CN111703038A - Rubber injection molding machine and method - Google Patents

Abstract

The invention relates to a rubber injection molding machine and a method thereof, wherein the rubber injection molding machine comprises a frame assembly, a mold closing oil cylinder is vertically arranged on the frame assembly, a sliding lower hot plate which can lift on the frame assembly is arranged on the mold closing oil cylinder, a fixed upper hot plate is arranged above the sliding lower hot plate, a mold with an upper surface which is used for being in pressure contact with the lower surface of the fixed upper hot plate is preset on the upper surface of the sliding lower hot plate, an injection oil cylinder is arranged on the frame assembly, a hydraulic motor is arranged on the injection oil cylinder in a lifting way, the lower end of the hydraulic motor is in transmission connection with an injection rod, and an injection machine barrel is arranged on the fixed upper hot plate.

Description

Rubber injection molding machine and method

technical field

The present invention relates to a rubber injection molding machine and method.

Background technique

At present, rubber injection molding machine is a technology for the production of rubber molded products. Referred to as injection machine, it is the main molding equipment for making rubber products of various shapes using molding dies. Injection molding is achieved through injection machines and molds. The working principle of the injection machine is to inject plasticized (that is, viscous flow) rubber into the closed mold cavity with the help of the thrust of the injection rod, and obtain the product after vulcanization. Injection molding is a cyclic process, each cycle mainly includes: melt plasticization - quantitative feeding - pressure injection - mold filling and vulcanization - mold opening and removal. After the workpiece is taken out, the mold is closed again for the next cycle. Quantitative feeding-melt plasticization: The screw of the feeder rotates, so that the rubber material fills the entire injection cavity under the rotation of the screw of the feeder, and the rubber material is mixed, plasticized and quantitatively fed. Pressurized injection: The injection rod injects molten rubber into the mold cavity through the injection rod under a certain pressure and speed under the push of the hydraulic cylinder. Vulcanization: After the injection is completed, the molten material injected into the mold cavity is kept in a fixed shape and vulcanized. After the vulcanization time is up, the mold is taken out.

As shown in Figure 1, in the prior art, the feeder stops working after quantitative feeding. During injection, the injection rod only moves axially to push the material and apply pressure to the rubber. The disadvantages are as follows:

1. Because there is a mutual moving assembly gap between the outer diameter of the injection rod and the inner diameter of the barrel, when the injection rod pushes the material forward, there will be a part of the material due to the reduction of the diameter of the nozzle or the friction between the material and the inner wall of the barrel Backflow from the gap.

2. In addition, the backflow of the rubber compound may lead to insufficient injection volume, resulting in poor compactness of the workpiece after vulcanization of the product, and defects such as pores.

3. The injection rod pushes the injection in a straight line, not only to overcome the resistance of the rubber material, but also to overcome the friction between the screw and the barrel. Long-term high pressure will cause certain damage to the hydraulic system.

4. Due to the relatively large aspect ratio of the injection rod, when the injection rod pushes the material forward, it will swing and the reaction force of the material will cause a gnawing phenomenon between the injection rod and the barrel, resulting in damage to the barrel or the injection rod. .

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is generally to provide a rubber injection molding machine and method. The innovation of the present invention lies in changing the head structure of the injection rod with a smooth (or having a plurality of annular grooves) to a structure with a reverse thread groove; the helix angle of the reverse thread groove is 8°∽12°; The single linear propulsion motion increases the rotary motion, and the injection rod implements both linear propulsion and rotary motion at the same time.

In order to solve the above problems, the technical scheme adopted by the present invention is:

A rubber injection molding machine includes a frame assembly, a mold clamping oil cylinder is vertically arranged on the frame assembly, and a sliding lower hot plate that rises and falls on the frame assembly is arranged on the mold clamping oil cylinder. A fixed upper heating plate is arranged above the heating plate, and a mold whose upper surface is used for pressure contact with the lower surface of the fixed upper heating plate is preset on the upper surface of the sliding lower heating plate. A hydraulic motor is set up and down on the injection cylinder, and the lower end of the hydraulic motor is connected with an injection rod. An injection barrel is arranged on the fixed upper hot plate. The injection rod performs lifting and rotating movements in the vertical injection channel of the injection barrel. An injection fixing sleeve is arranged on the fixed upper hot plate, the upper end of the injection fixing sleeve is connected to the injection channel, and the lower end of the injection fixing sleeve is provided with an injection head for injecting rubber into the inner cavity of the mold.

As a further improvement of the above technical solution:

A feeder is arranged on the frame assembly.

The feeder includes an inclined feeding barrel; a feeding channel inclined in the feeding barrel and the output port at the lower end communicated with the injection channel and used for outputting rubber,

A feeding screw is arranged in the feeding channel, and a feeding motor for driving the rotation of the feeding screw is arranged on the feeding barrel.

The lower part of the injection rod is provided with a thread groove opposite to the direction of rotation.

A rubber injection method, the method comprises the following steps;

Step 1: First, position the mold on the sliding lower hot plate; then, the sliding lower hot plate moves up and down under the push of the clamping cylinder and squeezes with the fixed upper hot plate to close the mold to the set pressure. ;Secondly, the feeding machine works, the rubber material is in a molten state under the extrusion and mixing action of the feeding screw; thirdly, the feeding motor drives the feeding screw to rotate on the feeding barrel, and the rubber material is plasticized through the feeding channel. Extruded into the injection barrel after melting;

Step 2, in the injection barrel, the injection oil cylinder drives the hydraulic motor, and the injection rod overcomes its gravity with the pressing of the rubber material, and continuously lifts until it reaches the required height;

Step 3: During injection, under the action of the injection cylinder, the injection rod moves downward to squeeze the rubber, and the hydraulic motor drives the injection rod to rotate and pressurize;

Step 4: The molten rubber is injected into the mold through the injection head. By controlling the temperature of the mold, the vulcanization and shaping are completed within the set time. After the vulcanization time is up, the mold is opened and the parts are taken out.

Because the injection rod pushes and rotates at the same time during the injection process, the invention effectively turns the sliding friction into rolling friction and greatly overcomes the resistance, thereby reducing the pressure of the hydraulic system, reducing the hydraulic load during the injection process, protecting the hydraulic station and improving the hydraulic pressure. The life of the station; during the injection process, the rotation of the injection rod straightens its swing in the linear motion and overcomes the phenomenon of gnawing between the injection rod and the barrel caused by the reaction force of the material; during the injection process, due to The reverse thread structure with 8°∽12° helix angle on the head of the injection rod and its rotation increase the driving effect and prevent the molten rubber from flowing back under high pressure. Prevent the workpiece from having defects such as insufficient compactness and air bubbles due to insufficient injection volume of rubber.

The invention has the advantages of reasonable design, low cost, strong durability, safety and reliability, simple operation, saving time and labor, saving money, compact structure and convenient use.

Description of drawings

FIG. 1 is a schematic structural diagram of the prior art.

Figure 2 is a schematic structural diagram of the present invention.

FIG. 3 is a schematic structural diagram of a part of the present invention.

Among them: 1. Mold; 2. Hydraulic motor; 3. Injection cylinder; 4. Injection rod; 5. Injection barrel; 6. Fixed upper hot plate; 7. Injection head; 8. Injection fixed sleeve; 9. Sliding lower heat plate; 10, clamping cylinder; 11, feeding barrel; 12, feeding screw; 13, feeding motor; 14, feeding channel; 15, injection channel; 16, thread groove.

Detailed ways

As shown in Figures 2-3, the rubber injection molding machine of this embodiment includes a frame assembly, a mold clamping oil cylinder 10 is vertically arranged on the frame assembly, and a mold clamping oil cylinder 10 is provided on the frame assembly. A sliding lower hot plate 9 is formed to rise and fall upward, a fixed upper hot plate 6 is arranged above the sliding lower hot plate 9, and an upper surface is preset on the upper surface of the sliding lower hot plate 9 for pressure with the lower surface of the fixed upper hot plate 6 The mold 1 that is in contact is provided with an injection cylinder 3 on the frame assembly, and a hydraulic motor 2 is set up and down on the injection cylinder 3. The lower end of the hydraulic motor 2 is driven and connected with an injection rod 4. The injection barrel 5 and the injection rod 4 perform lifting and rotating motions in the vertical injection channel 15 of the injection barrel 5. An injection fixing sleeve 8 is arranged on the fixed upper hot plate 6. The upper end of the injection fixing sleeve 8 is connected to the injection The lower end of the channel 15 is provided with an injection head 7 for injecting rubber into the cavity of the mold 1 .

A feeder is arranged on the frame assembly.

The feeder includes an inclined feeding barrel 11; a feeding channel 14 which is inclined in the feeding barrel 11 and communicates with the injection channel 15 and is used for outputting the rubber, and the output port at the lower end communicates with the injection channel 15.

The feeding channel 14 is provided with a feeding screw 12 , and the feeding barrel 11 is provided with a feeding motor 13 for driving the feeding screw 12 to rotate.

The lower part of the injection rod 4 is provided with a thread groove 16 opposite to the direction of rotation.

The rubber injection method of the present embodiment includes the following steps;

Step 1: First, position the mold on the sliding lower hot plate; then, the sliding lower hot plate moves up and down under the push of the clamping cylinder and squeezes with the fixed upper hot plate to close the mold to the set pressure. ;Secondly, the feeding machine works, the rubber material is in a molten state under the extrusion and mixing action of the feeding screw; thirdly, the feeding motor drives the feeding screw to rotate on the feeding barrel, and the rubber material is plasticized through the feeding channel. Extruded into the injection barrel after melting;

Step 2, in the injection barrel, the injection oil cylinder drives the hydraulic motor, and the injection rod overcomes its gravity with the pressing of the rubber material, and continuously lifts until it reaches the required height;

Step 3: During injection, under the action of the injection cylinder, the injection rod moves downward to squeeze the rubber, and the hydraulic motor drives the injection rod to rotate and pressurize;

Step 4: The molten rubber is injected into the mold through the injection head. By controlling the temperature of the mold, the vulcanization and shaping are completed within the set time. After the vulcanization time is up, the mold is opened and the parts are taken out.

Step 1, first, the mold 1 is positioned on the sliding lower hot plate 9; then, the sliding lower hot plate 9 moves up and down under the push of the mold clamping oil cylinder 10 and squeezes with the fixed upper hot plate 6, and the mold 1 is pressed. The mold is closed to the set pressure; secondly, the feeding machine works, and the rubber material is in a molten state under the extrusion and kneading action of the feeding screw 12; thirdly, the feeding motor 13 drives the feeding screw 12 to the feeding barrel 11. Rotate, plasticize the rubber material through the feeding channel 14 and squeeze it into the injection barrel 5;

Step 2, in the injection barrel 5, the injection cylinder 3 drives the hydraulic motor 2, and the injection rod 4 overcomes its gravity with the pressing of the rubber material, and continuously lifts until it reaches the required height;

Step 3: During injection, under the action of the injection cylinder 3, while the injection rod 4 moves downward to squeeze the rubber, the hydraulic motor 2 drives the injection rod 4 to rotate and pressurize;

Step 4, the molten rubber is injected into the mold 1 through the injection head 7, and the temperature of the mold is controlled to complete the vulcanization and setting within the set time. After the vulcanization time is up, the mold is opened and the parts are taken out.

When the injection is performed, the injection rod rotates and pushes to complete the injection, the pushing action of the injection rod realizes the pressurization, and the rotary motion of the injection rod corrects the swing of the injection rod, and at the same time, under the action of the reverse thread (thread groove 16) of the injection head Forcibly push the reverse movement of the returned material to prevent the return of the material, and prevent the insufficient injection volume due to the leakage of the rubber material, resulting in quality problems of the workpiece.

The innovation of the structure of the present invention lies in changing the head structure of the injection rod with a smooth (or having a plurality of annular grooves) to a structure with reverse thread grooves; the single linear propulsion motion of the traditional injection rod is added to the rotary motion, and the injection rod implements There is linear propulsion and rotary motion at the same time.

The present invention is fully described for the purpose of clearer disclosure, and the prior art will not be listed one by one.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that it can still be Modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; it is obvious for those skilled in the art to combine multiple technical solutions of the present invention. However, these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (5)

1. A rubber injection molding machine, characterized in that it comprises a frame assembly, a mold clamping oil cylinder (10) is vertically arranged on the frame assembly, and a mold clamping oil cylinder (10) is provided with a mold clamping oil cylinder (10) on the frame assembly. A sliding lower hot plate (9) that rises and falls upward is formed, a fixed upper hot plate (6) is arranged above the sliding lower hot plate (9), and an upper surface is preset on the upper surface of the sliding lower hot plate (9) for connecting with the sliding lower hot plate (9). A mold (1) that is in pressure contact with the lower surface of the upper hot plate (6) is fixed, an injection oil cylinder (3) is arranged on the frame assembly, and a hydraulic motor (2) is arranged to ascend and descend on the injection oil cylinder (3). The hydraulic motor (2) An injection rod (4) is connected to the lower end of the transmission, an injection barrel (5) is arranged on the fixed upper hot plate (6), and the injection rod (4) is in the vertical injection channel (5) of the injection barrel (5). 15) to perform lifting and rotating motions, an injection fixing sleeve (8) is arranged on the fixed upper hot plate (6), the upper end of the injection fixing sleeve (8) is connected to the injection channel (15), and the lower end is provided with a rubber injection sleeve (8). The injection head (7) injects into the cavity of the mould (1). 2. The rubber injection molding machine according to claim 1, characterized in that: a feeder is provided on the frame assembly. 3. The rubber injection molding machine and method according to claim 2, characterized in that: the feeder comprises a feeder barrel (11) set obliquely; the feeder barrel (11) is inclined and the output port at the lower end is The injection channel (15) communicates with the feeding channel (14) for outputting the rubber, A feeding screw (12) is arranged on the feeding channel (14), and a feeding motor (13) for driving the feeding screw (12) to rotate is arranged on the feeding barrel (11). 4. The rubber injection molding machine according to claim 1, characterized in that: the lower part of the injection rod (4) is provided with a thread groove (16) opposite to the direction of rotation. 5. a rubber injection method, is characterized in that: by means of the rubber injection molding machine of claim 1; The method comprises the following steps; Step 1: First, position the mold on the sliding lower hot plate; then, the sliding lower hot plate moves up and down under the push of the clamping cylinder and squeezes with the fixed upper hot plate to close the mold to the set pressure. ;Secondly, the feeding machine works, the rubber material is in a molten state under the extrusion and mixing action of the feeding screw; thirdly, the feeding motor drives the feeding screw to rotate on the feeding barrel, and the rubber material is plasticized through the feeding channel. Extruded into the injection barrel after melting; Step 2, in the injection barrel, the injection oil cylinder drives the hydraulic motor, and the injection rod overcomes its gravity with the pressing of the rubber material, and continuously lifts until it reaches the required height; Step 3: During injection, under the action of the injection cylinder, the injection rod moves downward to squeeze the rubber, and the hydraulic motor drives the injection rod to rotate and pressurize; Step 4: The molten rubber is injected into the mold through the injection head. By controlling the temperature of the mold, the vulcanization and shaping are completed within the set time. After the vulcanization time is up, the mold is opened and the parts are taken out.

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