scholarly journals Defects, Process Parameters and Signatures for Online Monitoring and Control in Powder-Based Additive Manufacturing

Author(s):  
Ehsan Malekipour ◽  
Hazim El-Mounayri
2017 ◽  
Author(s):  
Denis Daniel Störkle ◽  
Lars Thyssen ◽  
Bernd Kuhlenkötter

Author(s):  
Saideep Nannapaneni ◽  
Sankaran Mahadevan ◽  
Abhishek Dubey ◽  
Yung-Tsun Tina Lee

Author(s):  
Adamu Yebi ◽  
Beshah Ayalew ◽  
Satadru Dey

This article discusses the challenges of non-intrusive state measurement for the purposes of online monitoring and control of Ultraviolet (UV) curing processes. It then proposes a two-step observer design scheme involving the estimation of distributed temperature from boundary sensing cascaded with nonlinear cure state observers. For the temperature observer, backstepping techniques are applied to derive the observer partial differential equations along with the gain kernels. For subsequent cure state estimation, a nonlinear observer is derived along with analysis of its convergence characteristics. While illustrative simulation results are included for a composite laminate curing application, it is apparent that the approach can also be adopted for other UV processing applications in advanced manufacturing.


Author(s):  
Farhad Imani ◽  
Bing Yao ◽  
Ruimin Chen ◽  
Prahalada Rao ◽  
Hui Yang

Nowadays manufacturing industry faces increasing demands to customize products according to personal needs. This trend leads to a proliferation of complex product designs. To cope with this complexity, manufacturing systems are equipped with advanced sensing capabilities. However, traditional statistical process control methods are not concerned with the stream of in-process imaging data. Also, very little has been done to investigate nonlinearity, irregularity, and inhomogeneity in image stream collected from manufacturing processes. This paper presents the multifractal spectrum and lacunarity measures to characterize irregular and inhomogeneous patterns of image profiles, as well as detect the hidden dynamics of the underlying manufacturing process. Experimental studies show that the proposed method not only effectively characterizes the surface finishes for quality control of ultra-precision machining but also provides an effective model to link process parameters with fractal characteristics of in-process images acquired from additive manufacturing. This, in turn, will allow a swift response to processes changes and consequently reduce the number of defective products. The proposed fractal method has strong potentials to be applied for process monitoring and control in a variety of domains such as ultra-precision machining, additive manufacturing, and biomanufacturing.


2015 ◽  
Vol 785 ◽  
pp. 236-240
Author(s):  
Tan Jen Hau ◽  
N.M. Nor ◽  
T. Ibrahim ◽  
H. Daud

A new method for monitoring and control of domestic distribution box is proposed and developed for automated recovery of power continuity during interruption. The system automatically test each of the sockets to determine the source of the failure and isolate them. The data of the modified connection will be sent to the client through a server, wirelessly to notify the user the modifications made. Parallel processing via multi-threading in the server are used to increment the upper limit of TCP transmission's throughput. Multiple SQLite database are used by multiple threads for parallel storage of data to increase performance.


Water ◽  
2015 ◽  
Vol 7 (11) ◽  
pp. 6574-6597 ◽  
Author(s):  
Harsha Ratnaweera ◽  
Joachim Fettig

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