A non-contact method for rod straightness measurement based on quadrant laser sensor

This paper aims on the development of a non-contact method for measurement of straightness of the rods. The straightness of rod is a major concern in many industrial applications, especially, where rods are forcefully inserted in pipes by machines. If the rod is bent it may cause damage to the channel and the rod, which results in additional cost due to damage. This technique is based on transmitting the laser light from a laser source and the same is detected on the other end using quadrant laser sensor. If the rod is straight the transmitted beam travels along the surface of the rod and is detected by the receiving unit. If the rod is bent the transmitted beam may not reach the receiver or the receiver detects a change pattern of light. The change in detected light is calculated in terms of bend. Laser diode (wavelength 670nm) is used as source and photo diode as receiver. The signal, thus received is processed and acquired by a data acquisition cum analog to digital converter card PCL-207. The acquired signal is computed and displayed in graphical form on monitor. This method is very accurate and non-contact in nature as no direct apparatus or implantable sensor is used for measuring the bend.