A Low Cost Sensing Technique For Detecting Defects On Metal Sheets

2006 ◽  
Author(s):  
Haitian Chen ◽  
Udaya K. Madawala ◽  
Jonathan Tham
Keyword(s):  
Low Cost ◽  
Metal Sheets

scholarly journals New Four Points Initialization for Digital Image Correlation in Metal-Sheet Strain Measurements

2019 ◽  
Vol 9 (8) ◽  
pp. 1691 ◽  
Author(s):  
Alejandro-Israel Barranco-Gutiérrez ◽  
José-Alfredo Padilla-Medina ◽  
Francisco J. Perez-Pinal ◽  
Juan Prado-Olivares ◽  
Saúl Martínez-Díaz ◽  
...  
Keyword(s):  
Image Registration ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Surface Deformation ◽  
Initial Conditions ◽  
Low Cost ◽  
Digital Camera ◽  
Image Correlation ◽  
Camera System ◽  
Metal Sheets

Nowadays, the deformation measurement in metal sheets is important for industries such as the automotive and aerospace industries during its mechanical stamping processes. In this sense, Digital Image Correlation (DIC) has become the most relevant measurement technique in the field of experimental mechanics. This is mainly due to its versatility and low-cost compared with other techniques. However, traditionally, DIC global image registration implemented in software, such as MATLAB 2018, did not find the complete perspective transformation needed successfully and with high precision, because those algorithms use an image registration of the type “afine” or “similarity”, based on a 2D information. Therefore, in this paper, a DIC initialization method is presented to estimate the surface deformation of metal sheets used in the bodywork automotive industry. The method starts with the 3D points reconstruction from a stereoscopic digital camera system. Due to the problem complexity, it is first proposed that the user indicates four points, belonging to reference marks of a “Circle grid”. Following this, an automatic search is performed among the nearby marks, as far as one desires to reconstruct it. After this, the local DIC is used to verify that those are the correct marks. The results show reliability by reason of the high coincidence of marks in experimental cases. We also consider that the quality of mark stamping, lighting, and the initial conditions also contribute to trustworthy effects.

Automated Layer Aligning and Stacking System for the Fully Dense Freeform Fabrication Process

2013 ◽  
Vol 655-657 ◽  
pp. 1251-1255
Author(s):  
Bahram Asiabanpour ◽  
He Ping Chen
Keyword(s):  
Vision System ◽  
Low Cost ◽  
Thin Layers ◽  
Layer By Layer ◽  
Fabrication Method ◽  
Solid Materials ◽  
Existing Building ◽  
Freeform Fabrication ◽  
Metal Sheets ◽  
Complex Features

The existing building metallic prototypes from metal sheets or foil slices methods suffer some limitations, such as difficulty in making complex features and long process cycle time. The Fully Dense Freeform Fabrication (FDFF) process is a new freeform fabrication method capable of building fully dense prototypes from practically any materials in a layer-by-layer basis, which overcomes the limitations of other methods. However, layer aligning and stacking are still very challenging because aligning and stacking all thin layers takes a lot of time and effort. Therefore, an automated layer aligning and stacking system is proposed and implemented in this paper. A vision system together with a robotics system are developed to automate the FDFF process. Experiments were performed and the results demonstrate that the automated FDFF process can fundamentally improve the concept of rapid prototyping by enabling producing fully dense parts with any complexity and any solid materials for the sizes from micro scale to several feet in a very fast and low cost approach.

A New Approach to Retrofitting an Existing Roller Door by Using Viscoelastic Materials for Vibration Reduction with Experimental Verification

2020 ◽  
Vol 20 (06) ◽  
pp. 2040008
Author(s):  
Qian Feng ◽  
Liming Fan ◽  
Sijia Cai ◽  
Linsheng Huo ◽  
Yabin Liang
Keyword(s):  
Negative Impact ◽  
Low Cost ◽  
Adhesive Layer ◽  
Ease Of Use ◽  
Shaking Table ◽  
Viscoelastic Layer ◽  
Viscoelastic Materials ◽  
New Approach ◽  
Metal Sheets ◽  
Compact Design

Roller doors are popularly used in cities due to their compact design, low cost, and ease of use. However, roller doors are made of thin metal sheets and have low inherent damping, which causes roller doors in their closed configuration to experience strong vibration when subjected to external excitations, such as wind and passing vehicles. These vibrations also result in severe noise radiation. It is therefore necessary and important to minimize the vibrations and the noise emanating from the roller doors. This research develops a novel application method to suppress the vibration of existing roller doors and to mitigate the induced noise, and the main principle is using the high damping property of viscoelastic materials through retrofit to increase the damping of the roller door. The key component of the retrofit is a viscoelastic stripe of three layers: a self-adhesive layer, a viscoelastic layer and a constraining metallic layer. The proposed method can be easily applied to the existing roller doors and has nearly no negative impact on its daily usage. To validate the feasibility of this method, shaking table tests were conducted and investigated on a roller door model with and without viscoelastic retrofit, and the experimental results demonstrate that the proposed retrofit method can effectively mitigate the vibration and therefore reduce the induced noise for an existing roller door.

Low-Cost III-V Compound Semiconductor Solar Cells

2013 ◽  
pp. 254-293
Author(s):  
Michael G. Mauk
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Low Cost ◽  
Glass Ceramics ◽  
Cost Effective ◽  
Compound Semiconductor ◽  
Thin Film Solar Cells ◽  
Solar Cell Performance ◽  
Metal Sheets ◽  
Lift Off

The prospects for cost-effective flat plate (non-concentrator) solar cells based on III-V compound semiconductors (e.g., GaAs, InP, AlAs, and their alloys) are reviewed. Solar cells made in III-V materials are expensive, but outperform solar cells in every other materials system. The relatively high cost of compound semiconductor wafers necessitates a means to eliminate their use as substrates for epitaial growth of conventional III-V solar cells. There are several approaches to this end, including thin-film solar cells on low-cost, dissimilar substrates such as glass, ceramics, and metal sheets; III-V solar cells epitaxially grown on silicon wafers; film transfer (‘epitaxial lift off’) techniques that allow re-use of the seeding substrate; and assembled arrays of small III-V solar cells on low-cost substrates. Grain boundary effects in polycrystalline III-V films can severely degrade solar cell performance, and impede the application of established thin-film technologies, as developed for amorphous silicon and II-VI semiconductor photovoltaics, to III-V semiconductor-based solar cells. The nearly fifty years of effort in developing thin-film III-V solar cells has underscored the difficulty of achieving large-grain sizes and/or low recombination grain boundaries in polycrystalline films of III-V semiconductors.

scholarly journals Force Prediction for Incremental Forming of Polymer Sheets

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1597 ◽  
Author(s):  
Gustavo Medina-Sanchez ◽  
Alberto Garcia-Collado ◽  
Diego Carou ◽  
Rubén Dorado-Vicente
Keyword(s):  
Numerical Model ◽  
Specific Energy ◽  
Incremental Forming ◽  
Low Cost ◽  
Single Point ◽  
Experimental Tests ◽  
Element Model ◽  
Forming Force ◽  
Polymer Sheets ◽  
Metal Sheets

Incremental sheet forming (ISF) is gaining attention as a low cost prototyping and small batch production solution to obtain 3D components. In ISF, the forming force is key to define an adequate setup, avoiding damage and reducing wear, as well as to determine the energy consumption and the final shape of the part. Although there are several analytical, experimental and numerical approaches to estimate the axial forming force for metal sheets, further efforts must be done to extend the study to polymers. This work presents two procedures for predicting axial force in Single Point Incremental Forming (SPIF) of polymer sheets. Particularly, a numerical model based on the Finite Element Model (FEM), which considers a hyperelastic-plastic constitutive equation, and a simple semi-analytical model that extends the known specific energy concept used in machining. A set of experimental tests was used to validate the numerical model, and to determine the specific energy for two polymer sheets of polycarbonate (PC) and polyvinyl chloride (PVC). The approaches provide results in good agreement with additional real examples. Moreover, the numerical model is useful for accurately predicting temperature and thickness.

Decomposition of the metastable beta titanium alloy Ti-15-3

1983 ◽  
Vol 41 ◽  
pp. 264-265
Author(s):  
Y. L. Chen ◽  
S. Fujlshiro
Keyword(s):  
Low Cost ◽  
High Strength ◽  
Alpha Phase ◽  
Thick Sheet ◽  
Omega Phase ◽  
Beta Titanium Alloy ◽  
Beta Titanium ◽  
Beta Matrix ◽  
Metastable Beta ◽  
Very High

Metastable beta titanium alloys have been known to have numerous advantages such as cold formability, high strength, good fracture resistance, deep hardenability, and cost effectiveness. Very high strength is obtainable by precipitation of the hexagonal alpha phase in a bcc beta matrix in these alloys. Precipitation hardening in the metastable beta alloys may also result from the formation of transition phases such as omega phase. Ti-15-3 (Ti-15V- 3Cr-3Al-3Sn) has been developed recently by TIMET and USAF for low cost sheet metal applications. The purpose of the present study was to examine the aging characteristics in this alloy.The composition of the as-received material is: 14.7 V, 3.14 Cr, 3.05 Al, 2.26 Sn, and 0.145 Fe. The beta transus temperature as determined by optical metallographic method was about 770°C. Specimen coupons were prepared from a mill-annealed 1.2 mm thick sheet, and solution treated at 827°C for 2 hr in argon, then water quenched. Aging was also done in argon at temperatures ranging from 316 to 616°C for various times.

Chromic Acid Etching of Polyethylene

1973 ◽  
Vol 31 ◽  
pp. 72-73
Author(s):  
J. D. Muzzy ◽  
R. D. Hester ◽  
J. L. Hubbard
Keyword(s):  
Chromic Acid ◽  
Low Cost ◽  
Acid Etching ◽  
Crystalline Morphology ◽  
Bulk Specimen ◽  
Morphological Studies ◽  
Perfect Form ◽  
Molecular Length ◽  
Lamellar Texture ◽  
Cost Studies

Polyethylene is one of the most important plastics produced today because of its good physical properties, ease of fabrication and low cost. Studies to improve the properties of polyethylene are leading to an understanding of its crystalline morphology. Polyethylene crystallized by evaporation from dilute solutions consists of thin crystals called lamellae. The polyethylene molecules are parallel to the thickness of the lamellae and are folded since the thickness of the lamellae is much less than the molecular length. This lamellar texture persists in less perfect form in polyethylene crystallized from the melt.Morphological studies of melt crystallized polyethylene have been limited due to the difficulty of isolating the microstructure from the bulk specimen without destroying or deforming it.

Glass Knife Geometry as Seen by the SEM

1971 ◽  
Vol 29 ◽  
pp. 454-455
Author(s):  
J. Temple Black
Keyword(s):  
Low Cost ◽  
Amorphous Material ◽  
Stress Concentrations ◽  
Basic Tool ◽  
Tool Materials ◽  
Optical Inspection ◽  
Surface Flaws ◽  
Slip Planes ◽  
Glass Knife ◽  
Diamond Knife

In ultramicrotomy, the two basic tool materials are glass and diamond. Glass because of its low cost and ease of manufacture of the knife itself is still widely used despite the superiority of diamond knives in many applications. Both kinds of knives produce plastic deformation in the microtomed section due to the nature of the cutting process and microscopic chips in the edge of the knife. Because glass has no well defined slip planes in its structure (it's an amorphous material), it is very strong and essentially never fails in compression. However, surface flaws produce stress concentrations which reduce the strength of glass to 10,000 to 20,000 psi from its theoretical or flaw free values of 1 to 2 million psi. While the microchips in the edge of the glass or diamond knife are generally too small to be observed in the SEM, the second common type of defect can be identified. This is the striations (also termed the check marks or feathers) which are always present over the entire edge of a glass knife regardless of whether or not they are visable under optical inspection. These steps in the cutting edge can be observed in the SEM by proper preparation of carefully broken knives and orientation of the knife, with respect to the scanning beam.

Spectraplot: A PC-based spectrum translation and display program

1988 ◽  
Vol 46 ◽  
pp. 918-919
Author(s):  
H. O. Colijn
Keyword(s):  
Low Cost ◽  
Transfer Program ◽  
File Transfer ◽  
Transfer Data ◽  
Error Checking ◽  
Data Files ◽  
The University

Many labs today wish to transfer data between their EDS systems and their existing PCs and minicomputers. Our lab has implemented SpectraPlot, a low- cost PC-based system to allow offline examination and plotting of spectra. We adopted this system in order to make more efficient use of our microscopes and EDS consoles, to provide hardcopy output for an older EDS system, and to allow students to access their data after leaving the university.As shown in Fig. 1, we have three EDS systems (one of which is located in another building) which can store data on 8 inch RT-11 floppy disks. We transfer data from these systems to a DEC MINC computer using “SneakerNet”, which consists of putting on a pair of sneakers and running down the hall. We then use the Hermit file transfer program to download the data files with error checking from the MINC to the PC.

Transmission Electron Microscopy of oriented Co84Cr14Ta2 thin films for longitudinal magnetic recording

1991 ◽  
Vol 49 ◽  
pp. 756-757
Author(s):  
T. P. Nolan
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Low Cost ◽  
Low Noise ◽  
Information Storage ◽  
High Coercivity ◽  
Magnetic Alloy ◽  
Magnetic Media ◽  
Transmission Electron

Thin film magnetic media are being used as low cost, high density forms of information storage. The development of this technology requires the study, at the sub-micron level, of morphological, crystallographic, and magnetic properties, throughout the depth of the deposited films. As the microstructure becomes increasingly fine, widi grain sizes approaching 100Å, the unique characterization capabilities of transmission electron microscopy (TEM) have become indispensable to the analysis of such thin film magnetic media.Films were deposited at 225°C, on two NiP plated Al substrates, one polished, and one circumferentially textured with a mean roughness of 55Å. Three layers, a 750Å chromium underlayer, a 600Å layer of magnetic alloy of composition Co84Cr14Ta2, and a 300Å amorphous carbon overcoat were then sputter deposited using a dc magnetron system at a power of 1kW, in a chamber evacuated below 10-6 torr and filled to 12μm Ar pressure. The textured medium is presently used in industry owing to its high coercivity, Hc, and relatively low noise. One important feature is that the coercivity in the circumferential read/write direction is significandy higher than that in the radial direction.

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