Resin replacement assisting method and apparatus for molding machine

Abstract

This invention provides a resin replacement auxiliary method and apparatus for a molding machine. For each different resin R…, the zero-shear viscosity ηo… of each resin is calculated and registered using a transformation function with MFR (melt flow rate) and the set temperature of the heating cylinder (2) as parameters. The required amount of cleaning resin Wu… corresponding to the viscosity difference ηd… between the zero-shear viscosity ηof… of the previous resin Rf… and the zero-shear viscosity ηos… of the subsequent resin Rs… is also registered. When replacing the resin, the MFR of the previous resin Rf and the MFR of the subsequent resin Rs are input into the molding machine controller 3, thereby obtaining the zero-shear viscosity ηof of the previous resin Rf and the zero-shear viscosity ηos of the subsequent resin Rs, and obtaining the viscosity difference ηd between the zero-shear viscosity ηof of the previous resin Rf and the zero-shear viscosity ηos of the subsequent resin Rs. The required amount of cleaning resin Wu for resin replacement is then calculated, and at least a display process is performed.

Description

Technical Field

[0001] This invention relates to a resin replacement auxiliary method and apparatus for a molding machine when resin replacement is performed by supplying subsequent resin after the pre-resin is discharged from the heating cylinder. Background Technology

[0002] Typically, in injection molding machines, when continuously producing molded products of different resin types or colors, it is necessary to replace the resin used in the previous production with the resin used in the next production. Therefore, after the previous production is completed, a resin replacement process is performed to change the resin. In the resin replacement process, after the residual resin (pre-resin) in the heating cylinder is discharged, the resin for the next production is supplied. Therefore, it is required that no residual components of the pre-resin are mixed in at the start of the next production.

[0003] Previously, as a related technology to assist such resin replacement processes, the resin replacement assistance method (auxiliary device) for a molding machine described in Patent Document 1 previously filed by the applicant is known. The purpose of the resin replacement assistance method for a molding machine described in Patent Document 1 is to help reduce material costs and shorten resin replacement time by enabling the operator to accurately (correctly) understand the necessity of intermediate materials, thereby helping to suppress the generation of useless defective products. Specifically, when supplying subsequent resin for resin replacement after the preceding resin is discharged from the heating cylinder, for each type of resin, the apparent viscosity related to the specified physical quantity of the action in the molding machine is calculated in advance, the calculated apparent viscosity is set in a database, and during resin replacement in the molding machine, the molding machine controller is used to calculate the viscosity difference index related to the viscosity difference (the viscosity difference is obtained by subtracting the apparent viscosity of the preceding resin from the apparent viscosity of the subsequent resin to be replaced in the database), and by determining whether the calculated viscosity difference index is positive or negative, at least in the case of a negative determination, a determination result indicating that intermediate materials are needed is output.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Publication No. 2017-222144 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] However, the existing resin replacement technologies still have the following issues that need to be addressed.

[0009] In other words, the user's molding machine needs to be temporarily used as a testing machine to test each resin and determine its apparent viscosity as a relative viscosity. This results in production disruptions, such as the molding machine becoming unusable during testing. Furthermore, even if the specific calculations can be performed by software built into the molding machine controller, the testing operation itself requires resin to operate the molding machine, and the user (operator) also needs to conduct testing operations on-site according to the resin replacement process. Therefore, the testing operations also consume considerable labor and time.

[0010] As a result, existing methods that involve on-site testing may not be ideal for inexperienced beginners, leading to decreased productivity and increased production costs. Furthermore, there is a risk that deviations in the testing process may prevent the stability and reliability of the auxiliary methods from being fully guaranteed.

[0011] The purpose of this invention is to provide a resin replacement auxiliary method and apparatus for molding machines that solves the problems existing in the prior art.

[0012] Methods for solving problems

[0013] To address the aforementioned issues, the resin replacement auxiliary method for the molding machine of the present invention is characterized in that, when supplying a subsequent resin Rs for resin replacement after the preceding resin Rf is discharged from the heating cylinder 2, the zero-shear viscosity ηo... of each different resin R... is pre-estimated using a transformation function with melt flow rate (MFR) and the set temperature of the heating cylinder 2 as parameters, and registered as a first database DB1 in the molding machine controller 3. Furthermore, the viscosity difference ηd... corresponding to the zero-shear viscosity ηof... of the preceding resin Rf... and the zero-shear viscosity ηos... of the subsequent resin Rs... is cleaned. The required amount of (purge) resin, Wu…, is registered in the molding machine controller 3 as a second database, DB2. When replacing resin, the MFR of the front resin Rf and the MFR of the rear resin Rs are input into the molding machine controller 3. The zero-shear viscosity ηof of the front resin Rf and the zero-shear viscosity ηos of the rear resin Rs are obtained from the first database, DB1, and the viscosity difference ηd between the zero-shear viscosity ηof of the front resin Rf and the zero-shear viscosity ηos of the rear resin Rs is obtained. The required amount of cleaning resin, Wu, during resin replacement is calculated from the second database, DB2, and thus at least a display process is performed.

[0014] Furthermore, to solve the aforementioned problems, the resin replacement auxiliary device 1 of the molding machine of the present invention is characterized in that, when configured as an auxiliary device for resin replacement by discharging the preceding resin Rf from the heating cylinder 2 and supplying the following resin Rs, the auxiliary device 1 includes a molding machine controller 3, which has: a first database DB1, which registers the zero-shear viscosity ηo... of each resin R... estimated by a transformation function using MFR and the set temperature of the heating cylinder 2 as parameters; and a second database DB2, which registers the zero-shear viscosity ηof... corresponding to the zero-shear viscosity of the preceding resin Rf... and the zero-shear viscosity of the following resin Rs... The viscosity difference ηd... is the required amount of cleaning resin Wu...; the MFR input function Fi inputs the MFR of the front resin Rf and the MFR of the rear resin Rs; the viscosity difference calculation function Fs calculates the viscosity difference ηd between the zero-shear viscosity ηof of the front resin Rf and the zero-shear viscosity ηos of the rear resin Rs from the first database DB1 based on the input MFR; the required amount calculation function Fw calculates the required amount of cleaning resin Wu when replacing the resin from the second database DB2 based on the obtained viscosity difference ηd; and the display processing function Fo displays the calculated required amount of cleaning resin Wu.

[0015] On the other hand, according to the preferred embodiment of the invention, the post-resin Rs may contain an intermediate material Rms. Furthermore, regarding the setting temperature of the heating cylinder 2, when the heating cylinder 2 is divided axially into three regions—front 2f, middle 2m, and rear 2r—it is preferable to designate the area before front 2f as the high-temperature side region ZAu, and the area after middle 2m as the low-temperature side region ZAd, and set the temperature difference between the high-temperature side region ZAu and the low-temperature side region ZAd to a range of 0-50°C. In addition, the resin R… may contain general-purpose resins, engineering plastics, super engineering plastics, composite materials, cleaning agents, and special resins other than cleaning agents. Furthermore, in the auxiliary device 1, the viscosity difference calculation function unit Fs can output a message indicating the need for cleaning agent when the zero-shear viscosity ηos of the post-resin Rs is lower than the zero-shear viscosity ηof of the pre-resin Rf, and the display processing function unit Fo can set a cleaning agent recommendation display unit 4p on the display screen 4 to display the need for cleaning agent. It should be noted that, as a molding machine, an injection molding machine M is preferably suitable.

[0016] The effects of the invention

[0017] The resin replacement auxiliary method and apparatus 1 of the molding machine of the present invention achieves the following significant effects.

[0018] [1] By inputting the MFR of the front resin Rf and the MFR of the rear resin Rs into the molding machine controller 3, the zero-shear viscosity ηof of the front resin Rf and the zero-shear viscosity ηos of the rear resin Rs are obtained from the first database DB1, and the viscosity difference ηd between the zero-shear viscosity ηof of the front resin Rf and the zero-shear viscosity ηos of the rear resin Rs is obtained. The required amount of cleaning resin Wu during resin replacement is calculated from the second database DB2. Thus, at least the display processing is performed, thereby eliminating the need for experimental operations based on the resin replacement process using the user's molding machine, as in the prior art. As a result, it is possible to improve production efficiency and reduce production costs, and to obtain an accurate amount of cleaning resin Wu through a highly stable and reliable auxiliary method. This can be constructed as an optimal auxiliary method for inexperienced beginners, etc., and the required amount of cleaning resin Wu can be easily and quickly determined.

[0019] [2] According to the preferred method, if the intermediate material Rms is included in the post resin Rs, the required amount of cleaning resin Wu can also be known for the intermediate material Rms, so the same effect as that for the post resin Rs can be obtained in the intermediate material Rms.

[0020] [3] According to the preferred method, if the output indicates that cleaning agent is needed when the zero shear viscosity ηos of the post resin Rs is lower than the zero shear viscosity ηof of the pre resin Rf, then a substantive determination of whether cleaning agent is needed can be made. Therefore, the operator can quickly know the necessity of cleaning agent, and it can help reduce material costs and shorten resin replacement time, thereby helping to suppress the generation of useless defective products.

[0021] [4] According to the preferred method, when setting the temperature of the heating cylinder 2, if the heating cylinder 2 is divided into three regions in the axial direction: front 2f, middle 2m, and rear 2r, and the area before the front 2f is set as the high-temperature side region ZAu, and the area after the middle 2m is set as the low-temperature side region ZAd, and the temperature difference between the high-temperature side region ZAu and the low-temperature side region ZAd is set to a range of 0-50 [°C], then the operating environment of the molding machine (injection molding machine) M can be set to an effective operating state, and thus the required amount of cleaning resin Wu can be obtained more efficiently.

[0022] [5] According to the preferred method, if the resin includes general-purpose resin, engineering plastic, super engineering plastic, composite material, cleaning agent, and special resin other than cleaning agent, it can be applied to a wide range of resin materials, and thus can be constructed into a highly versatile method.

[0023] [6] According to the preferred embodiment, if the viscosity difference calculation function unit Fs of the auxiliary device 1 outputs the meaning of needing cleaning agent when the zero shear viscosity ηos of the subsequent resin Rs is lower than the zero shear viscosity ηof of the preceding resin Rf, and a cleaning agent recommendation display unit 4p is set on the display screen 4 in the display processing function unit Fo, then the operator (user) can confirm the situation of needing cleaning agent by visually looking at the display screen 4, and thus can quickly carry out the corresponding processing such as cleaning agent preparation.

[0024] [7] According to the preferred method, if it is applied to an injection molding machine as a molding machine, it can be used in injection molding machines with high necessity, and thus the most ideal performance can be obtained. Attached Figure Description

[0025] Figure 1 This is a flowchart illustrating the processing steps of the resin replacement auxiliary method according to a preferred embodiment of the present invention.

[0026] Figure 2 This is a system block diagram of the injection molding machine, including the auxiliary devices used in the implementation of the resin replacement auxiliary method.

[0027] Figure 3 This is a display screen of the auxiliary device used in the implementation of the resin replacement auxiliary method, showing a portion of the setting screen.

[0028] Figure 4 This is a screenshot of the condition table displayed on the screen, with a portion of it omitted.

[0029] Figure 5 This is a schematic diagram of a heating cylinder used in tests to verify the effectiveness of the resin replacement auxiliary method, illustrating the set temperature.

[0030] Figure 6 This is a graph illustrating the shear rate versus shear viscosity, which explains the coefficients of the transformation function used in this resin replacement auxiliary method to determine the zero shear viscosity.

[0031] Figure 7 This is a graph showing the results of the zero-shear viscosity and the amount of cleaning resin required for the test. Detailed Implementation

[0032] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0033] First, refer to Figures 2 to 4 The configuration of the injection molding machine M (molding machine) capable of implementing the resin replacement auxiliary method of this embodiment will be described.

[0034] Figure 2 In this context, M represents an injection molding machine, specifically an injection unit Mi that omits the mold clamping device. Within the injection unit Mi, 2 is a heating cylinder. A nozzle 2n is mounted and fixed at the front end of the heating cylinder 2 via a head 2h, and a feed hopper 11 is located at the upper rear end of the heating cylinder 2. The nozzle 2n functions to inject the molten resin inside the heating cylinder 2 into the mold (mold clamping device), and the feed hopper 11 functions to supply resin (molding material) R…, i.e., the pre-resin Rf (described later), and the post-resin Rs including the intermediate material Rms, into the interior of the heating cylinder 2.

[0035] Therefore, if the resin replacement assistance method of this embodiment is applied to an injection molding machine, it can be used in injection molding machines where such machines are essential, thus achieving optimal performance. Furthermore, since the intermediate material Rms can be included in the post-resin Rs, the required amount of cleaning resin Wu for the intermediate material Rms can also be determined. Thus, the same effect as that for the post-resin Rs can be obtained in the intermediate material Rms.

[0036] Furthermore, a screw 12 is rotatably and retractably loaded inside the heating cylinder 2. This screw 12 has a main body 12m with helical screw ridges 12mp, and a torpedo section 12t and a screw tip 12s at the front end of the main body 12m. The main body 12m has a metering zone Zm, a compression zone Zc, and a feeding zone Zf from front to rear. On the other hand, the rear end of the screw 12 is connected to a screw drive unit 13. The screw drive unit 13 includes a screw rotation mechanism 13r for rotating the screw 12 and a screw advance / retreat mechanism 13m for advancing and retracting the screw 12. It should be noted that the screw rotation mechanism 13r and the screw advance / retreat mechanism 13m can be driven by either a hydraulic system using a hydraulic circuit or an electrical system using an electric motor; either method is acceptable.

[0037] Furthermore, the heating cylinder 2 has a front heating cylinder portion 2f, a middle heating cylinder portion 2m, and a rear heating cylinder portion 2r extending from the front side (nozzle 2n side) towards the rear side. A front heating portion 14f, a middle heating portion 14m, and a rear heating portion 14r are respectively attached to the outer peripheral surfaces of each portion 2f, 2m, and 2r. Similarly, a head heating portion 14h is attached to the outer peripheral surface of the head portion 2h, and a nozzle heating portion 14n is attached to the outer peripheral surface of the nozzle 2n. These heating portions 14f, 14m, 14r, 14h, and 14n can be constructed from components such as belt heaters.

[0038] On the other hand, 3 represents the molding machine controller responsible for the overall control of the injection molding machine M. The molding machine controller 3 has a computer-functional controller body 15 with built-in hardware such as a CPU and an associated internal memory 15m, and a display screen 4 connected to the controller body 15. The display screen 4 is attached to a touch panel, so various operations such as setting, selection, and input can be performed using the display screen 4, and various displays can be made. Specifically, it is displayed in relation to this embodiment. Figure 3 The resin replacement setting screen Hc shown is as follows Figure 4 The condition table shown is displayed on screen Hm.

[0039] Furthermore, the controller body 15 is connected to the aforementioned screw rotation mechanism 13r and screw advance / retract mechanism 13m via a driver 16, and is also connected to each of the heating elements 14f, 14m, 14r, 14h, and 14n. Thus, the controller body 15 can drive and control the screw rotation mechanism 13r and screw advance / retract mechanism 13m via the driver 16, and can also energize and control each of the heating elements 14f, 14m, 14r, 14h, and 14n.

[0040] Therefore, the molding machine controller 3 includes an HMI (Human-Machine Interface) control system and a PLC (Programmable Logic Controller) control system, storing the PLC program and the HMI program in its internal memory 15m. It should be noted that the PLC program is software used to implement the timing actions of various processes in the injection molding machine M or to monitor the injection molding machine M, while the HMI program is software used to set and display the operating parameters of the injection molding machine M, and to display the operating monitoring data of the injection molding machine M. Furthermore, this molding machine controller 3 constitutes (and also serves as) the resin replacement auxiliary device 1 of this embodiment.

[0041] Next, refer to Tables 1 to 2 and... Figures 5 to 7 The basic auxiliary method of the resin replacement auxiliary method of this embodiment will be described.

[0042] This resin replacement assistance method is a method for estimating the required amount of cleaning resin, Wu, needed for resin replacement (including color replacement of the same resin) when performing resin replacement. Conventionally, the molding machine itself is used as a testing machine to actually determine the resin viscosity (apparent viscosity), and the required amount of cleaning resin, Wu, is predicted from the test results. In the resin replacement assistance method of this embodiment, the corresponding accurate amount of cleaning resin, Wu, can be estimated by directly using MFR values ​​known from product catalogs, i.e., through simple numerical input.

[0043] First, in order to confirm its advantages, a verification test was conducted on the resin replacement auxiliary method of this embodiment.

[0044] In the verification experiment, by using Resin replacement tests were conducted on a standard screw injection molding machine. A summary of the cleaning conditions used in the resin replacement tests is shown in [Table 1].

[0045] Table 1

[0046] project condition value unit Temperature in the high-temperature side region 250 ℃ Temperature of the low-temperature side region 200 ℃ Rotation speed 200 rpm Cleaning speed 100 mm / s back pressure 0.5 MPa Pressure limiting 196 MPa Pre-cleaning (mm) × Number of times 50×5 Post-cleaning (mm) × Number of times 10×20 Dry cleaning (mm) × number of times 50×5

[0047] In [Table 1], the high-temperature side region ( Figure 5 The temperature of ZAu in the heating cylinder 2 includes the temperature of the nozzle 2n, the head 2h, and the front 2f, and the temperature of the low-temperature side region ( Figure 5 The temperature of ZAd in the heating cylinder 2 includes the temperature of the middle part 2m and the rear part 2r.

[0048] During the verification test, firstly, the pre-resin Rf was adjusted to reach 1% by weight, and the black pre-resin Rf was filled into the heating cylinder 2. Then, after cleaning with post-resin Rs (LDPE) under the cleaning conditions specified in Table 1, the screw was pulled out, and after cooling, the resin was peeled off. The presence of any residual pre-resin Rf was visually confirmed. If pre-resin Rf was found, 500g of post-resin Rs was added to continue the cleaning process, repeating until the pre-resin Rf disappeared. The amount of cleaning resin required to completely eliminate the pre-resin Rf was then determined.

[0049] On the other hand, the calculation of zero shear viscosity uses (Equation 101) shown in [Number 1].

[0050]

Number 1

[0051] η=ηoγ n-1 exp{C(T-Tr)}…(Equation 101)

[0052] In (Equation 101), η represents shear viscosity [Pa·s], ηo represents zero shear viscosity [Pa·s], γ represents shear rate [1 / second], n represents viscosity index, C represents temperature constant, T represents measurement temperature [°C], and Tr represents reference temperature [°C].

[0053] A list of the zero-shear viscosity ηo of each resin R… at various temperatures (200 [°C], 250 [°C]) is shown in [Table 2], and the temperature range of the heating cylinder 2 is also shown. Figure 5 .

[0054] Table 2

[0055] Types of resins <![CDATA[μ o (200℃)]]> <![CDATA[μ o (250℃)]]> A 7285.9 3297.2 B 18507.0 4377.8 C 1384.1 365.0 D 22067.O 5811.8 E 12337.3 6494.4 F 32917.5 5117.8

[0056] Then, based on these values, the amount of cleaning resin required, Wum, is calculated using the formula (Equation 102) shown in [Equation 2].

[0057]

Number 2

[0058] Wum∝(ηOs-ηof)+(ηos-ηofe)…(Formula 102)

[0059] ηof: The zero-shear viscosity of the post-resin at 200 [°C]

[0060] ηofe: The zero-shear viscosity of the pre-resin at 250 °C

[0061] In this case, if the heating cylinder 2 is divided into three regions along the axial direction: front 2f, middle 2m, and rear 2r, and the area before front 2f is set as the high-temperature side region ZAu, and the area after middle 2m is set as the low-temperature side region ZAd, and the temperature of the high-temperature side region ZAu is set to 250 [°C] and the temperature of the low-temperature side region ZAd is set to 200 [°C] as illustrated, then the required amount of resin for the subsequent resin Rs, i.e. the amount of cleaning resin required Wum, is proportional to the value obtained by adding the difference values ​​obtained from ηos, ηof, and ηofe, as shown in Equation 102.

[0062] It should be noted that the temperature difference between the high-temperature side region ZAu and the low-temperature side region ZAd is preferably set to a range of 0-50°C. If set in this way, the operating environment of the molding machine (injection molding machine) M can be set to a highly efficient operating state, thus enabling the required amount of cleaning resin Wu to be obtained more efficiently and accurately.

[0063] Regarding the discharge theory of the pre-resin Rf in the high-temperature side region ZAu, it is believed that the greater the difference between the pre-resin Rf and the zero-shear viscosity of the subsequent resin Rs in the low-temperature side region ZAd (which has zero-shear viscosity), the easier it is to discharge. Furthermore, in the low-temperature side region ZAd, the greater the difference between the zero-shear viscosity of the subsequent resin Rs and the pre-resin Rf at that temperature, the easier it is for the pre-resin Rf to discharge. It should be noted that in color replacement between the same resins, since the apparent viscosity difference in the low-temperature side region ZAd is always 0, a larger amount of cleaning resin is required compared to resin replacement. Therefore, the more the value on the right side of (Equation 102) increases towards the positive side, the smaller the amount of cleaning resin Wum required.

[0064] On the other hand, using the MFR value, the zero-shear viscosity ηo of the pre-resin Rf and post-resin Rs (intermediate material Rms) is predicted by calculation.

[0065] That is, based on the MFR value (listed in the product catalog) of each resin R…, the shear viscosity variation characteristics are predicted by the function shown in (Equation 103) below, and then the zero shear viscosity ηo is predicted.

[0066] ηo=f(kx,MFR value,Th)…(Formula 103)

[0067] Here, kx is a coefficient proportional to the heating cylinder temperature Th and the MFR value. In (Equation 103), the zero-shear viscosity ηo of each resin R… is set correspondingly to the parameters (MFR value and heating cylinder temperature Th) that are different for each resin R…. Therefore, the coefficient kx is set for each resin R… in the form of kx = a, b, c, d…. Based on the differences in the coefficients kx = a, b, c, d…, the relationship between the shear viscosity η [Pa·s] and the shear rate γ [1 / second] is as follows: Figure 6 As shown. Therefore, the coefficient value of kx can be set to an appropriate value through prior experiments, etc.

[0068] The viscosity difference ηd, which is the zero-shear viscosity ηo, is then calculated. This is the viscosity difference ηd between the zero-shear viscosity ηof of the first resin Rf and the zero-shear viscosity ηos of the second resin Rs (ηof - ηos). The calculated viscosity difference ηd is presented in Table 3.

[0069] Table 3

[0070]

[0071] The relationship between the amount of cleaning resin Wu required for complete discharge and the subsequent resin Rs was investigated through verification experiments. Figure 7 This is a graph showing the relationship between the viscosity difference ηd and the amount of cleaning resin required, Wu. It should be noted that the amount of cleaning resin required, Wum, refers to the amount of cleaning resin needed to clean the subsequent resin Rs until the preceding resin Rs is completely discharged, as per the above verification test. Figure 7 It is evident that the required amount of cleaning resin based on MFR has advantages.

[0072] The actual required amount of post-resin, Wu, can be calculated using the formula (Equation 104) shown in [Equation 3].

[0073]

Number 3

[0074] Wu=[Du×3.7608×exp(-6E-05×

[0075] (2ηp(X)-ηq(X)-ηq(Y))] / Do…(Formula 104)

[0076] Wu: Required amount of post-resin

[0077] Du: Screw diameter of the molding machine used

[0078] Do: Standard screw diameter

[0079] ηq(X): Zero-shear viscosity of the pre-resin when the heating cylinder temperature in the low-temperature side region is X [°C].

[0080] ηq(Y): Zero-shear viscosity of the pre-resin when the heating cylinder temperature in the high-temperature side region is Y [°C].

[0081] ηp(X): Zero-shear viscosity of the resin in the low-temperature side region when the heating cylinder temperature is X [°C].

[0082] Equation 104 becomes the formula (predictive formula) for calculating the required amount of post-resin, Wu, when applying Equation 102 to other molding machines. The coefficient values ​​in Equation 104 are derived from... Figure 7 (The values ​​obtained by plotting the results in Table 3) are coefficients that change as the number of data points increases.

[0083] Next refer to Figures 2 to 4 The specific configuration of the resin replacement auxiliary device 1 in this embodiment will be described.

[0084] like Figure 2 As shown, the resin replacement auxiliary device 1 utilizes a controller body 15 with an internal memory 15m and a display screen 4 with a touch panel, which are included in the molding machine controller 3. As a basic configuration, it has a first database DB1 and a second database DB2 registered in the internal memory 15m, and has an MFR input function unit Fi, a viscosity difference calculation function unit Fs, a required amount calculation function unit Fw, and a display processing function unit Fo, which function as the molding machine controller 3.

[0085] Display screen 4 displays in connection with the present invention Figure 3 The resin replacement setting screen Hc shown is as follows Figure 4 The condition table display screen Hm shows the conditions. The resin replacement setting screen Hc allows you to set various action conditions related to resin replacement, such as cleaning conditions, and the condition table display screen Hm displays the condition table related to resin replacement.

[0086] exist Figure 3 In the resin replacement setting screen Hc shown, a molding machine (screw) setting bar 31 is located on the left side of the upper area Au, a temperature setting selection bar 32 is located on the right side of the setting bar 31, and a "Condition Table Display" button 33 is located on the right side of the selection bar 32. Additionally, a viscosity information selection bar 34 is located on the left side of the middle area Am, allowing selection of "None" for 34a, "MFR" for 34b (used in this invention), and "Molding Machine Viscosity" for 34c.

[0087] Additionally, a resin selection unit 35 is located to the right of selection bar 34. The resin selection unit 35 has a current resin (previous resin Rf) selection bar 35f on the left and a replacement resin (rear resin Rs) selection bar 35s on the right. A "START" button 37 is located between selection bars 35f and 35s. Furthermore, an MFR input unit 21f for inputting the MFR value of the selected resin is located below the current resin selection bar 35f, and an MFR input unit 21s for inputting the MFR value of the selected resin is located below the replacement resin selection bar 35s. These MFR input units 21f and 21s constitute the aforementioned MFR input function unit Fi.

[0088] In this case, the selectable resins can include general-purpose resins, engineering plastics, super engineering plastics, composite materials, cleaning agents, and special resins other than cleaning agents. Thus, the resin replacement assistance method of this embodiment can be applied to a wide range of resin materials, and therefore can be constructed as a highly versatile method.

[0089] A set temperature display unit 38 is provided in the lower Ad region, which displays an image of the heating cylinder of the molding machine. Therefore, the set temperature display unit 38 displays the nozzle temperature, head temperature, front temperature of the heating cylinder, middle temperature of the heating cylinder, and rear temperature of the heating cylinder from the front side.

[0090] Additionally, by turning the "Condition Table Display" button 33 on the resin replacement setting screen Hc to ON, it is possible to display... Figure 4 The condition table shown is displayed on screen Hm.

[0091] On the other hand, Figure 4 In the condition table display screen Hm shown, a cleaning agent recommendation display unit 4p is set in the upper area ASu. In the cleaning agent recommendation display unit 4p, when the zero-shear viscosity ηos of the resin Rs after the viscosity difference calculation function unit Fs is lower than the zero-shear viscosity ηof of the resin Rf before, a notification can be given by lighting up or flashing the cleaning agent recommendation display unit 4p, indicating that cleaning agent is needed. If a cleaning agent recommendation display unit 4p indicating that cleaning agent is needed is set in the display processing function unit Fo, the operator (user) can reliably confirm the need for cleaning agent through the display screen 4 and can quickly prepare for cleaning agent-related tasks.

[0092] Furthermore, in the central area ASm of the condition table display screen Hm, from left to right, there are a metering speed display bar 41, a cleaning speed display bar 42, a back pressure display bar 43, a material depletion monitoring time display bar 44, and an "OK" button 45. In the lower area ASd of the condition table display screen Hm, there are a front cleaning condition display bar 46a, a rear cleaning condition display bar 46b, and an empty cleaning condition display bar 46c, which respectively display the travel distance and number of cycles. And, at the right end of the lower area ASd, there is a resin input amount display unit 47.

[0093] In each functional unit constituting the resin replacement auxiliary device 1, the zero-shear viscosity ηo... of each resin R... (resin type, color) is calculated and registered in the first database DB1 using a function (Equation 103) with the MFR value and the set temperature of the heating cylinder 2 as parameters. The MFR value [g / 10min] is one of the resin characteristics that indicates the flowability of molten resin, and the value can be found in the product catalog of molding material (resin R).

[0094] The required amount of cleaning resin, Wu, is recorded in the second database DB2 and corresponds to the viscosity difference ηd (=ηof-ηos)…… between the zero-shear viscosity ηof…… of the pre-resin Rf…… and the zero-shear viscosity ηos…… of the post-resin Rs…….

[0095] On the other hand, the MFR input function unit Fi has the function of inputting the MFR value of the pre-resin Rf and the MFR value of the post-resin Rs, and it includes an MFR input unit 21, which has the function of inputting the MFR value of the pre-resin Rf and the post-resin Rs. Figure 3 The MFR input section 21f, which inputs the MFR value of the current resin (front resin Rf), and the MFR input section 21s, which inputs the MFR value of the replacement resin (back resin Rs), are shown on the resin replacement setting screen Hc on the display screen 4.

[0096] The viscosity difference calculation function unit Fs has a calculation function. Based on each MFR input by the MFR input unit 21, it reads the zero-shear viscosity ηof of the front resin Rf and the zero-shear viscosity ηos of the rear resin Rs from the first database DB1, and calculates the viscosity difference ηd (=ηof-ηos) between the zero-shear viscosity ηof of the front resin Rf and the zero-shear viscosity ηos of the rear resin Rs.

[0097] Furthermore, the required amount calculation function unit Fw has the function of calculating the required amount of cleaning resin Wu during resin replacement from the second database DB2 based on the obtained viscosity difference ηd. The display processing function unit Fo has the function of displaying the calculated required amount of cleaning resin Wu on the display screen 4. Figure 4 The function of the resin quantity display unit 47 in the condition table display screen Hm.

[0098] Next refer to Figures 2 to 7based on Figure 1 The flowchart shown illustrates in detail the resin replacement assistance method using the resin replacement assistance device 1 of this embodiment.

[0099] This assumes that a series of production processes using the specified resin (pre-resin Rf) has ended, and the resin is replaced with the next type of resin (post-resin Rs) to move on to the next production step. With the completion of production using pre-resin Rf, the operator will... Figure 3 The resin replacement setting screen Hc is displayed on the display screen 4 (step S1). Then, various setting items are selected or entered (step S2). In the example, the machine model of the molding machine used can be selected through the molding machine setting bar 31, which includes the screw size, and the temperature setting mode can be selected through the temperature setting selection bar 32, etc.

[0100] Next, viscosity information is selected via viscosity information selection field 34. In this embodiment, "MFR" 34b is selected to use MFR information (step S3). Additionally, the current resin used, i.e., the type of resin related to the previous resin Rf, is selected via current resin selection field 35f of resin selection unit 35 (step S4). An example is shown where "HDPE" is selected. Afterwards, the MFR value of the current resin (previous resin Rf) is entered in MFR input field 21f (step S5). An example is shown where "10" is entered.

[0101] Next, the type of replacement resin, i.e., the resin related to the subsequent resin Rs, is selected in the replacement resin selection field 35s (step S6). An example is shown where "PMMA" is selected. Then, the MFR value of the replacement resin (subsequent resin Rs) is entered in the MFR input field 21s (step S7). An example is shown where "10" is entered.

[0102] After completing the above settings, turn the "START" button 37 ON. This determines the heating temperature of the corresponding heating cylinder 2 and displays it as the set temperature on the set temperature display unit 38 (step S9). That is, the nozzle temperature, head temperature, front temperature of the heating cylinder, middle temperature of the heating cylinder, and rear temperature of the heating cylinder are displayed in each display column of the set temperature display unit 38.

[0103] Next, turn the "Condition Table Display" key 33 ON (step S10). This allows the determination of the operating conditions during the cleaning process and the cleaning conditions themselves. Figure 4The condition table display screen Hm shows the operation conditions and cleaning process conditions (steps S11 and S12). These operation conditions include metering speed, cleaning speed, back pressure, and material depletion monitoring time. As cleaning process conditions, the screw's travel stroke and number of strokes are displayed in the front cleaning condition display bar 46a, the rear cleaning condition display bar 46b, and the empty cleaning condition display bar 46c, respectively. Additionally, the resin input amount display unit 47 displays the amount of resin [kg] required for the cleaning process (step S13).

[0104] On the other hand, the condition table display screen Hm includes a cleaning agent recommendation display unit 4p. In the cleaning agent recommendation display unit 4p, when the zero-shear viscosity ηos of the resin Rs after the viscosity difference calculation function Fs is lower than the zero-shear viscosity ηof of the resin Rf before, a message indicating that cleaning agent is needed is output, and this is communicated by lighting up or flashing the cleaning agent recommendation display unit 4p.

[0105] This allows for a substantive determination of whether cleaning agent is needed. The operator (user) can quickly and reliably confirm the necessity of cleaning agent by visually inspecting the display screen 4, and thus can quickly carry out preparations and other related procedures for cleaning agent (steps S14, S15). As a result, it can help reduce material costs and shorten resin replacement time, thereby helping to suppress the generation of useless defective products.

[0106] After the above preparations are completed, the operator makes a final confirmation. If it is determined that there are no problems, the "OK" button 45 is turned ON (step S16). This leads to a series of resin replacement processes (step S17).

[0107] Therefore, according to this embodiment of the resin replacement auxiliary method (apparatus), as a basic method, the zero-shear viscosity ηo… of each resin R… is calculated in advance according to a transformation function with melt flow rate (MFR) and the set temperature of the heating cylinder 2 as parameters, and is registered in the molding machine controller 3 as a first database DB1. Furthermore, the required amount of cleaning resin Wu… corresponding to the viscosity difference ηd… between the zero-shear viscosity ηof… of the previous resin Rf… and the zero-shear viscosity ηos… of the subsequent resin Rs… is registered in the molding machine controller 3 as a second database DB2. During resin replacement… The MFR of the pre-resin Rf and the MFR of the post-resin Rs are input into the molding machine controller 3. From this, the zero-shear viscosity ηof of the pre-resin Rf and the zero-shear viscosity ηos of the post-resin Rs are obtained from the first database DB1, and the viscosity difference ηd between these two viscosity values ​​is obtained. The required amount of cleaning resin Wu for resin replacement is calculated from the second database DB2. This process, at least through display, eliminates the need for experimental operations based on the resin replacement process using the user's molding machine, as is done in the prior art. As a result, production efficiency (production capacity) and production costs can be improved, and the accurate required amount of cleaning resin Wu can be obtained through a stable and reliable auxiliary method. This makes it an optimal auxiliary method for inexperienced beginners, allowing for easy and rapid calculation of the required amount of cleaning resin Wu.

[0108] The above describes the suitable implementation methods in detail, but the present invention is not limited to such implementation methods. The details of the structure, shape, raw materials, materials, quantity, value, method, etc. can be arbitrarily changed, added, or removed without departing from the essence of the present invention.

[0109] For example, the concept of resin replacement includes not only changing to a different type of resin, but also changing to the same resin with a different color. MFR (MFR value) shows an example using a resin catalog value, and can also be obtained using values ​​from various sources, values ​​derived through experiments, etc. Furthermore, the subsequent resin Rs may include intermediate material Rms. Therefore, in this case, it can be implemented similarly by replacing the subsequent resin Rs with intermediate material Rms. On the other hand, regarding the set temperature of the heating cylinder 2, when dividing the heating cylinder 2 axially into three regions—front 2f, middle 2m, and rear 2r—it is preferable to designate the area before front 2f as the high-temperature side region ZAu and the area after middle 2m as the low-temperature side region ZAd, and to set the temperature difference between the high-temperature side region ZAu and the low-temperature side region ZAd to a range of 0-50 [°C], but this is not a necessary component. In addition, the resin includes not only general-purpose resins, but also various resins represented by engineering plastics, super engineering plastics, composite materials, cleaning agents, and special resins other than cleaning agents. In addition, as a display processing function unit Fo, an example is shown where a cleaning agent recommendation display unit 4p is provided on the display screen 4 to indicate that cleaning agent is needed. However, various other means such as voice (audio) or display means other than the display screen can also be used to indicate that cleaning agent is needed.

[0110] Industrial applicability

[0111] The resin replacement auxiliary method and apparatus of the present invention can be used in various molding machines, including injection molding machines, to carry out a resin replacement process in which the resin used in molding is replaced from a front resin to a different rear resin.

[0112] Symbol Explanation

[0113] 1: Resin replacement auxiliary device; 2: Heating cylinder; 2f: Front; 2m: Middle; 2r: Rear; 3: Molding machine controller; 4: Display screen; 4p: Cleaning agent recommendation display; R: Resin; Rf: Front resin; Rs: Back resin; Rms: Intermediate material; ηo: Zero shear viscosity; DB1: First database; DB2: Second database; Wu: Required amount of cleaning resin; Fi: MFR input function; Fs: Viscosity difference calculation function; Fw: Required amount calculation function; Fo: Display processing function; ZAu: High temperature side area; ZAd: Low temperature side area; M: Injection molding machine

Claims

1. A resin replacement auxiliary method for a molding machine, wherein a resin replacement auxiliary method for a molding machine is performed when a pre-resin is discharged from a heating cylinder and a post-resin is supplied for resin replacement, characterized in that, The zero-shear viscosity of each resin is pre-estimated using a transformation function with melt flow rate and set temperature of the heating cylinder as parameters, and is recorded in the molding machine controller as a first database. The required amount of cleaning resin corresponding to the viscosity difference between the zero-shear viscosity of the preceding resin and the zero-shear viscosity of the following resin is recorded in the molding machine controller as a second database. During resin replacement, the MFR of the preceding resin and the MFR of the following resin are input into the molding machine controller. The zero-shear viscosity of the preceding resin and the zero-shear viscosity of the following resin are obtained from the first database, along with the viscosity difference between them. The required amount of cleaning resin for resin replacement is calculated from the second database, thus enabling at least a display process.

2. The resin replacement assisting method of a molding machine according to claim 1, characterized by, The post-resin contains intermediate materials.

3. The resin replacement auxiliary method for a molding machine as described in claim 1 or 2, characterized in that, When the zero-shear viscosity of the subsequent resin is lower than that of the preceding resin, a signal indicating the need for a cleaning agent is displayed.

4. The resin replacement assisting method of a molding machine according to claim 1 or 2, characterized in that, Regarding the set temperature of the heating cylinder, when the heating cylinder is divided into three regions in the axial direction: front, middle and rear, the area before the front is set as the high-temperature side region, and the area after the middle is set as the low-temperature side region. The temperature difference between the high-temperature side region and the low-temperature side region is set to a range of 0°C-50°C.

5. The resin replacement assisting method of a molding machine according to Claim 1, wherein The resins include general-purpose resins, engineering plastics, super engineering plastics, composite materials, cleaning agents, and special resins other than cleaning agents.

6. A resin replacement assisting device of a molding machine, which is a resin replacement assisting device of a molding machine that discharges a preceding resin from a heating cylinder and supplies a succeeding resin to perform resin replacement, characterized by It includes a molding machine controller, which has: a first database that records the zero-shear viscosity of each resin, estimated by a transformation function using melt flow rate and a set temperature of the heating cylinder as parameters; a second database that records the amount of cleaning resin required corresponding to the viscosity difference between the zero-shear viscosity of the preceding resin and the zero-shear viscosity of the following resin; an MFR input function that inputs the melt flow rate of the preceding resin and the melt flow rate of the following resin; and a viscosity difference calculation function that calculates the viscosity difference between the zero-shear viscosity of the preceding resin and the zero-shear viscosity of the following resin from the first database based on the input melt flow rates. The required amount calculation function unit calculates the required amount of cleaning resin for resin replacement from the second database based on the obtained viscosity difference; and the display processing function unit displays at least the calculated required amount of cleaning resin.

7. The resin replacement assisting device of the molding machine according to claim 6, wherein The viscosity difference calculation function unit outputs a message indicating that a cleaning agent is needed when the zero-shear viscosity of the subsequent resin is lower than that of the preceding resin, and the display processing function unit sets up a cleaning agent recommendation display on the display screen to show the message that the cleaning agent is needed.

8. The resin replacement auxiliary device for the molding machine as described in claim 6, characterized in that, It is applied to the injection molding machine, which is the molding machine mentioned above.

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