JPS56102972A - Controlling method of paint thickness in automatic coating line - Google Patents

Abstract

PURPOSE: To automatically control a paint thickness constantly to a desired thickness in an automatic coating apparatus, by computing the thickness of a paint film on the basis of a paint spray amount from a nozzle and a moving speed of an article to be coated, and controlling the flow amount of the paint on the basis of a deviation between the computed thickness and an objective value.

CONSTITUTION: An article to be coated, e.g. a steel sheet 7, is carried on a table roller 8 along the arrow direction at a constant speed. A paint reserved in a tank 1 is sprayed through a nozzle 6 positioned above the steel sheet 7. The nozzle 6 goes and returns traversely above the steel sheet 7, to spray a paint onto the whole surface of the steel sheet. In this case, the speed of carrying the steel sheet 7 is detected as a rotation number of the table roller 8 by a speed signal generator 10, while a flow rate of the paint is detected by a flow amount detector 12 and converted to a flow rate signal by a convertor 13. A thickness of the paint film after dried is calculated by a computer 14 on the basis of the outputs of the flow rate signal and the speed signal with a reference value at a device 11. The value from the computer 14 is compared with an output from an objective film thickness settling device 16, by a controller 15 for indicating, recording and controlling the film thickness. The difference between these two values is detected by the controller 15, and used for controlling a valve 5 to control a flow rate of the paint in accordance with the difference. Thus, the flow amount of the paint is controlled appropriately.

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