设备对彩涂板涂层表面形成缺陷的原因

影响彩涂板表面处理的设备因素主要反映在脱脂槽的喷洗系统。清洗液喷洗系统影响基板清洗效果有如下几点:

(1)喷射距离及喷射角度。脱脂槽内的喷嘴与钢带之间的距离、喷嘴与钢带之间的喷射角度等都是喷射液流对污垢产生作用力大小的决定因素。

彩涂板表面是喷射流体的水平方向运动速度开始降低之前的位置，在这个位置与洗涤对象表面发生作用，清洗液展开的面积是大，但此时清洗液的有效动能造成的清洗效果已不好。彩涂板表面b的位置是喷嘴离洗涤对象很近时的情况，此时流体的冲击力大，但清洗液展开的面积过小，总的清洗效果不好。而在a。b位置之间有一个冲击力保持相对较大，而清洗液的展开面积也保持相对较大的位置c存在，在这个位置上放置清洗对象，能取得较好的清洗效果。而图中d 是喷嘴以斜方向喷射到清洗对象表面的最佳位置。斜向喷射比垂直喷射使污垢受到的解离作用更大，
洗距离喷射距离、喷射角与清洗力的关系 图4-6 斜向喷射与垂直喷射的比较可以看出，斜向喷射与垂直喷射相比，斜向喷射取得最佳清洗效果的距离要近一些;去污效果也比垂直喷射更好一些。
(2)喷嘴形状。常用于喷洗系统的喷嘴有不同的形状，从图4-7中所示有圆锥状、状、棒状、放射状等4 种，不同的形状适用于不同的清洗场合，其中扇形的喷嘴最适合清洗平面状的表面，彩涂板机组也大多使用这种扇形喷嘴。

(3)槽体材料。脱脂清洗设备均为碳钢材料，没有作任何防腐处理，箱体槽盖容易出现锈蚀。在反复的循环中，锈渣变为粉末，设备自身污染了槽内的水质。

The equipment factors affecting surface treatment are mainly reflected in the spray washing system of degreasing tank. The cleaning effect of the cleaning system is affected by the following points:

(1) Spray distance and spray angle. The distance between the nozzle and the steel strip in the degreasing tank and the spray angle between the nozzle and the steel strip are the decisive factors of the force of the spray flow on the dirt.

In Figure 4-5, a is the position before the horizontal movement speed of the jet fluid begins to decrease. At this position, the jet fluid interacts with the surface of the washing object, and the spreading area of the cleaning fluid is large, but the cleaning effect caused by the effective kinetic energy of the cleaning fluid is no longer good. The position B in Figure 4-5 is when the nozzle is very close to the washing object. At this time, the impact force of the fluid is large, but the spreading area of the cleaning solution is too small, and the overall cleaning effect is not good. And in a. There is a relatively large impact force between positions B, and a relatively large expansion area of cleaning solution also exists in position C. better cleaning effect can be achieved by placing cleaning objects in this position. D in the figure is the best position for the nozzle to spray obliquely to the surface of the cleaning object. The fouling dissociation effect of oblique jet is greater than that of vertical jet,

The relationship between cleaning distance, spraying distance, spraying angle and cleaning force is shown in Fig. 4-6. The comparison between oblique spraying and vertical spraying shows that the distance for oblique spraying to achieve the best cleaning effect is shorter than that of vertical spraying, and the decontamination effect is better than that of vertical spraying.

(2) Nozzle shape. The nozzles commonly used in spray washing system have different shapes. As shown in Figure 4-7, there are four kinds of nozzles: conical, rod-shaped, radial, etc. different shapes are suitable for different cleaning occasions. Among them, fan-shaped nozzle is most suitable for cleaning flat surface, and fan-shaped nozzle is also mostly used in color coating board unit.

(3) Tank material. The degreasing cleaning equipment is made of carbon steel without any anti-corrosion treatment, so the tank cover is easy to rust. In the repeated cycle, the rust slag turns into powder, and the equipment itself pollutes the water quality in the tank.