The Development Of Electrostatic Powder Coating Control System

The surface process of metal products not only prevents corrosion,but also beautifies its appearance.The traditional spraying technology is prone to produce paint residue,and bring about serious environmental pollution.Currently,Electrostatic spraying operation is widely used in industry.Compared with traditional technology,the powder coating of electrostatic spraying is adsorbed on the surface of work pieces with the effect of high voltage electrostatic.A small amount of powder dispersed in the air can also be recovered.So it's good for the environmental protection and reduces the harm to human body;the coating quality is better than the traditional method.At present,many small and medium enterprises are still using manual spraying,which is used the electrostatic spraying controller to regulate the press manually and cannot guarantee the accuracy of air pressure.Therefore,the design of an automatic spray control system is significance.This paper is based on the spraying production line of one company in Guangdong.On the basis of full investigation of the company,considered the standard of spraying control parameters in national and international,an electrostatic spraying control system suitable for assembly line operation is designed.The control system consists of electrostatic spraying control cabinet and PLC control system.In the Electrostatic spray control cabinet can be connected to a number of electrostatic spraying controllers through the internal RS485 bus.Each spraying controller can control an electrostatic spray gun for spraying operations.The PLC control system is used to control the reciprocating machine,while the main PLC controller is also responsible for detecting the speed,the size and the position of the work pieces.The electrostatic spray controller is triggered after determining the work piece information.The control cabinet and the PLC communicate with the host computer through the Ethernet bus.And the remote monitoring of the spraying operations is achieved through the monitoring software by the host computer.To design the electrostatic powder coating system,the works as follows: first of all,the overall architecture of the system is designed.Secondly,the communication coordinator and controller in the electrostatic spraying control cabinet are designed in detail.The communication coordinator uses STM32F407 as MCU to design the Ethernet and RS485 communication interface.And the solid-state relay trigger output circuit is designed for the trigger of the controller.The Controller is divided into operation panel and control panel.Respectively,the operation panel is designed by STM32F100 and the control board is designed by STM32F205.Its function is to control the output parameters of the electrostatic spraying,as well as the measure of the output parameters.Then,the software of the spray controller is designed in detail,including the design of controller driver software and control algorithm.Finally,the function of the electrostatic spraying controller has been tested,and the performance even has been tested on site.The result shows that the spraying effect was achieved and the feasibility of the electrostatic spraying controller was verified.