WO2020166333A1 - Workpiece heating device - Google Patents

Abstract

This workpiece heating device includes: a heat-sealing unit for heating and heat-welding a workpiece; a heat-weld strength evaluation unit for evaluating the strength of the heat-welded portion of the workpiece; and a temperature target value correction unit for correcting the temperature target value of the heat-sealing unit on the basis of the strength evaluation by the heat-weld strength evaluation unit.

Description

Work heating device

The present invention relates to a work heating device that heat-welds a work such as a packaging material. In particular, it relates to a temperature control technique of a heat seal portion for heat welding.

Previously, before production, the conditions under which abnormalities did not occur in the heat-welded part of the workpiece were determined by visual inspection through trial and error. The conditions in this case are heat treatment conditions such as a temperature target value for heat welding and a heat treatment time. Also, during actual production, the heat treatment conditions were fixed and used.

For example, a temperature control method of an impulse seal device is disclosed in which a non-contact thermometer is provided and the energization time or conduction angle to the heater wire is controlled based on the detection signal of the non-contact thermometer (for example, Patent Document 1). reference.).

JP-A-5-162723

In the temperature control method of the above-mentioned Patent Document 1, the seal strength varies greatly due to variations in packaging material lots and environmental conditions such as ambient temperature, and defective products are likely to occur. For example, when the initial temperature of the packaging material is decreased, the thickness of the packaging material is increased, or the air-conditioning air volume is increased, the temperature of the heat seal portion is decreased and the seal of the heat welded portion of the workpiece is reduced. The strength is reduced and defects are more likely to occur.

Therefore, an object of the present invention is to provide a work heating device capable of coping with changes in the lot of works and changes in environmental conditions such as ambient temperature.

The work heating device according to the present invention includes a heat seal part that heats and heat-welds a work,
A heat-welding strength evaluation section for evaluating the strength of the heat-welded section of the work;
Based on the strength evaluation by the heat-welding strength evaluation unit, a temperature target value correction unit for correcting the temperature target value of the heat seal unit,
Equipped with.

According to the work heating device of the present invention, the strength of the heat-welded portion of the work is evaluated by the heat-welding strength evaluation unit, and based on the strength evaluation, the heat-sealed portion is fed back, so that the lot variation of the work and the surroundings It can also handle changes in environmental conditions such as temperature.

FIG. 3 is a block diagram showing a configuration of a work heating device according to the first embodiment. It is a block diagram which shows the internal structure of the heat welding strength evaluation part of FIG. FIG. 3 is a block diagram showing a physical configuration and a functional configuration of a heat welding strength evaluation unit of FIG. 2. FIG. 3 is a schematic diagram showing an example of an appearance of a heat bar of the work heating device according to the first embodiment. FIG. 5 is a schematic diagram showing a heat bar and a temperature sensor of the work heating device of FIG. 4. FIG. 5 is a schematic diagram showing the relationship between the temperature of the heat bar, the temperature of the work, and the sealing operation of FIG. 4. It is a schematic diagram showing a relation between a temperature target value and occurrence of insufficient strength. 3 is a flowchart of a work heat welding method according to the first embodiment. 7 is a flowchart of a work heat welding method according to the second embodiment.

A work heating device according to a first aspect includes a heat seal portion that heats and heat-welds a work,
A heat-welding strength evaluation section for evaluating the strength of the heat-welded section of the work;
Based on the strength evaluation by the heat-welding strength evaluation unit, a temperature target value correction unit for correcting the temperature target value of the heat seal unit,
Equipped with.

A work heating apparatus according to a second aspect is the workpiece welding apparatus according to the first aspect, wherein the heat welding strength evaluation unit is
A pressurizing portion for pressurizing the heat-welded portion of the work,
A strength measuring unit that detects the presence or absence of peeling of the heat-welded portion under pressure to detect insufficient strength of the heat-welded portion,
Equipped with
The temperature target value correction unit may correct the temperature target value of the heat seal unit based on insufficient strength of the heat welded unit detected by the strength measurement unit.

In the work heating apparatus according to a third aspect, in the second aspect, the strength measuring unit further confirms whether or not the heat-welded portion under pressure is peeled off, and the heat-welded portion has sufficient strength. To have
The temperature target value correction unit may correct the temperature target value of the heat seal unit when the strength measurement unit detects that the heat welded unit has sufficient strength.

A work heating apparatus according to a fourth aspect is the work heating apparatus according to any one of the first to third aspects, wherein the heat seal portion is
With a heater,
A temperature sensor for measuring the temperature of the heater,
Based on the temperature measured by the temperature sensor, a heater temperature control unit for controlling the temperature of the heater to approach a temperature target value,
May be provided.

In the work heating apparatus according to a fifth aspect, in the fourth aspect, the heater temperature control unit corrects the temperature target value input in advance, and the corrected target temperature value is corrected by the temperature target value correction unit. Alternatively, the temperature of the heater may be controlled to approach the corrected target temperature value.

In the work heating apparatus according to a sixth aspect, in the fourth aspect, the strength is evaluated by the thermal welding strength evaluation section, and the temperature target value correction section corrects the temperature target value, and then the temperature sensor. It is determined whether or not the temperature measured in step 1 is stable, and if the temperature is not stable, the corrected temperature target value does not have to be corrected again.

A work heating apparatus according to a seventh aspect is the work heating apparatus according to any one of the first to fifth aspects, in which the strength is evaluated by the thermal welding strength evaluation unit, and the temperature target value correction unit corrects the temperature target value. The temperature target value after correction does not have to be corrected again within a predetermined time after this.

The work heating device according to the embodiment will be described below with reference to the accompanying drawings. In the drawings, substantially the same members are designated by the same reference numerals.

(Embodiment 1)
FIG. 1 is a block diagram showing the configuration of the work heating device 40 according to the first embodiment. FIG. 2 is a block diagram showing an internal configuration of the heat welding strength evaluation unit 20 of FIG. FIG. 3 is a block diagram showing a physical configuration and a functional configuration of the heat welding strength evaluation unit 20 of FIG. FIG. 4 is a schematic diagram showing an example of the appearance of the heat bars 2a and 2b of the work heating device according to the first embodiment.
The work heating device 40 according to the first embodiment includes a heat seal unit 10, a heat welding strength evaluation unit 20, and a temperature target value correction unit 24. The work 1 is heated by the heat seal portion 10 and heat-welded. The heat-welding strength evaluation unit 20 evaluates the strength of the heat-welding portion of the work 1. The temperature target value correction unit 24 corrects the temperature target value of the heat seal unit 10 based on the strength evaluation by the heat welding strength evaluation unit 20.
According to the work heating device 40, the strength of the heat-welded portion of the work 1 is evaluated by the heat-welding strength evaluation unit 20, and the heat-sealed portion 10 is fed back based on the strength evaluation. It can also handle changes in environmental conditions such as ambient temperature.

The members constituting the work heating device 40 will be described below.

<Heat seal part>
FIG. 5 is a schematic view showing the heat bars 2a and 2b and the temperature sensor 6 of the work heating device of FIG.
The heat seal unit 10 includes a heat bar 2 and a heater temperature control unit 8. As shown in FIGS. 4 and 5, the heat bars 2, 2a, 2b are, for example, sandwiching and heating the work 1 to heat-weld it. Further, in the example of FIGS. 4 and 5, the two heat bars 2a and 2b are provided so as to sandwich the work 1, but the present invention is not limited to this, and one heat bar may be used. In addition, in FIG. 4, the work 1 has a continuous bag shape and is heat-welded at predetermined intervals by the heat bars 2a and 2b. As shown in FIGS. 1 and 5, the heat bar 2 includes heaters 4, 4a, 4b and a temperature sensor 6 that measures the temperature of the heaters 4, 4a, 4b. The heaters 4a and 4b may be provided on each of the two heat bars 2a and 2b as shown in FIG. 5, or may be provided on only one of the heat bars. Further, although the temperature sensor 6 is provided at a position apart from the work 1 by a predetermined distance, the temperature sensor 6 is not limited to this, and may be provided close to the work 1.

FIG. 6 is a schematic diagram showing the relationship between the temperature of the heat bar of FIG. 4, the temperature of the work 1 and the sealing operation. FIG. 6A is a diagram showing the temperature of the heat bar during the continuous sealing operation. FIG. 6B is a diagram showing the temperature of the work during the continuous sealing operation. FIG. 6C is a schematic diagram showing the operation and the stop during the continuous sealing operation.
As shown in FIG. 6A, the heat bars 2, 2a, 2b are temperature-controlled so as to approach the temperature target value for heat welding the work 1. In this case, the temperature of the heat bar is somewhat lowered because the contact with the work is started at the start of the continuous sealing operation, and during the continuous sealing operation, the steady heat conduction to the work is continuously performed and the steady heat conduction is in an equilibrium state. It stabilizes the temperature. The continuous sealing of the work is performed, for example, in 0.1 second to 2 seconds. With the end of continuous sealing, the temperature of the heat bar returns to a temperature close to the target temperature.

The heater temperature control unit 8 controls the temperature of the heater 4 so as to approach the temperature target value based on the temperature measured by the temperature sensor 6. The heater temperature control unit 8 controls the heater 4 with the manipulated variable 2 such as a current value or a voltage value. Further, the heater temperature control unit 8 has a temperature target value which is an initial value input in advance. As will be described later, this temperature target value replaces the initial temperature target value by the temperature target value correction amount from the temperature target value correction unit or the manipulated variable 1 of the corrected temperature target value itself. After that, the heater temperature control unit 8 successively replaces the temperature target value with the manipulated variable 1 of the temperature target value correction amount from the temperature target value correction unit.

<Thermal welding strength evaluation section>
FIG. 3 is a block diagram showing a physical configuration and a functional configuration of the heat welding strength evaluation unit 20 of FIG.
As shown in FIG. 2, the heat welding strength evaluation unit 20 includes, for example, a pressure unit 22 and a strength measurement unit 35a. Further, the thermal welding strength evaluation unit 20 includes a pressurizing unit 22 and a control unit 30 as shown in FIG. 3 from the viewpoint of physical configuration and functional configuration. The pressing portion 22 applies a constant pressing or pulling force to the heat-welded portion of the work. The strength of the heat-welded portion of the work is measured by the strength measuring unit 35a.

<Control unit (computer device)>
The control unit 30 is, for example, a computer device. A general-purpose computer device can be used as this computer device, and includes, for example, a processing unit 31, a storage unit 32, and a display unit 33, as shown in FIG. Furthermore, an input device, a storage device, an interface, etc. may be included. The control unit 30 controls the pressure unit 22.

<Processing unit>
The processing unit 31 may be, for example, a central processing operator (CPU), a microcomputer, or a processing device capable of executing computer-executable instructions.

<Memory>
The storage unit 32 may be, for example, at least one of ROM, EEPROM, RAM, flash SSD, hard disk, USB memory, magnetic disk, optical disk, magneto-optical disk, and the like.
The storage unit 32 includes a program 35. When the control unit 30 is connected to the network, the program 35 may be downloaded from the network as needed.

<Program>
The program 35 may include the intensity measuring unit 35a. The strength of the heat-welded portion of the work is measured by the strength measuring unit 35a. Specifically, as shown in FIG. 7, when the work is heat-welded at a temperature lower than a predetermined temperature, the strength of the heat-welded portion of the work is low and the strength is insufficient. It should be noted that this predetermined temperature can change due to variations in the lot of the work and variations in environmental conditions such as ambient temperature. The strength measuring unit 35a may measure the peel strength, for example. The strength is not limited to the peel strength, and another strength may be measured.

<Display>
The display unit 33 may show, for example, the heat bar temperature (a), the work temperature (b), and the continuous sealing operation (c) for each heat seal in FIG. 6.

<Temperature target value correction unit>
FIG. 7 is a schematic diagram showing the relationship between the target temperature value and the occurrence of insufficient strength.
The temperature target value correction unit 24 corrects the temperature target value of the heat seal unit 10 based on the strength evaluation of the heat welded portion by the heat weld strength evaluation unit 20. Specifically, the temperature target value correction unit 24 may correct the temperature target value of the heat seal unit 10 based on the insufficient strength detected by the strength measurement unit 35a of the heat welding strength evaluation unit 20. Good. For example, the temperature target value may be increased by 1°C. That is, as shown in FIG. 7, the strength becomes insufficient as the temperature becomes lower. Therefore, in order to suppress the occurrence of the insufficient strength, this work heating device raises the target temperature value. The temperature target value may be sequentially raised, but may be set to an upper limit temperature that is an upper limit and does not cause a defective appearance due to heat welding of the work. The target temperature value may not exceed the upper limit temperature.

The temperature target value correction unit 24 sends the corrected temperature target value as the manipulated variable 1 to the heater temperature control unit. Further, the temperature target value correction unit 24 may not correct the corrected temperature target value again within a predetermined time after the correction of the temperature target value. That is, when the target temperature value is corrected, it is necessary for the heater to follow the temperature for a certain period of time. Therefore, it is possible to roughly estimate the stabilization of the heater temperature as a predetermined time, and consider that the heater temperature is not stable within the predetermined time, and not correct the target temperature value. In this case, the predetermined time may be set as appropriate, but the temperature of the heater may be measured by a temperature sensor, and when the change width falls within a predetermined range, it may be determined that the heater temperature has stabilized.

<Work heat welding method>
FIG. 8 is a flowchart of the heat welding method for the work according to the first embodiment.
(1) First, an initial value is input, or an initial value input in advance is read (S01). Specifically, the temperature target value SP is set to 150° C., and the heat sealing number n is set to zero. Further, the strength shortage flag F is set to 0. The upper limit value of the temperature target value SP is, for example, 200°C.
(2) The number n of heat sealing is updated to n+1 (S02). Specifically, 1 is added to the heat sealing number n.
(3) Heat sealing is performed n times (S03).
(4) It is determined whether the strength shortage flag F is 1 (S04). Since the strength shortage flag F is 0 at the first time, the process branches to No (S05). Insufficient strength may be detected after the second lap, and in that case, the process branches to YES (S10).
(5) When the determination of the strength insufficient flag F is No, the strength of the heat-sealed portion (heat-welded portion) is measured n times (S05).

(6) It is judged whether the strength is sufficient (S06). If it is determined that the strength is sufficient, the process branches to YES (S07). If it is determined that the strength is insufficient, the process branches to NO (S08).
(7) It is determined whether the end condition is satisfied (S07). The termination condition is, for example, when the number of heat sealing times n reaches a predetermined number of sealing times, when a stop button is pressed, or the like. If the end condition is satisfied, the process branches to YES and ends. When the end condition is not satisfied, the process branches to No (S02) and returns to the update of the heat sealing number. The termination condition is not limited to the above case.

(8) If it is determined in S06 that the strength is insufficient, 1 is substituted into the strength insufficient flag F (S08). Then, the process proceeds to S09.
(9) It is determined whether the heater temperature is stable (S08). The heater temperature is the temperature measured by the temperature sensor. The heater temperature may be the maximum temperature, the minimum temperature, or the average temperature of the heat bar for each heat seal. If the heater temperature is stable, the process branches to YES (S09). When it is determined that the heater temperature is not stable, the process branches to No (S07). This is to consider that it takes a certain time to follow the temperature in the heater when the temperature target value is corrected. That is, even if the temperature target value is corrected, the temperature of the heater does not immediately drop. Therefore, if the strength evaluation is performed as it is, the insufficient strength may be detected again. As a result, there is a problem that the temperature target value becomes cumulatively low before the heater temperature stabilizes. In this case, the temperature target value may be unintentionally lowered. In order to avoid such an inconvenience, it is effective to judge whether the heater temperature is stable. Instead of determining the stability of the heater temperature, it may be considered that the heater temperature is not stable within a predetermined time, and the process may branch to the determination of the next end condition (S07).

(10) The lower limit value of the upper limit temperature and the value obtained by increasing the original temperature target value by 1° C. is substituted into the temperature target value SP (S10). That is, a value obtained by increasing the temperature target value by 1° C. in the range of the upper limit temperature, for example, 200° C. or less is set as a new temperature target value. The function min(a,b) returns a smaller value of a and b. Then, it transfers to S11.
(11) 0 is substituted for the strength shortage flag F (S11). Then, the process proceeds to S02.
Through the above steps, the work can be heat-welded.

By the above-mentioned work heat welding method, it is possible to follow up even when there are changes in the lot of the work or environmental conditions such as ambient temperature. That is, when the strength is insufficient due to lot variation or environmental condition variation, it means that the temperature of thermal welding is lower than the appropriate temperature range (FIG. 7). Therefore, when insufficient strength is detected, by increasing the temperature target value of the heat seal portion, it becomes possible to realize heat welding in an appropriate temperature range.

(Embodiment 2)
FIG. 9 is a flowchart of the heat welding method for a work according to the second embodiment.
In contrast to the method for heat-welding a work according to the first embodiment, this method for heat-welding a work piece performs feedback so as to lower the temperature target value when the strength of the heat-welding portion is evaluated to be sufficient. The difference is in the inclusion. As a result, heat welding at high temperature can be avoided, and occurrence of poor appearance of the heat welded portion can be suppressed.

<Work heat welding method>
(1) First, an initial value is input or an initial value input in advance is read (S21). Specifically, the temperature target value SP is set to 150° C., and the heat sealing number n is set to zero. Further, the strength shortage flag F is set to 0. The upper limit of the temperature target value SP is, for example, 200° C., and the lower limit is 100° C.
(2) The number n of heat sealing is updated to n+1 (S22). Specifically, 1 is added to the heat sealing number n.
(3) Heat sealing is performed n times (S23).
(4) It is determined whether or not the strength shortage flag F is 1 (S24). Since the strength shortage flag F is 0 at the first time, the process branches to No (S25). Insufficient strength may be detected after the second lap, and in that case, the process branches to YES (S28).
(5) When the determination of the strength shortage flag F is No, the strength of the heat-sealed portion (heat-welded portion) is measured n times (S25).

(6) It is judged whether the strength of the heat-welded portion is insufficient (S26). If it is determined that the strength is insufficient, the process branches to YES (S27). If it is determined that the strength is sufficient, the process branches to NO (S31).
(7) If it is determined in S26 that the strength is insufficient, 1 is substituted into the strength insufficient flag F (S27). Then, the process proceeds to S28.

(8) It is determined whether the heater temperature is stable (S28). If the heater temperature is stable, the process branches to YES (S29). When it is determined that the heater temperature is not stable, the process branches to No (S33). This is to consider that it takes a certain time to follow the temperature in the heater when the temperature target value is corrected. In other words, even if the temperature target value is corrected, the temperature of the heater does not rise immediately, so if the strength evaluation is performed as it is, the lack of strength may be detected again. As a result, there is a problem that the temperature target value cumulatively increases before the heater temperature stabilizes. In this case, the temperature target value may unintentionally increase. In order to avoid such an inconvenience, it is effective to judge whether the heater temperature is stable. Instead of determining the stability of the heater temperature, it may be considered that the heater temperature is not stable within a predetermined time, and the process may branch to the determination of the next end condition (S33).

(9) The lower limit value of the upper limit temperature and the value obtained by increasing the original temperature target value by 1° C. is substituted into the temperature target value SP (S29). That is, the lower limit temperature, for example, a value obtained by reducing the temperature target value by 1° C. in the range of 100° C. or higher is set as the new temperature target value. The function min(a,b) returns a smaller value of a and b. Then, it transfers to S30.
(10) Substitute 0 for the appearance abnormality flag F1 (S30). Then, the process proceeds to S22.

(11) If it is determined in S06 that the strength is sufficient, it is determined whether the heater temperature is stable (S31). If the heater temperature is stable, the process branches to YES (S32). When it is determined that the heater temperature is not stable, the process branches to No (S33).
(12) When the heater temperature is stable, a higher value of the lower limit temperature and the value obtained by lowering the original temperature target value by 1° C. is substituted into the temperature target value SP (S10). That is, the lower limit temperature, for example, a value obtained by reducing the temperature target value by 1° C. in the range of 100° C. or higher is set as the new temperature target value. The function max(a,b) returns a larger value of a and b. Then, it transfers to S22.
(13) On the other hand, when it is determined in S28 or S31 that the heater temperature is not stable, it is determined whether the end condition is satisfied (S33). The termination condition is, for example, when the number of heat sealing times n reaches a predetermined number of sealing times, when a stop button is pressed, or the like. When the end condition is satisfied, the process branches to YES to end the heat welding of the work. When the end condition is not satisfied, the process branches to No (S22) and returns to the update of the heat sealing number. The termination condition is not limited to the above case.
Through the above steps, the work can be heat-welded.

By the above-mentioned work heat welding method, it is possible to follow up even when there are changes in the lot of the work or environmental conditions such as ambient temperature. Further, in comparison with the work welding method according to the first embodiment, when the strength of the heat-welded portion is evaluated to be sufficient, feedback is performed so as to lower the target temperature value. As a result, heat welding at high temperature can be avoided, and occurrence of poor appearance of the heat welded portion can be suppressed.

It should be noted that the present disclosure includes appropriately combining any of the various embodiments and/or examples described above with each embodiment, and/or each embodiment and/or example. The effects of the embodiment can be achieved.

According to the work heating device of the present invention, the strength of the heat-welded portion of the work is evaluated by the heat-welding strength evaluation unit, and based on the strength evaluation, the heat-sealed portion is fed back, so that the lot variation of the work and the surroundings It can also handle changes in environmental conditions such as temperature.

1 Work 2, 2a, 2b Heat bar 4, 4a, 4b Heater 6 Temperature sensor 8 Heater temperature control part 10 Heat seal part 20 Thermal welding strength evaluation part 22 Imaging part 24 Temperature target value correction part 30 Control part (computer device)
31 processing unit 32 storage unit 33 display unit 35 program 35a strength measuring unit 40 work heating device

Claims (7)

A heat seal part that heats and heat welds the work,
A heat-welding strength evaluation section for evaluating the strength of the heat-welded section of the work;
Based on the strength evaluation by the heat-welding strength evaluation unit, a temperature target value correction unit for correcting the temperature target value of the heat seal unit,
Work heating device equipped with. The heat welding strength evaluation unit,
A pressurizing portion for pressurizing the heat-welded portion of the work,
A strength measuring unit that detects the presence or absence of peeling of the heat-welded portion under pressure to detect insufficient strength of the heat-welded portion,
Equipped with
The workpiece heating according to claim 1, wherein the temperature target value correction unit corrects the temperature target value of the heat seal unit so as to be raised based on the insufficient strength of the heat welded unit detected by the strength measurement unit. apparatus. The strength measuring unit further confirms the presence or absence of peeling of the heat-welded portion under pressure to detect that the heat-welding portion has sufficient strength,
The temperature target value correction unit corrects the temperature target value of the heat sealing unit so as to lower the temperature target value when the strength measuring unit detects that the heat welding unit has sufficient strength. Work heating device. The heat seal portion is
With a heater,
A temperature sensor for measuring the temperature of the heater,
Based on the temperature measured by the temperature sensor, a heater temperature control unit for controlling the temperature of the heater to approach a temperature target value,
The work heating device according to any one of claims 1 to 3, further comprising: The heater temperature control unit replaces the temperature target value input in advance with the corrected temperature target value corrected by the temperature target value correction unit, and sets the heater temperature to the corrected temperature target value. The work heating device according to claim 4, wherein the work heating device is controlled to approach each other. After the strength is evaluated by the heat-welding strength evaluation unit and the temperature target value correction unit corrects the temperature target value, it is determined whether the temperature measured by the temperature sensor is stable, and the temperature is not stable. In the case, the work heating device according to claim 4, wherein the corrected temperature target value is not corrected again. The strength is evaluated by the heat welding strength evaluation unit, and the corrected temperature target value is not corrected again within a predetermined time after the temperature target value correction unit corrects the temperature target value. 5. The work heating device according to any one of 5 above.

Images