Forming method

Abstract

In the resin extrusion process, an inexpensive vacuum gauge and PID controller can be used to prevent mold clogging. This will stabilize the dimensions. High-temperature resin 8 coming out of the extruder die 6 passes through a sizing die 3 and is cooled by a cooling device 9. The mold 3 is cooled by the cooling water (piping The extruder 5 is operated by passing the material through a vacuum pipe 202 and creating a vacuum. This will cause the degree of vacuum on the electric vacuum gauge 2 to increase or decrease. If this is not discovered in time, clogging may occur in the sizing mold 3. This can cause problems such as over- or under-weight (dimension) defects. Detects the increase or decrease in void level and automatically increases or decreases the speed of the take-up machine or the rotation speed of the extruder to control the vacuum. The temperature is kept constant, and the state of filling of the polymer in the sizing mold 3 is stabilized.

Description

[Technical Field]

[0001] The present invention relates to a method for molding a resin using extrusion molding. [Background technology]

[0002] Conventionally, in resin extrusion molding, stable operation was performed to prevent mold clogging and dimensional abnormalities. To achieve this, the rotation speed of the extruder and the speed of the take-up machine are adjusted. Check for dimensional abnormalities using a size measuring instrument installed at the exit of a cooling device such as a cooling water tank or cooling spray, An experienced person checks the extrusion by visual inspection before and after the sizing mold, or by touching it with his / her hands inside the cooling device. The rotation speed of the machine and the speed of the take-up machine are adjusted (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-105102 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when the discharge is unstable with foam products, recycled raw materials, crushed scrap raw materials, etc., There was still room for improvement, as mold clogging and dimensional abnormalities could occur.

[0005] The present invention has been made in view of the above circumstances, and provides a composition that can suitably improve mold clogging and dimensional abnormalities. The present invention aims to provide a method for forming a [Means for solving the problem]

[0006] In order to solve the above problems, the molding method of the present invention includes: High temperature resin is extruded from the extruder die, passed through a sizing die, and then into a cooling water tank or cooling screen. In the molding method in which the product is taken up by a take-off machine through a cooling device such as a plate, the degree of vacuum in the sizing mold The increase or decrease in the vacuum level is detected by a vacuum gauge, and the controller controls the vacuum level detected by the vacuum gauge. The speed of the take-up machine is controlled to be increased or decreased so that the degree of vacuum is kept constant. Or, if there is stretching, slippage, or slack and the take-off machine cannot be controlled, the rotation speed of the extruder is It is characterized by the fact that control is performed to decrease or increase the amount of heat.

[0007] The extrusion molding apparatus of the present invention comprises: High temperature resin is extruded from the extruder die, passed through a sizing die, and then into a cooling water tank or cooling screen. In an extrusion molding device that can be taken up by a take-up machine through a cooling device such as a plate, a vacuum gauge that detects the increase or decrease in the degree of vacuum in the die, and a vacuum gauge that detects the degree of vacuum using the vacuum gauge. Control the take-off speed of the take-off machine or the rotation speed of the extruder so that the degree of vacuum is constant. and a controller that controls the operation of the device.

[0008] The controller of the present invention comprises: A vacuum gauge can be connected to the take-up machine or the extruder, and the degree of vacuum detected by the vacuum gauge is Use the vacuum pump to increase or decrease the take-off speed of the take-off machine or the rotation speed of the extruder so that the degree of vacuum is constant. The control output line is either the take-up machine or the extruder depending on the molding conditions. It will be connected to one of them. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a molding method that can suitably improve mold clogging and dimensional abnormalities. Cut. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a block diagram of an extrusion molding process including essential parts for controlling a take-up machine. [Figure 2] FIG. 1 is a block diagram of an extrusion molding process including essential parts for controlling an extruder. [Figure 3] This is a diagram showing the configuration of an extrusion molding process when the take-off machine is controlled by dimensional control using an optical outer diameter measuring device and an edge detector. [Figure 4] This is the scale plate of a deviation indicator used to control the degree of vacuum. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0012] First, the principle of the molding method of the present invention will be described with reference to the extrusion molding apparatus shown in FIG. The high-temperature resin 8 coming out of the mold 6 passes through the sizing mold 3 and is cooled by the cooling device 9. The mold is taken up by machine 4 and becomes product 10. Cooling water (piping not shown) is passed through sizing mold 3, In addition, the system is operated under vacuum through vacuum piping 202.

[0013] When the discharge rate of the extruder 5 increases or decreases, the degree of vacuum of the vacuum gauge (electric vacuum gauge 2) increases or decreases. If the change in weight (dimension) is not detected quickly enough, clogging may occur in the sizing mold 3, or the weight (dimension) may be lost. This invention detects the increase or decrease in the vacuum level and does not require manual adjustment. The speed of the take-off machine is automatically increased or decreased by the control of the controller 1, or the rotation speed of the extruder is automatically increased or decreased. The pressure is increased or decreased to keep the vacuum level constant and stabilize the filling state of the polymer in the sizing mold 3. do.

[0014] When the discharge rate of the extruder 5 increases, the degree of vacuum in the sizing die 3 increases. If the take-up speed of the machine 4 is increased slightly, the discharge rate will return to the original value (normal value). When the vacuum level is increased, the vacuum level decreases (shifts to the atmospheric pressure side). When the speed is reduced slightly, the vacuum level increases and tries to return to the original value (normal value). The extrusion speed is continuously controlled in units of 1 / 1000 (0.001 m / min) so that the reading of 2 becomes zero. The vacuum level can be kept constant without changing the rotation speed of the machine.

[0015] The vacuum level in the sizing mold 3 can be measured by an electric vacuum gauge 2, and the controller 1 The deviation calculated by the zero adjustment volume 103 on the surface and the internal circuit is The vacuum deviation indicator 102 on the front is displayed. This deviation is input to the internal PID calculator. A take-up speed correction signal (DC voltage 0 to 10V) is output to the control signal line 108, and the deviation approaches zero. It acts as it should.

[0016] When the cooling and solidification is incomplete when it leaves the sizing mold 3 (hereinafter referred to as "Case 1"), or In the case of a molded product where it is originally better to narrow the air gap 7 (hereinafter referred to as "Case 2"), In this way, it is advisable to control the discharge rate by adjusting the rotation speed of the extruder 5. In case 1, elongation occurs, so This is because there is a delay in the feedback, which causes hunting and cuts off. This is because the results of the adjustment are immediately fed back to the vacuum level, allowing for good control. Depending on the shape conditions, either the speed control of the take-up machine 4 or the rotation speed control of the extruder 5 is selected. .

[0017] Here, as a conventional technique, an edge detector 20 (projection detector) is provided in front of the sizing mold 3 as shown in FIG. The speed of the take-up machine 4 is controlled by placing a light source 211 and a light receiver 212, an outer diameter measuring instrument (not shown), etc. Continuous automatic fine-tuning is becoming increasingly popular.

[0018] However, the area between the extruder die 6 and the sizing die 3 (air gap 7) is a high-temperature environment. In addition, since there is gas from the molten resin 8, measuring the discharge fluctuation (dimensional fluctuation) requires expensive special equipment. Also, depending on the molded product, the air gap 7 may be narrow, and the temperature may be between 0 (close contact) and 1 The measurement was sometimes as low as 0 mm, and it was often impossible to set up the detector, making automation difficult.

[0019] In contrast to this, the molding method of the present invention is a method of extruding high-temperature resin from the extruder die 6 to form a sized resin. In the molding method, the material is passed through a molding die 3, and then through a cooling device 9 and taken up by a take-up machine 4. The increase or decrease in the vacuum level in the molding die 3 is detected by an electric vacuum gauge 2. The controller 1 controls the vacuum level to keep it constant (the deviation is zero). In the case of extruder control (FIG. 2), the take-up speed of the take-up machine 4 is increased or decreased, or the take-up speed of the extruder 5 is increased or decreased. This reduces clogging in the sizing die 3, This allows for stabilization of dimensions and quality, and also contributes to labor, resource and energy savings.

[0020] In addition, it is also possible to use an outer diameter measuring instrument (not shown in the drawing) or an edge detector 20 to detect irregular shapes and In the molding process with a narrow air gap where the container cannot be set, there is a lot of gas generation and an optical detector cannot be used. Even in extrusion molding processes where vacuum is not possible, the electric vacuum gauge 2 can be applied in most cases.

[0021] In addition, the electric vacuum gauge 2 is extremely inexpensive compared to the outer diameter measuring instrument and edge detector 20, and is environmentally resistant. It is also good, so it can be assembled as a control system at low cost.

[0022] In addition, optical detectors require experienced personnel to set up each time an extrusion molding line is started up. Once the electric vacuum gauge 2 is screwed onto the vacuum pipe, no adjustment is required at each start-up. is.

[0023] Next, an embodiment will be described with reference to the extrusion molding apparatus illustrated in Figures 1 and 2. 2, the air gap 7 is narrow and the destination of the control signal line 108 is the extruder 5. The only difference is the points.

[0024] First, the description will be made with reference to FIG. 1. The extrusion molding device includes a controller 1 and an electric vacuum gauge 2. The extruder includes a sizing die 3, a take-up machine 4, an extruder 5, and an extruder die 6. The air gap 7 between the extruder die 6 and the sizing die 3 is opened. The molten resin 8 passes through a cooling device 9, which is configured using a cooling water tank, a cooling spray, or the like, to form a product. This is item 10.

[0025] The controller 1 is configured using an electronic circuit that combines, for example, a PID calculation circuit. It can also be configured using a computer-based arithmetic device. The controller 1 includes a speed setting voltmeter 101, a vacuum deviation indicator 102, a zero adjustment volume 103, a speed Degree (rotation speed) setting volume 104, power switch 105, manual / automatic changeover switch 10 6, equipped with a buzzer 107, and connected to the take-up machine 4 by a control signal line 108. The hauling machine 4 can be configured to include a caterpillar 401. The rotation speed of O1 can be controlled to adjust the take-up speed.

[0026] The electric vacuum gauge 2 is connected to a vacuum pipe 202 leading to the sizing mold 3, and a detector signal line It can be configured by connecting it to the controller 1 via 203.

[0027] At the start of extrusion molding, the controller 1 manually operates the "manual / automatic changeover switch 106." The vacuum level is set to a predetermined value beforehand. The extruder rotation speed is also set to a predetermined value.

[0028] When the flow of the molded product is almost stabilized, adjust the indication (pointer position) of the vacuum deviation indicator 102 by adjusting the zero adjustment button. Then, set the manual / automatic changeover switch 106 to automatic. After that, the pointer of the vacuum deviation indicator 102 moves by the PID calculation circuit inside the controller 1. The speed of the take-up machine 4 is finely adjusted so that it always points to zero. In this embodiment, the take-up machine speed is 1.00 m / At 1000 rpm, the fluctuation of the vacuum level was within ±0.20 kPa. Of course, this fluctuation is due to the fluctuation of the discharge amount. The scale of the vacuum deviation indicator 102 shown in FIG. It is possible to control the value to within one division of this minimum scale. The resolution of the take-up machine speed adjustment was 0.001 m / min, allowing for highly precise control.

[0029] The present invention is not limited to the above-described embodiment, and may be modified within the scope of the present invention. It is easy to imagine that various improvements and modifications are possible within the scope of the invention, and it is possible to implement modifications and modifications. Good too. [Industrial Applicability]

[0030] The molding method of the present invention reduces defective products and scraps in extrusion molding, saves labor, saves resources, This can provide an effective solution in terms of energy conservation. [Explanation of symbols]

[0031] 1 Controller 2. Electric vacuum gauge (vacuum gauge) 3 Sizing mold 4. Pick-up machine 5. Extruder 6 Extruder mold 9 Cooling device

Claims

[Claim 1] High temperature resin is extruded from the extruder die, passed through a sizing die, and then into a cooling water tank or cooling screen. In the molding method in which the product is taken up by a take-off machine through a cooling device such as a plate, the degree of vacuum in the sizing mold The increase or decrease in the vacuum level is detected by a vacuum gauge, and the controller controls the vacuum level detected by the vacuum gauge. Increase or decrease the take-off speed of the take-off machine or the rotation speed of the extruder so that the degree of vacuum is constant. A molding method characterized in that control is performed to increase the

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