High-precision laser cutting method for FPC circuit board plug

The base material of flexible printed circuit board (FPC board) is copper, and the circuit needs to be covered with a cover film. The cover film material is generally polyimide. Thermosetting adhesive tightly combines the cover film with the circuit board at high temperature and presses it on the surface of the circuit board to play a protective role. The FPC board needs to be processed in the later stage of production, and there are plugs connected to other electronic products on the outer shape. The reliability of the circuit board connection makes the laser cutting accuracy higher.

The current batch processing method of FPC mainly includes stamping method, and small batch FPC and FPC samples are mainly cut by laser. So far, many manufacturers at home and abroad have developed UV laser cutting machines to make FPC samples, but the commonly used cutting methods for the shape of the FPC board plug are: cursor point recognition method and text recognition method, but there is no report on the plug edge recognition method, which makes the FPC board laser cutting operation simpler and the cutting accuracy is also higher.

FPC substrates are mainly divided into single-sided, double-sided and multi-layer substrates. Double-sided substrates are products developed from single-sided substrates. The production process of single-sided substrates is as follows:

The shrinkage rate and cutting accuracy curve of the FPC board shows that when the shrinkage rate is less than 0.8鈥? the cutting accuracy fluctuates within the range of 0.05 mm. As the shrinkage rate increases, the average cutting deviation value and variance value increase. When the shrinkage rate is greater than 0.8鈥? the cutting accuracy does not meet the customer's requirement of 0.05 mm.

When the shrinkage rate is above 0.8鈥? the average cutting deviation value is above 0.020mm, and the variance is greater than 0.025mm. This shows that when the lifting shrinkage rate exceeds 0.8鈥? the cutting accuracy of the FPC board cannot meet the accuracy requirement of the 0.05 mm shape.

The resolution of the positioning system of the new laser cutting machine is 3渭m, which clearly judges the boundary between the plug and the ordinary flexible board, and provides an accurate reference point for workpiece deformity correction compensation. Through the verification of the circuit board production site, the new laser cutting technology can control the size accuracy of the FPC board, which meets the application example of 0.05mm plug cutting deviation.