Development of a laser processing head to inspect and repair the damage inside of a half-inch pipe

In industrial factories and power generation plants, many drain pipes are used to transport various fluids from one location to another, and these pipes have to be regularly inspected for maintenance purposes. The widely used inspection methods are ultrasonic flaw detection, eddy current testing, and so on. Recently, these pipes have been inspected from the inside by using developed endoscopic devices, e.g., CCD devices and optical fiberscopes. However, when certain damages are detected inside of the pipes, many pipes are corked or exchanged because conventional endoscopic devices cannot repair the damage. Therefore, we have developed a laser processing head that can attach to the tip of an optical fiberscope for slender pipes with diameters as small as 12 mm. The laser processing head has a mirror inside of the moving sleeve. The main function of this laser processing head is to reflect the endoscopic images and lasers by using the mirror. In this paper, we describe the structure of the laser processing head designed using ultrasonic actuators and the results of its movement tests.