Analysis assistance device for resin melting state

Abstract

This invention provides an auxiliary device for analyzing the molten state of resin, enabling high-precision visualization of the resin's state within a heating cylinder. The conditions for the resin molten state analysis test are set via a setting screen (36) that displays the measurement conditions. The resin molten state analysis test begins when extrusion molding is switched from OFF to ON. When the extrusion start position is set, the screw only rotates at that position. The screw does not move axially.

Description

Technical Field

[0001] This invention relates to an auxiliary device for assisting in the analysis of the molten state of resin within the heating cylinder of an injection apparatus. Background Technology

[0002] [Definition of Injection Device] The injection unit is part of the injection molding unit.

[0003] The injection molding apparatus consists of a base, an injection unit placed on the base, and a mold closing device. The mold closing device closes the mold.

[0004] The injection unit has a heating cylinder and a screw. The resin material (hereinafter referred to as resin) fed from the drop-out port at the rear of the heating cylinder is plasticized, and the molten resin is injected into the mold by the forward movement of the screw.

[0005] Resin at room temperature is plasticized into a molten state through a heating cylinder. This plasticized state strongly affects the quality of the molded product. Therefore, analyzing the molten state of the resin within the heating cylinder becomes important.

[0006] However, the heating cylinder is made of steel, making it impossible to visually observe the dynamics of the resin from the outside. Therefore, various visualization techniques have been proposed as alternatives to visual observation (e.g., see Patent Document 1). Figure 2 )).

[0007] Patent Document 1 describes a technique for installing an AE sensor at the rear of a heating cylinder (Patent Document 1, paragraph 0032) and detecting the plasticizing quality of the resin based on the sound signal (AE signal) from the AE sensor (Patent Document 1, paragraph 0033). AE is short for acoustic emission.

[0008] The technology in Patent Document 1 has the following problems.

[0009] First, in Patent Document 1, only one AE sensor is installed in the heating cylinder. If the resin is near the AE sensor, the plasticizing state can be monitored, but it is difficult to monitor the plasticizing state of parts far from the AE sensor.

[0010] Furthermore, in Patent Document 1, the screw built into the heating cylinder moves axially from the metering start position to the metering completion position during plasticizing metering. This movement causes AE wave disturbance and reduces visualization accuracy.

[0011] As injection molding technology becomes more sophisticated, there is a need for analytical auxiliary devices that can monitor the state of the resin inside the heating cylinder over a wide range and provide high-precision visualization of the resin's molten state.

[0012] Existing technical documents Patent documents Patent Document 1: Japanese Patent No. 5388996 Summary of the Invention

[0013] The problem that the invention aims to solve The objective of this invention is to provide an analytical auxiliary device that can monitor the state of resin within a heating cylinder over a wide range and achieve high-precision visualization of the resin's melting state.

[0014] Methods for solving problems The invention of technical solution 1 is an analytical auxiliary device for measuring the molten state of resin, which is installed in an injection device and used when measuring the molten state of resin. The injection device includes: a heating cylinder; a screw that is rotatable and axially movable and housed in the heating cylinder; a screw rotation mechanism for rotating the screw; and a screw movement mechanism for advancing the screw. The analytical auxiliary device for measuring the molten state of resin includes: a setting screen for setting measurement conditions; multiple AE sensors arranged along the axis of the screw in the heating cylinder for detecting AE waves emitted by the resin; and a processing unit for processing the AE waves detected by the AE sensors. The setting screen for setting the measurement conditions includes setting items consisting of an extrusion metering speed corresponding to the rotational speed of the screw, an extrusion metering time corresponding to the time the screw rotates, an extrusion standby time corresponding to the time the screw stops, and an extrusion start position corresponding to the position of the front end of the screw at the start of the measurement. When the extrusion start position is set, the screw does not move in the axial direction but rotates at the extrusion start position.

[0015] Invention Effects In the invention of technical solution 1, multiple AE sensors are arranged along the axis of the screw in the heating cylinder. Since there are multiple AE sensors, the state of the resin inside the heating cylinder can be monitored over a wide range.

[0016] Furthermore, when setting the extrusion start position in the setting screen for setting measurement conditions, the screw rotates at that position without moving axially. Because it does not move axially, the AE wave is sufficiently stable.

[0017] Therefore, according to the present invention, an analytical auxiliary device is provided that can monitor the state of the resin in the heating cylinder over a wide range and can visualize the resin melting state with high precision. Attached Figure Description

[0018] Figure 1 This is a diagram showing the basic structure of the injection device and the analytical auxiliary device for the resin molten state of the present invention.

[0019] Figure 2 This is a diagram illustrating the setup screen of the main component of the analysis aid device.

[0020] Figure 3 (a) is the first chart. Figure 3 (b) is the second chart. Figure 3 (c) is the third chart. Figure 3 (d) is the fourth chart.

[0021] Figure 4 (a) is the fifth chart. Figure 4 (b) is the sixth chart. Figure 4 (c) is the seventh chart.

[0022] Figure 5 This is a flowchart illustrating the steps involved in creating the first and second charts.

[0023] Figure 6 This is a flowchart illustrating the steps involved in creating charts three through seven.

[0024] Figure 7 (a) and (b) are graphs illustrating that the technology of the present invention satisfies position dependence and rotational speed dependence.

[0025] Figure 8 This is a diagram illustrating the advantages of the diagnostic chart of the present invention. Detailed Implementation

[0026] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0027] [Injection device] like Figure 1 As shown, the injection device 10 is a device with the following basic components: a heating cylinder 14 having a resin inlet 11 and a nozzle 12 for injecting plasticized resin and a heater 13 wound around its outer periphery; a screw 15 that is rotatable and axially movable and housed in the heating cylinder 14; a screw rotation mechanism 16 that rotates the screw 15; a screw moving mechanism 17 that moves the screw 15 forward; and an operation panel 18.

[0028] [Control Panel] The control panel 18 controls the temperature of the heating cylinder 14, the rotation speed of the screw rotation mechanism 16, and the movement of the screw moving mechanism 17.

[0029] Therefore, the operation panel 18 has a display 19 that can perform various settings and a built-in control unit.

[0030] In addition, approximately four heaters 13 are wound around the outer periphery of the heating cylinder 14. The power supply to each heater 13 is controlled by the zone control unit 21 to ensure that the temperature information from the temperature sensor 22 matches the set temperature.

[0031] [The function of the control panel] Resin falls from the outlet 11 into the heating cylinder 14. The falling resin is guided towards the nozzle 12 by the spiral of the screw 15. During this movement, the resin changes from a solid to a molten state due to the heat of the heating cylinder 14 and the shear heat of the screw 15.

[0032] Molten resin accumulates near nozzle 12. The screw 15 retracts due to the reaction force of the accumulated resin. If the retraction distance reaches a predetermined value, plasticizing is complete. The product of the retraction distance and the inner cross-section of the heating cylinder 14 becomes the metering value (plasticizing metering process).

[0033] After metering, the screw 15 is advanced to inject plasticized resin into the mold (injection process).

[0034] The operation panel 18 performs the above series of procedures.

[0035] [Analysis aid for resin molten state] An auxiliary device 30 for analyzing the molten state of resin is attached to such an injection device 10.

[0036] The resin melting state analysis auxiliary device 30 serves to assist in the analysis of the resin melting state.

[0037] The resin melting state analysis auxiliary device 30 consists of the following parts: a plurality of waveguide rods 31, which are spaced apart along the axis of the screw 15 in the heating cylinder 14; an AE sensor 32, which is provided at the ends of these waveguide rods 31 (the ends away from the heating cylinder 14) to detect AE waves emitted by the resin; a calculation unit 33, which performs prescribed processing on the AE waveform detected by the AE sensor 32; a display unit 34, which displays the processed AE waveform in the form of graphs or the like; and a condition input unit 35, which can input various conditions to the calculation unit 33.

[0038] Furthermore, the arithmetic unit 33, display unit 34, and condition input unit 35 are preferably a so-called personal computer. Alternatively, the arithmetic unit 33, display unit 34, and condition input unit 35 may be the operation panel 18 of the injection device 10 or a mobile terminal utilizing the cloud.

[0039] If it is a personal computer, it has the advantage of being able to freely build software independently of the control panel 18.

[0040] Additionally, if it is the operation panel 18, software modifications are required, but it has the advantage of not requiring a personal computer or portable terminal.

[0041] In addition, portable terminals have limited processing power, so they need to utilize external cloud services, but they have the advantage of being able to freely build software independent of the control panel 18.

[0042] [The prescribed processing performed by the computation department] The arithmetic unit 33 obtains the resin-containing amplitude based on the AE wave detected when the injection device 10 is running with resin in the presence of resin, and the resin-free amplitude based on the AE wave detected when the injection device 10 is running without resin in the presence of resin. Then, it performs a process of deleting portions where the resin-containing amplitude and the resin-free amplitude are the same, and then performs a process of deleting the audible range.

[0043] [Condition Input Section] Figure 2 This shows a preferred example of the condition input unit 35.

[0044] like Figure 2 As shown, the condition input unit 35 is a setting screen 36 for setting measurement conditions, used for setting extrusion test conditions. That is, during the extrusion test, the setting screen 36 for setting measurement conditions takes precedence over the operation panel (…). Figure 1 The setting value set by symbol 18).

[0045] In the setting screen 36 for setting the measurement conditions, there are several commands available, which can be used to make the following settings.

[0046] [Order] Extrusion Molding: When OFF is clicked, the display switches to ON and the extrusion test begins.

[0047] Extrusion metering speed: The screw speed (rpm) can be set by inputting a value such as 150. rpm refers to the rotational speed per minute.

[0048] Extrusion metering position: The plasticizing metering position can be set.

[0049] Extrusion metering time: Sets the time for the screw to rotate. This, combined with the extrusion standby time (described later), constitutes one cycle time.

[0050] Extrusion metering times: The number of tests can be set.

[0051] Remaining: Displays the remaining number of extrusion cycles in the test. 0 indicates the end of the test.

[0052] Extrusion standby time: Sets the time during which the screw rotation is stopped.

[0053] Maximum back pressure usage: capable of passing Figure 1 The screw moving mechanism 17 shown applies pressure (back pressure) to the molten resin. The maximum back pressure is determined by the mechanical capacity of the screw moving mechanism 17. If the maximum back pressure is to be used, then the maximum back pressure is selected.

[0054] Extrusion start position: explained later.

[0055] Heating cylinder: For example, the set temperature of zones 1 to 4 can be set individually. Furthermore, these settings can also be accessed via... Figure 1 The settings are made on the operation panel 18 and removed from the setting screen 36 for setting measurement conditions. By removing it, the setting screen 36 for setting measurement conditions can be simplified.

[0056] [Reasons for using the term "squeezed out"] The inventors conducted repeated experiments, and the results showed that... Figure 1 When the screw 15 is rotated while simultaneously moving axially, the AE signal becomes disordered, raising questions about the reliability of the analysis. However, it can be confirmed that if the screw 15 is rotated without axial movement, the AE signal stabilizes, and the reliability of the analysis improves.

[0057] Therefore, in the tests of this invention, the screw 15 only rotates. Since it only rotates, it is close to the extrusion device. Therefore, although it is an injection device 10, the term extrusion is used in the tests.

[0058] Extrusion start position: Set the position of the front end of the screw. The screw rotates at this position. During the test, the screw is not allowed to move axially.

[0059] [Various charts] pass Figure 1 The injection device 10 and the resin melting state analysis auxiliary device 30 shown are used to conduct experiments, and the data is processed by the calculation unit 33 to generate various charts.

[0060] based on Figure 3 (a)~(d) and Figure 4 (a) to (c) describe the forms of the various charts produced.

[0061] [First Chart] The test was conducted without resin. Through this test, as... Figure 3 As shown in (a), a first graph was created with frequency on the horizontal axis and amplitude on the vertical axis, for example, CH4. This first graph is equivalent to a graph representing the so-called raw data.

[0062] [Second Chart] The resin was added and a test was conducted. Through this test, such as... Figure 3 As shown in (b), a second graph is created with frequency on the horizontal axis and amplitude on the vertical axis, for example, CH4. This second graph is also equivalent to a graph representing the original data.

[0063] [Third Chart] By removing the consistent amplitudes in the first and second charts, it is possible to create Figure 3 The third chart shown in (c)

[0064] By removing the consistent amplitudes in the first and second charts, it is possible to delete... Figure 3 The inherent noise in (b) has the advantage of further improving the reliability of the analysis.

[0065] [Fourth Chart] If you follow Figure 3 In (b), the peak amplitude is larger in the high-frequency domain of the second graph and smaller in the low-frequency domain. The boundary between the two is defined as point A. The inventors have found that point A coincides with the boundary between the audible and inaudible domains.

[0066] Therefore, the inventors removed the audible region with a small peak value. This removal allows for a stronger tendency to appear. Furthermore, it offers the advantage of halving the subsequent data processing volume.

[0067] Therefore, by removing the audible domain from the third chart, a [structure / structure] was created. Figure 3 The fourth chart is shown in (d).

[0068] [Fifth Chart] Figure 3 (d) Only the number of trials (e.g., 5) is produced. That is, the fourth chart consists of 5 sheets. The arithmetic mean of the 5 amplitudes for each CH is used to produce the results. Figure 4 The fifth chart is shown in (a).

[0069] This arithmetic averaging method can reduce data bias.

[0070] [Sixth Chart] Next, regarding Figure 4 The amplitudes shown in (a) are accumulated. Specifically, only the nine bars are summed.

[0071] Although the scale is omitted, compared to Figure 4 The vertical axis of (a), Figure 4 The vertical axis of (b) corresponds to a large amplitude.

[0072] Indicates to Figure 4 (b) shows the cumulative amplitude of CH4 on the horizontal axis. For convenience, the height of this amplitude is set as point B.

[0073] The above explains CH4.

[0074] For the remaining CH1~3 and CH5~6, implement Figure 3 (a)~(d) and Figure 4 The processing in (a) and (b) adds the accumulated amplitude in each CH to Figure 4 (b) thus completes the sixth chart.

[0075] [Seventh Chart] By modifying the completed sixth chart (bar chart) into a line chart, it is possible to create... Figure 4 The seventh chart shown in (c) is equivalent to a "diagnostic chart".

[0076] use Figure 5 and Figure 6 The flowchart shown illustrates the steps for creating the first to seventh charts mentioned above, arranged in chronological order.

[0077] exist Figure 5 The conditions are set in step number (hereinafter referred to as ST)01. That is, in Figure 2 Set the various conditions in the setting screen 36 for the measurement conditions.

[0078] In ST02, set flag F to 1.

[0079] In ST03, operation begins without the addition of resin. Figure 2 In the setting screen 36 for setting measurement conditions, set the extrusion molding command to ON.

[0080] In ST04, the AE of CHn (e.g., CH1~CH6) is measured and Fourier transform processing is performed. Then, the first graph is generated (ST05).

[0081] In ST06, resin is added and the system begins to operate.

[0082] In ST07, the AE of CHn is measured and Fourier transform processing is performed. Then, a second graph (ST08) is created.

[0083] Alternatively, ST03~ST05 and ST06~ST08 can be swapped.

[0084] exist Figure 6 In ST10, delete the parts that are consistent in the first and second charts, and create the third chart (ST11).

[0085] In the third chart, the audible domain is removed to create the fourth chart (ST13).

[0086] In ST14, investigate whether the extrusion metering number N has been reached by the indicator F. If not, increment the indicator F by 1 (ST15).

[0087] In ST14, if the result is "yes", then the N quantities are averaged (ST16) and a fifth chart is created (ST17).

[0088] In ST18, the amplitude of the fifth chart is accumulated to calculate the amplitude of any CH (ST19). This process is repeated from CH1 to CHn (ST20) to create the seventh chart (ST21).

[0089] [Example] To verify the position dependence, rotational speed dependence, and temperature dependence of the present invention, experiments were conducted under the following conditions.

[0090] [Experimental Conditions] • Injection device: NEX5EG manufactured by Nippon Resin Kogyo Co., Ltd. Screw outer diameter: 20mm • Screw type: Full-plane • Extrusion metering speed: 100 or 300 rpm • Extrusion metering time: 5.20 seconds • Extrusion standby time: 2.80 seconds • Number of extrusion metering cycles: 5 Maximum back pressure: 56MPa • Maximum back pressure operation: ON • Extrusion start position: 0mm Heating chamber: All four zones are 180℃ or 200℃. • Number of AE sensors: 6 (CH1~CH6) • Data processing: In the computing department, based on Figure 5 as well as Figure 6 The process involves creating the seventh chart.

[0091] [Experimental Results] The results of the experiment were obtained Figure 7 (a) shows broken lines C and D, and Figure 7 The broken lines E and F are shown in (b).

[0092] [Location Dependence of the Invention] according to Figure 7 The broken lines C and D shown in (a) have large amplitudes in CH6 when the resin is solid, smaller amplitudes in CH5 when the resin is slightly plasticized, smaller amplitudes in CH4 when plasticized, smaller amplitudes in CH3 when plasticized further, smaller amplitudes in CH2 when plasticized further, and smaller amplitudes in CH1 when plasticized further.

[0093] A correlation was established between the plasticization state and the position of CH6~CH1. Therefore, according to the present invention, the position dependence becomes good.

[0094] [Speed ​​Dependence of the Invention] exist Figure 7 In (a), the screw speed of line C is 300 rpm, and the screw speed of line D is 100 rpm. All other conditions are the same.

[0095] The amplitude of the impact sound caused by the resin increases with increasing screw speed and decreases with decreasing screw speed.

[0096] according to Figure 7 In (a), the line segment C with higher rotational speeds is larger than the line segment D with lower rotational speeds. That is, the amplitude is smaller at 100 rpm and larger at 300 rpm. According to the present invention, a good speed dependence has been confirmed.

[0097] [Temperature Dependence of the Invention] exist Figure 7 In (b), the temperature of the heating cylinder along line E is 180℃, and the temperature of the heating cylinder along line F is 200℃. All other conditions are the same.

[0098] It can be predicted that the lower the temperature of the resin, the greater the amplitude of the impact sound caused by the resin, and the higher the temperature of the resin, the smaller the amplitude of the impact sound caused by the resin.

[0099] according to Figure 7 (b) is set to a large line E at 180°C and a small line F at 200°C. Therefore, good temperature dependence can be confirmed according to the present invention.

[0100] [Benefits of the Diagnostic Charts of the Invention] The diagnostic charts obtained in this invention can be used in any way, but the following description is one example.

[0101] Figure 8 Is Figure 4 The diagnosis of (c) is illustrated by adding an imaginary straight line to the graph and adding point G.

[0102] like Figure 8 As shown, by lowering point B to point G, it can be assumed that the broken line becomes a more preferred form.

[0103] To address this assumption, consider the following countermeasures.

[0104] Solution a: Reduce the screw speed. The overall trend line decreases, but the broken line may become the preferred shape.

[0105] Solution b: Increase the overall set temperature of the heating cylinder. The overall trend line decreases, but the trend line may become the preferred shape.

[0106] Countermeasure c: Increase the set temperature only in the region containing CH4. A broken line may be a better configuration.

[0107] Previously, operators would observe the condition of the molded product. If the product was not a good (qualified) product, they would adjust the heating temperature or screw speed settings based on their experience and insights. This process would be repeated until a good product was obtained.

[0108] When adding such as Figure 8 When using the diagnostic charts shown, it is expected that these charts will provide operators with prompts for setting changes, reducing the number of repetitions until a satisfactory product is obtained.

[0109] Therefore, it can be said that the diagnostic charts of the present invention are highly beneficial.

[0110] The present invention described above can be summarized as follows.

[0111] like Figure 1 As shown, this is an analytical auxiliary device 30 for determining the molten state of resin, installed in the injection apparatus 10. The injection apparatus 10 includes: a heating cylinder 14; a screw 15 rotatably and axially movable and housed in the heating cylinder 14; a screw rotation mechanism 16 for rotating the screw 15; and a screw movement mechanism 17 for advancing the screw 15. The analytical auxiliary device 30 for the resin molten state has the following features: Settings such as Figure 2 The setting screen for the measurement conditions shown is 36; AE sensor 32, such as Figure 1 As shown, multiple detectors are arranged along the axis of the screw 15 on the heating cylinder 14 to detect the AE waves emitted by the resin; and The arithmetic unit 33 processes the AE wave detected by the AE sensor 32. exist Figure 2 The setting screen 36 shown, which sets the measurement conditions, includes setting items such as the extrusion metering speed corresponding to the rotational speed of the screw 15, the extrusion metering time corresponding to the time the screw 15 rotates, the extrusion standby time corresponding to the time the screw 15 stops, and the extrusion start position corresponding to the position of the front end of the screw 15 at the start of the measurement. When the extrusion start position is set, the screw 15 does not move axially, but rotates at the extrusion start position.

[0112] Multiple AE sensors 32 are arranged along the axis of the screw 15 in the heating cylinder 14. Because there are multiple AE sensors 32, the state of the resin in the heating cylinder 14 can be monitored over a wide range.

[0113] Furthermore, if the extrusion start position is set in the setting screen for setting measurement conditions, the screw 15 rotates at that position without moving axially. Because it does not move axially, the AE wave is sufficiently stable.

[0114] Preferably, such as Figure 2As shown, the setting also includes the use of maximum back pressure. When the use of maximum back pressure is selected, the measurement is performed by the maximum back pressure of the injection device 10.

[0115] When pressure (back pressure) is applied to molten resin, gas is expelled from the resin, and the resin becomes denser. This venting and densification can lead to improved quality of the molded product.

[0116] If tests are conducted at three different back pressures: maximum back pressure, 60% of maximum back pressure, and 30% of maximum back pressure, the number of tests increases, and so does the cost. As a countermeasure, when tests are conducted at 50% of maximum back pressure, the cost decreases, but the reliability of the analysis decreases because the tests at maximum back pressure are omitted.

[0117] In this invention, the test is conducted under the maximum back pressure, which is considered the most stringent condition. As a result, the cost of the test is reduced, and the reliability of the analysis is improved. In other words, this invention can be said to be excellent in terms of cost-effectiveness.

[0118] in addition, Figure 1 The number of AE sensors 32 shown is set to 6 in this embodiment, but it can be increased or decreased. However, even if the number is reduced, it should be more than two.

[0119] [Industrial Applicability] The resin melting state analysis auxiliary device of the present invention is applicable to injection devices.

[0120] Explanation of reference numerals in the attached figures 10…Injection device 14… Heating cylinder 15… Screw 16…Screw Rotation Mechanism 17…Screw moving mechanism 30…Analytical auxiliary device for resin molten state 32…AE sensor 33…Computation Department 36…Setting screen for setting measurement conditions

Claims

1. An auxiliary device for analyzing the molten state of resin, which is installed in an injection device and used to determine the molten state of the resin. The injection device includes: a heating cylinder; a screw rotatable and axially movable and housed within the heating cylinder; a screw rotation mechanism for rotating the screw; and a screw movement mechanism for advancing the screw. The auxiliary device for analyzing the molten state of the resin includes: Set the screen and measurement conditions; AE sensors, multiple of which are arranged along the axis of the screw in the heating cylinder, detect AE waves emitted by the resin; and The processing unit processes the AE wave detected by the AE sensor. The setting screen for setting the measurement conditions includes setting items consisting of an extrusion metering speed equivalent to the screw rotation speed, an extrusion metering time equivalent to the time the screw rotates, an extrusion standby time equivalent to the time the screw stops, and an extrusion start position equivalent to the position of the screw tip at the start of the measurement. When the extrusion start position is set, the screw does not move axially, but rotates at the extrusion start position.

2. The auxiliary device for analyzing the molten state of resin according to claim 1, characterized in that, The settings also include using the maximum back pressure, when the maximum back pressure is selected, the measurement is performed using the maximum back pressure of the injection device.

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