Search results

The purpose of this paper is to develop a novel automatic and accurate measurement technique for the volume of solder which is present in solder paste in pin‐in‐paste (PIP) technology and a calculation algorithm for predicting solder joint quality.

A new method is described for accurately determining the volume of solder alloy in solder paste that is present in and around the through hole, using X‐ray measurements (orthogonal view X‐ray images, instead of angle view), image processing and other calculations. In addition, various calibration tool constructions are investigated and a method is suggested for determining the calibration curve (for each solder paste) of an X‐ray machine.

A new calibration tool has been developed to accurately measure the calibration curve of X‐ray machines. Based on several tests, a fast and reliable image processing method for measuring the average grey scale of each pasted through hole is described. Numerous PIP solder joints have been created then analysed using the methodology. To verify the efficiency of the described methods, joints are soldered and inspected using cross‐sectioning and X‐ray imaging.

Calibration curve measurement of an X‐ray machine is done with the help of the developed tool for PIP technology. Orthogonal view X‐ray images are used to measure the volume of printed solder alloy (paste). During the image processing, circle fitting has been simplified to line fitting.