Measurement point sampling method for inspection of parts with free-form surfaces

Abstract

Parts must be measured to evaluate the manufacturing accuracy in order to check whether their dimension is in expected tolerance. In engineering, parts with free-form surfaces are generally measured by high-precision coordinatemeasuring machines. The measurement accuracy is usually improved by increasing the density of measurement points, which is time-consuming and costly. In this article, a novel sampling method of measurement points for free-form surface inspection is proposed. First, surface inspection is simplified into the inspection of a number of section curves of the surface. Second, B-spline curves constructed with an iterative method are employed to approximate these section curves. Subsequently, data points necessary to construct the B-spline curves are taken as the measurement points. Finally, the proposed method is compared with other two sampling methods. The results indicate that the proposed method greatly reduced the number of measurement points without decreasing the precision of surface modeling.

Early Stage Variation Simulation and Visualization of Compliant Part Based on Parametric Space Envelope

“…However, if certain real-deformation case is available through physical prototype run or collected from similar other assembly line, user can validate the simulation results by checking whether the real-case variation is captured in the simulation run output. On this, various methods are available [67], [68]. Under proposed framework and methodology, it involves fitting control points' movement to reproduce the real deformed manufacturing part.…”

Optimization method of on-machine inspection sampling points based on surface complexity

“…The algorithm adaptively detects integral points by modifying the B-spline least-squares fitting process, determining the profile curve of the measured surface by this method and using the main feature points of the profile to determine points in the measuring area [20]. Zhao et al proposed a new detection method for free-form surface inspection and inspection points, by dividing the surface to be measured into several sections that make it easy to construct B-splines, and obtain the data points needed to construct B-splines as inspection points [21].…”

Comparison of GA, ACO algorithm, and PSO algorithm for path optimization on free-form surfaces using coordinate measuring machines

“…Hwang et al [1] improved inspection planning using a greedy heuristic method to minimize the number of part setups, the probe orientations, and the inspection feature sequence. Zhao et al [2] introduced B-spline curves to minimize the number of sampling points to increase the efficiency of inspection. Obeidat et al [3] also improved the inspection efficiency by decreasing the number of testing points.…”