CN116329006A - Electrostatic spraying component with anode and cathode powder and one-coating one-baking spraying process - Google Patents

Abstract

An electrostatic spraying assembly with positive and negative electrodes and a one-coat-bake spraying process, including a conveying device, a spraying device, a baking device and a control device, by setting a negative electric spraying area and a positive electric spraying area in the spraying room, and the electrostatic spraying assembly It includes a high-voltage negative charge spraying assembly and a high-voltage positive charge spraying assembly. When the workpiece is sent into the negative charge spraying area, the paint powder is negatively charged and the workpiece is positively charged. The paint powder will be adsorbed on the workpiece, and then the workpiece is sent into the positive charge In the electric spraying area, the paint powder is positively charged at this time, and the workpiece is negatively charged. The positively charged paint powder will also be attracted by the negatively charged coating particles on the surface of the workpiece to achieve the effect of adhesion, which avoids when the coating reaches a certain thickness. The powder on the surface of the coating will produce the same-sex repulsion to the newly attached powder. The thickness of the paint surface achieved by positive and negative electrospraying is the same as the thickness of the paint surface achieved by two sprays and two bakes, that is, the process flow is reduced and the process is improved. Production efficiency, while also reducing equipment energy consumption, saving production costs.

Description

A powder electrostatic spraying assembly with positive and negative electrodes and a one-coat-one-bake spraying process

technical field

The invention relates to the technical field of electrostatic spraying, in particular to an electrostatic spraying assembly with positive and negative powder powders and a one-coat-bake spraying process.

Background technique

Electrostatic spraying technology is an important construction technology with the fastest development in the current powder coating process. Electrostatic powder spraying uses the principle of electrostatic adsorption. After the electrostatic powder spray gun is energized, a high voltage is generated at the front of the gun. After the powder is sprayed from the front of the gun, it is charged under the action of the high voltage field. The charged powder is blown to the surface of the workpiece by high-pressure air, and the workpiece is grounded. , so the charged powder will be well adsorbed on the surface of the workpiece. This method makes the powder cover the surface of the workpiece to form a certain thickness and uniform coating.

However, in the traditional process, when the coating reaches a certain thickness, the powder on the surface of the coating will produce the same-sex repulsion to the newly attached powder. At this time, the powder will not be able to continue to be adsorbed by the workpiece or the adsorption rate will decrease. , and even the phenomenon of "orange peel/orange peel" on the paint surface. In order to solve the above situation, in the traditional process, the workpiece will be sprayed multiple times to increase the thickness of the paint surface. For example, a plate disclosed in Chinese patent CN201921518167.1 The double-coating and double-baking production line includes an upper shell, the bottom of the upper shell is fixedly connected to the base, and the top of the inner wall of the base is rotatably connected to a conveying roller, and the top of the conveying roller is connected to the plate, and the inner wall of the upper shell is in turn It is connected with primary coating area, primary drying area, secondary coating area and secondary drying area. In this patent, two sets of spraying areas and drying areas are respectively arranged on the same production line to achieve the effect of double coating and double baking , although this design scheme can improve production efficiency, it also greatly increases equipment energy consumption, which is not conducive to cost saving.

Contents of the invention

In order to overcome the deficiencies of the prior art, the present invention provides a positive and negative electrode powder electrostatic spraying assembly and a one-coat-bake spraying process.

The technical solution adopted by the present invention to solve its technical problems is:

An electrostatic spraying assembly with positive and negative electrode powders, including a conveying device, a spraying device, a baking device and a control device, the conveying device passes through the spraying device and the baking device and is erected above the spraying device and the baking device, the The baking device is arranged on one side of the spraying device, and the control device is connected by a line and controls the work of the conveying device, the spraying device and the baking device, and the spraying device includes a spraying room for workpiece spraying and a Powder electrostatic spraying assembly, the spraying room is provided with a negative electric spraying area and a positive electric spraying area, the electrostatic spraying assembly includes a high-voltage negative electric spraying assembly and a high-voltage positive electric spraying assembly, the high-voltage negative electric spraying assembly and a high-voltage positive electric spraying assembly They are respectively set in the negative electrospray area and the positive electrospray area.

Further, the high-voltage negative charge spraying assembly and the high-voltage positive charge spraying assembly are equipped with a powder supply mechanism, a powder spray gun and an electrostatic generator, and the electrostatic generator in the high-voltage negative charge spraying assembly is connected to the powder spray gun in the negative charge spraying area for use In order to emit high-voltage negative electricity, the electrostatic generator in the high-voltage positive electricity spraying assembly is connected to the powder spray gun in the positive electricity spraying area for emitting high-voltage positive electricity.

Further, the conveying device above the negative electric spraying area and the positive electric spraying area are respectively provided with a negative electric grounding assembly and a positive electric grounding assembly. The workpieces in the area are connected to the high voltage positive electric spraying assembly and grounded through the positive electric grounding assembly.

Further, the negative grounding component and the positive grounding component are independent of each other.

Based on the above-mentioned electrostatic spraying assembly with positive and negative powder powder, the present invention also provides a one-paint-bake spraying process, using the above-mentioned electrostatic spraying assembly with positive and negative powder powder for spraying.

Further, the one-coating-baking spraying process includes the steps of workpiece treatment—positive and negative electrostatic spraying—baking and curing—paint surface inspection—finished product, and the specific operations include:

1. Workpiece treatment: remove oil, dust and corner burrs on the surface of the workpiece, and dry and cool the workpiece to room temperature;

2. Positive and negative electrostatic spraying: the conveying device is sequentially sent to the negative electric spraying area, positive electric spraying area and baking device through the hook. Electrostatic high voltage 60~90Kv, electrostatic current 10~20uA, control the flow rate pressure of the powder spray gun 0.3~0.55Mpa, control the distance from the nozzle of the spray gun to the workpiece 150~250mm;

3. Baking and curing: the conveying device sends the sprayed workpiece into the baking device through the hook, during which the baking temperature is controlled by the control device at 180°C, and the baking time is 20 minutes;

4. Paint surface detection: Check whether the appearance of the paint surface is smooth and flat, and check whether the thickness of the paint surface is between 300±15um;

5. Finished product: Classify and place the inspected workpieces in transport vehicles or turnover boxes.

The present invention has the following advantages and beneficial effects: by setting a negative electric spraying area and a positive electric spraying area in the spray booth, and the electrostatic spraying assembly includes a high-voltage negative electric spraying assembly and a high-voltage positive electric spraying assembly, the high-voltage negative electric spraying assembly and the high-voltage positive electric spraying assembly The components are respectively set in the negative charge spraying area and the positive charge spraying area, and the high-voltage negative charge spraying component and the high-voltage positive charge spraying component are not dry from each other. Spraying components, at this time, the paint powder is negatively charged, the workpiece is positively charged, the paint powder will be adsorbed on the workpiece, and then the workpiece is sent to the positive charge spraying area, and the workpiece is connected to the high voltage positive charge spraying component through the positive charge grounding component. At this time, the paint The powder is positively charged, and the workpiece is negatively charged. The positively charged paint powder will also be attracted by the negatively charged coating particles on the surface of the workpiece to achieve the effect of adhesion, which avoids that when the coating reaches a certain thickness, the powder on the coating surface will When the newly attached powder produces the repulsive force of the same sex, the thickness of the paint surface achieved by positive and negative electrospraying is the same as the thickness of the paint surface achieved by two sprays and two bakes, which reduces the process flow and improves production efficiency. Equipment energy consumption, saving production costs.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the present invention is further described:

Fig. 1 is the top view of positive and negative electrode powder electrostatic spraying assembly in the present embodiment;

Fig. 2 is the front view of electrostatic spraying assembly in the present embodiment;

Fig. 3 is a front view of the spray booth in this embodiment.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention, and the present invention is not limited to Examples below.

As shown in Figures 1 to 3, this embodiment discloses a positive and negative electrode powder electrostatic spraying assembly, including a conveying device 1, a spraying device 2, a baking device 3 and a control device 4, and the conveying device 1 traverses through the The spraying device 2 and the baking device 3 are erected above the spraying device 2 and the baking device 3. The conveying device 1 hangs the workpiece through the hook 5 and sends it into the spraying device 2 and the baking device 3 in sequence. The baking device 3 is arranged on the outlet side of the spraying device 2, and the control device 4 is connected by a line and controls the conveying device 1, the spraying device 2 and the baking device 3 to work, and the control device 4 can be manually operated or set. The program control process, the spraying device 2 includes a spraying room 21 for workpiece spraying and an electrostatic spraying assembly 22 for spraying powder on the workpiece, and the electrostatic spraying assembly 22 is arranged on both sides of the spraying room 21 to make the two sides of the workpiece All can be sprayed, and described spraying room 21 is provided with negative electric spraying area 211 and positive electric spraying area 212, and described negative electric spraying area 211 is near the entrance of spraying room 21, and described positive electric spraying area 212 is near the outlet of spraying. , the electrostatic spraying assembly 22 includes a high-voltage negative electrospray assembly 221 and a high-voltage positive electrospray assembly 222, and the high-voltage negative electrospray assembly 221 and the high-voltage positive electrospray assembly 222 are respectively arranged in the negative electrospray area 211 and the positive electrospray area 212.

After the workpiece is sent into the negative electricity spraying area 211 through the conveying device 1, the workpiece is connected to the high-voltage negative electricity spraying assembly 221 through the negative electricity grounding assembly 213. At this time, the paint powder is negatively charged, the workpiece is positively charged, and the paint powder will be adsorbed on the workpiece. The workpiece is sent into the positive electric spraying area 212, and the workpiece is connected to the high voltage positive electric spraying assembly 222 through the positive electric grounding assembly 214. At this time, the paint powder is positively charged, and the workpiece is negatively charged. The positively charged paint powder will also be negatively charged on the surface of the workpiece. The coating particles are attracted to achieve the effect of adhesion, which avoids the situation that when the coating reaches a certain thickness, the powder on the coating surface will produce the same-sex repulsion to the newly attached powder. The paint achieved by positive and negative electrospraying The surface thickness is the same as the paint surface thickness achieved by two sprays and two bakes, which reduces the process flow and improves production efficiency. At the same time, it also reduces equipment energy consumption and saves production costs.

Further, the high-voltage negative electricity spraying assembly 221 and the high-voltage positive electricity spraying assembly 222 are all provided with a powder supply mechanism, a powder spray gun 22a and an electrostatic generator, and the powder supply mechanism is connected to the powder spray gun 22a through a powder supply pipe to provide paint powder, electrostatic The generator is connected to the powder spray gun 22a through a line for making the powder spray gun 22a emit high-voltage static electricity. The powder spray gun 22a is arranged in the spraying room 21 to aim at the workpiece. The powder spray gun 22a is installed on the reciprocating machine. The electrostatic generator inside is connected on the powder spray gun 22a of negative electricity spraying area 211 and is used for sending out high-voltage negative electricity, and the electrostatic generator in the described high-voltage positive electricity spraying assembly 222 is connected on the powder spray gun 22a of positive electricity spraying area 212 for sending out High-voltage positive electricity, by setting two groups of electrostatic spraying components 22, the spraying of multiple workpieces can be carried out in the spraying room 21 at the same time, forming a process line and improving the spraying efficiency. Preferably, the powder spray gun 22a in the negative electricity spraying area 211 is provided with three group, in order to improve the powder feeding rate of the workpiece in the positive electrospray area 212, the powder spray guns 22a in the positive electrospray area 212 are provided with four groups, and the powder spray guns 22a are arranged horizontally, and the powder spray guns 22a can be reciprocated The machine moves up and down so that the workpiece can be powdered evenly.

Further, in order to prevent the workpieces on the same conveying device 1 from interfering with each other, the conveying device 1 above the negative electric spraying area 211 and the positive electric spraying area 212 are respectively provided with a negative electric grounding assembly 213 and a positive electric grounding assembly 214, located in the negative electric spraying The workpieces in zone 211 are connected to high-voltage negative electrical spraying assembly 221 through negative electrical grounding assembly 213 and grounded to form a loop, and the workpieces in positive electrical spraying area 212 are connected to high-voltage positive electrical spraying assembly 222 through positive electrical grounding assembly 214 and grounded to form a loop.

Further, both the negative grounding component 213 and the positive grounding component 214 are connected to the hook 5 through a conductor, and the hook 5 and the conveying device 1 are insulated from each other and do not conduct electricity, so that the negative grounding component 213 and the positive grounding component 214 are connected to each other. Independent and not dry.

Based on the powder electrostatic spraying assembly with positive and negative electrodes provided in the above embodiment, this embodiment also provides a one-paint-bake spraying process, using the powder electrostatic spraying assembly with positive and negative electrodes as described above for spraying.

Further, the one-coat-bake spraying process includes the steps of workpiece treatment—positive and negative electrostatic spraying—baking and curing—paint surface inspection—finished products, and the specific operations are as follows:

The one-coating-baking spraying process realized by the positive and negative electrode powder electrostatic spraying assembly 22 of the present invention includes the steps of workpiece treatment—positive and negative electrostatic spraying—baking and curing—paint surface inspection—finished products, and the specific operations include:

1. Workpiece treatment: send the workpiece to the pre-treatment area 7 for processing to remove the oil and dust on the surface of the workpiece before spraying powder to enhance the adhesion after powder spraying. At the same time, the processed workpiece must be completely dried and cooled to 35 The physical and chemical properties and appearance quality of the workpiece after powder spraying can be guaranteed only when the temperature is below °C;

2. Positive and negative electrostatic spraying: the conveying device 1 is sequentially sent to the negative spraying area 211, the positive spraying area 212 and the baking device 3 through the hook 5, during which the conveying speed of the conveying device 1 is controlled by the control device 4 to be 4m/min. When the workpiece is in the negative electric spraying area 211: control the electrostatic high voltage of the electrostatic generator to 60Kv, the electrostatic current to 20uA, control the flow rate pressure of the powder spray gun 22a to 0.55Mpa, and control the distance from the spray gun mouth to the workpiece to 240mm; when the workpiece is in the positive electric spraying area 212 : Control the electrostatic high voltage of the electrostatic generator to 90Kv, the electrostatic current to 20uA, control the flow rate and pressure of the powder spray gun 22a to 0.3Mpa, and control the distance from the nozzle of the spray gun to the workpiece to 180mm;

Because the electrostatic generator is under the same power, the ionization effect of high-voltage negative electricity is better than the ionization effect of high-voltage positive electricity, and the negatively charged particles produced are more than positively charged particles. The spraying effect is similar, it is necessary to increase the electrostatic high voltage in the positive charge spraying area 212 to enhance the ionization effect, and at the same time reduce the flow rate pressure of the powder spray gun 22a and the distance between the nozzle and the workpiece, so that the speed of paint powder spraying is reduced and the positively charged paint is reduced. The powder particles can fully adhere to the workpiece, improving the powder feeding rate.

3. Baking and curing: the conveying device 1 sends the sprayed workpiece to the baking device 3 through the hook 5. During this period, the control device 4 controls the baking device 3 to increase the temperature so that the surface temperature of the workpiece reaches 180 ° C. Due to the powder coating The thickness is twice that of the work-transfer process, so the workpiece needs to be baked at 180°C for 20 minutes; the curing process is divided into four stages: melting, leveling, gelling and curing. After the temperature rises to the melting point, the powder on the surface of the workpiece begins to melt, and gradually fuses with the inner powder until it is completely melted.

After the powder is completely melted, it starts to flow slowly, forming a thin and flat layer on the surface of the workpiece. This stage is called leveling. After the temperature continues to rise and reaches the glue point, there will be a short gelation state for a few minutes. At this time, the temperature remains unchanged. After that The temperature continues to rise and the powder undergoes a chemical reaction to solidify.

4. Paint surface inspection: After curing, the workpiece needs to check whether the paint surface is smooth and flat, whether there are particles, shrinkage cavities and other defects, and it is necessary to detect whether the thickness of the paint surface is 300±15um to meet the workpiece spraying requirements. If there are defects or In the case of insufficient thickness, manual spraying or rework is required.

5. Finished products: After inspection, the finished products should be sorted and placed in transport vehicles and turnover boxes, separated from each other with soft materials such as newspapers to prevent scratches and marked for use.

The above content described in this specification is only an illustration of the present invention, and those skilled in the art to which the present invention belongs can make various modifications or supplements to the described specific embodiments or replace them in similar ways, as long as Anything that does not deviate from the content of the description of the present invention or exceeds the scope defined in the claims shall belong to the protection scope of the present invention.

Claims (6)

1. An electrostatic spraying assembly with positive and negative powder powder, including a conveying device (1), a spraying device (2), a baking device (3) and a control device (4), and the conveying device (1) passes through the spraying device (2) and the baking device (3) are erected above the spraying device (2) and the baking device (3), the baking device (3) is set on one side of the spraying device (2), and the control The device (4) is connected by a line and controls the operation of the conveying device (1), the spraying device (2) and the baking device (3), and it is characterized in that: the spraying device (2) includes a spraying room (21 ) and an electrostatic spraying assembly (22) for spraying powder on the workpiece, the spraying room (21) is provided with a negative electric spraying area (211) and a positive electric spraying area (212), and the electrostatic spraying assembly (22) includes a high voltage Negative electrospraying assembly (221) and high-voltage positive electrospraying assembly (222), the high-voltage negative electrospraying assembly (221) and high-voltage positive electrospraying assembly (222) are respectively arranged in the negative electrospraying area (211) and the positive electrospraying area (212) . 2. An electrostatic spraying assembly with positive and negative powder powders according to claim 1, characterized in that: both the high-voltage negative-electrode spraying assembly (221) and the high-voltage positive-electrical spraying assembly (222) are equipped with a powder supply mechanism, powder The spray gun (22a) and the electrostatic generator, the electrostatic generator in the high-voltage negative charge spraying assembly (221) is connected to the powder spray gun (22a) in the negative charge spraying area (211) for emitting high-voltage negative charges, and the high-voltage positive charge spraying The electrostatic generator in the component (222) is connected to the powder spray gun (22a) in the positive electric spraying area (212) for emitting high voltage positive electricity. 3. An electrostatic spraying assembly with positive and negative powder powder according to claim 2, characterized in that: the conveying device (1) above the negative electrospraying area (211) and the positive electrospraying area (212) are respectively equipped with Negative grounding assembly (213) and positive grounding assembly (214), the workpiece located in the negative electrical spraying area (211) is connected to the high-voltage negative electrical spraying assembly (221) through the negative electrical grounding assembly (213) and grounded, located in the positive electrical spraying area (212) The workpiece is connected to the high voltage positive electric spray assembly (222) and grounded through the positive electric ground assembly (214). 4. The powder electrostatic spraying assembly with positive and negative electrodes according to claim 3, characterized in that: the negative grounding component (213) and the positive grounding component (214) are independent of each other and are not dry. 5. A spraying process of one coating and one baking, characterized in that: the electrostatic spraying assembly with positive and negative powder powders as described in any one of claims 1-4 is used for spraying. 6. A spraying process of one coating and one baking according to requirement 5, which is characterized in that it includes the steps of workpiece treatment - positive and negative electrostatic spraying - baking and curing - paint surface inspection - finished product, and the specific operations are as follows: 1) Workpiece treatment: remove oil, dust and corner burrs on the surface of the workpiece, dry and cool the workpiece to room temperature; 2) Positive and negative electrostatic spraying: the conveying device (1) is sent to the negative electrostatic spraying area (211), the positive electrostatic spraying area (212) and the baking device (3) sequentially through the hook (5), and the period is controlled by the control device (4) The conveying speed of the conveying device (1) is 4~4.5m/min, the electrostatic high voltage of the electrostatic generator is controlled at 60~90Kv, the electrostatic current is 10~20uA, the flow rate and pressure of the powder spray gun (22a) are controlled at 0.3~0.55Mpa, and the nozzle of the spray gun is controlled The distance to the workpiece is 150~250mm; 3) Baking and curing: the conveying device (1) sends the sprayed workpiece to the baking device (3) through the hook (5), during which the baking temperature is controlled by the control device (4) to 180°C, and the baking time is 20 minutes; 4) Paint surface inspection: check whether the appearance of the paint surface is smooth and flat, and check whether the thickness of the paint surface is between 300±15um; 5) Finished products: sort and place the inspected workpieces in transport vehicles or turnover boxes.

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