The Evolution of Transversal Surface Defects in the Axisymmetric Drawing of Copper Bars

2010 ◽  
Vol 89-91 ◽  
pp. 142-146
Author(s):  
Frederico de Castro Magalhães ◽  
Antonio Eustaquio de Melo Pertence ◽  
Haroldo Béria Campos ◽  
Maria Teresa Paulino Aguilar ◽  
Paulo Roberto Cetlin
Keyword(s):  
Surface Defects ◽  
Complete Healing ◽  
Raw Material ◽  
Defect Healing ◽  
Eventual Healing ◽  
Reduction Of Area

Surface defects are an inevitable characteristic of the raw material employed in the drawing of copper wires. These defects may cause problems in the processing of the material, both during the drawing down to wires and in the final manufacturing of artifacts with the produced wire. The literature reports few analyses covering the importance of these initial defects, as well as concerning their evolution or eventual healing during the drawing. The present paper presents such an analysis for a 12.7 mm diameter copper bar displaying artificial defects 1mm wide and 0.3mm deep. Low angle drawing led to the almost complete healing of the defect after three drawing passes with a 10% reduction of area each. The use of a high semi-angle die led to a completely different situation, where no such defect healing was observed.

scholarly journals A large-scale image dataset of wood surface defects for automated vision-based quality control processes

F1000Research ◽  
2021 ◽  
Vol 10 ◽  
pp. 581
Author(s):  
Pavel Kodytek ◽  
Alexandra Bodzas ◽  
Petr Bilik
Keyword(s):  
Quality Control ◽  
High Speed ◽  
Large Scale ◽  
Surface Defects ◽  
Recognition Rate ◽  
Raw Material ◽  
Technical Solution ◽  
Control Processes ◽  
Wide Range ◽  
Authentic Data

The wood industry is facing many challenges. The high variability of raw material and the complexity of manufacturing processes results in a wide range of visible structure defects, which have to be controlled by trained specialists. These manual processes are not only tedious and biased, but also less effective. To overcome the drawbacks of the manual quality control processes, several automated vision-based systems have been proposed. Even though some conducted studies achieved a higher recognition rate than trained experts, researchers have to deal with a lack of large-scale databases and authentic data in this field. To address this issue, we performed a data acquisition experiment set in the industrial environment, where we were able to acquire an extensive set of authentic data from a production line. For this purpose, we designed and implemented a complex technical solution suitable for high-speed acquisition during harsh manufacturing conditions. In this data note, we present a large-scale dataset of high-resolution sawn timber surface images containing more than 43 000 labelled surface defects and covering 10 types of the most common wood defects. Moreover, with each image record, we provide two types of labels allowing researchers to perform semantic segmentation, as well as defect classification, and localization.

scholarly journals An Artificial-Intelligence-Driven Predictive Model for Surface Defect Detections in Medical MEMS

Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6141
Author(s):  
Amin Amini ◽  
Jamil Kanfoud ◽  
Tat-Hean Gan
Keyword(s):  
Defect Detection ◽  
Surface Defects ◽  
Quality Standard ◽  
Human Interaction ◽  
Raw Material ◽  
Micro Electro Mechanical Systems ◽  
Medical Apparatus ◽  
Machine Learning Approach ◽  
Plenoptic Camera ◽  
Early Phases

With the advancement of miniaturization in electronics and the ubiquity of micro-electro-mechanical systems (MEMS) in different applications including computing, sensing and medical apparatus, the importance of increasing production yields and ensuring the quality standard of products has become an important focus in manufacturing. Hence, the need for high-accuracy and automatic defect detection in the early phases of MEMS production has been recognized. This not only eliminates human interaction in the defect detection process, but also saves raw material and labor required. This research developed an automated defects recognition (ADR) system using a unique plenoptic camera capable of detecting surface defects of MEMS wafers using a machine-learning approach. The developed algorithm could be applied at any stage of the production process detecting defects at both entire MEMS wafer and single component scale. The developed system showed an F1 score of 0.81 U on average for true positive defect detection, with a processing time of 18 s for each image based on 6 validation sample images including 371 labels.

scholarly journals Analisa Kecacatan Produk Baling-Baling Blower pada Proses Chasting ­Menggunakan Metode Seven Tools di CV. Anugerah Abadi

Rekayasa ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 66
Author(s):  
Sofiyanurriyanti Sofiyanurriyanti
Keyword(s):  
Rough Surface ◽  
Environmental Conditions ◽  
Surface Defects ◽  
Melting Furnace ◽  
Raw Material ◽  
Total Production ◽  
Defect Production ◽  
Disability Rate ◽  
Deformation Defects ◽  
Product Defect

<p>ABSTRAK<br />Terdapat lima kecacatan dalam pembuatan baling-baling blower U-8 yaitu cacat berlubang, permukaan kasar, retak, kekasaran meluas dan deformasi. Kecacatan yang dialami sebesar 1204 produk atau 20,27% dari jumlah produksi. Permukaan kasar merupakan jenis cacat yang mempunya tingkat kecacatan terbesar yaitu 53,08% dari total kecacatan atau sebanya 627 produk. Untuk mengurangi cacat produk baling-baling blower U-8 harus difokuskan pada jenis kecacatan permukaan kasar. Untuk mengurangi jenis kecacatan tersebut operator harus lebih teliti dalam melakukan pemeriksan cetakan pasir, bahan baku aluminium juga harus bersih dan sebagian dari bahan ingot (batangan), campuran pasir cetak harus diperhatikan, kondisi lingkungan harus menerapkan 5P dan menambah fasilitas kerja( lampu penerangan), pergantian alat seperti mold dan penambahan pengkur suhu pada tungku peleburan.<br />Kata Kunci: metode seven tools, cacat produk, proses produksi</p><p>Analysis of Blower Blacker Product Reality in Chasting Process <br />Using Seven Tools Method in CV. Anugerah Abadi<br />ABSTRACT<br />There are five defects in the manufacture of U-8 blower blades which are hollow defects, rough surfaces, cracks, widespread roughness, and deformation. Defects experienced by 1204 products or 20.27% of total production. The rough surface is a type of defect that has the biggest disability rate of 53.08% of the total disability or Seba 627 products. To reduce the defects of the U-8 blower products should be focused on the types of rough surface defects. In order to reduce the type of disability the operator must be more careful in examining the sand mold, the aluminum raw material must also be clean and part of the ingot material (bar), the mixture of printed and must be considered, the environmental conditions must apply 5P and add work facilities (lighting) replacement tools such as mold and the addition of temperature drier to the melting furnace.<br />Keywords: seven tools method, product defect, production process</p>

AUTOMATED VISION INSPECTION OF TIMBER SURFACE DEFECT: A REVIEW

2015 ◽  
Vol 77 (20) ◽  
Author(s):  
Ummi Rabaah Hashim ◽  
Siti Zaiton Hashim ◽  
Azah Kamilah Muda
Keyword(s):  
Feature Extraction ◽  
Defect Detection ◽  
Surface Defect ◽  
Surface Defects ◽  
Raw Material ◽  
Special Focus ◽  
Automated Inspection ◽  
Extraction Techniques ◽  
Vision Inspection ◽  
Surface Defect Detection

Automated inspection has proven to be of great importance in increasing the quality of timber products, optimising raw material resources, increasing productivity as well as reducing error related to human labour. This paper reviews automated inspection of timber surface defects with a special focus on vision inspection. Previous works on sensors utilised are presented and can be used as a reference for future researchers. General approaches to solving the problem of wood surface defect detection can be categorised into segmentation and non-segmenting approaches. The weaknesses and strengths of each approach are discussed along with feature extraction techniques and classifiers implemented in timber surface defect detection. Furthermore, insights into the practicality of implementing automated vision inspection of timber defects were also discussed. This paper shall benefit researchers and practitioners in understanding different approaches, sensors, feature extraction techniques as well as classifiers that have been implemented in automated inspection of timber surface defects, thus providing some direction for future research.

Defects in Crystals

1968 ◽  
Vol 26 ◽  
pp. 244-245
Author(s):  
Kenneth R. Lawless
Keyword(s):  
Electron Microscope ◽  
Point Defects ◽  
Surface Defects ◽  
Chemical Properties ◽  
Material Point ◽  
Crystal Defects ◽  
Defects In Crystals ◽  
Irradiation Effects ◽  
Normal Lattice ◽  
Line Defects

One of the most important applications of the electron microscope in recent years has been to the observation of defects in crystals. Replica techniques have been widely utilized for many years for the observation of surface defects, but more recently the most striking use of the electron microscope has been for the direct observation of internal defects in crystals, utilizing the transmission of electrons through thin samples.Defects in crystals may be classified basically as point defects, line defects, and planar defects, all of which play an important role in determining the physical or chemical properties of a material. Point defects are of two types, either vacancies where individual atoms are missing from lattice sites, or interstitials where an atom is situated in between normal lattice sites. The so-called point defects most commonly observed are actually aggregates of either vacancies or interstitials. Details of crystal defects of this type are considered in the special session on “Irradiation Effects in Materials” and will not be considered in detail in this session.

Characterization of homoepitaxial diamond films by Electron microscopy

1991 ◽  
Vol 49 ◽  
pp. 880-881
Author(s):  
D.P. Malta ◽  
S.A. Willard ◽  
R.A. Rudder ◽  
G.C. Hudson ◽  
J.B. Posthill ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Surface Defects ◽  
Substrate Surface ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Large Degree ◽  
Rf Plasma ◽  
Semiconducting Diamond

Semiconducting diamond films have the potential for use as a material in which to build active electronic devices capable of operating at high temperatures or in high radiation environments. A major goal of current device-related diamond research is to achieve a high quality epitaxial film on an inexpensive, readily available, non-native substrate. One step in the process of achieving this goal is understanding the nucleation and growth processes of diamond films on diamond substrates. Electron microscopy has already proven invaluable for assessing polycrystalline diamond films grown on nonnative surfaces.The quality of the grown diamond film depends on several factors, one of which is the quality of the diamond substrate. Substrates commercially available today have often been found to have scratched surfaces resulting from the polishing process (Fig. 1a). Electron beam-induced current (EBIC) imaging shows that electrically active sub-surface defects can be present to a large degree (Fig. 1c). Growth of homoepitaxial diamond films by rf plasma-enhanced chemical vapor deposition (PECVD) has been found to planarize the scratched substrate surface (Fig. 1b).

Microstructure of sputter deposited Ni-Sb ohmic contacts on GaAs

1989 ◽  
Vol 47 ◽  
pp. 450-451
Author(s):  
S. Yegnasubramanian ◽  
V.C. Kannan ◽  
R. Dutto ◽  
P.J. Sakach
Keyword(s):  
High Performance ◽  
Ohmic Contacts ◽  
Surface Defects ◽  
Pure Metal ◽  
Device Fabrication ◽  
Native Oxide ◽  
Metal Thin Films ◽  
Recent Developments ◽  
Different Temperatures ◽  
Sputter Deposited

Recent developments in the fabrication of high performance GaAs devices impose crucial requirements of low resistance ohmic contacts with excellent contact properties such as, thermal stability, contact resistivity, contact depth, Schottky barrier height etc. The nature of the interface plays an important role in the stability of the contacts due to problems associated with interdiffusion and compound formation at the interface during device fabrication. Contacts of pure metal thin films on GaAs are not desirable due to the presence of the native oxide and surface defects at the interface. Nickel has been used as a contact metal on GaAs and has been found to be reactive at low temperatures. Formation Of Ni2 GaAs at 200 - 350C is reported and is found to grow epitaxially on (001) and on (111) GaAs, but is shown to be unstable at 450C. This paper reports the investigations carried out to understand the microstructure, nature of the interface and composition of sputter deposited and annealed (at different temperatures) Ni-Sb ohmic contacts on GaAs by TEM. Attempts were made to correlate the electrical properties of the films such as the sheet resistance and contact resistance, with the microstructure. The observations are corroborated by Scanning Auger Microprobe (SAM) investigations.

Contrasts of planar defects in reflection electron microscopy

1993 ◽  
Vol 51 ◽  
pp. 1004-1005
Author(s):  
Feng Tsai ◽  
J. M. Cowley
Keyword(s):  
Electron Microscopy ◽  
Surface Defects ◽  
Practical Importance ◽  
Theoretical Treatment ◽  
Crystal Surfaces ◽  
Planar Defects ◽  
Surface Steps ◽  
Surface Reconstructions ◽  
Domain Boundaries ◽  
Reflection Electron Microscopy

Reflection electron microscopy (REM) has been used to study surface defects such as surface steps, dislocations emerging on crystal surfaces, and surface reconstructions. However, only a few REM studies have been reported about the planar defects emerging on surfaces. The interaction of planar defects with surfaces may be of considerable practical importance but so far there seems to be only one relatively simple theoretical treatment of the REM contrast and very little experimental evidence to support its predications. Recently, intersections of both 90° and 180° ferroelectric domain boundaries with BaTiO3 crystal surfaces have been investigated by Tsai and Cowley with REM.The REM observations of several planar defects, such as stacking faults and domain boundaries have been continued by the present authors. All REM observations are performed on a JEM-2000FX transmission electron microscope. The sample preparations may be seen somewhere else. In REM, the incident electron beam strikes the surface of a crystal with a small glancing angle.

Electron Channelling Contrast Imaging of Dislocations

1990 ◽  
Vol 48 (1) ◽  
pp. 600-601
Author(s):  
J.T. Czernuszka ◽  
N.J. Long ◽  
P.B. Hirsch
Keyword(s):  
Field Emission ◽  
Secondary Electron ◽  
Surface Defects ◽  
Spot Size ◽  
Beam Divergence ◽  
Contrast Imaging ◽  
Scattered Electron ◽  
Near Surface ◽  
Filter System ◽  
Electron Channelling

In the 1970s there was considerable interest in the development of the electron channelling contrast imaging (ECCI) technique for imaging near surface defects in bulk (electron opaque) specimens. The predictions of the theories were realised experimentally by Morin et al., who used a field emission gun (FEG) operating at 40-50kV and an energy filter such that only electrons which had lost no more than a few 100V were detected. This paper presents the results of a set of preliminary experiments which show that an energy filter system is unneccessary to image and characterise the Burgers vectors of dislocations in bulk specimens. The examples in the paper indicatethe general versatility of the technique.A VG HB501 STEM with a FEG was operated at 100kV. A single tilt cartridge was used in the reflection position of the microscope. A retractable back-scattered electron detector was fitted into the secondary electron port and positioned to within a few millimetres of the specimen. The image was acquired using a Synoptics Synergy framestore and digital scan generator and subsequently processed using Semper 6. The beam divergence with the specimen in this position was 2.5 mrads with a spot size of approximately 4nm. Electron channelling patterns were used to orientate the sample.

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