Analysis of Tool Geometry for the Stamping Process of Large-Size Car Body Components Using a 3D Optical Measurement System

The paper presents a method for checking the geometry of stamped car body parts using a 3D optical measurement system. The analysis focuses on the first forming operation due to the deformation and material flow associated with stall thresholds. An essential element of the analysis is determining the actual gap occurring between the forming surfaces based on the die and punch geometry used in the first stamping operation. The geometry of car body elements at individual production stages was analyzed using an optical laser scanner. The control carried out in this way allowed one to correctly position the tools (punch and die), thus introducing the correction of technological parameters, having a fundamental influence on the specific features of the final product. This type of approach has not been used before to calibrate the technological line and setting of shaping tools. The influence of the manufactured product geometry in intermediate operations on the final geometry features was not investigated.

Digital Twin of an Optical Measurement System

Digital twins of measurement systems are used to estimate their measurement uncertainty. In the past, virtual coordinate measuring machines have been extensively researched. Research on digital twins of optical systems is still lacking due to the high number of error contributors. A method to describe a digital twin of an optical measurement system is presented in this article. The discussed optical system is a laser line scanner mounted on a coordinate measuring machine. Each component of the measurement system is mathematically described. The coordinate measuring machine focuses on the hardware errors and the laser line scanner determines the measurement error based on the scan depth, in‑plane angle and out‑of‑plane angle. The digital twin assumes stable measurement conditions and uniform surface characteristics. Based on the Monte Carlo principle, virtual measurements can be used to determine the measurement uncertainty. This is demonstrated by validating the digital twin on a set of calibrated ring gauges. Two validation tests are performed: the first verifies the virtual uncertainty estimation by comparison with experimental data. The second validates the measured diameter of different ring gauges by comparing the estimated confidence interval with the calibrated diameter.

Development of a Compact Optical Measurement System to Quantify the Optical Properties of Fluorescently Labeled Cervical Cancer Cells

The flow cytometer is an instrument that can measure the characteristics of cells such as the number of cells, the degree of internal composition of the cells, the size of the cells, and the cell cycle etc. This equipment has been used to study leukemia, DNA and RNA analysis, protein expression, cell death, and immune response. However, a flow cytometer is expensive equipment and requires an operator with expertise for use and maintenance. When only simple data are needed, such as measuring the number of cells or quantitative analysis of cell growth and inhibition, the use of a flow cytometer is not suitable in terms of cost and requires unnecessary measurement time consumption. In this study, a compact optical measurement system using commercially available light-emitting diodes (LED), photodiode, and Arduino Mega ADK was developed, and the body structure was printed and utilized by a 3D printer. Cervical cancer cells, known as one of the major cancers of women, were fluorescently treated with fluorescent dyes such as Calcein-AM and DiD, and performance of the system was verified. The side scattering measured using various filters with different transmission wavelengths of light showed high linearity in proportion to the number of cells. By measuring the side scattering of the untreated cervical cancer cells, fluorescence scattering could be confirmed from the difference in the side scattering intensity according to the fluorescence treatment.

Alignment Method of an Axis Based on Camera Calibration in a Rotating Optical Measurement System

The alignment problem of a rotating optical measurement system composed of a charge-coupled device (CCD) camera and a turntable is discussed. The motion trajectory model of the optical center (or projection center in the computer vision) of a camera rotating with the rotating device is established. A method based on camera calibration with a two-dimensional target is proposed to calculate the positions of the optical center when the camera is rotated by the turntable. An auxiliary coordinate system is introduced to adjust the external parameter matrix of the camera to map the optical centers on a special fictitious plane. The center of the turntable and the distance between the optical center and the rotation center can be accurately calculated by the least square planar circle fitting method. Lastly, the coordinates of the rotation center and the optical centers are used to provide guidance for the installation of a camera in a rotation measurement system. Simulations and experiments verify the feasibility of the proposed method.

Development of a Rapid Optical Measurement System for Circular Workpieces with Irregular Tooth Contours after Broaching Process

During a manufacturing process, it is essential to quickly identify whether a tool needs to be replaced or adjusted, to ensure that production quality is not compromised. Therefore, the re-inspection of the product or first article inspection is an important process. Reducing the inspection time can reduce the time spent waiting for a product in the production line. This research aimed to design a system that can automatically and rapidly measure the dimensions of irregular tooth contours in the broaching process, to ensure cutting tools are replaced when necessary. This study developed an automatic machine for measuring the irregular tooth contours of large ring parts; the tooth root, tooth height, and tooth thickness of the workpiece are measured. The measurement diameter is approximately 200 mm, and the radial inspection accuracy is within ±20 μm; we aimed to reduce the detection time considerably. An optical micrometer and an automatic rotating platform were used in the measurement system. The workpieces to be measured were easy to install, and the eccentricity was automatically corrected by the system, thus saving time that would be taken to correct Abbe errors. This research successfully developed a rapid optical measurement system that can reduce the inspection time from 30 min to 60 s. Moreover, the maximum radial measurement error is −0.02 mm, which means that the measurement accuracy is within ±20 μm (total: 40 μm).