Nonlinear PCB Compensation Based on Intel® HD graphics for Manufacturing Processing

Printed Circuit Board (PCB) has the situation of expansion or shrinkage in the manufacturing processing. Moreover, the circuit is more complicated and the line width/spacing is more precise, so that the circuit file becomes very large. Traditionally, four-point registration holes and sub- block are used for the bilinear compensation. Although the traditional methods can be quickly compensated, it cannot enhance the precision. In contrast, using the polynomial compensation can have good precision but time consuming. Moreover, considering the IPC (Industrial Personal Computer) heat dissipation and cost issues, GPU (Graphics Processing Unit) card is rarely used at the factory. In present, Intel CPU contains the Intel® HD graphics which is implemented the bilinear technology by OpenGL texture mapping. Therefore, this paper proposed the polynomial texture mapping algorithm by OpenGL, which calculated the nonlinear straight trace according to the registration holes. The non-uniform interpolation control points are generated by using the slope relationship of the registration holes. Finally, using Intel® HD graphics on multiple IPCs, multi-thread division processing and pipeline processing which can improve the precision of PCB compensation and save the computing time. The experimental results show the proposed method has the smallest XOR (Exclusive-OR) value at the 2.5um resolution and 1um resolution. Meanwhile, the computing time can still maintain 1.749 seconds at the 2.5um resolution and 9.588 seconds at the 1um resolution. In addition, the offset less than 1 pixel of the polynomial texture mapping algorithm accounts for about 65 percent at the 2.5um resolution, and the offset less than 2 pixels of the polynomial texture mapping algorithm accounts for about 57 percent at the 1um resolution. Finally, simulate two IPCs computing time in the image size 510mm x 610mm (resolution is 25400dpi) through the proposed method in this paper, we obtain the 20.618s on IPC1 and 20.30s on IPC2 which is better than [8]. The proposed method in this paper can not only quickly compensate PCB substrate but also solve the problem of low precision.