Local micro-foaming filling method and equipment for thin-wall part of sole of EVA slipper

Abstract

The invention discloses a local micro-foaming filling method and equipment for a thin-wall part of an EVA slipper sole, and relates to the technical field of foaming filling. A control assembly with a control function is fixedly installed at the front end of the mold containing table through bolts, a distributed injection system of an array module and a needle valve is combined with a local controllable temperature field, accurate control over the foaming position is achieved, and the product has customizable multifunctionality; by means of multi-stage precision metering and real-time closed-loop control, it is ensured that the micro-bubble structure is uniform and fine and high in stability, and the product quality consistency and the yield are greatly improved; a local foaming mode is adopted, so that raw materials are saved, the production efficiency is improved through process optimization, and cost reduction and benefit increase are realized; and finally, the light weight of the product is successfully realized while the buffering and resilience performance of the key part of the sole is ensured, and a solid foundation is laid for digital production through intelligent control in the whole process.

Description

Technical Field

[0001] This invention relates to the field of foam filling technology, specifically a method and equipment for localized micro-foam filling of thin-walled areas of EVA slipper soles. Background Technology

[0002] Traditional EVA slipper soles are typically formed using an in-mold foaming process. This process involves injecting EVA raw material containing chemical foaming agents into a mold in one go, and then heating it to make the entire sole foam evenly. While this method is simple and low-cost, it has significant limitations: First, it makes it difficult to differentiate the performance of different areas of the sole, resulting in the arch area, which requires high elasticity, and the heel area, which requires wear resistance, having the same density and hardness, affecting the product's functionality and wearing comfort. Second, to achieve compromises in overall performance, a high foaming rate is often required, which may sacrifice the overall structural strength and durability of the sole. Summary of the Invention

[0003] Therefore, in order to overcome the above-mentioned shortcomings, the present invention provides a method and apparatus for local micro-foaming filling of the thin-walled part of the sole of an EVA slipper.

[0004] This invention is implemented as follows: a method and device for local micro-foaming filling of thin-walled areas of EVA slipper soles are constructed. The device includes a mold placement platform; a control component with control function is fixedly installed at the front end of the mold placement platform by bolts; an upper mold is fixedly installed at the bottom of the adjusting component of the mold placement platform by bolts, and a lower mold is fixedly installed on the mold placement platform by bolts; a combined mold component is fixedly arranged inside the upper mold and the lower mold.

[0005] Preferably, the combined mold component includes a fixed mold fixedly installed inside the upper mold; a heat-conducting metal frame is pressed and fixedly installed on the bottom side of the fixed mold, and a heat-absorbing material layer is fixedly provided at the bottom of the heat-conducting metal frame, and a connecting pipe is provided inside the heat-absorbing material layer for connection with an external heating pipe; the heat-absorbing material layer is disposed inside the lower mold; a horizontal groove is opened on the bottom side of the inner side of the heat-conducting metal frame, and a sealing rubber is provided in the horizontal groove; an array module is pressed and fixed inside the sealing rubber; an injection component is inserted and fixed at the bottom of the array module.

[0006] Preferably, the array module includes an installation module sealed inside the transverse groove of the heat-conducting metal frame; a precision connector is fixedly installed on the bottom middle side of the installation module, and the top side of the precision connector is connected to the pressure chamber.

[0007] Preferably, a sensor assembly with data acquisition function is inserted and fixedly connected to the side of the pressure chamber; an array of air ports is opened at the top of the pressure chamber, and the air ports are fixedly connected to the bottom of the needle valve interface through a pipe; the side of the needle valve piston is fixedly connected to the first piezoelectric actuator.

[0008] Preferably, the injection component includes a compression cylinder that is inserted and installed in the middle of the bottom of the fixed mold; the bottom of the piston rod inside the compression cylinder is fixedly connected to a second piezoelectric actuator; a main injection cylinder is inserted and fixedly installed at the side interface of the compression cylinder, and the piston inside the main injection cylinder is fixedly installed with a linear ball transmission displacement rod.

[0009] Preferably, the sensor assembly includes a pressure sensor and a temperature sensor. The pressure sensor is used to monitor pressure changes within the pressure chamber in real time, and the temperature sensor is used to monitor the temperature of the thermally conductive metal frame. The sensor assembly is electrically connected to the control assembly.

[0010] Preferably, a heat insulation layer with heat insulation function is adhered to the top of the installation module, and the through holes inside the heat insulation layer are inserted and fixed to the needle body of the needle valve.

[0011] Preferably, the control component includes a programmable logic controller (PLC), which is signal-connected to the sensor component, the first piezoelectric actuator, and the second piezoelectric actuator, for precisely controlling the parameters of the microfoam filling process.

[0012] Preferably, the linear ball drive component includes a ball screw and a guide rail. The ball screw is connected to the piston of the main injection cylinder and is driven by a servo motor to achieve precise linear displacement of the piston.

[0013] Preferably, the heat-absorbing material layer is made of phase change material, and the internal connecting pipe is connected to the external heating pipe through a quick connector. The external heating pipe is filled with heat-conducting oil to maintain a constant temperature of the combined mold parts.

[0014] A method for localized microfoaming filling of thin-walled areas in the soles of EVA slippers includes the following steps: Step 1: Mold Closure and Thermal Field Establishment; After the equipment closes the mold, the external heat-conducting oil circulates in the heat-absorbing material layer, and establishes a uniform and stable high-temperature environment for the mold cavity through the heat-conducting metal frame, preparing the thermal conditions for subsequent local foaming. Step 2: Precise metering and dispensing of foaming agent; the main injection cylinder precisely meters the foaming fluid under servo drive and pushes it to the compression cylinder for pressure stabilization; subsequently, the fluid is transported to the common pressure chamber of the array module for later use; Step 3: Targeted injection and localized foaming; The control component instructs the first piezoelectric actuator at a specific location to activate, instantly opening the corresponding needle valve; The foaming fluid in the pressure chamber is precisely injected into the pre-set thin-walled part of the sole and activated at high temperature to form uniform microbubble pores; Step 4: Real-time monitoring and closed-loop control; The sensor assembly integrated on the side of the pressure chamber monitors pressure and temperature data in real time and feeds it back to the control assembly; The system dynamically adjusts the injection parameters accordingly to ensure that the foaming process is consistent and stable in each cycle. Step 5: Cooling and shaping and mold opening; After injection, all needle valves are closed; The mold cooling system is started to quickly shape the foam structure, and finally the mold is opened to obtain the finished shoe sole with local micro-foam structure.

[0015] The present invention has the following advantages: The present invention provides an improved method and apparatus for localized micro-foaming filling of thin-walled areas in the soles of EVA slippers, which, compared with similar equipment, has the following improvements: This invention discloses a method and equipment for localized microfoaming filling of thin-walled areas in EVA slipper soles. By combining an array module and needle valve distributed injection system with a locally controllable temperature field, precise control of the foaming location is achieved, enabling the product to possess customizable multi-functionality. Multi-level precision metering and real-time closed-loop control ensure a uniform, dense, and highly stable microfoam structure, significantly improving product quality consistency and yield. The localized foaming mode not only saves raw materials but also improves production efficiency through process optimization, achieving cost reduction and efficiency enhancement. Ultimately, while ensuring the cushioning and rebound performance of key parts of the sole, the invention successfully achieves product lightweighting and lays a solid foundation for digital production through intelligent control throughout the entire process. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is an exploded structural diagram of the combined mold component of the present invention; Figure 3 This is a cross-sectional view of the array module of the present invention; Figure 4 This is a schematic diagram of the axial structure of the injection component of the present invention.

[0017] The components include: mold placement platform-1, control assembly-2, upper mold-3, lower mold-4, combined mold assembly-5, fixed mold-51, heat-conducting metal frame-52, heat-absorbing material layer-53, sealing rubber-54, array module-55, injection component-56, mounting module-551, precision connector-552, pressure chamber-553, sensor assembly-554, needle valve-555, first piezoelectric actuator-556, compression cylinder-561, second piezoelectric actuator-562, main injection cylinder-563, and linear ball drive component-564. Detailed Implementation

[0018] The following is in conjunction with the appendix Figures 1-4 The principles and features of the present invention are described below. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. The invention is described more specifically in the following paragraphs by way of example with reference to the accompanying drawings. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the invention.

[0019] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0020] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. The embodiments of this invention will now be described according to its overall structure.

[0021] Example 1:

[0022] Please see Figures 1-4The present invention discloses a method and apparatus for local micro-foaming filling of thin-walled parts of EVA slipper soles, comprising a mold placement platform 1; a control component 2 with control function is fixedly installed at the front end of the mold placement platform 1 by bolts; an upper mold 3 is fixedly installed at the bottom of the adjustment component of the mold placement platform 1 by bolts, and a lower mold 4 is fixedly installed on the mold placement platform 1 by bolts; a combined mold component 5 is fixedly arranged inside the upper mold 3 and the lower mold 4.

[0023] The combined mold component 5 includes a fixed mold 51 fixedly installed inside the upper mold 3; a heat-conducting metal frame 52 is pressed and fixedly installed on the bottom side of the fixed mold 51, and a heat-absorbing material layer 53 is fixedly provided at the bottom of the heat-conducting metal frame 52, and a connecting pipe is provided inside the heat-absorbing material layer 53 for connecting to an external heating pipe; the heat-absorbing material layer 53 is located inside the lower mold 4; a horizontal groove is opened on the bottom side of the inner side of the heat-conducting metal frame 52, and a sealing rubber 54 is provided in the horizontal groove; an array module 55 is pressed and fixed inside the sealing rubber 54; an injection component 56 is inserted and fixed at the bottom of the array module 55.

[0024] The array module 55 includes a mounting module 551 sealed inside the transverse groove of the heat-conducting metal frame 52; a precision connector 552 is fixedly mounted on the bottom middle side of the mounting module 551, and the top side of the precision connector 552 is connected to the pressure chamber 553; a sensor assembly 554 with data acquisition function is inserted and fixedly connected to the side of the pressure chamber 553; an array of air ports is opened on the top of the pressure chamber 553, and the air ports are fixedly connected to the bottom of the needle valve 555 interface through pipes; the side of the piston of the needle valve 555 is fixedly connected to the first piezoelectric actuator 556.

[0025] The top of the mounting module 551 is fitted with a heat insulation layer, and the through holes inside the heat insulation layer are inserted and fixed to the needle body of the needle valve 555. The control component 2 includes a programmable logic controller, which is connected to the sensor component 554, the first piezoelectric actuator 556 and the second piezoelectric actuator 562 for precise control of the parameters of the microfoam filling process.

[0026] The heat-absorbing material layer 53 is specifically made of phase change material, and the internal connecting pipe is connected to the external heating pipe through a quick connector. The external heating pipe is filled with heat-conducting oil to maintain a constant temperature of the combined mold part 5.

[0027] Example 2:

[0028] Please see Figures 1-4The present invention discloses a method and apparatus for local micro-foaming filling of thin-walled areas of EVA slipper soles. Compared with Embodiment 1, this embodiment further includes: an injection component 56 comprising a compression cylinder 561 inserted and installed in the middle of the bottom of a fixed mold 51; the bottom of the piston rod inside the compression cylinder 561 is fixedly connected to a second piezoelectric actuator 562; a main injection cylinder 563 is inserted and fixedly installed at the side interface of the compression cylinder 561, and the piston inside the main injection cylinder 563 is fixedly installed to the displacement rod of a linear ball bearing transmission component 564; a sensor assembly 554 includes a pressure sensor and a temperature sensor, the pressure sensor being used to monitor the pressure change in the pressure chamber 553 in real time, the temperature sensor being used to monitor the temperature of the heat-conducting metal frame 52, and the sensor assembly 554 being electrically connected to the control assembly 2.

[0029] The linear ball drive component 564 includes a ball screw and a guide rail. The ball screw is connected to the piston component of the main injection cylinder 563 and is driven by a servo motor to achieve precise linear displacement of the piston component.

[0030] The working principle of the above-mentioned method and equipment for local micro-foaming filling of thin-walled areas of EVA slipper soles is as follows: First, when using this device, place it in the work area, and then connect it to an external power source to provide the power required for its operation. Second, the upper mold 3 and the lower mold 4 close under the command of the control component 2. The external heat-conducting oil circulates in the heat-absorbing material layer 53 made of phase change material, and together with the heat-conducting metal frame 52, it establishes a stable and uniform high-temperature environment to prepare a thermal field for local foaming. Then, the EVA melt is injected into the cavity, and the temperature of its thin-walled part is maintained under the action of the thermal field, thereby defining the foaming area in space. Then, the key distributed injection step is entered: the main injection cylinder 563 accurately measures the foaming fluid under the drive of the linear ball drive component 564 and pushes it into the compression cylinder 561. After secondary compression and stabilization by the second piezoelectric actuator 562, it is delivered to the pressure chamber 553 of the array module 55. The control component 2 then commands the first piezoelectric actuator 556 at a specific position to instantly open the corresponding needle valve 555, and accurately inject the foaming fluid into the target thin-walled part. Third, at the same time, the sensor component 554 integrated in the pressure chamber monitors and feeds back pressure and temperature data in real time, forming a closed-loop control to dynamically adjust the injection parameters and ensure the stability of foaming power and thermal environment; finally, after all needle valves 555 are closed, the injected foaming agent is activated at local high temperature to form uniform and fine microbubbles, which are then molded by the mold cooling system and opened to finally obtain an EVA slipper sole with a dense main body and a high-performance micro-foamed structure in specific thin-walled parts.

[0031] Example 3: The actual effect of this micro-foaming filling method was tested by those skilled in the art through the following experiments: Foamed Structure and Performance Testing Localized micro-foaming treatment was performed on typical thin-walled areas of EVA shoe soles (forefoot and arch), with a foaming thickness of 2.5 mm. Test results showed that: The average diameter of the microbubbles is 80±10μm, and the uniformity of distribution reaches 92%. The density of the foamed area decreased by about 35%, while the density of the unfoamed area remained unchanged; The resilience of the locally foamed areas was increased to 68%, which is about 23.6% higher than that of the traditional integral foaming process (average 55%). The cushioning performance (tested according to ASTM F1614 standard) is improved by approximately 18%, and the structure did not collapse after durability testing (5000 bends).

[0032] Statistics on Process Stability and Yield In a trial involving the continuous production of 1000 shoe soles: The foaming position deviation is controlled within ±0.3mm; Cell structure uniformity (CV value) is less than 5%; The product yield rate increased from 87% with traditional processes to 96%; Material savings of approximately 12% per unit and an increase in production efficiency of approximately 15%.

[0033] Effects of Closed-Loop Control of Temperature and Pressure During real-time monitoring: The mold cavity temperature control accuracy is ±1.5℃; The pressure fluctuation range of the pressure chamber is ±0.05MPa; Through closed-loop regulation, the repeatability of each injection volume reaches 98.5%.

[0034] The above data shows that the present invention has significant advantages in improving product performance, saving materials, and increasing yield through local micro-foaming filling method. Moreover, the process is highly controllable and suitable for large-scale, digital production.

[0035] This invention provides an improved method and equipment for localized micro-foaming filling of thin-walled areas in EVA slipper soles. By combining an array module with a 555 needle valve distributed injection system and a locally controllable temperature field, precise control of the foaming location is achieved, enabling the product to have customizable multi-functionality. Multi-level precision metering and real-time closed-loop control ensure a uniform, fine, and highly stable micro-foam structure, significantly improving product quality consistency and yield. The localized foaming mode not only saves raw materials but also improves production efficiency through process optimization, achieving cost reduction and efficiency improvement. Ultimately, while ensuring the cushioning and rebound performance of key parts of the sole, the invention successfully achieves product lightweighting and lays a solid foundation for digital production through intelligent control throughout the entire process.

[0036] The above description shows and illustrates the basic principles, main features, and advantages of the present invention. Standard parts used in the present invention can be purchased from the market, and irregular parts can be customized according to the description and drawings. The specific connection methods of each part adopt conventional methods such as bolts, rivets, and welding that are mature in the prior art. The machinery, parts, and equipment adopt conventional models in the prior art, and the circuit connection adopts conventional connection methods in the prior art, which will not be described in detail here.

[0037] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A device for local micro-foaming filling of thin-walled parts of EVA slipper soles, comprising a mold placement platform (1); a control component (2) with control function is fixedly installed at the front end of the mold placement platform (1) by bolts; an upper mold (3) is fixedly installed at the bottom of the adjustment component of the mold placement platform (1) by bolts, and a lower mold (4) is fixedly installed on the mold placement platform (1) by bolts; a combined mold component (5) is fixedly arranged inside the upper mold (3) and the lower mold (4); Its features are: The combined mold component (5) includes a fixed mold (51) fixedly installed inside the upper mold (3); a heat-conducting metal frame (52) is pressed and fixedly installed on the bottom side of the fixed mold (51), and a heat-absorbing material layer (53) is fixedly provided at the bottom of the heat-conducting metal frame (52), and a connecting pipe is provided inside the heat-absorbing material layer (53) for connecting to an external heating pipe; the heat-absorbing material layer (53) is provided inside the lower mold (4); a horizontal groove is opened on the bottom side of the heat-conducting metal frame (52), and a sealing rubber (54) is provided in the horizontal groove; an array module (55) is pressed and fixed inside the sealing rubber (54); an injection component (56) is inserted and fixed at the bottom of the array module (55).

2. The device for localized micro-foaming filling of the thin-walled portion of the sole of an EVA slipper according to claim 1, characterized in that: The array module (55) includes an installation module (551) sealed inside the horizontal groove of the heat-conducting metal frame (52); a precision connector (552) is fixedly installed on the bottom middle side of the installation module (551), and the top side of the precision connector (552) is connected to the pressure chamber (553).

3. The device for localized micro-foaming filling of the thin-walled portion of the sole of an EVA slipper according to claim 2, characterized in that: A sensor assembly (554) with data acquisition function is inserted and fixed to the side of the pressure chamber (553); an array of air ports is opened at the top of the pressure chamber (553), and the air ports are fixedly connected to the bottom of the needle valve (555) interface through a pipe; the side of the piston of the needle valve (555) is fixedly connected to the first piezoelectric actuator (556).

4. The device for localized micro-foaming filling of the thin-walled portion of the sole of an EVA slipper according to claim 3, characterized in that: The injection component (56) includes a compression cylinder (561) that is inserted and installed on the bottom side of the fixed mold (51); the bottom of the piston rod inside the compression cylinder (561) is fixedly connected to the second piezoelectric actuator (562); a main injection cylinder (563) is inserted and fixedly installed on the side interface of the compression cylinder (561), and the piston inside the main injection cylinder (563) is fixedly installed with the displacement rod of the linear ball transmission component (564).

5. The device for localized micro-foaming filling of the thin-walled portion of the sole of an EVA slipper according to claim 4, characterized in that: The sensor assembly (554) includes a pressure sensor and a temperature sensor. The pressure sensor is used to monitor the pressure change in the pressure chamber (553) in real time, and the temperature sensor is used to monitor the temperature of the thermally conductive metal frame (52). The sensor assembly (554) is electrically connected to the control assembly (2).

6. The device for localized micro-foaming filling of the thin-walled portion of the sole of an EVA slipper according to claim 5, characterized in that: The top of the installation module (551) is provided with a heat insulation layer, and the through hole inside the heat insulation layer is inserted and fixed to the needle body of the needle valve (555).

7. The device for localized micro-foaming filling of the thin-walled portion of the sole of an EVA slipper according to claim 6, characterized in that: The control component (2) includes a programmable logic controller (PLC), which is signal-connected to the sensor component (554), the first piezoelectric actuator (556), and the second piezoelectric actuator (562) for precisely controlling the parameters of the microfoam filling process.

8. The device for localized micro-foaming filling of the thin-walled portion of the sole of an EVA slipper according to claim 7, characterized in that: The linear ball drive (564) includes a ball screw and a guide rail. The ball screw is connected to the piston of the main injection cylinder (563) and is driven by a servo motor to achieve precise linear displacement of the piston.

9. The device for localized micro-foaming filling of the thin-walled portion of the sole of an EVA slipper according to claim 8, characterized in that: The heat-absorbing material layer (53) is specifically made of phase change material, and the internal connecting pipe is connected to the external heating pipe through a quick connector. The external heating pipe is filled with heat-conducting oil to maintain a constant temperature of the combined mold part (5).

10. A method for localized microfoaming filling of thin-walled areas of EVA slipper soles, used to implement the localized microfoaming filling device for thin-walled areas of EVA slipper soles as described in claim 9, characterized in that: Includes the following steps: Step 1: Mold closing and thermal field establishment; After the equipment is closed, the external heat-conducting oil circulates in the heat-absorbing material layer (53), and establishes a uniform and stable high-temperature environment for the mold cavity through the heat-conducting metal frame (52), which prepares the thermal conditions for subsequent local foaming. Step 2: Precise metering and distribution of foaming agent; The main injection cylinder (563) accurately meters the foaming fluid under servo drive and pushes it to the compression cylinder (561) for pressure stabilization; Subsequently, the fluid is transported to the common pressure chamber (553) of the array module (55) for later use; Step 3, Targeted Injection and Localized Foaming; The control component (2) instructs the first piezoelectric actuator (556) at a specific location to act, instantly opening the corresponding needle valve (555); The foaming fluid in the pressure chamber is precisely injected into the preset thin-walled part of the sole and activated at high temperature to form uniform microbubble pores; Step 4: Real-time monitoring and closed-loop control; The sensor assembly (554) integrated on the side of the pressure chamber (553) monitors the pressure and temperature data in real time and feeds it back to the control assembly (2); The system dynamically adjusts the injection parameters accordingly to ensure that the foaming process of each cycle is consistent and stable; Step 5: Cooling and shaping and mold opening; After injection, all needle valves (555) are closed; The mold cooling system is started to quickly shape the foam structure, and finally the mold is opened to obtain the finished shoe sole with local micro-foam structure.

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