Plant fiber thermoplastic composite material soft mold stress plasticizing forming device and method
By using a soft mold stress plasticization forming device in the forming process of plant fiber thermoplastic composite materials to provide controllable normal stress and pressurization, combined with heating and cooling mechanisms, the problems of product defects and slow cooling caused by the relative flow of fiber and resin during the forming process are solved, and uniform strain of the parts and improved production efficiency are achieved.
Patent Information
- Application Number
- CN202410260895.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-07
- Publication Date
- 2025-09-09
AI Technical Summary
During the forming process of plant fiber thermoplastic composites, there are defects such as uneven mechanical properties, warping, wrinkling and delamination of the products caused by the relative flow between the fibers and the resin, and the cooling speed is slow, which affects the processing efficiency.
The soft mold stress plasticizing forming device is adopted to provide controllable normal stress through the soft mold and the booster pump to increase the pressure inside the soft mold. Combined with the heating and cooling mechanism, the forming accuracy and cooling speed are ensured.
The uniform strain of the parts is achieved, the bonding between the plant fiber and the resin matrix is enhanced, the forming accuracy and production efficiency are improved, and the resin aggregation and fiber flow during the forming process are reduced.
Smart Images
Figure CN120606524A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the processing of plant fiber thermoplastic composite materials, and in particular to a soft mold stress plasticization forming device and method for plant fiber thermoplastic composite materials. Background Art
[0002] Plant fiber thermoplastic composite material is an environmentally friendly green composite material composed of natural plant fibers and thermoplastic resin matrix. It has the characteristics of recyclability, biodegradability and low cost, and has broad development prospects.
[0003] In the traditional fiber-reinforced resin matrix forming process, the blank is first preheated and heated, then pressed and formed while in a softened solid state, and then cooled to set. However, in the thermoforming process of plant fiber thermoplastic composites: First, due to temperature and force differences, relative sliding and rotation will occur, and relative flow will occur between fibers and between fibers and resin. The formed product may have fiber-rich and resin-rich areas, resulting in differences in mechanical properties in all directions of the product, causing defects such as warping, wrinkling, and delamination; second, the input of external pressure will destroy the bonding between the plant fiber and the resin matrix, reducing the forming quality of the part. At the same time, the residual stress of the resulting part is large, and the precision is difficult to ensure, which may cause the part to fail; third, the cooling of the part mainly relies on the natural heat dissipation and cooling of the mold, which is slow and reduces processing efficiency. Summary of the Invention
[0004] The purpose of the present invention is to provide a soft mold stress plasticization forming device and method for plant fiber thermoplastic composite materials. The present invention has uniform strain on the parts, enhances the bonding degree between plant fiber and resin matrix, has good forming accuracy, and improves production efficiency.
[0005] The technical solution adopted in the present invention is: A plant fiber thermoplastic composite material soft mold stress plasticization forming device, comprising a punch, a die, a soft mold, a booster pump, a pressure mechanism, a heating mechanism, a cooling mechanism and a temperature and pressure controller; the soft mold is placed in a groove of the die facing the punch and can cooperate with the punch to form a forming cavity for a panel to be formed, the outside of the soft mold adopts a high-temperature resistant and ductile capsule, and the inside is filled with liquid; the booster pump is connected to the soft mold through a pressure pipe and can pressurize the inside of the soft mold; the pressure mechanism is located above the die and is used to limit the pressure of the panel to be formed on the die; the heating mechanism is respectively installed on the punch and the die and is used to heat the punch and the die respectively; the cooling mechanism acts on the die and is used to cool the die; the temperature and pressure controller is electrically connected to the booster pump, the heating mechanism and the cooling mechanism respectively, can monitor the temperature feedback from the heating mechanism and the pressure feedback from the booster pump, and is used to adjust the temperature of the punch, the temperature of the die and the internal pressure of the soft mold according to the process stage to ensure forming accuracy.
[0006] Preferably, the capsule outside the soft mold is made of rubber.
[0007] Preferably, the pressure pipe extends from a through hole opened in the side surface of the female mold and is connected to the side of the soft mold.
[0008] Preferably, the heating mechanism adopts a contact thermocouple.
[0009] Preferably, contact thermocouples are installed in the side wall and bottom areas inside the male mold and inside the female mold.
[0010] Preferably, a cooling channel is provided on the die; the cooling mechanism adopts a cooling water circulation cooling method, including a water tank and a water pump, the inlet end of the water pump is connected to the water tank through a pumping pipe, and the outlet end is connected to the cooling channel inlet through a water supply pipe, and the cooling channel outlet is connected to the water tank through a return pipe.
[0011] Preferably, a plurality of cooling channels are provided on the die.
[0012] Preferably, the water tank is equipped with a fan for heat dissipation.
[0013] A plant fiber thermoplastic composite material soft mold stress plasticization forming method, using the plant fiber thermoplastic composite material soft mold stress plasticization forming device, comprising the steps of: S1. Using natural plant fibers and thermoplastic resin matrix as raw materials to produce a panel to be formed; S2, placing the plate to be formed on the die, and the edge pressing mechanism presses the plate to be formed on the die to limit the position; S3, preheating stage: control the heating mechanism to start, so that the punch, die and the soft mold inside the die are heated and preheated; S4, stamping and forming stage: When the temperatures of the punch and die reach the required levels, the punch is controlled to move downward to stamp the sheet metal to be formed. At the same time, the booster pump is controlled to increase the pressure inside the soft die. Under the combined action of the punch pressure and the soft die pressure, the sheet metal to be formed gradually deforms to obtain a non-solidified target shape part. S5, solidification stage: When the punch drops to the set position, the feeding is stopped, and the punch and die are kept within the set temperature range by controlling the heating mechanism to solidify the target shape part. At the same time, the internal pressure of the soft mold is reduced by controlling the booster pump; S6, cooling stage: After the solidification is completed, the heating mechanism is controlled to be turned off and the cooling mechanism is turned on. The cooling mechanism acts on the die to cool the die and the soft mold inside it and the target shape part; S7. After the target shape part is cooled, the punch and the edge holding mechanism are retracted, the cooling mechanism is controlled to be closed, and the target shape part is taken out.
[0014] Preferably, in step S1, the method for making the panel to be formed is: extracting fibers from plants, obtaining plant fibers after alkali treatment and cleaning and drying, mixing the plant fibers, resin matrix and additives to obtain felt, and molding the felt to obtain the panel to be formed.
[0015] The beneficial effects of the present invention are: The present invention introduces a soft mold and a cooling mechanism into the processing technology of plant fiber thermoplastic composite materials. The soft mold can provide controllable normal stress, and the cooling mechanism can accelerate the cooling speed of the mold. The present invention can also maintain heat and pressure during the curing process and utilize stress-induced plasticization effect to form. Therefore, the present invention reduces resin aggregation and fiber flow during the forming process, the strain of the workpiece is uniform, the bonding degree between the plant fiber and the resin matrix is enhanced, the forming accuracy is good, and the production efficiency is improved. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 It is a schematic diagram of the preparation process of the plate to be formed in an embodiment of the present invention.
[0017] Figure 2 It is a structural schematic diagram of a soft mold stress plasticization forming device for plant fiber thermoplastic composite materials in an embodiment of the present invention.
[0018] Figure 3 Schematic diagram of the soft mold stress plasticization forming device of the plant fiber thermoplastic composite material during forming in an embodiment of the present invention.
[0019] Figure 4 Schematic diagram of the plant fiber thermoplastic composite material soft mold stress plasticization forming device during solidification and cooling in an embodiment of the present invention.
[0020] Figure 5 It is a schematic diagram of the plant fiber thermoplastic composite material soft mold stress plasticization forming device in the embodiment of the present invention when the mold is opened and the part is taken out.
[0021] In the figure: 1-punch; 2-heating mechanism; 3-edge holding mechanism; 4-plate to be formed; 5-heating mechanism; 6-cooling channel; 7-water supply pipe; 8-water pump; 9-water suction pipe; 10-water storage tank; 11-return pipe; 12-die; 13-soft mold; 14-boosting pump; 15-pressure pipe; 16-temperature and pressure controller. DETAILED DESCRIPTION
[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.
[0023] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in the present application without creative work are within the scope of protection of the present application.
[0024] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not require further definition or explanation in subsequent drawings.
[0025] It should also be noted that, in the description of this application, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.
[0026] The features and performance of the present application are further described in detail below with reference to the embodiments.
[0027] Example 1 This embodiment discloses a plant fiber thermoplastic composite material soft mold stress plasticization forming device, such as Figures 2 to 5 As shown, it includes a punch 1, a die 12, a soft die 13, a booster pump 14, a side holding mechanism 3, a heating mechanism (2, 5), a cooling mechanism and a temperature and pressure controller 16; wherein: The soft mold 13 is placed in the groove of the female mold 12 facing the male mold 1 and can cooperate with the male mold 1 to form a forming cavity for the panel 4 to be formed. The outer surface of the soft mold 13 is made of a high temperature resistant and ductile capsule, and the inner surface is filled with liquid. Figures 2 to 5 ; The booster pump 14 is connected to the soft mold 13 through a pressure pipe 15 and can increase the pressure inside the soft mold 13. Figures 2 to 5 ; The edge pressing mechanism 3 is located above the die 12 and is used to press the edge of the plate 4 to be formed on the die 12. Figures 2 to 5 ; The heating mechanisms (2, 5) are respectively installed on the punch 1 and the die 12, and are used to heat the punch 1 and the die 12 respectively. Figures 2 to 5 ; The cooling mechanism acts on the die 12 to cool the die 12. Figures 2 to 5 ; The temperature and pressure controller 16 is electrically connected to the booster pump 14, the heating mechanism (2, 5) and the cooling mechanism respectively, and can monitor the temperature feedback from the heating mechanism (2, 5) and the pressure feedback from the booster pump 14, and is used to adjust the temperature of the punch 1, the temperature of the die 12 and the internal pressure of the soft die 13 according to the process stage to ensure the forming accuracy. Figures 2 to 5 .
[0028] The specific material and manufacturing method of the capsule are not limited, and the type of liquid filled in the soft mold 13 is also not limited, as long as it meets the high temperature and high pressure working requirements. In this embodiment, preferably: the capsule outside the soft mold 13 is made of rubber material.
[0029] In order to avoid interference of the pressure pipe 15 during operation, in this embodiment, preferably: the pressure pipe 15 extends from the through hole opened on the side of the die 12 and is connected to the side of the soft die 13, see Figures 2 to 5 .
[0030] Regarding the heating mechanism (2, 5), in this embodiment, preferably: the heating mechanism (2, 5) adopts a contact thermocouple (for the convenience of observation, the figure only shows that the temperature and pressure controller 16 is electrically connected to the two contact thermocouples), and the contact thermocouples are installed in the side wall and bottom area inside the punch 1 and the inside of the die 12, see Figures 2 to 5 .
[0031] Regarding the cooling mechanism, in this embodiment, preferably: a cooling channel 6 is opened on the die 12; the cooling mechanism adopts a cooling water circulation cooling method, including a water tank 10 and a water pump 8, the inlet end of the water pump 8 is connected to the water tank 10 through a water pumping pipe 9, and the outlet end is connected to the inlet of the cooling channel 6 through a water supply pipe 7, and the outlet of the cooling channel 6 is connected to the water tank 10 through a return pipe 11. Figures 2 to 5 Furthermore, a plurality of cooling channels 6 can be opened on the die 12 , and the cooling channels 6 to be used can be selected according to actual needs. A fan for heat dissipation can also be configured in the water tank 10 .
[0032] Example 2 This embodiment discloses a method for soft mold stress plasticization forming of a plant fiber thermoplastic composite material, using the above-mentioned soft mold stress plasticization forming device for the plant fiber thermoplastic composite material, comprising the following steps: S1, using natural plant fibers and thermoplastic resin matrix as raw materials to produce a panel 4 to be formed; S2, the plate to be formed 4 is placed on the die 12, and the edge pressing mechanism 3 presses the plate to be formed 4 on the die 12 to limit the edge, see Figure 2 ; S3, preheating stage: control and start the heating mechanism (2, 5) to heat up the punch 1, the die 12 and the soft mold 13 in the die 12; S4, stamping and forming stage: When the temperature of the punch 1 and the die 12 reaches the required level, the punch 1 is controlled to move downward to stamp the sheet 4 to be formed. At the same time, the booster pump 14 is controlled to increase the pressure inside the soft die 13, so that the sheet 4 to be formed gradually deforms under the combined action of the pressure of the punch 1 and the pressure of the soft die 13 to obtain a non-solidified target shape part. Figure 3 ; S5, solidification stage: When the punch 1 drops to the set position, the feeding is stopped, and the punch 1 and the die 12 are kept within the set temperature range by controlling the heating mechanism (2, 5) to solidify the target shape part. At the same time, the internal pressure of the soft mold 13 is reduced by controlling the booster pump 14. Figure 4 ; S6, cooling stage: after the solidification is completed, the heating mechanism (2, 5) is controlled to be turned off and the cooling mechanism is turned on. The cooling mechanism acts on the die 12 to cool the die 12 and the soft mold 13 inside it and the target shape parts. Figure 4 ; S7, after the target shape part is cooled, the punch 1 and the edge holding mechanism 3 are retracted, the cooling mechanism is controlled to be closed, and the target shape part is taken out. Figure 5 .
[0033] In this embodiment, preferably, in step S1, the method for manufacturing the panel 4 to be formed is as follows: extracting fibers from plants, treating them with alkali, cleaning and drying them to obtain plant fibers, mixing the plant fibers, a resin matrix and additives to obtain a felt material, and molding the felt material to obtain the panel 4 to be formed. Figure 1 .
[0034] The present invention introduces a soft mold 13 in the processing technology of plant fiber thermoplastic composite materials. The soft mold 13 can provide controllable normal stress, effectively improve the strain distribution, and make the stress distribution of the to-be-formed plate 4 uniform during the deformation process. The present invention can also keep warm and maintain pressure during the curing process, and use the stress-induced plasticization effect to form, avoiding the defects caused by the constant changes and large differences in the stress and strain states of various parts of the sheet material in the traditional process method, reducing the resin aggregation and fiber flow in the forming process, making the strain of the workpiece uniform, and enhancing the bonding degree between the plant fiber and the resin matrix; during forming, the to-be-formed plate 4 is simultaneously subjected to the pressure of the punch 1 and the axial pressure of the soft mold 3, and each part is tightly fitted into the mold, with good forming accuracy; the present invention also introduces a cooling mechanism in the processing technology of the plant fiber thermoplastic composite material, which can accelerate the cooling speed of the mold and improve production efficiency.
[0035] The embodiments described above are part of the embodiments of the present application, rather than all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.
Claims
1. A plant fiber thermoplastic composite material soft mold stress plasticization forming device, characterized by: It includes a punch, a die, a soft die, a booster pump, a edge pressing mechanism, a heating mechanism, a cooling mechanism and a temperature and pressure controller; the soft die is placed in a groove of the die facing the punch and can cooperate with the punch to form a forming cavity for the panel to be formed, the outside of the soft die adopts a high-temperature resistant and ductile capsule, and the inside is filled with liquid; the booster pump is connected to the soft die through a pressure pipe and can pressurize the inside of the soft die; the edge pressing mechanism is located above the die and is used to limit the edge of the panel to be formed on the die; the heating mechanism is respectively installed on the punch and the die and is used to heat the punch and the die respectively; the cooling mechanism acts on the die and is used to cool the die; the temperature and pressure controller is electrically connected to the booster pump, the heating mechanism and the cooling mechanism respectively, and can monitor the temperature feedback from the heating mechanism and the pressure feedback from the booster pump, and is used to adjust the temperature of the punch, the temperature of the die and the internal pressure of the soft die according to the process stage to ensure the forming accuracy.
2. The plant fiber thermoplastic composite material soft mold stress plasticization forming device according to claim 1, characterized in that: The outer capsule of the soft mold is made of rubber.
3. The plant fiber thermoplastic composite material soft mold stress plasticization forming device according to claim 1, characterized in that: The pressure pipe extends from a through hole opened on the side of the female mold and is connected to the side of the soft mold.
4. The plant fiber thermoplastic composite material soft mold stress plasticization forming device according to claim 1, characterized in that: The heating mechanism adopts contact thermocouple.
5. The soft mold stress plasticization forming device for plant fiber thermoplastic composite materials according to claim 4, characterized in that: Contact thermocouples were installed inside the punch and inside the die in the side wall and bottom areas.
6. The plant fiber thermoplastic composite material soft mold stress plasticization forming device according to claim 1, characterized in that: A cooling channel is provided on the die; the cooling mechanism adopts a cooling water circulation cooling method, including a water tank and a water pump, the inlet end of the water pump is connected to the water tank through a pumping pipe, and the outlet end is connected to the cooling channel inlet through a water supply pipe, and the cooling channel outlet is connected to the water tank through a return pipe.
7. The soft mold stress plasticization forming device for plant fiber thermoplastic composite materials according to claim 6, characterized in that: There are multiple cooling channels on the die.
8. The plant fiber thermoplastic composite material soft mold stress plasticization forming device according to claim 6, characterized in that: The water tank is equipped with a fan for heat dissipation.
9. A soft mold stress plasticization forming method for plant fiber thermoplastic composite materials, characterized in that: The plant fiber thermoplastic composite material soft mold stress plasticization forming device according to any one of claims 1 to 8 comprises the following steps: S1. Using natural plant fibers and thermoplastic resin matrix as raw materials to produce a panel to be formed; S2, placing the plate to be formed on the die, and the edge pressing mechanism presses the plate to be formed on the die to limit the position; S3, preheating stage: control the heating mechanism to start, so that the punch, die and the soft mold inside the die are heated and preheated; S4, stamping and forming stage: When the temperatures of the punch and die reach the required levels, the punch is controlled to move downward to stamp the sheet metal to be formed. At the same time, the booster pump is controlled to increase the pressure inside the soft die. Under the combined action of the punch pressure and the soft die pressure, the sheet metal to be formed gradually deforms to obtain a non-solidified target shape part. S5, solidification stage: When the punch drops to the set position, the feeding is stopped, and the punch and die are kept within the set temperature range by controlling the heating mechanism to solidify the target shape part. At the same time, the internal pressure of the soft mold is reduced by controlling the booster pump; S6, cooling stage: After the solidification is completed, the heating mechanism is controlled to be turned off and the cooling mechanism is turned on. The cooling mechanism acts on the die to cool the die and the soft mold inside it and the target shape part; S7. After the target shape part is cooled, the punch and the edge holding mechanism are retracted, the cooling mechanism is controlled to be closed, and the target shape part is taken out.
10. The soft mold stress plasticization forming method of plant fiber thermoplastic composite material according to claim 9, characterized in that: In step S1, the method for making the panel to be formed is: extracting fibers from plants, obtaining plant fibers after alkali treatment and cleaning and drying, mixing the plant fibers, a resin matrix and additives to obtain a felt material, and molding the felt material to obtain the panel to be formed.