An Optical-Triangulation-Based Method for Measurement of Blade Sections

Blades are an important part of aviation engine, its manufacturing compliance seriously affect the performance of the engine. Blades tend to be free-form surface modeling, which makes it extremely difficult to measurement. Since no probe radius compensation, high efficiency, non-contact optical measurement methods get more and more attention, but the inspection uncertainty of optical measurement is usually between 30um to 50um .To reduces the optical non-contact measurement uncertainty, this paper presents an Optical-triangulation-based method for measurement of blade sections. There is a data optimization process in the method, and this feature makes the proposed method can obtain better measurement results. At last, some experiments demonstrate the effectiveness of this method.

Probe-Radius Compensation of the Bevel Gears Tooth Surface Using 3D Measured Points

First of all, using the coordinate measuring machines 3D measured points are acquired. These machines are widely used in gear manufacturing industry but each of them handles the compensation problem in different ways. Thus, the aim of this paper is to compensate the measured data points on the tooth surface of bevel gears with the value of probe radius. This paper presents an option to solve the compensation with the value of probe radius and shows the steps, the methodology to implement this idea in practical use. There are used triangular meshes on the measured data points and determined the normal vector of each point detected on the tooth surface of the bevel gears.

Research on High-Precision Measurement Platform for Optical Aspheric Surface and Corresponding Error Compensation

With a hardware and software control scheme which including high-precision linear motors, contacting and non-contacting measurement sensor and a new developed of measuring software, this paper designs and establishes a high-precision measurement platform. This paper not only implements the hardware build, measuring software development, but also discusses corresponding error compensation, for example, probe radius compensation, rough error canceling and so on. The experimental results indicate that the measurement platform is suitable for high-precision measurement for optical aspheric surface.

Probe Radius Compensation for On-Machine Measurement of Sculptured Surfaces

Accurate dimensional measurement of freeform surfaces is a key step in CNC machining. Usually, a CMM equipped with a touch trigger probe is employed for measurement of such surfaces. In such a precision measurement, probe radius error is a serious concern. Traditionally, probe radius compensation methods are based on using the design (CAD) surface. In specific instances, the inaccuracy of these compensation techniques could be one order magnitude higher than the repeatability of the probe. Probe radius compensation based on ideal machined surface (generated when the milling cutter accurately moves through the cutter location (CL) points) is superior in principle to the one based on design surface, since it is one level of abstraction closer to the final surface realized. On Machine Measurement (OMM), where the measurement process is accomplished on the machining center by replacing the milling cutter with the Touch Trigger Probe, affords such a possibility without resorting to computationally intensive surface localization. This paper presents the implementation and performance analysis of a proposed new probe radius compensation technique based on both the design surface data (CAD model) and machined surface data (CL points). The proposed method efficiently compensates the probe radius error of on-machine measurement data for sculptured surfaces. The model was implemented on the simulated CMM data of a bi-cubic Bezier surface machined by a ball-end mill and compared with the conventional compensation techniques. The results show that this method compensates the probe radius error better than the existing techniques and yields superior precision.

Reverse engineering of simple surfaces of unknown shape with touch probes: Scanning and compensation issues

This work discusses issues concerning the implementation of scanning of unknown engineering objects containing just simple (i.e. no freeform) surfaces with touch probes on three-axis computer numerical control (CNC) measuring machines in order to reconstruct their shape in a computer aided design (CAD) system. Several ideas are put forward e.g. scanning along vertical slicing planes adaptive point sampling distances in-process ‘proactive’ segmentation of points into curve sections and probe radius compensation in two directions as well as limited remedy of edge scanning ambiguities. Most of the suggested algorithms are implemented as parametric numerical control (NC) programs on an OKUMA machining centre.