In situ measurement of cylindricity—Problems and solutions

The paper is a critical review of existing methods that permit in situ measurement of large external cylindrical surfaces. Large size cylindrical elements are used in many industries, e.g. papermaking, metallurgy or shipbuilding. Their diameter can sometimes reach even a few meters and they can be several meters long. Such elements should be characterized by high dimensional and form accuracy. Excessive loads or changes in temperature during use may result in their deformation. It is thus important for such elements to have their surface quality and form accuracy controlled not only during production but also during use. Measurement with conventional devices would involve transport, which may be impractical or impossible due to the large size and mass. That is why industries where such elements are produced or employed expect measurements to be performed in situ, for example, directly on a machine tool. Methods that can be used for this purpose are generally divided into three groups: V-block measurement, multi-probe measurement and measurements with Articulated Arm Coordinate Measuring Machines (AACMMs). This paper describes advantages and disadvantages of all the three groups of methods suggesting which one best meets the requirements of modern manufacturing processes and which are the most prospective.