Measurement and quality control of turbine blades is critical to the successful operation of power plants. It has a key role in manufacturing and reverse engineering. Novel technologies continue to be developed to measure parts with complex geometries, such as turbine blades. Digitizing techniques, using both contact and noncontact methods, are used. Selecting the most appropriate digitizing method for a turbine blade requires consideration of the measuring performance of the alternative methods, including criteria such as accuracy, speed and cost. This study seeks to evaluate the practical accuracy and efficiency of various contact and noncontact digitizing methods through measurement and associated quality control of a complex part, that is, a turbine blade airfoil. Four popular technologies, using distinct underlying measurement methods, were chosen to measure a Frame 5 gas turbine blade, namely, a touch trigger probe mounted on a Zeiss coordinate measuring machine, a touch scanning probe and a spot laser probe separately mounted on Renishaw coordinate measuring machine and a linear laser system from ZScanner. The measured point cloud resulting from each method was then used to reconstruct three-dimensional computer-aided design models of the blade. The accuracy of each measuring system was evaluated against the original blade. The evaluation incorporated a comparative study of design parameters derived from the point cloud and reconstructed surfaces associated with each measurement method. The maximum error of point clouds were −123, 2530 and 2173 µm for the ZScanner linear laser, Renishaw spot laser and Renishaw touch scan, respectively. These measured errors indicated higher accuracy from linear laser method than spot laser scanning and touch scanning methods. Furthermore, the achieved standard deviations of 42, 170 and 269 µm for point clouds of ZScanner linear laser, Renishaw spot laser and Renishaw touch scan, respectively, showed that the manufacturer reported that information cannot be always reliable.

This paper presents the development of a new Coordinate Metrology Machine (CMM) using a novel four degrees of freedom parallel kinematics, namely C4, with three translations and one rotation about its X-axis. Design of the configuration, selection of the components, and detailing their interactions are among the most challenging tasks in this process. A detailed kinematic model of the designed configuration is derived, and the velocity Jacobian matrix for the moving platform and legs is calculated. Using the developed analytical approach, a novel graphical approach, and an experimental method the singularity and dexterity of the mechanism in the CMM’s workspace are defined. Following a systematic design improvement process, variety of design parameters and components’ details were analysed to select the optimum mechanism with the greatest dexterity and stiffness, and without singular points in a well-formed workspace. The final design is validated by construction of a fully functioning prototype of the mechanism, and experimentally testing variety of case studies. The results showed that the developed C4 mechanism presents a satisfactory level of dexterity and stiffness within a well-formed workspace as a CMM machine.

Fused filament fabrication (FFF) and Fused deposition modeling (FDM) are among the most common methods of additive manufacturing technology for a variety of industries. However, the extrusion-based process of these technologies has qualified the usable materials to thermoplastics with inherently limited mechanical properties. Augmenting the properties of these materials by blending them with other polymers or their reinforcement with various additives are among the solutions to overcome this issue. This study examines the result of the introduction of Polybutylene Terephthalate (PBT) to acrylonitrile butadiene styrene (ABS), as one of the most common thermoplastics used in FDM/FFF processes, and explores the effects of the incorporation of Multi-Walled Carbon Nanotubes (MWCNT) to ABS/PBT blend with different filler fractions (0.1, 0.3, and 0.5 wt.%) on the mechanical properties of the printed specimens. In order to assess the mechanical behavior of the printed parts, standard melt flow index (MFI), tensile, three-point flexural, and notched impact tests have been performed on the produced parts. The morphological analyses through Scanning Electron Microscopy (SEM) micrographs have been conducted to inspect the distribution of impregnated MWCNTs and the fracture behavior of the specimens. The most satisfactory improvement has been observed in printed parts of the ABS/PBT/CNT nanocomposites containing 0.3 wt.% of MWCNTs.

Computer aided optimization and quality improvement of the performance of industrial machinery, without changing the original design, is one of the important challenges of intelligent manufacturing science, especially for robotic systems. In this paper, improving the performance of the new C4 robot serving as a coordinate measuring system (CMM) was considered. Since the efficiency of a robot is directly related to its work-space, calculating the quality improved work-space of this mechanism was studied. The new inverse and forward error models considering 48 error parameters were obtained using inverse kinematics. Afterward, a sensitivity analysis of the mechanism was implemented. Using the inverse kinematics and the discretization method, the work-space was calculated. Applying a new method, singularity tolerance, singular and quasi-singular points of the work-space were determined. In this proposal of a new computer integrated quality improvement algorithm, the work-space was investigated in various aspects including singularity, dexterity, and sensitivity analysis. The comparison between various indices for dexterity analysis was implemented and reliability and accuracy index was presented. Finally, the quality improved work-space was achieved without any physical changes to the structure. Selecting high-quality regions of work-space for operational intelligently can help to gain accurate results in industrial applications especially measuring tasks.