Critical Sensor Density

2010 ◽  
pp. 99-119 ◽  
Author(s):  
Bang Wang
Keyword(s):  
Sensor Density

Electric Resistance Welded Seam Inspection Using Circumferential Flux

2008 ◽  
Author(s):  
Natalia K. Nikolova ◽  
Duane Cronin ◽  
Sabir M. Pasha ◽  
Reza K. Amineh ◽  
Ian Smith ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Crack Detection ◽  
Axial Direction ◽  
Metal Loss ◽  
Electric Resistance ◽  
Field Uniformity ◽  
Axial Crack ◽  
Resistance Weld ◽  
Sensor Density ◽  
Welded Seam

For conventional magnetic flux leakage (MFL) inspection where an excitation magnetic field is generated in the axial direction of a pipeline, axially oriented crack detection is impossible [1][2]. A new MFL tool design is presented that creates an excitation field in the circumferential or transverse direction, allowing for axial crack detection, as well as the more conventional metal loss detection. Design criteria that ensure detection include sufficient sensor density and magnetic field uniformity at sensor locations. The result is a new type of circumferential MFL inspection tool that can not only detect corrosion and other metal losses, but also axially oriented cracks. Based on the results of a series of inspection runs 22 crack-like features in the electric resistance weld (ERW) were investigated with 19 of those being verified as linear long seam features and were subsequently permanently repaired. Further information on the efficacy of this design is clarified in [2].

Temperature history within laser sintered part cakes and its influence on process quality

2016 ◽  
Vol 22 (5) ◽  
pp. 788-793 ◽  
Author(s):  
Stefan Josupeit ◽  
Hans-Joachim Schmid
Keyword(s):  
Temperature Distribution ◽  
Three Dimensional ◽  
Process Quality ◽  
Temperature Measurements ◽  
Temperature History ◽  
Content Type ◽  
Sintered Part ◽  
Ageing Effects ◽  
Sensor Density ◽  
Set Up

Purpose The temperature distribution and history within laser sintered part cakes is an important aspect regarding the process quality and reproducibility of the polymer laser sintering process. This paper aims to an analysis of the temperature history during the build and cooling phase, which is decisive for powder ageing effects and the development of part quality characteristics. Design/methodology/approach A measurement system for three-dimensional in-process temperature measurements is set up and the influence of different parameters on the inner part cake temperature distribution and history is analyzed. In addition, position dependent temperature histories are finally correlated with powder ageing effects. Findings The main parameters influencing the part cake temperature history are figured out. Temperature inhomogeneities on the powder bed surface are detectable within the part cake, but only for a specific time or additional build height. Heat flux through the build frame results in different cooling rates dependent on z height. A combination of process parameters and build job layout results in individual, position-dependent temperature histories. As a consequence, completely different ageing intensities are found within one part cake. Research limitations/implications Temperature measurements are limited to part-free powder cakes so far. To transfer the results to other boundary conditions and machine types, simulation tools have to be developed and validated. Originality/value For the first time, the inner part cake temperature distribution and history have been measured during all build phases and with a high sensor density. The results of this work help to understand the temperature history dependency of powder and part properties and can therefore be used to develop optimized process controls.

Very high sensor-density multiplexing using a wavelength-to-time domain reflectometry approach based on a rapidly swept akinetic laser

2015 ◽  
Author(s):  
M. P. Minneman ◽  
E. Hoover ◽  
P. Boschert ◽  
J. Ensher ◽  
M. Crawford ◽  
...  
Keyword(s):  
Time Domain ◽  
Time Domain Reflectometry ◽  
Sensor Density ◽  
Very High
Sign in / Sign up

Export Citation Format

Share Document