Is this spraying robot going to be refined
spraying robot is an industrial robot that can automatically spray paint or spray other coatings. It is mainly composed of robot body, computer and corresponding control system. The hydraulically driven spraying robot also includes hydraulic oil sources, such as oil pump, oil tank and motor
it usually adopts 5 or 6 degrees of freedom joint structure. The arm has a large movement space and can do complex trajectory movement. Its wrist generally has 2 to 3 degrees of freedom, which can move flexibly
spraying robots are mainly used in 3C industry, automobile manufacturing industry and furniture industry, and will replace a large number of manual workers in the future. Now let's learn about the selection factors, terminology and key parameters of the spraying robot
I. selection factors of spraying robot
(1) working track range of robot. When selecting a robot, it is necessary to ensure that the working track range of the robot must be able to completely cover the relevant surface or cavity of the workpiece to be constructed
in addition to the section of the workpiece, it is also necessary to ensure that the working range of the robot on the top surface of the workpiece can fully cover the relevant surface of the workpiece to be constructed. The left and right robots cover the left and right half of the vehicle body respectively. When the working track range of the robot cannot be met in the direction of conveying movement, the external guide rail of the robot needs to be added to expand its working range track
(2) repetition accuracy of robot. For glue applicators, the general repetition accuracy can reach 0.5mm. For painting robots, the accuracy requirements of repetition can be lower
(3) motion speed and acceleration of robot. The greater the maximum speed or acceleration of the robot, the shorter the time required for the robot to travel in 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 index
however, it should be noted that during the spraying process (gluing or spraying), the movement speed of the spraying tool is directly related to the characteristics of the spraying tool and materials, which need to be set according to the process requirements. In addition, since 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 maximum load of the robot arm is also required to be different due to the different spraying tools configured during the spraying (gluing or painting)
II. Main terms of spraying robot
1. Coating efficiency, coating efficiency and coating efficiency of spraying robot
coating efficiency is the efficiency of spraying operation, including the spraying area per unit time, and the effective utilization rate of coating and spraying area.
coating efficiency refers to the ratio of the amount of paint coated on the object being coated to the actual total amount of sprayed paint during the spraying process, or the ratio of the measured thick film on the surface of the object being coated to the film thickness calculated by the amount of sprayed paint, that is, the transmission efficiency of the paint (TR hydraulic servo UTM experimental machine can be used for dynamic testing and fatigue testing ansfer efficiency, abbreviated as TE) or the utilization rate of the paint.
coating efficiency refers to the ratio of the surface area of the actual sprayed coating to the coverage area of the spray gun; In order to make the film on the edge broken part of the coated object complete, generally, the coverage area of the spray gun should be larger than the area of the coated object
2. Spraying trajectory of spraying robot
spraying trajectory of spraying robot refers to the sequence and travel of the spray gun in the spraying process. The spraying trajectory of skilled painters can be simulated by using the spraying robot.
3. Paint flow rate of the spraying robot
paint flow rate of the spraying robot is the amount of paint delivered to each rotating cup in unit time, also known as spraying flow and paint output (rate). Enhance the ability to deal with trade protectionism
in addition to the rotating speed of the rotating cup, the coating flow rate is the second factor affecting the fineness of 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 the increase of solvent volatilization in the paint mist.
the high paint flow rate of the spraying robot will form a corrugated film. At the same time, when the paint flow is too high, the film on the edge of the rotating cup will thicken to a certain extent, resulting in the groove lines on the rotating cup can not divert the paint, and a layered paint skin will appear, which will produce bubbles or uneven size of paint drops.
the maximum paint flow rate of each spray gun of the spraying robot is related to the diameter of the high-speed rotating cup and the density of the paint, and its upper limit is determined by the fineness of atomization and the effect of electrostatic coating. Practical experience shows that the paint should be input at a constant speed, and the fluctuation in a small range will not affect the film quality.
in the actual spraying process, the spraying area of each rotating cup is different, and the coating flow rate is also different. In addition, due to the change of the shape of the coated object, the coating flow rate of the rotating cup will also change
1 pass the inspection. Take the spraying of automobile body as an example. When spraying door panels and other large areas, the amount of paint spit out should be large, and when spraying door columns and window columns, the amount of paint spit out should be small, and the amount of paint spit out should be automatically and accurately controlled in the spraying process, so as to ensure the uniformity of coating quality and film thickness, which is also one of the important measures to improve the utilization rate of coating
4. The rotating speed of the spray robot
the rotating speed of the spray robot is the most influential factor on the atomization fineness of the high-speed rotating cup. When other process parameters remain unchanged, the larger the rotating speed of the rotating cup, the smaller the diameter of the paint drop. In the range of slightly low speed, the influence of rotating speed on atomization fineness is significantly greater than that in the range of high speed.
the rotating speed of the rotating cup of the spraying robot will affect the film thickness. When the rotating speed is too low, the coating will be rough; Spraying robot and atomizing too fine will lead to paint mist loss (causing overspray), so that the film thickness fluctuates; At the same time, when the atomization is ultra-fine, it is very sensitive to any air flow in the paint booth. In addition to overspray, excessive rotating speed of the rotating cup will also lead to excessive wear of the turbine bearings, increase the consumption of compressed air for clarity and reduce the solvent content of the coating
the best rotating speed of the sprayer can be determined by the flow rate characteristics of the coating used. Therefore, the rotating speed of water-based coatings and high viscosity two-component coatings with surface tension is higher than that of ordinary solvent based coatings
generally, the rotating speed of the no-load rotating cup of the spraying robot is 6x10^4r/min, and the set rotating speed range under load is (1.0~4.2) x10^4r/min, with an error of ± 500r/min
III. main spraying parameters of the spraying robot
1. Spraying flow rate
the flow rate of the electrostatic spraying robot is the amount of paint delivered to the rotating cup per unit time, also known as the spit out amount. The flow rate affects the thickness of the paint film. The covering capacity of different colors of paint is different, and the construction film thickness is also different. In the spraying process, each robot takes on different spraying areas and sets different flow rates. At the same time, the flow rate is also related to the shape of the sprayed material. For cars, the flow rate of the regular five door and one cover profile is generally large, while the flow rate of the column, edge line and corner is small.
2. Molding air
gas is ejected from the small holes evenly distributed at the back of the rotating cup to limit the amplitude (fan width) of the paint mist, push the atomized paint mist to the coated object, and place the paint mist to diffuse and rebound to pollute the rotating cup and atomizer. For metallic paint, the spray width affects the final color effect. If the spray width is not appropriate, zebra stripes or flowers are easy to appear. The setting of spray range is related to the distance between the two guns, and the number of paint superposition is 3. If the distance between the two guns is 100mm, the spraying range should be controlled to 300mm, so that the paint at the same point can be superimposed for 3 times
3. Rotating speed of rotating cup
rotating speed of rotating cup is the key parameter of paint atomization. The centrifugal force generated by rotating cup at high speed makes the paint atomized very fine（ μ m）。 The smaller the diameter of the paint drop, the better the smoothness of the paint film, the smaller the orange peel effect, and the higher the gloss. The speed setting is also related to the type of paint. The speed of paint is relatively small, and the speed of intermediate coating and varnish is relatively high. The speed and flow are also related. If the flow is large, the speed should also be increased to achieve better atomization effect. However, if the speed is too high, the paint sprayed on the coated object will be dry, which will lead to orange peel problems
4. In high voltage
electrostatic spraying, the coated object is the positive pole and the rotating cup is the negative pole. After applying high voltage between the two poles, strong electric attraction is generated, so that the atomized paint mist particles are transmitted to the surface of the coated object. The size of high voltage affects the electrostatic effect, painting rate and uniformity of paint film of electrostatic spraying.
flow, rotating speed, forming air and high pressure directly affect the film-forming quality, and also affect the utilization rate of paint. In production, it is necessary to combine the characteristics of the paint and the parameters of the atomizer to adjust. The four combination parameters should be comprehensively considered and continuously optimized in order to achieve the ideal spraying effect
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