JP2020132166A - Work heating device - Google Patents

Abstract

To provide a work heating device that can address a lot change of a work and change in environmental condition such as ambient temperature.SOLUTION: A work heating device includes: a heat seal part for heating and thermally welding a work; a thermal welding strength evaluation part for evaluating a strength of a thermally welded part of the work; and a temperature target value correction part for correcting a temperature target value of the heat seal part on the basis of a strength evaluation by the thermal welding strength evaluation part.SELECTED DRAWING: Figure 1

Description

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

Conventionally, before production, the conditions under which no abnormality occurs in the heat-welded portion of the work are visually changed by trial and error. The conditions in this case are, for example, heat treatment conditions such as a temperature target value for heat welding and a heat treatment time. Moreover, at the time of actual production, the heat treatment conditions were fixed and operated.

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

Japanese Unexamined Patent Publication No. 5-162723

In the temperature control method of Patent Document 1, the seal strength varies widely due to the lot variation of the packaging material and the variation of the environmental conditions such as the ambient temperature, and defective products are likely to occur. For example, when the initial temperature of the packaging material decreases, the thickness of the packaging material increases, or the air conditioning air volume increases, the temperature of the heat-sealed portion decreases, and the heat-welded portion of the work is sealed. The strength is reduced and defects are likely to occur.

Therefore, an object of the present invention is to provide a work heating device capable of responding to fluctuations in lots of workpieces and fluctuations in environmental conditions such as ambient temperature.

The work heating device according to the present invention includes a heat seal portion that heats the work and heat-welds it.
A heat welding strength evaluation unit that evaluates the strength of the heat welding unit of the work,
A temperature target value correction unit that corrects the temperature target value of the heat seal unit based on the strength evaluation by the heat welding strength evaluation unit,
To be equipped.

According to the work heating device according to the present invention, the strength of the heat-welded portion of the work is evaluated by the heat-welded strength evaluation unit, and the strength is fed back to the heat-sealed portion based on the strength evaluation. It can respond to fluctuations in environmental conditions such as temperature.

It is a block diagram which shows the structure of the work heating apparatus which concerns on Embodiment 1. FIG. It is a block diagram which shows the internal structure of the heat welding strength evaluation part of FIG. It is a block diagram which shows the physical structure and the functional structure of the heat welding strength evaluation part of FIG. It is the schematic which shows an example of the appearance of the heat bar of the work heating apparatus which concerns on Embodiment 1. FIG. It is the schematic which shows the heat bar and the temperature sensor of the work heating apparatus of FIG. It is the schematic which shows the relationship between the temperature of a heat bar of FIG. 4, the temperature of a work, and a sealing operation. It is the schematic which shows the relationship between the temperature target value and the occurrence of lack of strength. It is a flowchart of the heat welding method of the work which concerns on Embodiment 1. FIG. It is a flowchart of the heat welding method of the work which concerns on Embodiment 2.

The work heating device according to the first aspect includes a heat seal portion that heats and heat-welds the work.
A heat welding strength evaluation unit that evaluates the strength of the heat welding unit of the work,
A temperature target value correction unit that corrects the temperature target value of the heat seal unit based on the strength evaluation by the heat welding strength evaluation unit,
To be equipped.

In the work heating device according to the second aspect, in the first aspect, the heat welding strength evaluation unit is
A pressurizing part that pressurizes the heat-welded part of the work,
A strength measuring unit that confirms the presence or absence of peeling of the pressurized heat-welded portion and detects an insufficient strength of the heat-welded portion.
With
The temperature target value correction unit may make corrections so as to raise the temperature target value of the heat seal unit based on the insufficient strength of the heat-welded unit detected by the strength measurement unit.

In the work heating device according to the third aspect, in the second aspect, the strength measuring unit further confirms the presence or absence of peeling of the pressurized heat-welded portion, and the heat-welded portion has sufficient strength. Detected to have
When the strength measuring unit detects that the heat-welding unit has sufficient strength, the temperature target value correcting unit may correct the temperature target value of the heat sealing unit so as to lower it.

In the work heating device according to the fourth aspect, in any one of the first to third aspects, the heat seal portion is
With a heater
A temperature sensor that measures the temperature of the heater and
A heater temperature control unit that controls the temperature of the heater to approach the temperature target value based on the temperature measured by the temperature sensor.
May be provided.

In the work heating device according to the fifth aspect, in the fourth aspect, the heater temperature control unit corrects the temperature target value input in advance by the temperature target value correction unit, and the corrected temperature target value is corrected. May be replaced with to control the temperature of the heater so as to approach the corrected temperature target value.

The work heating device according to the sixth aspect evaluates the strength by the heat welding strength evaluation unit in the fourth aspect, corrects the temperature target value by the temperature target value correction unit, and then corrects the temperature target value, and then the temperature sensor. It is not necessary to correct the corrected temperature target value again when it is determined whether or not the temperature measured in 1 is stable and the temperature is not stable.

The work heating device according to the seventh aspect evaluates the strength by the heat welding strength evaluation unit in any one of the first to fifth aspects, and corrects the temperature target value by the temperature target value correction unit. It is not necessary to correct the corrected temperature target value again within a predetermined time after the correction.

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

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of a work heating device 40 according to a 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 view 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 sealing 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 sealing portion 10 and heat-welded. The heat welding strength evaluation unit 20 evaluates the strength of the heat welding part 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 heat welding strength evaluation unit 20 evaluates the strength of the heat welding part of the work 1 and feeds back to the heat sealing part 10 based on the strength evaluation, so that the lot variation of the work 1 It can also respond to 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 and 2b are, for example, heated with the work 1 sandwiched between them and heat-welded. Further, in the examples of FIGS. 4 and 5, 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 FIG. 4, the work 1 has a continuous bag shape, and is heat-welded by heat bars 2a and 2b at predetermined intervals. As shown in FIGS. 1 and 5, the heat bar 2 includes heaters 4, 4a and 4b, and a temperature sensor 6 for measuring the temperatures of the heaters 4, 4a and 4b. The heaters 4a and 4b may be provided in each of the two heat bars 2a and 2b as shown in FIG. 5, or may be provided only in one of the heat bars. Further, the temperature sensor 6 is provided at a position separated from the work 1 by a predetermined interval, but the present invention is not limited to this, and the temperature sensor 6 may be provided close to the work 1.

FIG. 6 is a schematic view 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. 6 (c) is a schematic view showing the operation and the stop during the continuous sealing operation.
As shown in FIG. 6A, the heat bars 2, 2a and 2b are temperature-controlled so as to approach the temperature target value due to heat welding of the work 1. In this case, since the heat bar comes into contact with the work at the start of the continuous sealing operation, the temperature of the heat bar drops somewhat, and during the continuous sealing operation, the steady heat conduction to the work is in equilibrium. The temperature becomes stable. The continuous sealing of the workpieces is performed, for example, in 0.1 to 2 seconds for each workpiece. At the end of continuous sealing, the temperature of the heat bar returns to a temperature close to the temperature target value.

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 by, for example, an operation amount 2 based on a current value, a voltage value, or the like. 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, the temperature target value is replaced with the initial temperature target value by the temperature target value correction amount from the temperature target value correction unit or the operation amount 1 of the corrected temperature target value itself. After that, the heater temperature control unit 8 sequentially replaces the temperature target value with the operation amount 1 of the temperature target value correction amount from the temperature target value correction unit.

<Heat welding strength evaluation unit>
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 pressurizing unit 22 and a strength measuring unit 35a. Further, the heat 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. A constant pressing force or tensile force is applied to the heat-welded portion of the work by the pressing portion 22. 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. As this computer device, a general-purpose computer device can be used, and for example, as shown in FIG. 3, a processing unit 31, a storage unit 32, and a display unit 33 are included. Further, an input device, a storage device, an interface and the like may be included. The pressurizing unit 22 is controlled by the control unit 30.

<Processing unit>
The processing unit 31 may be, for example, a central processing unit (CPU), a microcomputer, or a processing device capable of executing instructions that can be executed by the computer.

<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 the 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 strength 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 fluctuations in the lot of workpieces and fluctuations 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 other strengths may be measured.

<Display unit>
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 shown in FIG.

<Temperature target value correction unit>
FIG. 7 is a schematic view showing the relationship between the temperature target value and the occurrence of insufficient strength.
The temperature target value correction unit 24 corrects the temperature target value of the heat sealing unit 10 based on the strength evaluation of the heat welding unit by the heat welding strength evaluation unit 20. Specifically, even if the temperature target value correction unit 24 corrects to raise the temperature target value of the heat seal unit 10 based on the strength shortage detected by the strength measurement unit 35a of the heat welding strength evaluation unit 20. Good. For example, the temperature target value may be raised by 1 ° C. That is, as shown in FIG. 7, the strength becomes insufficient as the temperature becomes low. Therefore, in order to suppress the occurrence of the insufficient strength, the temperature target value is raised in this work heating device. The temperature target value may be raised sequentially, but an upper limit temperature may be set so that appearance defects do not occur due to heat welding of the work. The temperature target value may not exceed this upper limit temperature.

The temperature target value correction unit 24 transmits the corrected and corrected temperature target value as the operation amount 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 temperature target value is corrected. That is, when the temperature target value is corrected, it takes a certain period of time to follow the temperature in the heater. Therefore, it is possible to estimate the time until the heater temperature stabilizes as a predetermined time, consider that the heater temperature is not stable within the predetermined time, and do not correct the temperature target value. In this case, the predetermined time may be set as appropriate, but the temperature of the heater may be measured by the temperature sensor, and it may be determined that the heater temperature is stable when the change width is within the predetermined range.

<Heat welding method of workpiece>
FIG. 8 is a flowchart of a work welding method according to the first embodiment.
(1) First, the initial value is input, or the initial value input in advance is read (S01). Specifically, the temperature target value SP is set to 150 ° C., and the number of heat seals n is set to 0. Further, the insufficient strength flag F is set to 0. The upper limit of the temperature target value SP is, for example, 200 ° C.
(2) The number of heat seals n is updated to n + 1 (S02). Specifically, 1 is added to the number of heat seals n.
(3) The nth heat seal is executed (S03).
(4) It is determined whether or not the strength insufficient flag F is 1. (S04). Since the strength insufficient flag F is 0 when the first operation is performed, 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 insufficient strength flag F is No, the strength of the nth heat-sealed portion (heat-welded portion) is measured (S05).

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

(8) When it is determined in S06 that there is insufficient strength, 1 is substituted for the insufficient strength flag F (S08). Then, it shifts 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 either the maximum temperature, the minimum temperature, or the average temperature of the heat bar for each heat seal. When the heater temperature is stable, it branches to YES (S09). If it is determined that the heater temperature is not stable, it branches to No (S07). This is because it takes a certain period of 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 drop immediately. Therefore, if the strength is evaluated as it is, insufficient strength may be detected again. As a result, there is a problem that the temperature target value is cumulatively lowered before the heater temperature becomes stable. In this case, the temperature target value may be unintentionally lowered. In order to avoid such inconvenience, it is effective to determine 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 the predetermined time, and the process may be branched to the determination of the next end condition (S07).

(10) Substitute the lower value of the upper limit temperature and the value raised by 1 ° C. from the original temperature target value into the temperature target value SP (S10). That is, the upper limit temperature, for example, a value obtained by raising the temperature target value by 1 ° C. in the range of 200 ° C. or lower is set as the new temperature target value. The function min (a, b) returns a smaller value among a and b. After that, it shifts to S11.
(11) Substitute 0 for the insufficient strength flag F (S11). After that, it shifts to S02.
By the above steps, the work can be heat-welded.

By the above-mentioned heat welding method of the work, even if there is a change in the lot of the work or a change in the environmental conditions such as the ambient temperature, it can be followed and dealt with. That is, when the strength is insufficient due to the fluctuation of the lot or the fluctuation of the environmental conditions, it means that the temperature of the heat welding is lower than the appropriate temperature range (Fig. 7). Therefore, when insufficient strength is detected, heat welding in an appropriate temperature range can be realized by increasing the temperature target value of the heat-sealed portion.

(Embodiment 2)
FIG. 9 is a flowchart of a work welding method according to the second embodiment.
Compared with the heat welding method of the work according to the first embodiment, the heat welding method of this work provides feedback so as to lower the temperature target value when it is evaluated that the strength of the heat welding portion is sufficient. It differs in that it includes. As a result, heat welding at a high temperature can be avoided, and the occurrence of poor appearance of the heat-welded portion can be suppressed.

<Heat welding method of workpiece>
(1) First, the initial value is input, or the initial value input in advance is read (S21). Specifically, the temperature target value SP is set to 150 ° C., and the number of heat seals n is set to 0. Further, the insufficient strength 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 of heat seals n is updated to n + 1 (S22). Specifically, 1 is added to the number of heat seals n.
(3) The n-th heat seal is executed (S23).
(4) It is determined whether or not the strength insufficient flag F is 1. (S24). Since the strength insufficient flag F is 0 when the first operation is performed, the process branches to No (S25). After the second lap, insufficient strength may be detected, and in that case, the process branches to YES (S28).
(5) When the determination of the insufficient strength flag F is No, the strength of the nth heat-sealed portion (heat-welded portion) is measured (S25).

(6) It is determined 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, it branches to NO (S31).
(7) When it is determined in S26 that the strength is insufficient, 1 is substituted for the strength insufficient flag F (S27). Then, it shifts to S28.

(8) It is determined whether the heater temperature is stable (S28). When the heater temperature is stable, it branches to YES (S29). If it is determined that the heater temperature is not stable, it branches to No (S33). This is because it takes a certain period of 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 rise immediately. Therefore, if the strength is evaluated as it is, insufficient strength may be detected again. As a result, there is a problem that the temperature target value is cumulatively increased before the heater temperature stabilizes. In this case, the temperature target value may be unintentionally high. In order to avoid such inconvenience, it is effective to determine 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 the predetermined time, and the process may be branched to the determination of the next end condition (S33).

(9) Substitute the lower value of the upper limit temperature and the value raised by 1 ° C. from the original temperature target value into the temperature target value SP (S29). That is, the lower limit temperature, for example, a value obtained by lowering 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 among a and b. After that, it shifts to S30.
(10) Substitute 0 for the appearance abnormality flag F1 (S30). After that, it shifts to S22.

(11) When it is determined in S06 that the strength is sufficient, it is determined whether the heater temperature is stable (S31). When the heater temperature is stable, it branches to YES (S32). If it is determined that the heater temperature is not stable, it branches to No (S33).
(12) When the heater temperature is stable, the higher value of the lower limit temperature and the value lowered by 1 ° C. from the original temperature target value is substituted into the temperature target value SP (S10). That is, the lower limit temperature, for example, a value obtained by lowering 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 among a and b. After that, it shifts 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 termination condition is satisfied (S33). The end condition is, for example, when the number of heat seals n reaches the planned number of seals, when the stop button is pressed, and the like. If the end condition is satisfied, the process branches to YES and the heat welding of the work is completed. If the end condition is not satisfied, the process branches to No (S22) and returns to the update of the number of heat seals. The termination condition is not limited to the above case.
By the above steps, the work can be heat-welded.

By the above-mentioned heat welding method of the work, even if there is a change in the lot of the work or a change in the environmental conditions such as the ambient temperature, it can be followed and dealt with. Further, in comparison with the work welding method of the first embodiment, when it is evaluated that the strength of the heat-welded portion is sufficient, feedback is given so as to lower the temperature target value. As a result, heat welding at a high temperature can be avoided, and the 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, and the respective embodiments and / or embodiments. The effects of the examples can be achieved.

According to the work heating device according to the present invention, the strength of the heat-welded portion of the work is evaluated by the heat-welded strength evaluation unit, and the strength is fed back to the heat-sealed portion based on the strength evaluation. It can respond to fluctuations in environmental conditions such as temperature.

1 Work 2, 2a, 2b Heat bar 4, 4a, 4b Heater 6 Temperature sensor 8 Heater temperature control unit 10 Heat seal unit 20 Heat welding strength evaluation unit 22 Imaging unit 24 Temperature target value correction unit 30 Control unit (computer device)
31 Processing unit 32 Storage unit 33 Display unit 35 Program 35a Strength measurement unit 40 Work heating device

Claims (7)

A heat seal part that heats the work and heat-welds it,
A heat welding strength evaluation unit that evaluates the strength of the heat welding unit of the work,
A temperature target value correction unit that corrects the temperature target value of the heat seal unit based on the strength evaluation by the heat welding strength evaluation unit,
A work heating device equipped with. The heat welding strength evaluation unit
A pressurizing part that pressurizes the heat-welded part of the work,
A strength measuring unit that confirms the presence or absence of peeling of the pressurized heat-welded portion and detects an insufficient strength of the heat-welded portion.
With
The work heating according to claim 1, wherein the temperature target value correction unit corrects to raise the temperature target value of the heat seal portion based on the insufficient strength of the heat-welded portion detected by the strength measurement unit. apparatus. The strength measuring unit further confirms the presence or absence of peeling of the pressurized heat-welded portion and detects that the heat-welded portion has sufficient strength.
The second aspect of the present invention, wherein when the strength measuring unit detects that the heat-welded portion has sufficient strength, the temperature target value correcting unit corrects the temperature target value of the heat sealing unit so as to lower it. Work heating device. The heat seal portion is
With a heater
A temperature sensor that measures the temperature of the heater and
A heater temperature control unit that controls the temperature of the heater to approach the temperature target value based on the temperature measured by the temperature sensor.
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 temperature of the heater to the corrected temperature target value. The work heating device according to claim 4, which is controlled so as to be close to each other. The strength is evaluated by the heat welding strength evaluation unit, and after the temperature target value correction unit corrects the temperature target value, it is determined whether or not the temperature measured by the temperature sensor is stable, and the temperature is not stable. In this case, the work heating device according to claim 4, wherein the corrected temperature target value is not corrected again. From claim 1, the strength is evaluated by the heat welding strength evaluation unit, and the temperature target value correction unit does not correct the corrected temperature target value again within a predetermined time after the temperature target value is corrected. 5. The work heating device according to any one of 5.

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