JP6966296B2 - Control method of coating equipment - Google Patents

Description

The present invention relates to a method for controlling a coating device.

A coating device that discharges a coating liquid from a nozzle to coat the surface of a work to be coated is known. Patent Document 1 describes a technique in such a coating apparatus for sucking back the coating liquid at the tip of a nozzle (sackback) for a certain period of time when stopping the discharge of the coating liquid (at the end of coating). It is disclosed.

Japanese Unexamined Patent Publication No. 2000-005682

The above-mentioned suckback is performed for the purpose of preventing the coating liquid from dripping at the end of coating. However, with a coating liquid having a viscosity higher than a predetermined value (a coating liquid having a predetermined high viscosity), the coating liquid does not drain well even if suckback is performed at the end of coating, and dripping occurs in the work. The coating liquid sometimes adhered to an unintended part. On the other hand, even in the case of a coating liquid having a relatively high viscosity, in order to allow the coating liquid to drain well at the end of coating, a suckback is performed at the end of coating and the nozzle is brought closer to the work. It is also conceivable to rub the coating liquid at the tip of the nozzle onto the surface of the work. However, if such a coating operation of the coating liquid is performed at the end of coating, the length of the coating end region in the film forming layer becomes long and the film thickness of the coating end region decreases. As a result, there is a problem that the film formation quality is remarkably deteriorated.

The present invention has been made in view of the above background, and control of a coating apparatus capable of suppressing deterioration of film formation quality at the end of coating even when a predetermined high-viscosity coating liquid is applied. The purpose is to provide a method.

In the present invention, a predetermined high-viscosity coating liquid is discharged from a nozzle to be applied to a work, and the coating liquid adhering to the discharge port of the nozzle is sucked at the end of coating the coating liquid on the work. It is a control method of a coating device capable of returning, and the coating device creates a negative pressure with respect to atmospheric pressure in the upstream space in the coating direction in the vicinity of the discharge port of the nozzle at the end of coating. A decompression chamber is provided for this purpose, and the negative pressure operation period in which the upstream space is negatively pressured with respect to the atmospheric pressure at the end of the coating wraps with the suction operation period in which the coating liquid is sucked back. Is what you do.

Due to the suction back operation, a pulling force is applied to the end of the film-forming layer toward the nozzle. On the other hand, due to the negative pressure operation, a pulling force is applied to the end portion of the film-forming layer in the coating direction. At the end of coating, the negative pressure operation period is wrapped in the suction operation period, and the edge of the film thickness layer is balanced between the force pulling toward the nozzle and the force pulling in the coating direction to improve liquid drainage. , It is possible to suppress a decrease in the film thickness at the end of the film-forming layer. As a result, even when a predetermined high-viscosity coating liquid is applied, deterioration of film formation quality can be suppressed at the end of application.

Further, during the negative pressure operation period, the upstream space is maintained at a predetermined negative pressure with respect to the atmospheric pressure. In this way, during the negative pressure operation period, the force of pulling the end of the film-forming layer toward the nozzle by the suckback operation and the force of pulling the end of the film-forming layer in the coating direction by the negative pressure operation are generated. It can be maintained in the optimum balance. As a result, the liquid drainage can be improved, and the decrease in the film thickness at the end of the film-forming layer can be suppressed more satisfactorily.

Further, the relationship between the length t of the negative pressure operation period and the discharge amount a of the coating liquid at the nozzle satisfies 2 / a ≦ t ≦ 10 / a. When the discharge amount a of the coating liquid is within the above range, the liquid drainage can be improved and the decrease in the film thickness at the end of the film-forming layer can be suppressed more effectively.

Further, during the suction back operation period, the upstream space is maintained at a predetermined negative pressure with respect to the atmospheric pressure by the negative pressure operation. During the suction back operation period, the upstream space is maintained at a predetermined negative pressure with respect to the atmospheric pressure by the negative pressure operation to improve the liquid drainage and the film thickness at the end of the film forming layer. Can be suppressed.

A predetermined high-viscosity coating liquid is discharged from the nozzle to be applied to the work, and at the end of coating the work with the coating liquid, the coating liquid adhering to the ejection port of the nozzle is sucked back. A coating device capable of performing the coating, the depressurizing chamber for making the upstream space in the coating direction in the vicinity of the ejection port and the discharge port of the nozzle a negative pressure with respect to the atmospheric pressure at the end of the coating, and the coating. A control unit is further provided so that the negative pressure operation period for making the upstream space negative pressure with respect to the atmospheric pressure at the end wraps with the suction operation period for sucking back the coating liquid. be.
At the end of coating, the control unit wraps the negative pressure operation period during the suction operation period, and balances the force that pulls the end of the film thickness layer toward the nozzle and the force that pulls it in the coating direction, thereby preventing the liquid from running out. It can be improved and the decrease in film thickness at the end of the film-forming layer can be suppressed.

According to the present invention, even when a predetermined high-viscosity coating liquid is applied, deterioration of film formation quality can be suppressed at the end of application.

It is a schematic diagram which shows the schematic structure of the coating apparatus which concerns on this embodiment. It is a schematic diagram which expanded the region (the region surrounded by the broken line A of FIG. 1) of the nozzle in the coating apparatus which concerns on this embodiment. It is an arrow view seen from the direction of the arrow B of FIG. It is a schematic diagram explaining the problem which may occur in the suckback performed at the end of coating of the coating liquid on a work. It is a schematic diagram explaining the problem which may occur in the suckback performed at the end of coating of the coating liquid on a work. It is a flowchart which shows the flow of processing in the control method of the coating apparatus which concerns on this Embodiment. It is a schematic diagram explaining the mechanism which makes it possible to satisfactorily drain the liquid while suppressing the deterioration of the film formation quality by the control method of the coating apparatus which concerns on this Embodiment. It is a list showing the result of the experiment which evaluated the relationship between the length of the negative pressure operation period and the discharge amount of the coating liquid in a nozzle. It is a graph which shows the relationship between the length of a negative pressure operation period and the length of a coating end area, and the relationship between the length of a negative pressure operation period and the edge thickness in the case of a discharge amount a = 5.7 [cc]. .. It is a graph which shows the relationship between the length of a negative pressure operation period and the length of a coating end area, and the relationship between the length of a negative pressure operation period and the edge thickness when the discharge amount a = 11.4 [cc]. .. It is a list which shows the result of the experiment which shook the viscosity of the coating liquid. It is a graph which plotted the data of the experimental result shown in FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In order to clarify the explanation, the following description and drawings have been omitted or simplified as appropriate. In each drawing, the same elements are designated by the same reference numerals, and duplicate explanations are omitted as necessary. The right-handed xyz coordinates shown in the figure are for convenience to explain the positional relationship of the components.
First, a schematic configuration of the coating apparatus 1 according to the present embodiment will be described with reference to FIG. FIG. 1 is a schematic view showing a schematic configuration of a coating device 1. As shown in FIG. 1, the coating apparatus 1 includes a coating liquid storage unit 2, a dispenser 3, a static mixer 5, a nozzle 10, and a stage 20.

In the present invention, the coating liquid has a viscosity higher than a predetermined value (a predetermined high viscosity), for example, a high viscosity of 100 [Pa · s] or more. In the present embodiment, as the coating liquid, a type in which two materials, a main agent and a curing agent, are mixed (two-component mixed coating liquid) is used. The coating liquid storage unit 2 is a tank for storing the material of the coating liquid, and is composed of a first coating liquid storage unit 2a for storing the main agent and a second coating liquid storage unit 2b for storing the curing agent. Will be done.

The dispenser 3 is for sucking the material of the coating liquid from the coating liquid storage unit 2 and supplying a predetermined amount to the static mixer 5 described later. The dispenser 3 is composed of a first dispenser 3a and a second dispenser 3b. The first dispenser 3a sucks the main agent of the coating liquid from the first coating liquid storage unit 2a and supplies a predetermined amount to the static mixer 5. Similarly, the second dispenser 3b sucks the curing agent of the coating liquid from the second coating liquid storage unit 2b and supplies a predetermined amount to the static mixer 5.

The static mixer 5 is for stirring and mixing the materials of the coating liquid supplied by the dispenser 3. The static mixer 5 has no driving portion, and a plurality of elements having a twisted portion are spirally formed inside. By arranging these a plurality of elements, the materials of the coating liquid that have entered the inside of the static mixer 5 are sequentially stirred and mixed to generate the coating liquid. The generated coating liquid is sent to the nozzle 10.

The nozzle 10 is a flat nozzle capable of discharging the coating liquid in a strip shape to the work 50 to be coated. The nozzle 10 is formed with a discharge port 10a for discharging the coating liquid. The discharge port 10a may have a protruding shape. Further, the nozzle 10 is provided with a flow rate adjusting mechanism for adjusting the discharge amount of the coating liquid.

The stage 20 is for placing the work 50. The stage 20 includes a drive mechanism 70. The drive mechanism 70 has, for example, a ball screw 70a and a servomotor 70b that rotationally drives the ball screw 70a, and can reciprocate the stage 20 in the X-axis direction. As a result, the coating liquid can be applied to the work 50 placed on the stage 20 at a predetermined coating speed, and the film forming layer 60 can be formed on the surface of the work 50. The coating device 1 may be configured such that the stage 20 is fixed and the nozzle 10 is moved to apply the coating liquid.

The coating device 1 is configured to be capable of sucking back (sucking back) the coating liquid adhering to the discharge port 10a of the nozzle 10 at the end of coating the coating liquid on the work 50. Specifically, the flow rate adjusting mechanism of the nozzle 10 described above is configured to be able to adjust not only the discharge amount of the coating liquid but also the suckback amount at the end of coating. In addition, "at the end of coating" means a period after stopping the discharge of the coating liquid from the nozzle 10 in the coating process.

Next, a detailed configuration in the vicinity of the discharge port 10a of the nozzle 10 will be described.
FIG. 2 is an enlarged schematic view of a region near the discharge port 10a of the nozzle 10 (a region surrounded by a broken line A in FIG. 1). In FIG. 2, the nozzle 10 and the decompression chamber 11 described later are shown in cross section for easy understanding of the structure. FIG. 3 is an arrow view seen from the direction of arrow B in FIG. As shown in FIGS. 2 and 3, the nozzle 10 is provided with a decompression chamber 11.

The decompression chamber 11 is for making the space 30 on the upstream side in the coating direction in the vicinity of the discharge port 10a of the nozzle 10 negative with respect to the atmospheric pressure at the end of coating. The upstream space 30 is surrounded by the discharge port 10a of the nozzle 10, the end of the film forming layer 60, the surface of the work 50, and the decompression chamber 11. The upstream space 30 communicates with the internal space 11a of the decompression chamber 11.

A vacuum pump 13 as a decompression means is connected to the decompression chamber 11 via a pipe 16 having a flow rate control valve 14. Although the upstream space 30 and the internal space 11a of the decompression chamber 11 are not completely airtight spaces, the pressure can be made negative with respect to the atmospheric pressure (absolute pressure is about several kPa) by operating the vacuum pump 13. .. A pressure gauge 15 is provided in the internal space 11a of the decompression chamber 11. As will be described later, the control unit 12 may adjust the opening degree of the flow rate control valve 14 based on the measured value of the pressure gauge 15.

Next, problems that may occur when sucking back at the end of coating with a predetermined high-viscosity coating liquid will be described.
4 and 5 are schematic views illustrating problems that may occur in the sackback performed at the end of applying the coating liquid to the work 50. Note that FIGS. 4 and 5 show a portion of the existing coating apparatus corresponding to FIG. 2, that is, the vicinity of the discharge port 10a of the nozzle 10.

As shown in the upper part of FIG. 4, if only suckback is performed at the end of coating, the high-viscosity coating liquid does not drain well, so not only the coating liquid adhering to the discharge port 10a of the nozzle 10 but also the film-forming layer 60 The end is also pulled toward the nozzle 10 (direction indicated by the arrow C). Therefore, as shown in the lower part of FIG. 4, the end portion of the film-forming layer 60 has a jagged and unstable shape, and the end portion of the film-forming layer 60 is liquid at an unintended portion (for example, a side surface portion) of the work 50. There is also a risk of dripping.

On the other hand, as shown in the upper part of FIG. 5, so that the end portion of the film forming layer 60 does not have an unstable shape, suckback is performed at the end of coating and the nozzle 10 is brought closer to the work 50 to eject the nozzle 10. There is a method of rubbing the coating liquid at the outlet 10a on the surface of the work 50. That is, the end portion of the film forming layer 60 is pressed by the discharge port 10a of the nozzle 10 in the direction opposite to the direction indicated by the arrow C (the direction indicated by the arrow D) and rubbed against the surface of the work 50. However, when such rubbing is performed, as shown in the lower part of FIG. 5, the length L of the coating end region becomes long, and the film thickness becomes the target film thickness in the coating end region length L. On the other hand, the film thickness is remarkably reduced, which causes a problem that the film thickness quality is remarkably lowered.

For example, when the work 50 is a cooler of an EV battery pack, if the length of the coating end region is long and the film thickness is thin in the film forming layer of the cooler, the coating end region is a battery. Since it cannot be brought into close contact with the stack of the pack, the heat dissipation efficiency of the cooler is reduced. In order to obtain sufficient heat dissipation performance in such a cooler having low heat dissipation efficiency, it is necessary to make the length of the cooler excessively long in anticipation of the coating end region having poor heat dissipation performance. As a result, there is a problem that the cooler becomes long and the battery pack becomes large.

Next, a control method of the coating device 1 according to the present embodiment, which is performed at the end of coating in order to deal with the above-mentioned problems, will be described below. In the following description, FIG. 3 will also be referred to as appropriate.

FIG. 6 is a flowchart showing a processing flow in the control method of the coating device 1 according to the present embodiment. As shown in FIG. 6, first, when the coating liquid has been applied to a predetermined range of the work 50, the discharge of the coating liquid from the nozzle 10 is stopped (step S1). Subsequently, along with a suction back operation (sackback operation) in which the coating liquid is sucked back, the pressure reducing chamber 11 makes the upstream space 30 in the coating direction in the vicinity of the discharge port 10a of the nozzle 10 negative pressure with respect to the atmospheric pressure. (Negative pressure operation) is performed (step S2). Subsequently, it is determined whether or not the length t of the predetermined negative pressure operation period has elapsed (step S3). In step S3, when the length t of the predetermined negative pressure operation period has elapsed (YES), the negative pressure operation and the suckback operation are stopped (step S4).

FIG. 7 is a schematic view illustrating a mechanism by which the control method of the coating apparatus 1 according to the present embodiment enables good liquid drainage while suppressing deterioration of film formation quality. Note that FIG. 7 corresponds to FIG. As described above, in the control method of the coating device 1 according to the present embodiment, at the end of coating, no rubbing is performed, and a negative pressure operation is performed together with a suckback operation. Also, the negative pressure operation period should be substantially the same as the sackback operation period.

As shown in FIG. 7, a pulling force Fz is applied to the end of the film forming layer 60 toward the nozzle 10 by the suckback operation. On the other hand, due to the negative pressure operation, a pulling force Fx is applied to the end portion of the film forming layer 60 in the coating direction. At the end of coating, the negative pressure operation period and the suckback operation period are substantially matched, and the force Fz and the force Fx are balanced to improve the liquid drainage and the film thickness at the end of the film forming layer 60. Can be suppressed.

From the above, according to the control method of the coating apparatus 1 according to the present embodiment, even when a predetermined high-viscosity coating liquid is applied, the liquid is satisfactorily suppressed at the end of coating while suppressing deterioration of the film forming quality. Can be cut.

In the control method of the coating device 1 according to the present embodiment, the upstream space 30 (see FIG. 7) may be maintained at a predetermined negative pressure with respect to the atmospheric pressure during the negative pressure operation period. Specifically, the control unit 12 acquires the measured value of the pressure in real time from the pressure gauge 15 provided in the internal space 11a of the decompression chamber 11 during the negative pressure operation period, and the measured value of the pressure is predetermined. The opening degree of the flow rate control valve 14 is adjusted so as to maintain the value of. Here, the predetermined negative pressure means that the absolute pressure is about several kPa. By doing so, during the negative pressure operation period, the force Fz that pulls the end portion of the film forming layer 60 toward the nozzle 10 by the suckback operation and the film forming layer 60 by the negative pressure operation, as shown in FIG. The force Fx that pulls the end portion in the coating direction can be maintained in an optimum balance. As a result, the liquid drainage can be improved, and the decrease in the film thickness at the end of the film forming layer 60 can be suppressed more satisfactorily. The opening degree of the flow rate control valve 14 may be adjusted manually while checking the value of the pressure gauge 15.

Next, an experiment evaluating the relationship between the length t of the negative pressure operation period and the discharge amount a of the coating liquid in the nozzle 10 will be described below. In the following description, FIG. 3 will also be referred to as appropriate.
First, the experimental conditions will be described. The configuration of the coating apparatus used in this experiment is basically the same as the configuration of the coating apparatus 1 shown in FIGS. 1 to 3. A manometer was used for the pressure gauge 15. In this experiment, an aluminum plate was used as a dummy test piece for the cooler.

The coating liquid used in the experiment was a silicon-based heat-dissipating resin having a viscosity of 205 [Pa · s] at a shear rate (shear rate) of 2.51 [1 / s]. The viscosity is a value at room temperature (30 ° C.). The coating conditions were a coating width of 60 [mm] and a coating speed of 0.75 [m / min]. Here, the coating speed (deposition speed) is equal to the moving speed of the stage 20. Further, the discharge amount a of the coating liquid in the nozzle 10 was evaluated for two patterns of 5.7 [cc] and 11.4 [cc]. Here, when the discharge amount a = 5.7 [cc] is converted into the target value of the film thickness, it becomes 3.8 mm, and when the discharge amount a = 11.4 [cc] is converted into the target value of the film thickness, it becomes 7.6 mm. become.

The suckback amount b was set to (b = −a / 2) so that the size was set to be half of the discharge amount a. That is, when the discharge amount a is 5.7 [cc], the suckback amount is -2.85 [cc], and when the discharge amount a is 11.4 [cc], the suckback amount is -5.7 [cc]. Is.

As in the control method of the coating device 1 described above, also in this experiment, the negative pressure operation period in which the upstream space 30 is made negative pressure with respect to the atmospheric pressure at the end of coating is the suction back that sucks back the coating liquid. It is made to substantially match the operation period. During the negative pressure operation period, the flow rate control valve 14 was adjusted so that the value of the pressure gauge 15 was 10 kPa. The flow rate control valve 14 was adjusted manually, not by the control unit 12, but by observing the value of the manometer.

FIG. 8 is a list showing the results of an experiment evaluating the relationship between the length of the negative pressure operation period and the discharge amount of the coating liquid at the nozzle. In FIG. 8, the relationship between the length t of the negative pressure operation period and the discharge amount a of the coating liquid in the nozzle 10 is within the range of 2 / a ≦ t ≦ 10 / a in Examples, 2 / a. Those deviating from the range of ≦ t ≦ 10 / a were used as comparative examples. Comparative Examples 1 to 5 and Examples 1 to 3 have a discharge amount a of 5.7 [cc], and Comparative Examples 6 to 9 and Examples 4 to 6 have a discharge amount a of 11.4 [cc]. .. In addition, Comparative Examples 1, 2, 6 and 7 correspond to the control method of the existing coating apparatus which has the problems described with reference to FIGS. 4 and 5. That is, Comparative Examples 1 and 6 correspond to the case of FIG. 4 in which only the sackback is rubbed, and Comparative Examples 2 and 7 correspond to the case of FIG. 5 in which the sackback is rubbed.

Here, the "length of the coating end region" means the length of the film forming layer 60 from the position where the ejection of the coating liquid from the nozzle 10 is stopped to the end. Further, the "edge thickness" means the film thickness of the coating end region in the film forming layer 60. The edge thickness may be calculated, for example, by averaging the film thicknesses of a plurality of locations measured in the coating end region.

The pass / fail judgment is passed if the "length of the coating end area" is 1 mm or less and the "edge thickness" is within ± 10% of the target value of the film thickness (marked with a circle in the list), otherwise. If so, it was rejected (x mark in the list). As described above, when the discharge amount a = 5.7 [cc], the target value of the film thickness is 3.8 mm, so the range of ± 10% of the target value of the film thickness is 3.4 mm or more and 4.2 mm. It becomes as follows. Similarly, when the discharge amount a = 11.4 [cc], the target value of the film thickness is 7.6 mm, so the range of ± 10% of the target value of the film thickness is 6.8 mm or more and 8.4 mm or less.

As shown in FIG. 8, the pass / fail judgment was passed in Examples (Examples 1 to 6) and failed in Comparative Examples (Comparative Examples 1 to 9). That is, when the relationship between the length t of the negative pressure operation period and the discharge amount a of the coating liquid in the nozzle 10 is within the range of 2 / a ≦ t ≦ 10 / a, the “length of the coating end region”. Was 1 mm or less, and the "edge thickness" was within the range of ± 10% of the target value of the film thickness. However, when the discharge amount a = 5.7 [cc], the length of the coating end region is longer in Comparative Examples 3 to 5 than in Comparative Examples 1 and 2 corresponding to the control method of the existing coating device. It turns out that it can be shortened. Further, even when the discharge amount a = 11.4 [cc], the length of the coating end region is longer in Comparative Examples 8 and 9 than in Comparative Examples 6 and 7 corresponding to the control method of the existing coating device. It turns out that it can be significantly shortened. That is, by performing the negative pressure operation together with the sackback operation so that the negative pressure operation period substantially matches the sackback operation period, deterioration of the film formation quality is suppressed as compared with the case of only the sackback operation. I was able to confirm that I could do it.

FIG. 9 shows the relationship between the length t of the negative pressure operation period and the length of the coating end region when the discharge amount a = 5.7 [cc], and the length t of the negative pressure operation period and the end thickness. It is a graph which shows the relationship with. Here, in the upper part of FIG. 9, the horizontal axis is the length t of the negative pressure operation period, and the vertical axis is the length of the coating end region. Further, in the lower part of FIG. 9, the horizontal axis is the length t of the negative pressure operation period, and the vertical axis is the end thickness. This graph is a plot of the data of Comparative Examples 3 to 5 and Examples 1 to 3 which are the experimental results of the discharge amount a = 5.7 [cc] shown in FIG.

As shown in FIG. 9, when the length t of the negative pressure operation period is within the range of 2 / a ≦ t ≦ 10 / a, both the length of the coating end region and the edge thickness are substantially constant values. ing. When the length t of the negative pressure operation period is shorter than 2 / a, the length of the coating end area cannot reach the target of 1 mm or less (longer than 1 mm), and the edge thickness also becomes thicker than the target value + 10%. .. Further, when the length t of the negative pressure operation period is longer than 10 / a, the length of the coating end region cannot reach the target of 1 mm or less, and the edge thickness becomes thinner than the target value + 10%. This is because when the length t of the negative pressure operation period is made too long, the force Fz that pulls the end portion of the film forming layer 60 toward the nozzle 10 by the suckback operation is compared with the force Fz of the film forming layer 60 due to the negative pressure operation. It is considered that the force Fx (see FIG. 7) that pulls the end portion in the coating direction becomes excessive.

FIG. 10 shows the relationship between the length t of the negative pressure operation period and the length of the coating end region when the discharge amount a = 11.4 [cc], and the length t of the negative pressure operation period and the end thickness. It is a graph which shows the relationship with. Here, in the upper part of FIG. 10, the horizontal axis is the length t of the negative pressure operation period, and the vertical axis is the length of the coating end region. Further, in the lower part of FIG. 10, the horizontal axis is the length t of the negative pressure operation period, and the vertical axis is the end thickness. In addition, this graph is a plot of the data of Comparative Examples 8 to 9 and Examples 4 to 6, which are the experimental results of the discharge amount a = 11.4 [cc] shown in FIG.

As shown in FIG. 10, when the length t of the negative pressure operation period is within the range of 2 / a ≦ t ≦ 10 / a, the same as in the case of the discharge amount a = 5.7 [cc] shown in FIG. , Both the length of the coating end area and the edge thickness are almost constant values. Further, in the case of the discharge amount a = 11.4 [cc] shown in FIG. 10, the same was true for the other tendencies considered for the graph of FIG.

From the above, as shown by the results of the above-mentioned experiment, the relationship between the length t of the negative pressure operation period and the discharge amount a of the coating liquid at the nozzle 10 is determined.
2 / a ≤ t ≤ 10 / a
By satisfying the above conditions, the length of the coating end region at the end of the film forming layer 60 can be shortened, and the decrease in the film thickness of the coating end region can be satisfactorily suppressed.

Next, an experiment in which the viscosity of the coating liquid is changed will be described below. In the following description, FIG. 3 will also be referred to as appropriate.
The configuration of the coating apparatus used in this experiment is the same as the above-mentioned experiment evaluated for the relationship between the length t of the negative pressure operation period and the discharge amount a of the coating liquid at the nozzle 10. Also in this experiment, an aluminum plate was used as a dummy test piece for the cooler. The coating conditions are basically the same as in the above experiment, with a coating width of 60 [mm] and a coating speed of 0.75 [m / min]. The discharge amount a of the coating liquid in the nozzle 10 was set to 5.7 [cc], and the size of the suckback amount b was set to half the discharge amount a, that is, -2.85 [cc].

The coating liquid used in this experiment had a viscosity of 2.51 [1 / s] and was 2.4 [Pa · s], 34 [Pa · s], 103 [Pa · s], 205 [Pa · s]. There are four patterns. The viscosity is a value at room temperature (30 ° C.).

In this experiment, for each of the coating liquids having the above four patterns of viscosity, at the end of coating, a case where a rubbing operation is performed together with a sackback operation and a case where a negative pressure operation is performed together with a sackback operation are performed. Each was evaluated. The control method of the coating device when the negative pressure operation is performed together with the suckback operation is evaluated by the relationship between the length t of the negative pressure operation period and the discharge amount a of the coating liquid in the nozzle 10 described above. Same as the experiment. That is, the flow rate control valve 14 was adjusted so that the negative pressure operation period substantially coincided with the suction operation period at the end of coating and the value of the pressure gauge 15 became 10 kPa during the negative pressure operation period.

FIG. 11 is a list showing the results of an experiment in which the viscosity of the coating liquid was changed. Further, FIG. 12 is a graph in which the data of the experimental results shown in FIG. 11 are plotted. Here, in the upper part of FIG. 12, the horizontal axis is the viscosity and the vertical axis is the length of the coating end region. Further, in the lower part of FIG. 12, the horizontal axis is the viscosity and the vertical axis is the end thickness.

As shown in FIGS. 11 and 12, when the rubbing operation is performed together with the suckback operation, the viscosity of the coating liquid is relatively low, 2.4 [Pa · s] and 34 [Pa · s]. In, the length of the coating end area became 1 mm or less, which is the target. However, when the rubbing operation is performed together with the suckback operation, the length of the coating end region is aimed at at 103 [Pa · s] and 205 [Pa · s], where the viscosity of the coating liquid is relatively high. It has deviated significantly from 1 mm or less. In addition, when the rubbing operation is performed together with the suckback operation, the edge thickness of the coating liquid of any viscosity is about -39 to 56% with respect to the target 3.42 mm, which is extremely thin. It ends up.

On the other hand, when the negative pressure operation is performed together with the suckback operation, the coating end area length is aimed at 103 [Pa · s] and 205 [Pa · s], where the viscosity of the coating liquid is relatively high. It became 1 mm or less. However, when the negative pressure operation is performed together with the suckback operation, the coating end region length is set at 2.4 [Pa · s] and 34 [Pa · s], where the viscosity of the low-viscosity coating liquid is relatively low. Deviated from the target of 1 mm or less and became about 2 mm. However, when the negative pressure operation was performed together with the suckback operation, the end thickness was about -7 to + 17% with respect to the target 3.42 mm, and both were within the range of ± 20%.

From the above, when the negative pressure operation is performed together with the suckback operation at the end of coating, the coating end region is formed in 103 [Pa · s] and 205 [Pa · s] where the viscosity of the coating liquid is relatively high. It was confirmed that the target length was 1 mm or less. That is, it can be said that the control method of the coating device 1 according to the present embodiment is effective for a coating liquid having a high viscosity of 100 [Pa · s] or more.

The present invention is not limited to the above embodiment, and can be appropriately modified without departing from the spirit. In the above embodiment, the negative pressure operation period is substantially the same as the sackback operation period, but there is no problem even if the negative pressure operation period is slightly different from the sackback operation period. That is, the negative pressure operation period may wrap with the suction operation period.

1 Coating device 2 Coating liquid storage 2a 1st coating liquid storage 2b 2nd coating liquid storage 3 Dispenser 3a 1st dispenser 3b 2nd dispenser 5 Static mixer 10 Nozzle 10a Discharge port 11 Decompression chamber 11a Internal space 12 Control unit 13 Vacuum pump 14 Flow control valve 15 Pressure gauge 16 Piping 20 Stage 30 Upstream space 50 Work 60 Formation layer 70 Drive mechanism 70b Servo motor

Claims (4)

A predetermined high-viscosity coating liquid is discharged from a nozzle to be applied to a work, and at the end of application of the coating liquid to the work, the coating liquid adhering to the discharge port of the nozzle is sucked back. It is a control method of the coating equipment that can be used.
The coating device includes a decompression chamber for making the space on the upstream side in the coating direction in the vicinity of the discharge port of the nozzle a negative pressure with respect to atmospheric pressure at the end of coating.
The viscosity of the coating liquid is 100 Pa · s or more, and the viscosity is set to 100 Pa · s or more.
The negative pressure operation period in which the upstream space is made negative with respect to the atmospheric pressure at the end of the coating wraps with the suction operation period in which the coating liquid is sucked back.
The relationship between the length t of the negative pressure operation period and the discharge amount a of the coating liquid at the nozzle is
2 / a ≤ t ≤ 10 / a
How to control the coating equipment to meet the requirements. The method for controlling a coating device according to claim 1, wherein the upstream space is maintained at a predetermined negative pressure with respect to atmospheric pressure during the negative pressure operation period. The control method for a coating device according to claim 1 or 2, wherein the upstream space is maintained at a predetermined negative pressure with respect to atmospheric pressure by the negative pressure operation during the suction back operation period. A predetermined high-viscosity coating liquid is discharged from a nozzle to be applied to a work, and at the end of application of the coating liquid to the work, the coating liquid adhering to the discharge port of the nozzle is sucked back. It is a coating device that can
At the end of the coating, a decompression chamber for making the space on the upstream side in the coating direction in the vicinity of the discharge port of the nozzle negative with respect to the atmospheric pressure,
A pressure gauge that measures the pressure in the upstream space,
The negative pressure operation period in which the upstream space is made negative with respect to the atmospheric pressure based on the measured value of the pressure gauge at the end of the coating wraps with the suction operation period in which the coating liquid is sucked back. With a control unit,
The viscosity of the coating liquid is 100 Pa · s or more, and the viscosity is set to 100 Pa · s or more.
The control unit
The relationship between the length t of the negative pressure operation period and the discharge amount a of the coating liquid at the nozzle is
2 / a ≤ t ≤ 10 / a
A coating device that meets the requirements.

Images