The main advantages of spraying robots (1) Great flexibility. The scope of work is huge. (2) Improve the quality of spraying and the utilization rate of materials. (3) Easy to operate and maintain. It can be programmed offline, which greatly shortens the on-site debugging time. (4) The equipment utilization rate is high. The utilization rate of spraying robots can reach 90%-95%. Types and characteristics of spraying robots

1. Air spraying robot

Air spraying robot is also called low-pressure air spraying . The spraying machine relies on low-pressure air to make the paint form an atomized airflow to act on the surface of the object (wall or wood surface). There are no brush marks , and the plane is relatively uniform, and the unit working time is short, which can effectively shorten the construction period. However, there is splashing in air spraying, and there is a waste of paint. When viewed at a close distance, very fine particles can be seen. Generally, the air compressor used in the decoration industry is used for air spraying . Relatively speaking, one machine is multi-purpose and the investment cost is low. There are also special machines such as pumping air spraying machines and self-falling air spraying machines on the market.

2. Airless spraying robot

The airless spraying robot can be used for the construction of high-viscosity paint, and the edges are clear, and it can even be used for some spraying projects with boundary requirements. Depending on the type of machinery, it can be divided into pneumatic airless spraying machines , electric airless spraying machines, internal combustion airless spraying machines, automatic spraying machines , etc. In addition, it should be noted that if the metal surface is sprayed , it is best to use metallic paint ( enamel paint ).

The main advantages of spraying robots

1. Good flexibility.

(1) Large active radius and good flexibility.

(2) It can realize the spraying of inner surface and outer surface .

(3) It can realize the mixed-line production of various models, such as the mixed-line production of cars, station wagons, pickup trucks and other bodies.

2. Improve the quality of spraying and the utilization rate of materials.

(1) The trajectory of profiling spraying is accurate, which improves the uniformity of coating film and other appearance spraying quality.

(2) Reduce the amount of overspray and cleaning solvent, and improve the utilization rate of materials .

Three, easy to operate and maintain.

(1) It can be programmed offline, greatly shortening the on-site debugging time.

(2) The pluggable structure and modular design can realize quick installation and replacement of components, and greatly shorten the maintenance time.

(3) The maintenance accessibility of all components is good, which is convenient for maintenance.

Fourth, the equipment utilization rate is high.

(1) The utilization rate of reciprocating automatic spraying machines is generally only 40%-60%, and the utilization rate of spraying robots can reach 90%-95%.

The characteristics comparison of spraying robot, manual spraying and reciprocating automatic spraying machine are listed in the table below.

Selection factors of spraying robot

(1) The working trajectory range of the robot. When selecting a robot, it is necessary to ensure that the working trajectory range of the robot must be able to completely cover the relevant surface or inner cavity of the workpiece to be constructed. As shown in Figure 1, it is a schematic cross-sectional diagram of the painting robot and the moving body (installed on the conveying trolley). It can be seen that this painting is the configuration of the robot to meet the painting requirements of the body surface.

The intermittent conveying robot is used for the construction of stationary workpieces. In addition to the cross section of the workpiece, it is also necessary to ensure that the working range of the robot on the overlooked surface of the workpiece can completely cover the relevant surface of the workpiece to be constructed. The left and right robots each cover the left and right half of the car body. When the working trajectory range of the robot cannot be satisfied in the direction of the conveying movement, it is necessary to increase the external guide rail of the robot to expand its working range trajectory.

(2) Repeatability of the robot. For gluing robots , the general repeatability can reach 0.5mm. For painting robots , the repeatability requirements can be lower.

(3) The speed and acceleration of the robot. The greater the maximum movement speed or maximum acceleration of the robot, the shorter the time required for the robot to travel in the empty space, and the longer the absolute construction time of the robot within a certain beat, which can improve the utilization rate of the robot. Therefore, the maximum speed and acceleration of the robot is also an important technical indicator. However, the problem to be noted is that during the spraying process (gluing or spraying), the movement speed of the spraying tool is directly related to the characteristics and materials of the spraying tool, and needs to be set according to the process requirements. In addition, because the technical indicators of the robot are directly related to its price, the robot with high cost performance is selected according to the process requirements.

(4) The maximum load that the robot arm can bear. For different spraying occasions, the spray tools configured in the spraying (glue or paint) process are different, and the maximum load of the robot arm is required to be different.

Terminology for painting robots

(1) Coating efficiency, coating efficiency and coating efficiency

Coating efficiency is the efficiency of spraying operation, including the effective utilization rate of spraying area per unit time, paint and spraying area. Coating efficiency is the ratio of the amount of paint applied to the object to be coated during the spraying process to the total amount of actual sprayed paint, or the ratio of the measured thick film on the surface of the object to be coated to the thickness of the coating film calculated from the amount of sprayed paint , that is, the transfer efficiency (TE for short) of the coating or the utilization rate of the coating. Coating efficiency refers to the ratio of the surface area of the actual sprayed object to the coverage area of the spray gun operation; in order to make the coating film on the edge of the object to be coated complete, the general coverage area of the spray gun should be larger than the area of the object to be coated. The relationship and concepts among coating efficiency, coating efficiency and coating efficiency

(2) Spraying track

The spraying trajectory refers to the sequence and stroke of the spray gun during the spraying process. The spraying robot can imitate the spraying trajectory of a skilled painter. A Japanese automobile company uses a reciprocating automatic electrostatic spraying machine and a spraying robot to spray the car body, and compares the spraying trajectory and painting efficiency of the two

(3) Rotary cup speed

The rotational speed of the rotary cup is the most influential factor on the atomization fineness of the high rotational speed rotary cup. When other process parameters remain unchanged, the greater the rotating speed of the rotary cup, the smaller the diameter of the paint droplet. In the slightly lower speed range, the influence of the rotational speed on the atomization fineness is significantly greater than in the high speed range.

The rotating speed of the rotary cup will affect the film thickness, and the relationship curve is shown in Figure 4. When the speed is too low, the coating film will be rough; if the atomization is too fine, the paint mist will be lost (causing overspray), and the thickness of the coating film will fluctuate; at the same time, when the atomization is ultra-fine, it is very sensitive to any air flow in the spray booth.

The relationship between film thickness and rotational speed

In addition to causing overspray, the excessively high rotational speed of the rotary cup will also cause excessive wear of the turbine bearing, increase the consumption of compressed air for clearing and reduce the amount of solvent contained in the coating film. The optimal rotating speed of the rotating cup can be determined according to the flow rate characteristics of the coating used. Therefore, the rotating speed of the rotating cup for water-based coatings with high surface tension and high-viscosity two-component coatings is higher than that of ordinary solvent-based coatings .

In general, the no-load rotary cup speed is 6X10^4 r/min, and the set speed range under load is (1.0~4.2)X10^4 r/min error ±500r/min.

(4) Paint flow rate

It is the amount of paint lost to each rotary cup per unit time, also known as spray flow and paint output (rate).

In addition to the rotating speed of the rotary cup, the paint flow rate is the second factor that affects the fineness of the atomized particles. When other parameters remain unchanged, the lower the paint flow rate, the finer the atomized particles, but at the same time it will also lead to an increase in the solvent volatilization in the paint mist.

A high paint flow rate will form a corrugated coating film. At the same time, when the paint flow rate is too high to overload the rotary cup, the coating film on the edge of the rotary cup will thicken to a certain extent, causing the grooves on the rotary cup to fail to divert the paint and appear. Layered paint , which can create undesirable phenomena of air bubbles or uneven paint droplet sizes.

The maximum paint flow rate of each spray gun is related to the caliber of the high-speed rotary cup and the density of the paint at the rotating speed, and the upper limit is determined by the fineness of atomization and the effect of electrostatic painting . Practical experience shows that the paint should be fed at a constant speed, and fluctuations in a small range will not affect the quality of the paint film.

In the actual spraying process, the area sprayed by each rotary cup is different, and the flow rate of the paint is also different. In addition, due to the change of the shape of the object to be coated, the paint flow rate of the rotary cup also changes. Taking spraying the car body as an example, when spraying a large area such as a door panel, the amount of sprayed paint should be large, and when spraying door pillars and window pillars, the amount of sprayed paint should be small, and the sprayed paint should be automatically and accurately controlled during the spraying process In order to ensure the uniformity of coating quality and film thickness, this is also one of the important measures to improve the utilization rate of coatings.

    The online spraying robot adopts an online tracking system and an encoder. This system is the key equipment to ensure the movement of the workpiece and the online spraying robot. The system monitors the chain speed change in real time through the encoder and transmits the value to the online spraying robot controller, and always maintains the mutual position and action relationship between the spraying robot action and the workpiece during teaching, so as to ensure the quality of the robot tracking spraying under the condition of the workpiece moving . If the conveyor chain stops, the spraying robot can memorize the current position and stop, and the conveyor chain restarts and the spraying robot continues to execute the unfinished part of the program.
Since the conveyor chain can output corresponding signals to the online spraying robot system when it stops in an emergency or normal state, the spraying robot will take corresponding actions according to the operating state of the system, and it is very easy to understand the current working state. When the conveyor chain returns to normal, the spraying robot will also Revert to the previous working state.
      Robot automatic spraying production line type: robot spraying line, fixed spray gun spraying line, disk automatic spraying equipment line, plane reciprocating machine spraying line, hanging product spraying line, electrostatic powder spraying line, double cabinet high-speed spraying line, floor rail automatic spraying line Features of the online spraying robot on the production line
:
1. The robot is explosion-proof, environmentally friendly, and easy to learn
. It has the function of memory and memory, which is convenient and simple to manage;
3. The spraying robot can spray 2--5 different products at the same time, and one
can reach multiple sets. Switch the gun to reduce paint waste
5. The spraying robot has a long life, no wearing parts, easy maintenance, small footprint and compact design.
6. Accurate spraying, long uptime, low paint consumption, short working cycle, 24 hours uninterrupted work, high reliability 7. Fast spraying speed,
uniform spraying, automatic adjustment of spray gun height, front and rear, according to workpiece changes Angle position, flexible control of spraying size, 360-degree omnidirectional without dead angle
8. For the corner of the motion track, the circular arc filter function can be used. There is no need to stop at the end of the straight line, and the circular arc is directly filtered to the next line. The speed does not stop, which improves the efficiency. , also reduces the start-stop shock.
9. The automatic conveying speed is fast and the production efficiency is high. Increase the surface dehumidification preheating treatment to make the product free of watermarks and mimeographs, increase the paint adsorption effect, fully automated production, and save labor costs