WO2024036944A1

WO2024036944A1 - Demolding mechanism and method for precisely controlled injection molding machine and with integrated digital hydraulic cylinder

Info

Publication number: WO2024036944A1
Application number: PCT/CN2023/081846
Authority: WO
Inventors: 李君�; 张贤宝; 张�雄
Original assignee: 西诺控股集团有限公司
Priority date: 2022-08-15
Filing date: 2023-03-16
Publication date: 2024-02-22
Also published as: CN117124547A

Abstract

A demolding mechanism of a precisely controlled injection molding machine and with an integrated digital hydraulic cylinder. The mechanism is arranged on an injection molding machine mold base (4), and the injection molding machine mold base (4) has a rear-end top clamping plate (16) and a front-end top clamping plate (17), a mold core (6) being fixed to the rear-end top clamping plate (16). The mechanism further comprises an integrated digital hydraulic cylinder (1), a demolding ejector pin (2) and an auxiliary demolding rod (3), wherein the integrated digital hydraulic cylinder (1) is fixed to the injection molding machine mold base (4) and is electrically connected to an intelligent driver for the digital hydraulic cylinder, and the intelligent driver for the digital hydraulic cylinder is electrically connected to a control device. The demolding ejector pin (2) and the auxiliary demolding rod (3) are connected to the rear-end top clamping plate (16) in a penetrating manner, and are in transmission connection with a piston rod of the integrated digital hydraulic cylinder (1). The demolding mechanism of the precisely controlled injection molding machine and with the integrated digital hydraulic cylinder has high control precision and fast frequency response.

Description

An integrated digital hydraulic cylinder precision control injection molding machine demoulding mechanism and method

Technical field

The present invention relates to the technical field of injection molding machines, and more specifically, to an integrated digital hydraulic cylinder precision control injection molding machine demoulding mechanism and method.

Background technique

The traditional way of controlling the demoulding of the injection molding machine is to use PLC + valve + driver. The hydraulic cylinder is connected to the second plate of the injection molding machine. The front end of the piston rod is fixed on the demoulding plate with a nut. The demoulding rod is fixed on the demoulding plate. The cylinder piston rod reciprocates. The movement drives the demoulding plate to reciprocate, and the demoulding plate drives the demoulding rod to reciprocate for ejection and retraction. In this process, due to the use of external indirect closed-loop feedback of PLC + valve + driver + sensor, the control accuracy is relatively low. The response is relatively slow. The operation of the injection molding machine requires relatively high position control accuracy to ensure the stable production of plastic products. Therefore, the traditional injection molding machine control demoulding method needs to be improved. The utility model patent with publication number CN201626110U discloses a one-step plastic injection blow molding machine demoulding device. This solution installs the demoulding cylinder on the side wall of the workbench, shortening the transmission rod connecting the demoulding cylinder to the demoulding frame. The demoulding is stable and the movement is smooth. No manual participation is required in the production process, and artificial secondary pollution is eliminated. Plastic bottles directly enter the filling line, which improves the degree of automation in the production of products in industries such as food and medicine. However, this utility model also adopts the traditional injection molding machine control demoulding method, so it has the disadvantages of low control accuracy and slow response.

Contents of the invention

The traditional injection molding machine control demoulding method has relatively low control accuracy and relatively slow response, which is not conducive to the stable production of injection molded products. In order to overcome these shortcomings, the present invention provides a method that can improve the operation control accuracy and response speed of the injection molding machine. Integrated digital hydraulic cylinder precisely controls the demoulding mechanism and method of an injection molding machine.

The technical solution of the present invention is: an integrated digital hydraulic cylinder precision-control injection molding machine demoulding mechanism, which is located on the injection molding machine mold base. The injection molding machine mold base has a rear end panel and a front end panel, and a mold core is fixed on the rear end panel. , this demoulding mechanism includes an integrated digital hydraulic cylinder, a demoulding ejector pin and an auxiliary demoulding rod. The integrated digital hydraulic cylinder is fixed on the mold base of the injection molding machine. The integrated digital hydraulic cylinder is electrically connected to a digital hydraulic cylinder intelligent driver. The digital The intelligent driver of the hydraulic cylinder is electrically connected to a control device. The demoulding ejector pin and auxiliary demoulding rod are connected to the rear panel and are drivingly connected to the piston rod of the integrated digital hydraulic cylinder. Ejector pin channel and demoulding pin channel. When demoulding, under the control of the control device and the intelligent driver of the digital hydraulic cylinder, the piston rod of the integrated digital hydraulic cylinder extends, driving the demoulding ejector pin and auxiliary demoulding rod to directly or indirectly input the demoulding force into the mold core, which will The product formed in the mold core is pushed out and demoulding is completed. The demoulding ejector pin and auxiliary demoulding rod correspond to different positions of the mold core, so that the demoulding power is reasonably distributed in different parts of the product, which is more conducive to the balanced force of the product and overcomes the problem of the product sticking to the mold core due to its own elasticity, thus Easier to demold. This demoulding mechanism uses an integrated digital hydraulic cylinder to provide demoulding power. The integrated digital hydraulic cylinder is a device that combines valves, cylinders, feedback and drive control. Frequency It has fast response and can achieve micron-level repeatability, which can meet the system requirements of precise force control.

Preferably, a stripping plate is fixed on the piston rod of the integrated digital hydraulic cylinder. The stripping plate is slidingly connected to the mold seat of the injection molding machine. The stripping ejector pin is connected to the center of the stripping plate. The auxiliary stripping rod is connected to the stripping plate and arranged on the stripping plate. around the mold ejector pin. The demoulding ejector pin usually exerts force in the center of the mold core, and the auxiliary demoulding rod is dispersed in other positions corresponding to the mold core to ensure a balanced distribution of the demoulding force.

Preferably, one end of the auxiliary demoulding rod is fixed on the end surface of the demoulding plate, and the other end is connected to the rear end panel. When the demoulding plate moves with the piston rod of the integrated digital hydraulic cylinder, the auxiliary demoulding rod also moves with the demoulding plate, thereby directly exerting axial demoulding force on the molded product in the mold core, or driving other structures to promote product demoulding.

Preferably, the free end of the auxiliary demoulding rod is provided with a top cone head, and a demoulding module is provided in the channel of the demoulding rod. One end of the demoulding module is connected to the top cone head, the other end of the demoulding module is provided with a split claw, and a cone is provided inside the demoulding module. Shape cavity, the top cone head is located in the cone-shaped cavity, the large diameter end of the cone cavity is provided with a closing portion, and the end surface of the large diameter end of the top cone head forms a snap connection with the closing portion. The diameter of the end face of the auxiliary demoulding rod is limited. If the product is pushed directly, the demoulding force will be buffered by elastic deformation under point stress due to the small contact area, resulting in poor demoulding effect. In this technical solution, the auxiliary demoulding rod cannot directly push the product out of the mold, but conducts the demoulding force to the demoulding module, which directly pushes the product. When the piston rod of the integrated digital hydraulic cylinder extends, the auxiliary demoulding rod moves axially accordingly. When the conical surface of the top cone head has not yet touched the inner surface of the split claw, the demoulding force that can be transmitted by the demoulding module is weak. When the conical surface of the top cone head touches the inner surface of the split claw, the force between the top cone head and the inner surface of the split claw is decomposed into an axial driving force and a radial expansion force, and the ejection module is pushed out axially. At the same time, the split claws are opened to expand the contact surface between the demoulding module and the product, so that the demoulding module can transfer the demoulding force from the auxiliary demoulding rod to the product through the split claws, so that the product can be demoulded more smoothly.

As an alternative, the auxiliary demoulding rod is installed on the mold base of the injection molding machine. Both ends of the auxiliary demoulding rod are rotated and connected to the rear end panel and the front end panel respectively, and the end of the auxiliary demoulding rod near the rear end panel is inserted into the demoulding machine. In the rod channel, a demoulding module is slidably embedded in the demoulding rod channel. The auxiliary demoulding rod is connected to the demoulding module through threads. The auxiliary demoulding rod is a screw rod. The auxiliary demoulding rod penetrates the demoulding plate and is threadedly connected with the demoulding plate. When the piston rod of the integrated digital hydraulic cylinder extends, it pushes the demoulding plate to move axially. Since the demoulding plate and the auxiliary demoulding rod are connected through threads, the relative axial movement between the demoulding plate and the auxiliary demoulding rod is converted into the auxiliary demoulding rod. When the ejector rod rotates, it drives the ejector module to move axially through the spiral pair between the ejector module and the ejector module. When the ejector module exposes the ejector rod channel, it pushes the product to demould.

Preferably, a plurality of parallel guide rods are provided between the rear end panel and the front end panel. The two ends of the guide rods are fixed on the rear end panel and the front end panel respectively, and the guide rods slide through the stripper plate. By cooperating with the guide rod, the sliding connection between the stripper plate and the mold base of the injection molding machine can be realized, and the movement path of the stripper plate can be accurately defined.

Preferably, a displacement sensor is provided between the demoulding plate and the mold base of the injection molding machine. The integrated digital hydraulic cylinder has a high-precision mechanical feedback device inside, and the displacement sensor is used to provide redundant monitoring and protection functions, so that the demoulding mechanism has double insurance, works safer and more reliably, and can be adapted to many applications that require higher safety levels. .

Preferably, a pressure sensor is provided on the piston rod of the integrated digital hydraulic cylinder. Setting up a pressure sensor can better monitor the working conditions of the integrated digital hydraulic cylinder and facilitate more precise control of the demoulding force.

A demoulding method using the integrated digital hydraulic cylinder to precisely control the demoulding mechanism of an injection molding machine, including the following steps:

Step 1. The control device outputs instructions to the integrated digital hydraulic cylinder;

Step 2. The integrated digital hydraulic cylinder works to drive the movement of the demoulding plate, which then drives the movement of the demoulding ejector pin and auxiliary demoulding rod to complete product demoulding;

Step 3. The piston rod of the integrated digital hydraulic cylinder is reset, and the demoulding plate, demoulding ejector pin and auxiliary demoulding rod are also reset accordingly. Then the integrated digital hydraulic cylinder generates mechanical self-closed loop position feedback and maintains the reset state.

The beneficial effects of the present invention are:

High control accuracy. The invention uses an integrated digital hydraulic cylinder to provide demolding power, has position closed-loop capability, can digitize motion characteristics, achieve precise micron-level position and speed control, and achieve closed-loop force control through precise position control.

Fast frequency response. The integrated digital hydraulic cylinder in the present invention combines valves, cylinders, feedback and drive control into one body, with fewer links in the closed-loop control chain and fast response speed.

Compact structure and high integration. The integrated digital hydraulic cylinder in the present invention combines valve, cylinder, feedback and drive control into an independent working device, which has good integrity and is easy to use.

Description of the drawings

Figure 1 is a schematic structural diagram of the present invention;

Figure 2 is a structural schematic diagram for installing the mold base of the injection molding machine of the present invention;

Figure 3 is a structural schematic diagram from another perspective of installing the injection molding machine mold base of the present invention;

Figure 4 is a schematic structural diagram of the integrated digital hydraulic cylinder in the present invention;

Figure 5 is a schematic diagram of a matching structure between the present invention and the mold core;

Figure 6 is a schematic diagram of another matching structure between the present invention and the mold core;

Figure 7 is a schematic diagram of the matching structure between the present invention and the mold core in Embodiment 3.

In the picture, 1-integrated digital hydraulic cylinder, 2-demould ejector pin, 3-auxiliary demoulding rod, 4-injection molding machine mold base, 5-ejector plate, 6-mold core, 7-ejector rod channel, 8- Remove the module, 9-top cone head, 10-splitting claw, 11-tapered cavity, 12-closing part, 13-guide rod, 14-reducing step, 15-compression spring, 16-rear end panel, 17- Front panel.

Detailed ways

The present invention will be further described below in conjunction with the specific embodiments of the accompanying drawings.

Example 1:

As shown in Figures 1 to 5, an integrated digital hydraulic cylinder precisely controls the ejection mechanism of an injection molding machine, which is located on the injection molding machine mold base 4. The injection molding machine mold base 4 has a rear end panel 16 and a front end panel 17. The rear end A mold core 6 is fixed on the panel 16. The integrated digital hydraulic cylinder precision control injection molding machine demoulding mechanism includes an integrated digital hydraulic cylinder 1, a demoulding ejector pin 2 and an auxiliary demoulding rod 3. The integrated digital hydraulic cylinder 1 has an outer fixed sleeve. A flange is connected, which penetrates the front panel 17 and is connected with the front panel 17 through bolts, so that the integrated digital hydraulic cylinder 1 is fixed on the mold base 4 of the injection molding machine. The integrated digital hydraulic cylinder 1 is electrically connected to a digital hydraulic cylinder intelligent driver, and the digital hydraulic cylinder intelligent driver is electrically connected to a control device, and the control device is a PLC. The demoulding ejector pin 2 and the auxiliary demoulding rod 3 are connected to the rear end panel 16 and are drivingly connected to the piston rod of the integrated digital hydraulic cylinder 1. The mold core 6 is provided with an ejector pin channel and a demoulding pin channel that penetrates the inner and outer surfaces of the mold core 6. Rod channel 7. A stripper plate 5 is fixed on the piston rod of the integrated digital hydraulic cylinder 1. Four parallel guide rods 13 are provided between the rear end panel 16 and the front end panel 17. The two ends of the guide rod 13 are respectively fixed on the rear end panel and the front end panel. , the guide rod 13 slides through the stripper plate 5, so that the stripper plate 5 is slidably connected to the mold base 4 of the injection molding machine. The demoulding ejector pin 2 is connected to the center of the demoulding plate 5 . There are four auxiliary demoulding rods 3, which are parallel to the guide rods 13. The auxiliary demoulding rods 3 and the guide rods 13 are arranged at intervals. The auxiliary demoulding rod 3 is connected to the demoulding plate 5 and is arranged around the demoulding ejector pin 2 . One end of the auxiliary demoulding rod 3 is fixed on the end surface of the demoulding plate 5, and the other end is connected to the rear end panel. A displacement sensor is provided between the demoulding plate 5 and the mold base 4 of the injection molding machine. The piston rod of the integrated digital hydraulic cylinder 1 is provided with a pressure sensor.

Step 1. The control device outputs instructions to the digital hydraulic cylinder intelligent driver, and the digital hydraulic cylinder intelligent driver outputs instructions to the integrated digital hydraulic cylinder 1;

Step 2. The piston rod of the integrated digital hydraulic cylinder 1 extends, driving the demoulding plate 2 to move, and then driving the demoulding ejector pin 2 and auxiliary demoulding rod 3 to move. The mold rod channel 7 advances and extends into the mold cavity of the mold core 6, ejecting the formed and solidified product out of the mold cavity to complete product demoulding;

Step 3. The piston rod of the integrated digital hydraulic cylinder 1 is reset, the demoulding plate 2, the demoulding ejector pin 2 and the auxiliary demoulding rod 3 are also reset accordingly. Then the integrated digital hydraulic cylinder 1 generates mechanical self-closing position feedback to block the integrated digital All oil circuits inside the hydraulic cylinder 1 keep the integrated digital hydraulic cylinder 1 in the reset state.

Example 2:

As shown in Figure 6, the free end of the auxiliary demoulding rod 3 is provided with a tapered top cone head 9, and a demoulding module 8 is provided in the demoulding rod channel 7. One end of the demoulding module 8 is connected to the top cone head 9, and the other end of the demoulding module 8 is connected to the top cone head 9. Two splitting claws 10 are provided at one end, and a tapered cavity 11 is provided in the stripping module 8. The splitting claws 10 are formed by processing longitudinal incisions on the wall of the tapered cavity 11. The front end of the tapered cavity 11 is formed by the splitting claws 10. The top cone head 9 is located in the cone-shaped cavity 11, and the axial length of the top cone head 9 is smaller than the axial length of the cone-shaped cavity 11. The large-diameter end of the tapered cavity 11 is provided with a closing portion 12. The large-diameter end surface of the top cone head 9 forms a snap connection with the closing portion 12. The auxiliary demoulding rod 3 is provided with a diameter-reducing step 14. A compression spring 15 is provided between the reducing step 14 and the take-off module 8. The compression spring 15 must be selected through testing to ensure an appropriate elastic coefficient.

In step two, when the piston rod of the integrated digital hydraulic cylinder 1 extends, the auxiliary demoulding rod 3 moves axially accordingly. When the cone surface of the top cone head 9 has not yet touched the inner surface of the split claw 10, the compression spring 15 Being gradually squeezed by the reducing step 14 and the stripping module 8, the elastic force gradually increases, pushing the stripping module 8 to move toward the cavity of the mold core 6, and pressing the molded product in the cavity. If the elastic force of the compression spring 15 is enough to overcome the Due to the binding force between the product and the mold cavity, the ejection module 8 can directly push and displace the molded and solidified product. All the ejection modules 8 and the demoulding ejector pin 2 work together to eject the product out of the cavity; if at this time the elastic force of the compression spring 15 is only It can cause the product to deform and move a little, but it cannot completely overcome the bonding force between the product and the mold cavity. The demoulding force that can be transmitted by the demoulding module 8 cannot complete the demoulding. As the piston rod of the integrated digital hydraulic cylinder 1 continues to extend, , the top cone head 9 continues to move forward. When the conical surface of the top cone head 9 touches the inner surface of the split claw 10, the force between the top cone head 9 and the inner surface of the split claw 10 is decomposed into an axial driving force and The radial expansion force pushes out the demoulding module 8 axially and at the same time opens the splitting claw 10, expanding the contact surface between the front end surface of the demoulding module 8 and the product, so that the demoulding module 8 can push out the auxiliary demoulding rod 3 through the splitting claw 10. The demoulding force is transmitted to the product, and the formed and solidified product is ejected from the mold cavity to complete product demoulding.

The rest is the same as in Embodiment 1.

Example 3:

As shown in Figure 7, the auxiliary demoulding rod 3 is installed on the mold base 4 of the injection molding machine. Both ends of the auxiliary demoulding rod 3 are rotated and connected to the rear end panel and the front end panel respectively. The end panel end is inserted into the demoulding rod channel 7. The cross section of the demoulding rod channel 7 is a regular hexagon. A demoulding module 8 adapted to the shape of the demoulding rod channel 7 is slidably embedded in the demoulding rod channel 7 to assist in demoulding. The mold rod 3 is connected to the demoulding module 8 through threads. The auxiliary demoulding rod 3 is a screw rod. The auxiliary demoulding rod 3 penetrates the demoulding plate 5 and is connected to the demoulding plate 5 through threads. The control device is a computer.

In step two, when the piston rod of the integrated digital hydraulic cylinder 1 extends, the demoulding plate 5 moves axially simultaneously. Since the demoulding plate 5 and the auxiliary demoulding rod 3 are connected through threads, the gap between the demoulding plate 5 and the auxiliary demoulding rod 3 is The relative axial movement is converted into the rotation of the auxiliary demoulding rod 3. When the auxiliary demoulding rod 3 rotates, it drives the demoulding module 8 to move axially through the spiral pair with the demoulding module 5. The demoulding module 8 exposes the demoulding rod channel 7. , promote product demoulding.

The rest is the same as in Embodiment 1.

Example 4:

There are three auxiliary demoulding rods 3 and three guide rods 13 respectively. The rest is the same as in Embodiment 1.

Claims

An integrated digital hydraulic cylinder precisely controls the ejection mechanism of an injection molding machine, which is located on the injection molding machine mold base (4). The injection molding machine mold base (4) has a rear end panel and a front end panel, and a mold core (4) is fixed on the rear end panel. 6), which is characterized by including an integrated digital hydraulic cylinder (1), a demoulding ejector pin (2) and an auxiliary demoulding rod (3). The integrated digital hydraulic cylinder (1) is fixed on the mold base (4) of the injection molding machine. The integrated digital hydraulic cylinder (1) is electrically connected to a digital hydraulic cylinder intelligent driver, the digital hydraulic cylinder intelligent driver is electrically connected to a control device, and the demoulding ejector pin (2) and auxiliary demoulding rod (3) are connected to the rear panel and is drivingly connected to the piston rod of the integrated digital hydraulic cylinder (1). The mold core (6) is provided with an ejector pin channel and a demoulding rod channel (7) that penetrate the inner and outer surfaces of the mold core (6).
The integrated digital hydraulic cylinder precision control injection molding machine demoulding mechanism according to claim 1, characterized in that a demoulding plate (5) is fixed on the piston rod of the integrated digital hydraulic cylinder (1), and the demoulding plate (5) is slidingly connected On the mold base (4) of the injection molding machine, the demoulding ejector pin (2) is connected to the center of the demoulding plate (5), and the auxiliary demoulding rod (3) is connected to the demoulding plate (5) and arranged around the demoulding ejector pin (2). .
The integrated digital hydraulic cylinder precision control injection molding machine demoulding mechanism according to claim 2, characterized in that one end of the auxiliary demoulding rod (3) is fixed on the end surface of the demoulding plate (5), and the other end is connected to the rear end of the demoulding plate (5). on the end panel.
The integrated digital hydraulic cylinder precision control injection molding machine demoulding mechanism according to claim 3, characterized in that the free end of the auxiliary demoulding rod (3) is provided with a top cone head (9), and the demoulding rod channel (7) is equipped with There is a stripping module (8). One end of the stripping module (8) is connected to the top cone head (9). The other end of the stripping module (8) is provided with a split claw (10). The stripping module (8) is provided with a tapered cavity ( 11), the top cone head (9) is located in the tapered cavity (11), the large diameter end of the tapered cavity (11) is provided with a closing portion (12), and the end surface of the large diameter end of the top cone head (9) is connected with the closing portion (12) ) forms a snap connection.
The integrated digital hydraulic cylinder precision control injection molding machine demoulding mechanism according to claim 2, characterized in that the auxiliary demoulding rod (3) is installed on the mold base (4) of the injection molding machine, and both ends of the auxiliary demoulding rod (3) It is rotated and connected to the rear end panel and the front end panel respectively, and the end of the auxiliary demoulding rod (3) near the rear end panel is inserted into the demoulding rod channel (7). There is a slide embedded in the demoulding rod channel (7). The demoulding module (8), the auxiliary demoulding rod (3) and the demoulding module (8) are connected through threads. The auxiliary demoulding rod (3) is a screw rod, and the auxiliary demoulding rod (3) penetrates the demoulding plate (5) and is connected with the demoulding module (5). The formwork (5) is connected via threads.
The integrated digital hydraulic cylinder precision control injection molding machine demoulding mechanism according to claim 2, characterized in that a plurality of parallel guide rods (13) are provided between the rear end panel and the front end panel, and two guide rods (13) The ends are respectively fixed on the rear end panel and the front end panel, and the guide rod (13) slides through the stripper plate (5).
The integrated digital hydraulic cylinder precision control injection molding machine demoulding mechanism according to claim 2, characterized in that a displacement sensor is provided between the demoulding plate (5) and the injection molding machine mold base (4).
The integrated digital hydraulic cylinder precision control injection molding machine demoulding mechanism according to claim 1, characterized in that a pressure sensor is provided on the piston rod of the integrated digital hydraulic cylinder (1).
The integrated digital hydraulic cylinder accurately controls the demoulding mechanism of an injection molding machine according to any one of claims 1 to 8, characterized in that the control device is a PLC or a computer.
A demoulding method using the integrated digital hydraulic cylinder to precisely control the demoulding mechanism of an injection molding machine according to any one of claims 1 to 9, characterized by comprising the following steps:

Step 1. The control device outputs instructions to the integrated digital hydraulic cylinder (1);

Step 2. The piston rod of the integrated digital hydraulic cylinder (1) extends, driving the demoulding plate (2) to move, and then driving the demoulding ejector pin (2) and auxiliary demoulding rod (3) to move, completing product demoulding;

Step 3. The integrated digital hydraulic cylinder (1) piston rod is reset, the demoulding plate (2), demoulding ejector pin (2) and auxiliary demoulding rod (3) are also reset accordingly, and then the integrated digital hydraulic cylinder (1) generates mechanical Self-closed loop position feedback, maintain reset state.