JP4609785B2 - Steel workpiece coating apparatus and steel workpiece coating method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a coating apparatus or a coating method capable of forming a uniform coating film without unevenness on a steel workpiece having a complicated shape such as an iron pipe joint, and in particular, the adhesion of the coating film to a steel workpiece. The present invention relates to a steel workpiece coating apparatus and a steel workpiece coating method that improve the efficiency of the painting work by omitting the degreasing step and thus increase the productivity.
[0002]
[Prior art]
The conventional coating method first performs degreasing to remove foreign substances such as oils and fats adhering to the surface of the steel workpiece to be painted, then passes through washing, draining and drying processes, followed by painting, dry baking by irradiation with far infrared rays, and cooling. Each process was performed.
However, dry baking by far-infrared irradiation heats the paint from the outside, and especially for steel workpieces with complex shapes, there is a tendency for the paint surface to be over-baked and for the paint fixing surface to be under-baked. Was uneven. Further, drying and baking by irradiation with far infrared rays has a drawback that it takes time to dry. Furthermore, if uniform drying is performed by far-infrared irradiation, the apparatus becomes large, making it difficult to secure the installation space and increasing the equipment cost.
[0003]
Moreover, in the above-mentioned conventional coating method, it is necessary to degrease the steel workpiece prior to coating. This is because, in the case of heating from the outside by irradiation with far infrared rays, when foreign matter such as oil or fat is present at the interface between the steel workpiece and the coating film, the adhesion is insufficient and the coating film peels off.
However, it is natural that the degreasing process is performed on all individual steel workpieces, which is extremely complicated and greatly hinders the efficiency of the painting operation.
In addition, when painting steel workpieces, work hangers that hold a large number of steel workpieces are used, but as the coating is repeated, the scattered excess paint adheres to the work hangers and is heated and strengthened. In order to stick, it was necessary to perform an additional work of peeling off the excess paint attached to the stick.
[0004]
[Problems to be solved by the invention]
In consideration of the problems of the conventional technology, the present invention makes it possible to form a uniform and strong coating film without unevenness, further downsizing the apparatus, and further improving the efficiency of the painting work. It is an object of the present invention to provide a useful steel workpiece coating apparatus and to establish a steel workpiece coating method.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the invention described in claim 1 is directed to a coating device for applying a powder coating to the surface of a steel workpiece by electrostatic induction, and a high frequency to the steel workpiece to which the powder coating is applied. In a steel workpiece coating apparatus equipped with a high frequency induction heating device that heats, solidifies and dries a steel workpiece and powder paint, the inside of a cylindrical cylindrical working chamber is partitioned, and a communication processing chamber And a coating processing chamber and a drying processing chamber are provided along the conveying direction, and a rotation shaft at the center of the work chamber, a rotation arm extending radially from the rotation shaft, and a free end side of the rotation arm. A conveying device comprising a work hanger that holds the steel work piece in a suspended state, an arm drive motor that rotates the rotating shaft, and a work reversing motor that rotates the work hanger relative to the rotating arm. A nozzle of the paint applicator provided outside the working chamber faces the coating processing chamber, and a high-frequency induction coil of the high-frequency induction device has a concave shape in the drying processing chamber so that the open portion faces upward. The steel workpiece is suspended and held by the work hanger in the communication processing chamber and taken into the work chamber. In the coating processing chamber, the paint is uniformly applied to the surface of the steel workpiece by the rotation of the work hanger. In the drying process chamber, it is heated without being coated in the slit of the concave portion of the induction coil, returned to the communication process chamber, and carried out from there .
[0006]
According to a second aspect of the present invention, in the steel workpiece coating apparatus according to the first aspect, the work hanger is made of copper that is not heated by high frequency.
[0008]
According to a third aspect of the present invention, there is provided a steel workpiece coating method carried out using the steel workpiece coating apparatus according to the first or second aspect, wherein the powder coating is applied to the surface of the steel workpiece by electrostatic induction. It has a coating application process to be applied and a high frequency induction heating process in which a high frequency is applied to the steel workpiece coated with the powder coating, the powder coating is heated from the inside, solidified, and dried. Become.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the steel workpiece coating apparatus 1 of the present invention will be described in detail by taking the embodiment shown in FIGS. 1 to 3 as an example, and the steel workpiece coating method of the present invention will be described together with the description of the operation thereof.
The steel workpiece coating apparatus 1 according to the present invention is used when, for example, coating is performed on a steel workpiece 3 having a complicated shape such as an iron pipe joint.
Specifically, as shown in FIGS. 1 and 2, the inside of the cylindrical container-like working chamber 5 is divided into six processing chambers 7, 9, 11, 13, 15, and 17 as an example, and each processing chamber 7, 9 is further divided. , 11, 13, 15, and 17, an accessory device for performing individual processing and a transport device 19 that holds and transports the steel workpiece 3 are provided.
[0010]
Among them, the communication processing chamber 7 receives the steel workpiece 3 conveyed from the outside by the conveying conveyor 21 into the working chamber 5 and, after the completion of a series of painting operations, again communicates with the outside conveying chamber 21 to the outer conveying conveyor 21. As a role. A rotating shaft 23 is provided at the center of the working chamber 5, and six rotating arms 25 extending radially are provided as an example at the upper portion of the rotating shaft 23.
Further, the rotation of the output shaft of the arm drive motor 27 is transmitted to the rotation shaft 23 through appropriate transmission means 29 such as a chain and a timing belt.
[0011]
A work hanger 31 for holding the steel work 3 in a suspended state is provided on the free end side of the rotary arm 25. The work hanger 31 can be rotated by 180 degrees as an example by a work reversing motor 33. It can be configured.
The work hanger 31 is configured by attaching a plurality of holding arm rods 37 that are arranged horizontally with an appropriate interval to a suspension rod 35 that is suspended in the vertical direction. The work hanger 31 is made of copper as an example of a material that is not heated by high frequency.
The transfer device 19 includes the rotation shaft 23, the rotation arm 25, the drive motor 27, the transmission means 29, and the work hanger 31 to which the transfer conveyor 21 is added.
[0012]
A coating processing chamber 9 is provided adjacent to the communication processing chamber 7 in the workpiece conveyance direction, and a coating processing chamber 11 is provided next to the coating processing chamber 9. The coating processing chamber 9 and the coating processing chamber 11 are basically arranged in parallel in order to cope with the production of various kinds of products in small quantities. Comb-like nozzles 41 of a paint application device 39 provided outside the working chamber 5 face the coating processing chambers 9 and 11, respectively.
[0013]
The coating material application device 39 is a device that applies the powder coating material P to the surface of the steel workpiece 3 by using an electrostatic induction action. The reason why the powder paint P is used here is that a solvent is required when the liquid paint is used, but it is not used in consideration of the fact that the solvent is a factor such as environmental pollution.
A suction duct 45 is connected to the coating processing chambers 9 and 11. The suction duct 45 is connected to a recovery device 43 that recovers excess powder paint P that has not been used for coating the steel workpiece 3.
Adjacent to the coating processing chamber 11 in the workpiece conveyance direction, there is provided a drying processing chamber 13 that functions as a heating chamber for heating, solidifying and drying the powder coating P applied to the surface of the steel workpiece 3.
In the drying processing chamber 13, an induction heating coil 49 having a cross-sectional “concave” shape, which is a part of the high-frequency induction heating device 47, has a steel work 3 and a work hanger 31 that are conveyed with the open part up. The slit 51 is provided toward the workpiece conveyance direction side so that it can pass through.
[0015]
The induction heating coil 49 is supplied to the steel workpiece 3 by receiving a current from an induction heating power supply device 53 which is another part of the high frequency induction heating device 47 and applying a high frequency current to the steel workpiece 3. The powder coating P is heated from the inside. Although illustration is omitted, in order to prevent excessive heat generation of the induction heating coil 49, a pipe line for flowing cooling water is provided in the induction heating coil 49.
[0016]
When the coating film is formed by using induction heating by high frequency in this way, the powder coating material P is heated from the inside, solidified and dried. Therefore, even if a small amount of foreign matter such as fats and oils adheres to the surface of the steel workpiece 3, they are vaporized by heating and disappear from the interface between the iron and the coating film, so there is no shortage of adhesion. The degreasing process which becomes is unnecessary.
Further, the hanger 31 is made of a material that is not heated by high frequency, for example, copper, and the powder paint P adhering to the surface of the work hanger 31 is maintained without being heated. It can be easily removed by spraying high-pressure air on it.
[0017]
An air processing chamber 15 for removing the remaining powder coating P adhering to the coating surfaces of the steel workpiece 3 and the work hanger 31 is provided next to the drying processing chamber 13 in the workpiece conveyance direction. The air processing chamber 15 faces the injection port 57 of the air blower 55. Further, an auxiliary drying processing chamber 17 that performs an auxiliary heating operation on the surface side of the coating film formed mainly on the steel workpiece 3 is provided adjacent to the air processing chamber 15 in the workpiece conveyance direction. As an example, a plurality of 2 kw far-infrared lamps 59 are provided in the auxiliary drying processing chamber 17, thereby ensuring complete solidification and drying of the uniform coating film without unevenness. Note that the solidification and drying of the coating film by the far-infrared lamp 59 in the auxiliary drying treatment chamber 17 is only auxiliary, and coagulation and drying by high frequency is sufficient for most workpieces.
[0018]
Next to the auxiliary drying processing chamber 17 in the workpiece transfer direction, the communication processing chamber 7 serving as a communication chamber with the outside described above is located. The steel workpiece 3 taken into the communication processing chamber 7 is in a state where a coating film is formed on the surface, and is carried out toward the conveyor 21 located outside. A cooling fan 61 is provided on the carry-out side of the conveyor 21, and the steel work 3 and the coating film are cooled by the cooling fan 61.
[0019]
Next, the steel workpiece coating method will be described together with the description of the operation of the steel workpiece coating apparatus 1.
The steel workpiece 3 set on the workpiece hanger 31 is conveyed by a predetermined distance by the conveying conveyor 21 and then taken into the communication processing chamber 7 by an appropriate transfer device. When taken into the communication processing chamber 7, the upper end of the suspension rod 35 of the work hanger 31 is connected to the free end of the rotary arm 25 so that the steel workpiece 3 can move on the horizontal circular orbit transfer path in the work chamber 5. become. The process up to this point is referred to as a workpiece take-in process.
[0020]
The steel workpiece 3 taken into the working chamber 5 in the communication processing chamber 7 is rotated by a predetermined angle by the rotating shaft 23 and reaches the coating processing chamber 9 or the coating processing chamber 11. In the coating processing chambers 9 and 11, the powder coating material P supplied by the coating material application device 39 is sprayed from the nozzle 41 and is adsorbed and applied to the surface of the steel workpiece 3 by electrostatic induction.
In addition, when the work hanger 31 is rotated 180 degrees by being driven by the work reversing motor 33, the powder coating P is uniformly applied to the surface of the steel work 3 set on the work hanger 31. On the other hand, surplus powder paint P that has not been adsorbed and applied to the steel workpiece 3 is recovered by the recovery device 43. This process is referred to as a paint application process.
[0021]
Next, the steel workpiece 3 moves into the processing chamber 13 and comes to be positioned in the slit 51 formed in the induction heating coil 49. Here, a high frequency generated from the induction heating coil 49 in response to the supply of current from the induction heating power supply 53 acts on the steel workpiece 3 to heat the steel workpiece 3. As the steel workpiece 3 is heated, the powder coating P applied to the surface of the steel workpiece 3 is heated from the inside and is subjected to solidification and drying. At the same time, foreign matters such as oils and fats adhering to the surface of the steel workpiece 3 are vaporized by heating and disappear. Since the temperature at which the oil and fat is heated and vaporized is lower than the temperature at which the powder coating P solidifies, even after the powder coating P is applied to the steel workpiece 3, the vaporized oil and fat is the powder before solidification. It is released through the paint P. This process is called a high frequency induction heating process. In addition, foreign matters such as fats and oils vaporized by heating are adsorbed and filtered by an adsorbing filtration device (not shown). Thereby, clean air containing no foreign matter is discharged to the outside.
[0022]
The steel workpiece 3 on which the coating film is formed by the high frequency induction heating process reaches the air processing chamber 15 and the remaining powder coating P adhering to the coating film surface is blown off by the air blown from the air blower 55. At the same time, the powder paint P adhering to the work hanger 31 is also removed. This process is called an air blow process.
Next, the steel workpiece 3 reaches the auxiliary drying chamber 17 and is irradiated with the far-infrared lamp 59 to be used for auxiliary drying, so that uniform and uniform coating of the coating film and drying are ensured. This process is called an auxiliary drying process.
[0023]
Then, the steel workpiece 3 returns to the communication processing chamber 7 again and is conveyed toward the external conveyor 21 via an appropriate transfer device. The steel workpiece 3 conveyed to the conveyor 21 is cooled by receiving cooling air from the cooling fan 61 on the way, and is carried out as a product.
In the same manner, the steel workpieces 3 suspended from the conveyor 21 by the work hangers 31 are successively taken into the work chamber 5, and are transferred to the conveyor 21 again and carried out through the above-described steps. It is.
[0024]
The embodiment of the present invention has been described in detail above, but the specific configuration is not limited to this embodiment, and the present invention can be changed even if there is a design change without departing from the gist of the present invention. include.
For example, in the above-described embodiment, the coating application process is provided in two steps and the coating processing chambers 9 and 11 having the same configuration are provided side by side. However, the coating coating process is performed only in one step, for example, the coating processing chamber 11. Of course, it is possible to omit this, and conversely, it is possible to further increase the coating treatment chamber and provide three or more coating application processes.
[0025]
It is also possible to adjust the interval between the slits 51 of the induction heating coil 49. In this way, it is possible to cope with steel workpieces 3 of various sizes, and adjustment of the heating temperature in the high frequency induction heating process. Also, it can be made uniform.
In addition, it is possible to omit the air blowing process by the air blower 55 if there is no concern about the excessive powder coating P adhering to the coating film surface.
Further, if it is possible to form a uniform coating film without unevenness only by the high frequency induction heating process, the auxiliary drying process by the far infrared lamp 59 can be omitted.
[0026]
In the above embodiment, the steel workpiece 3 is received and delivered to the work chamber 5 by the single communication processing chamber 7. However, as shown in FIG. It is also possible to use the receiving process chamber 63 and the transfer process chamber 65.
Furthermore, the conveyance path of the steel workpiece 3 in the work chamber 5 is not limited to the rotary type as shown in the above embodiment and FIG. 4A, but can be formed linearly, as shown in FIG. It is also possible to use a trolley system as shown in FIG.
Further, the movement of the steel workpiece 3 is not limited to intermittent movement, but can be continuously moved by changing the size, action length, etc. of each processing chamber. In addition to this, it is possible to coat the work hanger 31 other than the energizing portion with Teflon or the like, and this makes the work hanger 31 cleaning operation easier.
[0027]
【The invention's effect】
According to the present invention, heating from the inside of the coating film is possible by heating and drying using high frequency induction, uniform drying without unevenness is performed, drying time is shortened, and the apparatus is downsized. I can plan.
Moreover, since foreign matters such as oil and fat adhering to the surface of the steel workpiece 3 are vaporized and lost during high-frequency induction heating, the degreasing treatment, which has been indispensable in the past, is no longer necessary, and work efficiency can be greatly improved. .
[0028]
Further, since the coating is performed using the powder paint P, no solvent is required when the liquid paint P is used, and problems such as environmental pollution do not occur. In addition, since the work hanger 31 is made of a material that is not heated by high frequency, for example, copper, even if surplus paint adheres to the work hanger 31, it is not heated and dried, so it does not stick firmly and is easily removed. It becomes possible.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a steel work coating apparatus according to an embodiment of the present invention as seen through.
FIG. 2 is a plan view showing a steel workpiece coating apparatus according to an embodiment of the present invention.
FIG. 3 is a longitudinal side view showing a processing chamber in which powder electrostatic coating is performed in the steel workpiece coating apparatus according to the embodiment of the present invention.
FIG. 4 is a plan view showing two types of layouts of a processing chamber in a steel workpiece coating apparatus according to another embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Steel workpiece coating device 3 Steel workpiece 5 Work chamber 7 Contact processing chamber 9 Coating processing chamber 11 Coating processing chamber 13 Drying processing chamber 15 Air blow processing chamber 17 Auxiliary drying processing chamber 19 Conveying device 21 Conveying conveyor 23 Rotating shaft 25 Rotation Arm 27 Arm drive motor 29 Transmission means 31 Work hanger 33 Work reversing motor 35 Suspension rod 37 Holding arm rod 39 Paint application device 41 Nozzle 43 Recovery device 45 Suction duct 47 High frequency induction heating device 49 Induction heating coil 51 Slit 53 Induction heating power source Device 55 Air blower 57 Injection port 59 Far infrared lamp 61 Cooling fan 63 Reception processing chamber 65 Delivery processing chamber P Powder coating material

Claims (3)

A coating device that applies powder coating to the surface of a steel workpiece by electrostatic induction, and a high frequency applied to the steel workpiece to which the powder coating has been applied, heating the steel workpiece and the powder coating to solidify it. In a steel workpiece coating device equipped with a high-frequency induction heating device for drying ,
The inside of the cylindrical cylindrical work chamber is partitioned, a communication processing chamber, a coating processing chamber and a drying processing chamber are provided along the transport direction,
A rotating shaft at the center of the working chamber, a rotating arm extending radially from the rotating shaft, a work hanger provided on a free end side of the rotating arm and holding a steel workpiece in a suspended state, and the rotating shaft A conveying device comprising an arm driving motor for rotating the workpiece hanger and a workpiece reversing motor for rotating the workpiece hanger with respect to the rotating arm,
In the paint processing chamber, the nozzle of the paint coating device provided outside the working chamber is faced,
In the drying treatment chamber, the high-frequency induction coil of the high-frequency induction device is formed in a concave shape with the open part facing up,
The steel workpiece is suspended and held by the work hanger in the communication processing chamber and taken into the work chamber, and in the coating processing chamber, the paint is uniformly applied to the surface of the steel workpiece by the rotation of the work hanger, An apparatus for coating a steel workpiece, wherein the drying processing chamber is heated in a slit of a concave portion of the induction coil, returns to the communication processing chamber, and is unloaded therefrom . The steel workpiece coating apparatus according to claim 1, wherein the work hanger is made of copper that is not heated by high frequency. In the steel workpiece coating method performed using the steel workpiece coating apparatus according to claim 1 or 2,
Applying powder coating to the surface of steel workpieces by electrostatic induction, and applying high frequency to the steel workpiece coated with powder coating, heating the powder coating from the inside, solidifying and drying And a high-frequency induction heating process.

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