Guns Test and Pattern Test in Coating Process
Guns Test
It is a test of the accuracy of the guns in terms of the spray rate and to ensure that there is no significant difference between each gun and the other.
How is the Guns test done?
1: Cylinders are brought according to the number of guns and of course they are graduated so that it is easy to know the quantity or they are weighed and a tare weight of the cylinders is done before the test.
2: We connect the pump to the solution tank and turn on the pump until it delivers the solution to each gun. We start running the Timer at a high, medium, and low pump speed. We follow each gun. It will give us how much solution. We follow the difference between each gun, which is specified in the BMR. We should not exceed it. Thus We know the condition of the guns and whether there is a Variation in their spray rates or not.
So what are the reasons for there being a difference in the rate of one gun and the other?
There are some reasons.
1: spray line hoses worn out.
2: Worn out internal Orcels guns.
3: The presence of airbubles in large quantities in the solution.
4: Worn and leaking air hoses in your guns.
5: The solution does not dissolve and there is sedimentation inside the hoses.
What problems can occur if there is a large difference in spray rates between each gun and the other?
1: color variation..
2: over wetting..
3: sticking..
4: roughness..
5: Twinning..
6: shipping
2. Pattern Test
What is pattern test?
It is a test to distribute the solution on the tablets properly so that there is no overwetting or vice versa that it is in a part of the tablets that no solution reaches.
How does the pattern test work?
We bring a white sheet of paper and place it under the guns, and we adjust the required distance between the guns and the paper, just like we spray on the tablets, and we monitor the distribution of the solution on the paper, how it will be.
In some machines, the air pattern has another name, such as (Spray Width).
It is better to set the value of Atomizing air to the same value as Pattern air.
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