Improving Surface Based Clamping Simulations by Measuring the Position of Active Surfaces during the Clamping Process

2013 ◽  
Vol 554-557 ◽  
pp. 2312-2317 ◽  
Author(s):  
Welf Guntram Drossel ◽  
Martin Wahl ◽  
Frank Schulz ◽  
Reinhard Mauermann ◽  
Wilhelm Schützle ◽  
...  
Keyword(s):  
Optical Measurement ◽  
Active Surface ◽  
The State ◽  
Body Parts ◽  
Process Chain ◽  
High Reproducibility ◽  
Measurement Systems ◽  
Active Surfaces ◽  
Body Construction ◽  
Clamping Device

The manufacturing process of body parts starts with the step of sheet metal forming. The single parts, produced at the press shop, are put into clamping devices in order to align and to fix them. The fixation takes part before further operations like joining can be carried out. In order to simulate the process chain of add-on body parts realistically, the clamping process (closing the clamping device) has to be taken into account. The stationary surfaces of a clamping device are called passive and the moveable surfaces are called active surfaces. If the clamping process is calculated by means of active surfaces, their positions need to be measured in the state of a closed clamping device. While the passive surfaces of a body construction device can be measured with high reproducibility, the measurement of active surfaces in the state of a closed device is impracticable because of the loss of accessibility. Furthermore, if the parts to be clamped or the position of the clamping device differ from their designed position, the assembly works like a flat spring against the clamping device force in all spatial directions. The active surface does not reach the position which was measured before. In order to take these facts in clamping simulations into account, the end position of the active surfaces should be known. A clamping device concept on the basis of a measuring probe for optical measurement systems was developed. It is possible to determine the position of active surfaces with high reproducibility while the parts are clamped. It can be shown, that the presented clamping device concept contributes to significantly better results of clamping simulations. Thus a better starting basis for further simulations along the process chain is offered.

Improving the Ramp-Up Process of a Body-Construction Line by Numerical Supported Design of Clamping Devices and FEM Based Tolerance Prognosis

2015 ◽  
Vol 651-653 ◽  
pp. 932-937 ◽  
Author(s):  
Dirk Landgrebe ◽  
Patrick Ackert ◽  
Raik Grützner ◽  
Johannes Weber ◽  
Reinhard Mauermann ◽  
...  
Keyword(s):  
Metal Forming ◽  
Dimensional Accuracy ◽  
The Body ◽  
Body Parts ◽  
Cooperative Effort ◽  
Car Body ◽  
Body Construction ◽  
The Body Shop ◽  
Clamping Device

The use of FEM (finite element method) to assistant in ramp-up processes of car body construction lines is increasing, thanks to developments in recent years [1-3]. Car body manufacturing begins with sheet metal forming, while in subsequent steps the inner structures of the vehicle are assembled and connected to the outer skin by hemming. With reference to the current state of the art, there is no methodology which can reliably predict the dimensional accuracy of body parts through metal forming [4].Additionally, several methods to predict the distortion of joining and the dimensional effect of clamping during the assembly process were presented and validated [4-11]. Dimensional effects of the clamping process are basically the result of a deliberate alignment, other than the given values of construction to compensate dimensional inaccuracy of single parts from the body shop. These deliberate alignments are generally effected through a translation of clamps and pins in the clamping device. Until now, most of the methods of clamping and joining simulation presented have been verified using academic samples.In this report, the quality of forecasting in real problems during a ramp-up process will be verified and expanded. As part of a national project, co-funded by Sächsische Aufbaubank (SAB), the potential of FEM to assist in the ramp-up process were reviewed in a cooperative effort between Porsche Leipzig GmbH and Fraunhofer Institute for Machine Tools and Forming Technology (IWU). Furthermore, it will be shown that developed methods are able to represent the influence of deliberate positioning of clamps in complex samples. For the first time the quality of forecasting through the translation of locating pins is numerically and experimentally qualified.

scholarly journals Nano-imprinted subwavelength gratings as polarizing beamsplitters

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Julian Wüster ◽  
Yannick Bourgin ◽  
Patrick Feßer ◽  
Arne Behrens ◽  
Stefan Sinzinger
Keyword(s):  
Nanoimprint Lithography ◽  
Optical Measurement ◽  
Design Method ◽  
Optical Systems ◽  
Surface Metrology ◽  
Measurement Systems ◽  
Common Path ◽  
Dielectric Coatings ◽  
Subwavelength Gratings ◽  
Wide Range

AbstractPolarizing beamsplitters have numerous applications in optical systems, such as systems for freeform surface metrology. They are classically manufactured from birefringent materials or with stacks of dielectric coatings. We present a binary subwavelength-structured form-birefringent diffraction grating, which acts as a polarizing beamsplitter for a wide range of incidence angles −30∘…+30∘. We refine the general design method for such hybrid gratings. We furthermore demonstrate the manufacturing steps with Soft-UV-Nanoimprint-Lithography, as well as the experimental verification, that the structure reliably acts as a polarizing beamsplitter. The experimental results show a contrast in efficiency for TE- and TM-polarization of up to 1:18 in the first order, and 34:1 in the zeroth order. The grating potentially enables us to realize integrated compact optical measurement systems, such as common-path interferometers.

scholarly journals Detection of foot contact in treadmill running with inertial and optical measurement systems

2021 ◽  
pp. 110419
Author(s):  
Jasper Reenalda ◽  
Marit A. Zandbergen ◽  
Jelle D. Harbers ◽  
Max R. Paquette ◽  
Clare E. Milner
Keyword(s):  
Optical Measurement ◽  
Treadmill Running ◽  
Measurement Systems

Methods of temperature measurement in microwave heating technologies

2021 ◽  
pp. 20-28
Author(s):  
Boris A. Lapshinov
Keyword(s):  
Temperature Measurement ◽  
Microwave Heating ◽  
Microwave Radiation ◽  
Electromagnetic Fields ◽  
Optical Measurement ◽  
Measurement Methods ◽  
Heating Systems ◽  
Measurement Systems ◽  
Processed Material ◽  
Spectral Pyrometry

In industrial technological processes associated with the heating of the processed material by microwave radiation, it is necessary to measure the temperatures of objects. Methods for measuring temperatures in the fields of technology using microwave heating systems are considered. The main possibilities, disadvantages and limitations of the used contact and non-contact (optical) measurement methods are determined. The requirements for temperature measurement systems under conditions of exposure to strong electromagnetic fields are listed. The possibilities of the spectral pyrometry method are especially noted.

scholarly journals Multi-layered tissue head phantoms for noninvasive optical diagnostics

2015 ◽  
Vol 08 (03) ◽  
pp. 1541005 ◽  
Author(s):  
M. S. Wróbel ◽  
A. P. Popov ◽  
A. V. Bykov ◽  
M. Kinnunen ◽  
M. Jędrzejewska-Szczerska ◽  
...  
Keyword(s):  
Optical Properties ◽  
Near Infrared ◽  
Optical Measurement ◽  
Human Head ◽  
Medical Diagnostics ◽  
Optical Parameters ◽  
Measurement Systems ◽  
Tissue Phantoms ◽  
Optical And Mechanical Properties

Extensive research in the area of optical sensing for medical diagnostics requires development of tissue phantoms with optical properties similar to those of living human tissues. Development and improvement of in vivo optical measurement systems requires the use of stable tissue phantoms with known characteristics, which are mainly used for calibration of such systems and testing their performance over time. Optical and mechanical properties of phantoms depend on their purpose. Nevertheless, they must accurately simulate specific tissues they are supposed to mimic. Many tissues and organs including head possess a multi-layered structure, with specific optical properties of each layer. However, such a structure is not always addressed in the present-day phantoms. In this paper, we focus on the development of a plain-parallel multi-layered phantom with optical properties (reduced scattering coefficient [Formula: see text] and absorption coefficient μa) corresponding to the human head layers, such as skin, skull, and gray and white matter of the brain tissue. The phantom is intended for use in noninvasive diffuse near-infrared spectroscopy (NIRS) of human brain. Optical parameters of the fabricated phantoms are reconstructed using spectrophotometry and inverse adding-doubling calculation method. The results show that polyvinyl chloride-plastisol (PVCP) and zinc oxide ( ZnO ) nanoparticles are suitable materials for fabrication of tissue mimicking phantoms with controlled scattering properties. Good matching was found between optical properties of phantoms and the corresponding values found in the literature.

Optical measurement systems

Mechatronics ◽  
1991 ◽  
pp. 49-74
Author(s):  
D. A. Bradley ◽  
D. Dawson ◽  
N. C. Burd ◽  
A. J. Loader
Keyword(s):  
Optical Measurement ◽  
Measurement Systems

Centering of Camera Principal Point and Turntable Axis in Optical Measurement Systems

2019 ◽  
Vol 46 (11) ◽  
pp. 1104002
Author(s):  
侯艳丽 Hou Yanli ◽  
苏显渝 Su Xianyu ◽  
陈文静 Chen Wenjing
Keyword(s):  
Optical Measurement ◽  
Principal Point ◽  
Measurement Systems

High-speed laser interferometric distance sensor with reference mirror oscillating at ultrasonic frequencies

2019 ◽  
Vol 86 (3) ◽  
pp. 164-174 ◽  
Author(s):  
Sebastian Hagemeier ◽  
Stanislav Tereschenko ◽  
Peter Lehmann
Keyword(s):  
High Speed ◽  
Optical Measurement ◽  
Limited Range ◽  
Distance Measurement ◽  
Reference Mirror ◽  
Acquisition Rate ◽  
Measurement Systems ◽  
3D Topography ◽  
Distance Sensor ◽  
Laser Interferometric

AbstractOptical measurement systems are an important part of the portfolio of 3D topography sensors. By precise, contactless and rapid measurements these sensors constitute an alternative to tactile instruments. In this contribution the principle of a laser interferometric distance sensor is presented, which in combination with lateral scan axes acts as a topography sensor and also as distance sensor for the compensation of vibrations in a coherence scanning Linnik interferometer. An advantage of this distance sensor is its high acquisition rate of height values, which in case of working as a topography sensor enables high scan velocities as it is demonstrated at a chirp standard measured with a scan velocity of 80 mm/s. This is much higher than the scan velocity of tactile instruments, which are typically limited up to 1 mm/s. In addition, the compensation of vibration disturbances demonstrates the capability of the fast distance measurement.In contrast to other existing high-speed point sensors the relevant components are mass products. This keeps the costs of the sensor setup in a limited range. Furthermore, the sensor shows potential of much higher measurement rates than 116 kHz provided by the sensor used here.

scholarly journals Analysis of Modern Optical Inspection Systems for Parts Manufactured by Selective Laser Melting

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3202
Author(s):  
Sara Giganto ◽  
Susana Martínez-Pellitero ◽  
Eduardo Cuesta ◽  
Víctor M. Meana ◽  
Joaquín Barreiro
Keyword(s):  
Selective Laser Melting ◽  
Optical Measurement ◽  
Point Of View ◽  
Laser Triangulation ◽  
Laser Melting ◽  
Measurement Systems ◽  
Geometric Dimensioning And Tolerancing ◽  
Inspection Systems ◽  
Conoscopic Holography ◽  
T Values

Metal additive manufacturing (AM) allows obtaining functional parts with the possibility of optimizing them topologically without affecting system performance. This is of great interest for sectors such as aerospace, automotive, and medical–surgical. However, from a metrological point of view, the high requirements applied in these sectors constitute a challenge for inspecting these types of parts. Non-contact inspection has gained great relevance due to the rapid verification of AM parts. Optical measurement systems (OMSs) are being increasingly adopted for geometric dimensioning and tolerancing (GD&T) verification within the context of Industry 4.0. In this paper, the suitability (advantages and limitations) of five different OMSs (based on laser triangulation, conoscopic holography, and structured light techniques) for GD&T verification of parts manufactured by selective laser melting (SLM) is analyzed. For this purpose, a specific testing part was designed and SLM-manufactured in 17-4PH stainless steel. Once the part was measured by contact (obtaining the reference GD&T values), it was optically measured. The scanning results allow comparing the OMSs in terms of their inspection speed as well as dimensional and geometrical accuracy. As a result, two portable systems (handheld laser triangulation and structured blue-light scanners) were identified as the most accurate optical techniques for scanning SLM parts.

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