering to the surface of the upper mold C. Step S6: After demoulding is completed, the upper and lower molds are reset, and the sheet fixing frame A is opened to take out the molded product.

[0026] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely preferred examples of the present invention and are not intended to limit the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A blister forming device, comprising upper and lower modules and a sheet material fixing frame, characterized in that: The upper and lower mold assemblies include an upper mold assembly and a lower mold assembly. The sheet fixing frame is located between the upper mold assembly and the lower mold assembly. The sheet fixing frame is used to fix the sheet. The upper mold assembly and the lower mold assembly move downward and upward respectively toward the sheet to perform vacuum forming and demolding on the sheet after forming. The lower mold assembly includes a lower mold and a pneumatic control system, and the pneumatic control system is used to control the lower mold assembly to vacuum form the sheet and pneumatically eject the sheet after the sheet is formed; The upper mold assembly includes an upper mold and a pressure difference control system, and the pressure difference control system is used to control the upper mold assembly to provide air pressure to balance the force applied to the sheet during pneumatic ejection and demoulding.

2. A vacuum forming device according to claim 1, characterized in that: It also includes a heating plate, a vacuum pump and a high-pressure gas tank. The heating plate is used to heat the sheet material to raise the temperature of the sheet material to a softening temperature. The vacuum pump and the high-pressure gas tank provide negative pressure and positive pressure for the pneumatic control system and the pressure difference control system.

3. A vacuum forming device according to claim 1, characterized in that: The sheet fixing frame is a double-layer annular structure, which evenly clamps the edges of the sheet when fixing the sheet to ensure that the sheet is flat and free of deformation during the heating and forming process.

4. A vacuum forming device according to claim 2, characterized in that: The surfaces of the lower mold and the upper mold are both provided with evenly distributed air holes, which are connected to the vacuum pump and the high-pressure gas tank when the upper and lower mold assemblies are installed. The pneumatic control system controls the vacuum pump and the high-pressure gas tank to provide the vacuum molding air pressure and the ejection air pressure for pneumatic ejection and demolding through the air holes on the surface of the lower mold. The pressure difference control system controls the vacuum pump and the high-pressure gas tank to provide the balancing air pressure through the air holes on the surface of the upper mold to balance the force on the sheet during pneumatic ejection and demolding.

5. The blister forming device according to claim 1, characterized in that: The pneumatic control system controls the vacuum blister pressure to be: Sheet thickness : ; Sheet thickness : ; in, Expressed as vacuum blister pressure; The pneumatic control system controls the ejection pressure of the pneumatic ejection demoulding to be: ； in, Indicates the ejection pressure of pneumatic ejection. Expressed as the adhesion of the sheet, Expressed as the sheet projected area, Expressed as safety margin, Expressed as a safety factor.

6. A vacuum forming device according to claim 5, characterized in that: The pressure differential control system controls the upper mold assembly to provide a balanced air pressure to balance the force on the sheet during pneumatic ejection and demolding, specifically including: The pressure difference control system controls the ejection pressure of the pneumatic ejection according to the pneumatic control system And the size of the equilibrium air pressure provided by the real-time calculation of the sheet's gravity: ； in, Expressed as equilibrium pressure, Expressed as the weight of the sheet, Expressed as ejection pressure and balance air pressure The pressure difference between Expressed as the balance coefficient.

7. A blister forming method, implemented by using a blister forming device according to any one of claims 1 to 6, characterized in that: The specific steps include: Step S1: Install the corresponding upper mold and lower mold according to the blister product, fix the sheet on the sheet fixing frame between the upper mold and the lower mold, and heat the sheet through the heating plate. After the sheet is heated to the softening temperature, remove the heating plate; Step S2: Control the lower mold to move upward to contact the sheet and start the vacuum pump through the pneumatic control system to absorb and adhere the softened sheet to the surface of the lower mold for vacuum forming; Step S3: After vacuum forming and holding pressure for 5-30 seconds, the upper mold is controlled to move down to a position 0.5 mm above the sheet, and a cavity environment is formed between the upper mold and the sheet; Step S4: Control the lower mold to switch to the high-pressure gas tank through the pneumatic control system to reversely pressurize the high-pressure gas, so that the sheet attached to the surface of the lower mold is separated from the surface of the lower mold and moved toward the upper mold; Step S5: The pressure differential control system synchronously controls the upper mold to start the vacuum pump and the high-pressure gas tank to provide balanced air pressure to balance the force on the sheet during pneumatic ejection and prevent the sheet from deforming and further adhering to the surface of the upper mold; Step S6: After demoulding is completed, the upper and lower molds are reset, and the sheet fixing frame is opened to take out the molded product.

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