TWI703306B - Correction method of optical lens mold - Google Patents

Abstract

A method for calibrating an optical lens mold. The mold includes a male mold body and a female mold body. The calibration method includes a data establishment step and a temperature control step. In the data establishment step, the mold core eccentricity values of the male mold body and the female mold body at different instantaneous temperature differences are obtained, and the mold core eccentricity value range within the target error is selected to obtain the target temperature difference range. In the temperature control step, the real-time temperature of the male phantom and the female phantom are subtracted to calculate the real-time temperature difference, and the temperature of the male phantom and the female phantom is obtained through fuzzy control operations according to the target temperature difference range Adjust the amount, and finally adjust the temperature of the coolant in the male mold body and the female mold body to make the instant temperature difference between the male mold body and the female mold body converge within the target temperature difference range, so that the mold core eccentricity value converges to the target Within error.

Description

Correction method of optical lens mold

The present invention relates to a calibration method, in particular to a calibration method for a mold for injection molding optical lenses.

It is a very common technology to mold optical lenses through injection molding. However, during the process from mold preheating to injection molding, thermal deformation (usually thermal expansion) occurs due to the rise and fall of its own temperature, plus mutual alignment The temperature of the male mold body and the female mold body may not be the same due to various factors, resulting in different deformations of the male mold body and the female mold body, and finally the mold core of the male mold body and the mold body of the female mold body are not the same. The eccentricity value is generated between the cores, which will cause the problem of insufficient precision due to excessive eccentricity of the prepared optical lens.

In order to maintain the yield and accuracy of the product, the general injection molding process usually improves the parameters of the injection machine through various control methods or optimization methods, so that the material injected by the injection machine can indeed conform to the shape of the mold cavity, so as to achieve Reduce or avoid surface unevenness, internal bubbles, and uneven edge thickness, but this does not solve the problem of excessive eccentricity due to thermal expansion between the male and female molds, so even if the parameters of the injection machine are improved As a result, it can perfectly conform to the shape of the mold, and the resulting optical lens still has the problem of excessive eccentricity due to the excessive eccentricity of the mold itself.

Therefore, the object of the present invention is to provide a correction method that can correct the eccentricity of the mold due to thermal deformation.

Therefore, the calibration method of the present invention is applicable to a mold including a male mold body and a female mold body that can be matched with the male mold body. The calibration method includes a data establishment step and a temperature control step. In the data creation step, thermal analysis is performed on the mold and the real-time temperature measured by the temperature detection module is used to obtain the mold core eccentricity values of the male mold body and the female mold body under different real-time temperature differences. Then select the range of the mold core eccentricity value within the target error to obtain the target temperature difference range, and record the target temperature difference range in the fuzzy controller.

In the temperature control step, the temperature detection module separately measures the real-time temperature of the male mold body and the female mold body, and subtracts the real-time temperatures of the male mold body and the female mold body to calculate the real-time temperature difference, The fuzzy controller obtains the temperature adjustment values of the male mold body and the female mold body through fuzzy control operations according to the target temperature difference range, and finally the mold temperature control module adjusts the male mold body and the female mold body according to the obtained temperature adjustment amount. The temperature of the coolant in the female mold body makes the instantaneous temperature difference between the male mold body and the female mold body converge within the target temperature difference range, so that the core eccentricity of the male mold body and the female mold body converges to the target error Inside.

The effect of the present invention is that the correction method adjusts the respective temperatures of the male mold body and the female mold body through fuzzy control operations, thereby respectively controlling the degree of thermal expansion so that the mold core eccentricity value converges within the target error. The problem of excessive mold eccentricity can be fundamentally improved, thereby reducing the eccentricity of the manufactured optical lens and improving its yield and accuracy.

1 and FIG. 2 are an embodiment of the calibration method of the present invention. This embodiment is used in conjunction with a calibration system 1 and is suitable for a mold 2 of an optical lens. The mold 2 includes a male mold body 21 and a female mold body 22 that can be opposed to the male mold body 21. The male mold body 21 and the female mold body 22 are each provided with water channels 210 and 220 for cooling liquid to circulate and mold cores for alignment. Since the aforementioned mold cores are common knowledge in the conventional mold 2 field, they are not It is shown in the diagram and will not be repeated here. The calibration system 1 includes a temperature detection module 11 arranged on the mold 2, a mold temperature control module 12 connected to the mold 2, and an electrical connection between the temperature detection module 11 and the mold temperature control module Group 12 fuzzy controller 13. The temperature detection module 11 includes four first sensors 111 that are embedded on the male mold body 21 and can sense the real-time temperature of the male mold body 21, and four are embedded on the mother mold body 22 and The second sensor 112 can sense the instantaneous temperature of the mother mold body 22. In this embodiment, the configuration of the first sensors 111 is as shown in FIG. 2, and the second sensors 112 are also configured in a similar manner, but of course, it can also be based on the actual mold 2 state. Change the configuration like this, not limited to this. The mold temperature control module 12 includes a male mold temperature controller 121 connected to the male mold body 21 for controlling the temperature of the coolant in the water path 210, and a water path 220 connected to the female mold body 22. A master mold temperature controller 122 for controlling the temperature of the coolant in the water circuit 220.

Referring to FIG. 1, FIG. 2, and FIG. 3, the calibration method of this embodiment includes a data creation step and a temperature control step. In the data establishment step, the mold 2 is first subjected to multiple thermal analyses (simulation or experiment) under different conditions to obtain multiple mold core eccentricities A between the male mold body 21 and the female mold body 22. In addition to obtaining a mold core eccentricity value A in each thermal analysis, four instantaneous temperatures T _{11 are} measured (or simulated) by the first sensors 111, and the second sensors 112 measured (or simulated) four real-time temperatures T ₂₁ , and after averaging the aforementioned two groups of real-time temperatures T ₁₁ and T ₂₁ respectively, the real-time temperature T _{1 of} the male mold body 21 and the female mold body can be obtained 22 real-time temperature T ₂ , after subtracting the two real-time temperatures T ₁ and T ₂ , the real-time temperature difference ΔT between the male mold body 21 and the female mold body 22 can be obtained, so each mold core eccentricity value A corresponds to a real-time Temperature difference ΔT, after finishing the mold core eccentricity value A (unit: μm) and instant temperature difference ΔT (unit: °C) obtained from each thermal analysis, the relationship diagram shown in Figure 3 can be obtained. In this embodiment, take The target error range of the mold core eccentric value A is ±1, and the corresponding target temperature difference range can be seen from Fig. 3 (from the average instant temperature T _{1 of} the male mold body 21, minus the instantaneous temperature after the average of the female mold body 22 The temperature T ₂ is -0.5°C~-1°C, and the aforementioned target temperature difference range is input into the database of the fuzzy controller 13. In addition, in this embodiment, the limit value of the temperature AT of the overall mold 2 is set to 110°C according to the characteristics of the plastic material placed in the mold 2, and the aforementioned algorithm for the temperature AT of the overall mold 2 is the instant temperature T of the first sensors 111 ₁₁ and the real-time temperature T _{21 of the} second sensors 112 are added together and averaged.

When the temperature of the mold 2 changes due to actions such as preheating, injection molding, or mold opening, the calibration system 1 can be activated to perform the temperature control step. In the temperature control step, the first sensors 111 and the second sensors 112 will input the measured real-time temperature T ₁₁ and T ₂₁ into the fuzzy controller 13, and the fuzzy controller 13 will calculate the common model body 21 and The instantaneous temperature difference ΔT of the mother mold body 22. Then the fuzzy controller 13 will use the instantaneous temperature difference ΔT as the fuzzy input variable, and then use a temperature adjustment value B of the male phantom 21 or the female phantom 22 as the output variable. After the attribution function and knowledge base are established, the fuzzy first Inference method (Min-Min-Max), and then defuzzification by the maximum center method (COM), to obtain the output control value (temperature adjustment amount B).

Then, when the real-time overall mold 2 temperature AT is greater than the limit value of 110°C, if the real-time temperature difference ΔT is greater than the upper limit of the target temperature difference range -0.5°C, the male mold temperature machine 121 is used to adjust the temperature according to the temperature adjustment amount B. The coolant temperature of the mold body 21, if the instantaneous temperature difference ΔT is less than the lower limit of the target temperature difference range -1°C, the master mold temperature machine 122 adjusts the coolant temperature of the mother mold body 22 according to the temperature adjustment amount B . Conversely, when the real-time overall mold 2 temperature AT is less than the limit value 110°C, if the real-time temperature difference ΔT is greater than the upper limit of the target temperature difference range -0.5°C, the master mold temperature machine 122 is used to increase the master mold according to the temperature adjustment B If the real-time temperature difference ΔT of the body 22 is less than the lower limit of the target temperature difference range -1°C, the male mold temperature machine 121 will increase the temperature of the male mold body 21 according to the temperature adjustment amount B. Adjusting or increasing the temperature of the coolant can adjust the temperature of the male mold body 21 and the female mold body 22 itself, so that the instant temperature difference ΔT between the male mold body 21 and the female mold body 22 converges within the target temperature difference range, and then The core eccentricity value A between the male mold body 21 and the female mold body 22 is converged within ±1 of the target error.

The fuzzy controller 13 can directly perform thermal compensation on the male mold body 21 and the female mold body 22 through the cooling liquid, so as to control the thermal expansion of the male mold body 21 and the female mold body 22 separately, thereby controlling the The eccentricity of the mold core between the male mold body 21 and the female mold body 22 converges within the target error, so that the precision and quality of the manufactured optical lens can be greatly improved.

The following experiments further illustrate the effectiveness of the calibration method. The embodiments described below are all obtained by thermal analysis and simulation using ANSYS software, and the target error range of the selected mold core eccentricity A is ±1, the target The temperature difference ranges from -0.5°C to -1°C, the limit value of the temperature AT of the overall mold 2 is 110°C, and the coolant temperature of the male mold body 21 and the female mold body 22 are both 110°C.

Experimental example one

Referring to FIGS. 2 and 4 to 7, in this experimental example, the temperature control step is performed after the mold 2 is preheated for 1 hour. The temperature of the first sensors 111 and the second sensors 112 is captured The cycle is 30 seconds/time, and the ambient temperature is 25°C. The final results are shown in Figures 4 to 7. Figure 4 shows that after the fuzzy controller 13 calculates the temperature adjustment value B, the male mold temperature controller 121 and the female mold temperature controller 122 control the male mold body 21 and the female mold body 22 to obtain a trend graph of the coolant temperature. FIG. 5 shows the first sensors 111 and the second sensors 111 The trend graph of the real-time temperature T ₁ and T ₂ measured by the two sensors 112. Fig. 6 is a trend graph of the real-time temperature difference ΔT between the male mold body 21 and the female mold body 22. The mold body 21 and the mother mold body 22 are different in mold structure, resulting in slight differences in the instantaneous temperature T ₁ and T ₂ between the male mold body 21 and the mother mold body 22, resulting in an instant temperature difference ΔT, but Under the control of this correction method, after the sixth correction, the instantaneous temperature difference ΔT gradually converges to the target temperature difference range, and it can be clearly seen from the trend graph of mold core eccentricity A in Fig. 7 that as the correction progresses, The mold core eccentricity value A of the mold 2 gradually converges to within the target error range, so this correction method can indeed reduce the mold core eccentricity value A for the preheated mold 2.

Experimental example two

Referring to Figures 2 and 8 to Figure 11, in this experimental example, injection molding is performed after the mold 2 is preheated for 1 hour, and then the temperature control step is performed. The preheating parameters of the mold 2 are the same as the experimental example 1. The parameters for injection molding of the mold 2 are: the temperature of the vertical runner is set to 271℃, the temperature of the runner is set to 273℃, the temperature of the product is set to 275℃, the injection time is 0.2 seconds, the mold opening time (air heat transfer) Time) 5 seconds, the time point of temperature capture is the 25th second after the cycle starts. FIG. 8 is also a trend diagram of the coolant temperature of the male mold body 21 and the female mold body 22 during the experiment, and FIG. 9 is the measurement of the first sensors 111 and the second sensors 112 The obtained real-time temperature T ₁ and T ₂ trend graphs. Fig. 10 is the real-time temperature difference ΔT between the male phantom 21 and the female phantom 22. It can be clearly seen from Fig. 10 that although the real-time temperature difference at the beginning of the experiment ΔT is large, but through the thermal compensation of the correction system 1, the instant temperature difference ΔT gradually converges to the target temperature difference range, and it can be clearly seen from the trend graph of the mold core eccentric value A in Fig. 11 that as the correction proceeds, The mold core eccentricity value A of the mold 2 also gradually converges to within the target error range, so the correction method can indeed reduce the mold core eccentricity value A for the mold 2 after preheating and injection molding.

Experimental example three

Refer to Figure 2 and Figures 12 to 17, this experimental example is roughly the same as experimental example 2, but after the injection molding reaches a stable level, the mold 2 is opened and the mold surface is cooled for 5 minutes as the interference value. The foregoing process is performed on an experimental group and a control group. The experimental group is equipped with the calibration system 1 of the present invention. Both the experimental group and the control group adopt the optimal coolant temperature obtained in the second experimental example (Figure 8). The 17th calculation value) as the initial value, that is, the coolant temperature of the male mold body 21 is 102.8°C, and the coolant temperature of the mother mold body 22 is 107.4°C. The difference is that the control group is not set The correction system 1. The results of the experiment are shown in Figures 12 to 17. Figure 12 shows that the temperature of the coolant in the control group was maintained at 102.8°C and 107.4°C, respectively. Figure 13 shows the comparison of the male phantom 21 and the female phantom 22 The real-time temperature T ₁ , T ₂ trend graph. Figure 14 is the cooling liquid temperature trend graph of the male mold body 21 and the female mold body 22 of the experimental group during the experiment. When the instant temperature difference ΔT converges within the target error range When the temperature of the coolant is adjusted back to the initial value (that is, the calculated value of the 17th time in Figure 8), if the instantaneous temperature difference ΔT exceeds the target error range, the correction system 1 will be activated for adjustment. Figure 15 is the experimental group The real-time temperature T ₁ and T ₂ trend graphs of the male phantom 21 and the female phantom 22. Figure 16 is a trend comparison chart of the instant temperature difference ΔT between the experimental group and the control group. It can be seen from Figure 16 that although the experimental group and the control group finally converged within the target error range, the experimental group was in the first time After calculation and control, the instant temperature difference ΔT converges to within the target error range, and the control group does not make the instant temperature difference ΔT converge within the target error range until the 9th molding. Figure 17 shows the results of the experimental group and the control group. The trend graph of mold core eccentricity value A can be calculated from Figure 17. The average eccentricity error value of the experimental group is 0.18 μm, and the average eccentricity error value of the control group is 0.3 μm. It can be seen that this correction method not only returns to the most The speed of the instant temperature difference is faster, and the overall eccentricity error performance is better than the control group without the correction system 1.

In summary, the present invention can perform thermal compensation on the mold 2 through the correction method, thereby controlling the thermal expansion of the male mold body 21 and the female mold body 22 by adjusting the temperature of the coolant, and then control the mold 2 of the mold. The core eccentricity value effectively reduces the error of the manufactured optical lens and improves its accuracy, so it can indeed achieve the purpose of the invention.

However, the above are only examples of the present invention. When the scope of implementation of the present invention cannot be limited by this, all simple equivalent changes and modifications made in accordance with the scope of the patent application of the present invention and the content of the patent specification still belong to This invention patent covers the scope.

1‧‧‧Calibration system 11‧‧‧Temperature detection module 111‧‧‧First sensor 112‧‧‧Second sensor 12‧‧‧Mold temperature control module 121‧‧‧Male mold temperature Machine 122‧‧‧Master mold temperature controller 13‧‧‧Fuzzy controller 2‧‧‧Mould 21‧‧‧Male mold body 210‧‧Waterway 22‧‧‧Female mold body 220‧‧‧Waterway A‧‧‧ Mold core eccentric value B‧‧‧Temperature adjustment amount T ₁ ‧‧‧Instant temperature T ₂ ‧‧‧Instant temperature T ₁₁ ‧‧‧Instant temperature T ₂₁ ‧‧‧Instant temperature ΔT‧‧‧Instant temperature difference

Other features and effects of the present invention will be clearly presented in the embodiments with reference to the drawings, in which: FIG. 1 is a schematic diagram of a calibration system matched in an embodiment of the calibration method of the present invention; Fig. 2 is a schematic diagram showing the configuration of the four first sensors of the calibration system on a male phantom; Figure 3 is a relationship curve diagram illustrating the relationship between the mold core eccentricity value and the instant temperature difference in this embodiment; Figures 4 to 7 are graphs of relationships, illustrating the results of a first experimental example; Figures 8 to 11 are graphs of relationships, illustrating the results of a second experimental example; and Figures 12 to 17 are all relational graphs illustrating the results of a third experimental example.

1‧‧‧Correction system

11‧‧‧Temperature detection module

111‧‧‧First sensor

112‧‧‧Second sensor

12‧‧‧Mold temperature control module

121‧‧‧Male mold temperature controller

122‧‧‧Master Mold Temperature Controller

13‧‧‧Fuzzy Controller

2‧‧‧Mould

21‧‧‧Male phantom

210‧‧‧Waterway

22‧‧‧Female phantom

220‧‧‧Waterway

Claims (6)

A calibration method is used in conjunction with a calibration system. The calibration system includes a temperature detection module, a mold temperature control module, and a fuzzy controller electrically connected to the temperature detection module and the mold temperature control module, The correction method is suitable for a mold, and the mold includes a male mold body and a female mold body that can be matched with the male mold body. The correction method includes: A data creation step is to perform thermal analysis on the mold and cooperate with the real-time temperature measured by the temperature detection module to obtain the mold core eccentricity values of the male mold body and the female mold body under different real-time temperature differences, and then select The range of the mold core eccentricity value within the target error is used to obtain the target temperature difference range, and the target temperature difference range is recorded in the fuzzy controller; and In a temperature control step, the temperature detection module measures the real-time temperature of the male mold body and the female mold body, and subtracts the real-time temperatures of the male mold body and the female mold body to calculate the real-time temperature difference. The controller obtains the temperature adjustment values of the male mold body and the female mold body according to the target temperature difference range through fuzzy control operations, and finally the mold temperature control module adjusts the male mold body and the female mold body according to the obtained temperature adjustment amount The temperature of the coolant in the body causes the instantaneous temperature difference between the male mold body and the female mold body to converge within the target temperature difference range, so that the mold core eccentricity values of the male mold body and the female mold body converge within the target error. The correction method according to claim 1, wherein, in the temperature control step, the fuzzy controller performs temperature control after the mold is preheated. The correction method according to claim 1, wherein, in the temperature control step, the fuzzy controller performs temperature control after the mold is injection molded. The calibration method according to claim 1, wherein, in the data creation step, a limit value of the overall mold temperature is established in the fuzzy controller, and in the temperature control step, the male mold body and the female mold are acquired After the real-time temperature of the body, the real-time overall mold temperature is calculated from the average of the real-time temperatures of the male mold body and the female mold body. When the real-time overall mold temperature is greater than the limit value, if the real-time temperature difference is greater than the upper limit of the target temperature difference range , The mold temperature control module is used to reduce the coolant temperature of the male mold body. If the real-time temperature difference is less than the lower limit of the target temperature difference range, the mold temperature control module is used to reduce the coolant temperature of the mother mold body Temperature. When the real-time overall mold temperature is less than the limit value, if the real-time temperature difference is greater than the upper limit of the target temperature difference range, the mold temperature control module is used to increase the coolant temperature of the mother mold body. If the real-time temperature difference is less than the target temperature difference range When the lower limit is reached, the temperature of the coolant of the male mold body is increased through the mold temperature control module. The calibration method according to claim 4, wherein, in the data creation step, the limit value of the overall mold temperature is 110°C. The calibration method according to claim 1, wherein, in the data establishment step, the target error range of the mold core eccentricity value is ±1, and the target temperature difference range is -0.5°C to -1°C.

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