FPCWAY

Preparation of flexible printed circuits based on ultrasonic spraying method_2_Experimental Platform and Principle

1 Experimental Platform and Principle

The ultrasonic spraying equipment mainly consists of a liquid supply system, ultrasonic atomization system, motion control system, mechanical system, etc., as shown in Figure 1. It specifically includes an ultrasonic power box, atomizing nozzle, nozzle holder and its motion control system, touch screen control module, adsorption heating platform, and so on.

The ultrasonic atomization system is the key to the ultrasonic spraying equipment, mainly composed of an ultrasonic generator and a transducer vibration system (including ultrasonic atomization piezoelectric transducers and amplitude rods). The ultrasonic generator is used to generate the electrical signals required for the operation of the ultrasonic atomization piezoelectric transducers, which then convert the electrical signals into mechanical vibrations using the inverse piezoelectric effect of piezoelectric ceramics. Due to the constraints of the material and mechanical properties of the piezoelectric transducer itself, the mechanical vibration amplitude at its output end is only a few micrometers, which cannot meet the requirements of processing loads. Therefore, an amplitude rod is added to the output end of the piezoelectric transducer to amplify the mechanical vibration of the transducer. The amplified mechanical vibration amplitude can reach dozens of micrometers, allowing the ultrasonic vibration to act effectively on the acoustic load. For this paper, the acoustic load is the nano silver conductive ink to be atomized.

The specific implementation method for preparing FPC is as follows: successively place the substrate (PI film) and metal mask (see Figure 2, overall size is 30 mm × 30 mm, minimum conductive line width is 500 μm) on the substrate placement platform. Set the relevant process parameters on the touch screen according to the required spraying range and the properties of the conductive ink to be sprayed. Perform ultrasonic atomization of the conductive ink, and use the movement of the nozzle holder to drive the nozzle to print precision circuits on the substrate covered with the mask. After completing the coating, sinter the PI film at 125 °C for 20 minutes to complete the preparation of the FPC, as shown in Figure 3.