Threading Defects Research Articles

Internal Thread Defect Generation Algorithm and Detection System Based on Generative Adversarial Networks and You Only Look Once.

In the field of industrial inspection, accurate detection of thread quality is crucial for ensuring mechanical performance. Existing machine-vision-based methods for internal thread defect detection often face challenges in efficient detection and sufficient model training samples due to the influence of mechanical geometric features. This paper introduces a novel image acquisition structure, proposes a data augmentation algorithm based on Generative Adversarial Networks (GANs) to effectively construct high-quality training sets, and employs a YOLO algorithm to achieve internal thread defect detection. Through multi-metric evaluation and comparison with external threads, high-similarity internal thread image generation is achieved. The detection accuracy for internal and external threads reached 94.27% and 93.92%, respectively, effectively detecting internal thread defects.

Optimum Splice Thickness Ratio Splicer of a Winding Machine to PE20KT Thread Splicing Quality

Winding machines are needed after the spinning process on ring-spinning machines because small packages of spinnerets are mostly not suitable for efficiently carrying out subsequent processes such as weaving and knitting. The splicer is independently actuated to optimize splicing cycles. PT Delta Dunia Tekstil II (DDT 2) is a company operating in the spinning industry, with the CD line producing 100% polyester yarn, which is used to make fabric in the knitting process. Based on observations, thread defects occur, such as loops and holes in the knitted fabric, because the thread splices resulting from the winding process are brittle and thin. Experiments on setting joint thickness parameters on splicer adjustment indicators 1–5 with a ratio of 0.25 were carried out. After carrying out the experiment, 3 ratios were obtained for sampling visual tests and joint strength, namely a ratio of 2.5, 2.75, and 3. Observing and calculating the splice strength of the three splicer ratios sampled, it was found that the ratio of parameter 3 in the splicer was visually very good and consistent. Strange results also meet the standard, of 92.37%. The optimal splicer ratio setting that can be used for the Carded 20 KT production process is setting the splicer ratio with a splice thickness parameter of 3.

A Novel Three-Dimensional Reconstruction Technology for the Defect Inspection of Tubing and Casing

The three-dimensional reconstruction of high-gloss/reflection and low-texture objects (e.g., oil casing threads) is a complex task. In this paper, we present a novel approach that combines convolutional neural networks (CNNs) and multi-layer perception (MLP) with traditional three-dimensional reconstruction methods, thereby enhancing the detection efficiency. Our method utilizes a dataset of 800 samples that includes a variety of thread defects to train a U-net-like model as a three-dimensional reconstructor. Then, an MLP model is proposed to improve the accuracy of the three-dimensional reconstructed thread profile to the level of three-coordinate measurements through a regression analysis. The experimental results demonstrate that the method can effectively detect the black-crested threads of oil casing threads and quantify their proportions in the entire sample for accurate quality assessment. The method is easy to operate and can detect black threads effectively, providing a powerful tool for oil companies to ensure exploration benefits.

Method to detect the bolt thread defect in the aerospace vehicle with ultrasonic image and its implementation

PurposeThis study aims to solve the problems of ambiguous localization, large calculation, poor real-time and limited applicability of bolt thread defect detection.Design/methodology/approachFirst, the acquired ultrasound image is used to acquire the larger area of the image, which is set as the compliant threaded area. Second, based on the determined coordinates of the center point in each selected region, the set of coordinates on the left and right sides of the bolts is acquired by DBSCAN method with parameters eps and MinPts, which is determined by data set dimension D and the k-distance curve. Finally, the defect detection boundary line fitting is completed using the acquired coordinate set, and the relationship between the distance from each detection point to the curve and d, which is obtained from the measurement of the standard bolt sample with known thread defect, is used to locate the bolt thread defect simultaneously.FindingsIn this paper, the bolt thread defect detection method with ultrasonic image is proposed; meanwhile, the ultrasonic image acquisition system is designed to complete the real-time localization of bolt thread defects.Originality/valueThe detection results show that the method can effectively detect bolt thread defects and locate the bolt thread defect location with wide applicability, small calculation and good real-time performance.

Implementasi Metode Six Sigma Dalam Pengendalian Kualitas Produksi Di Industri Tekstil Sarung Tenun (Studi Kasus: Ud. Boi Tulus)


 Boi Tulus in Balige is one of the industries engaged in the processing of woven sarongs. In order for a product to be said to be of high quality, the product must meet the specifications that have been set. To obtain a quality product, a quality control measure is needed. Quality control carried out at UD. Boi Tulus has not been carried out optimally on woven sarong products. There are obstacles that result in the quality of the woven sarong products that are not in accordance with standards, such as the discovery of defects. For that, a quality improvement action is needed at UD. Boi Tulus so as to be able to produce quality sarong products. The use of the Six Sigma method in quality control at UD. Boi Tulus is the right step in dealing with the problems faced in the industry. Based on data processing, the percentage of defects in woven sarong products at UD. Boi Tulus for the period May 2021-March 2022 is 5-9%. By using the DMAIC approach, there are 4 categories of defects in the weaving gloves, namely uneven color defects, sizes not according to specifications, torn thread defects, broken thread defects or knots. After calculating the value of DPMO on UD. Boi Tulus is 10,884 with a Sigma level value of 3,800. This means that from a million opportunities, there will be a possibility of 10,884 UD. Boi Tulus, can not meet the quality control standards carried out. Furthermore, fishbone tools are used to analyze the factors causing defects in weaving gloves, then recommendations for improvement are given in the form of SOPs and supervision is carried out in the form of control check sheets. After implementation, there are changes, namely a decrease in the value of DPMO to 4.462 and the Sigma level to 4.1239.
 
 
 Keywords : Quality Control, Defect, DMAIC, Six Sigma

Low-Cost Real-Time Automated Optical Inspection Using Deep Learning and Attention Map

The recent trends in Industry 4.0 and Internet of Things have encouraged many factory managers to improve inspection processes to achieve automation and high detection rates. However, the corresponding cost results of sample tests are still used for quality control. A low-cost automated optical inspection system that can be integrated with production lines to fully inspect products without adjustments is introduced herein. The corresponding mechanism design enables each product to maintain a fixed position and orientation during inspection to accelerate the inspection process. The proposed system combines image recognition and deep learning to measure the dimensions of the thread and identify its defects within 20 s, which is lower than the production-line productivity per 30 s. In addition, the system is designed to be used for monitoring production lines and equipment status. The dimensional tolerance of the proposed system reaches 0.012 mm, and a 100% accuracy is achieved in terms of the defect resolution. In addition, an attention-based visualization approach is utilized to verify the rationale for the use of the convolutional neural network model and identify the location of thread defects.

Dual-Step Selective Homoepitaxy of Ge with Low Defect Density and Modulated Strain Based on Optimized Ge/Si Virtual Substrate.

In this manuscript, a novel dual-step selective epitaxy growth (SEG) of Ge was proposed to significantly decrease the defect density and to create fully strained relaxed Ge on a Si substrate. With the single-step SEG of Ge, the threading defect density (TDD) was successfully decreased from 2.9 × 107 cm−2 in a globally grown Ge layer to 3.2 × 105 cm−2 for a single-step SEG and to 2.84 × 105 cm−2 for the dual-step SEG of the Ge layer. This means that by introducing a single SEG step, the defect density could be reduced by two orders of magnitude, but this reduction could be further decreased by only 11.3% by introducing the second SEG step. The final root mean square (RMS) of the surface roughness was 0.64 nm. The strain has also been modulated along the cross-section of the sample. Tensile strain appears in the first global Ge layer, compressive strain in the single-step Ge layer and fully strain relaxation in the dual-step Ge layer. The material characterization was locally performed at different points by high resolution transmission electron microscopy, while it was globally performed by high resolution X-ray diffraction and photoluminescence.

A Scanning Induction Thermography System for Thread Defects of Drill Pipes

A Scanning Induction Thermography System for Thread Defects of Drill Pipes

Methods to improve hackles in the production of quality yarn

The article covers the analysis of work members and mechanisms of hackles, substantiation of technical parameters and modes of operation in order to improve the quality of yarn, to eliminate thread irregularities, to reduce thread breakage and defects by changing the hackling segments and supply table spacing. The work members of the hackles, the traction forces of the roving and the hackle, as well as the productivity of the machine are theoretically determined. The hackling level indicates the thickness of the fiber layer on the surface of the main drum, or how many fibers fit into a single headset tooth. By varying the spacing between the receiving drum and the supply table, the fibers are better hackled, the degree of hackling increases - the higher the quality of the hackle and the effect on the quality of the roving has been determined theoretically and experimentally.

Structural and Mechanical Preparation of Rolled Products for Fasteners

Based on the analysis of quality factors of calibrated rolled products, the structural and mechanical properties of steel 20Mn2Si for cold heading of hardware products are formed. The balance is established during the preparation of gauged bars to manufacture fasteners from it. To produce gauged bars with a diameter of 7.75 mm, a new technological flow is proposed using hot rolled products with a diameter of 8.5 mm. The proposed resource-saving technology for preparing rolled steel 20Mn2Si excludes spheroidize annealing, which reduces labor and energy costs, increases the environmental friendliness of production and operational reliability of fasteners. This eliminates the possibility of quenching cracks, the need for straightening products, the risk of thread defects and reduces the cost of manufacturing long bolts. This makes it possible to significantly reduce the process chain, reduce the cost of manufacturing fasteners and meet regulatory requirements for their mechanical properties.

The achieved result of the introduction of the universal accelerometric control station and further prospects for determining railcar wheel thread defects

The achieved result of the introduction of the universal accelerometric control station and further prospects for determining railcar wheel thread defects

Shear deformation characteristics and defect evolution of the biaxial ±45° and 0/90° glass non-crimp fabrics

Currently, the shear pre-tension coupling behavior and evolution of various mesoscopic defects for the biaxial non-crimp fabric (NCF) are not revealed. Here, this work systematically conducted the picture frame shear with applied pre-tension and hemisphere forming for the ±45° and 0/90° glass NCF. In the picture frame shearing, it is identified that the effective shear response of the biaxial NCF in the positive shear mode should be characterized in the cycle 1 due to the irreversible destruction of the NCF architecture. Besides, the applying pre-tension is originally demonstrated to be capable of effectively suppressing the wrinkle defect and delaying the triggering shear angle of the wrinkle. Moreover, for the ±45° NCF, the stitching thread suffers tension in positive shear mode, and the wrinkle is the main defect. In the negative shear mode, due to the non-pure shearing at high shear angle and compression of stitching thread, the mesoscopic defects, including bending and unit cell buckling of the stitching thread, are generated. In the hemisphere forming, it is revealed that the shear deformation is certainly arose in the tensile region of the ±45° NCF due to the asymmetrical yarn shrink. The same fabric wrinkle and mesoscopic stitching thread defects are also originally identified, demonstrating the hemisphere forming is highly correlated to the large shear deformation. The results here provide a basic reference to suppress the defects in the performing process of the biaxial NCF.

Real-Time Image-Based Defect Inspection System of Internal Thread for Nut

The most important components of the internal nut thread inspection process are measuring the pitch and pitch diameter value and comparing these with their respective specifications, as a test nut is considered to be abnormal when its pitch or pitch diameter does not meet specifications. This paper focuses on defects arising when the pitch diameter does not meet its specification. Because conventional contact strategies are not suited to the real-time inspection of internal thread defects, there have been a number of recent attempts to develop noncontact methods for real-time measurement. Some approaches have applied laser triangulation techniques in which reflected light is used to measure the z-axis depth on an object’s surface. Although point lasers have been shown to be highly precise in measuring pitch diameter, the optical architecture involved in these approaches is complicated and, as the laser must be scanned in a pointwise manner to derive cross-sectional measurements, the measurement process is too long to be compatible with real-time defect inspection. In this papere, an image-based method employing a line laser projector was used to develop a real-time image-based nut pitch diameter defect inspection system. The proposed method, which improves upon the conventional, widely used template-matching method for rapid defect detection, was shown to be effective through experimental validation.

A nanoporous GaN photoelectrode on patterned sapphire substrates for high-efficiency photoelectrochemical water splitting

The photoelectrode of highly ordered nanoporous GaN on patterned sapphire substrate (PSS) is exploited to address issues of optical absorption and photocarrier separation efficiency in solar water splitting. The introduced PSS reduces the threading dislocation (TD) density and defects of the GaN epilayer, resulting in the improved crystalline quality, which suppresses recombination of electron-hole pairs. A single-step top-down etching approach is developed to fabricate the nanoporous GaN using an anodic aluminum oxide (AAO) mask conveniently and economically. The highly ordered nanoporous morphologies of AAO membrane are well transferred into the GaN surface grown on PSS via inductively coupled plasma (ICP) dry etching. Surface nanostructuring significantly increases surface-volume ratio of GaN, more incident light is trapped and absorbed by nanoporous structure, and the unabsorbed light scattered by PSS upwards is re-absorbed in nanoporous GaN. The ultraviolet light absorptance and reflectance of nanoporous GaN grown on PSS were improved significantly, close to 89% and 9% respectively. The resulting improved absorption in the nanoporous GaN further enhances the generation of photocarriers. The increasing surface-volume ratio also contributes to increasing of photoelectrochemical (PEC) reaction area and photocarrier separation efficiency, decrease of photocarrier migration distance towards the GaN-electrolyte interface, more holes participate in the PEC reaction, leading to an improved PEC efficiency and photocurrent density by 470% times with respect to planar counterpart. This work will pave the way towards low-cost and mass production of nanoporous GaN photoelectrode for efficient solar water splitting.

Rolled Metal Structure Resource Saving Preparation for Long-Length Hardened Bolt Upsetting

Along with design factors, reliability of the work-pieces for machines and mechanisms is a function of the structure and the properties of the implied materials; these properties depend significantly on the kind and the mode of the process treatment. Taking into account hardwares production, along with the increased structural integrity and service reliability, a reduction of costs starts from the rolled metal production to manufacturing of the finished parts of required quality. This is particularly relevant under the conditions of mass-production. The article presents a resource saving process flow for a 40X rolled steel, developed as a result of studying the influence of thermal and plastic treatment modes on its structural and mechanical properties. The purpose of the new process flow is the production of hardened bolts, involving drawing and isothermal treatment, but excluding the volume quenching and tempering. Spheroidizing annealing is substituted with an isothermal operation, patenting, which allows to reduce energy costs and to increase environmental compatibility of production and service reliability of bolted items. This makes it possible to shorten the process chain and to reduce the cost of long-length bolts production. The method prevents any potential quench cracking, eliminates the necessity for work-pieces' straightening, decreases the risk of thread defects.

Investigation of defect creation in GaP/Si(0 0 1) epitaxial structures

This work investigates defect formation and evolution associated with the deposition of GaP layers on precisely oriented Si(0 0 1) substrates. The GaP layers were grown with thicknesses ranging from ∼37 nm to ∼2 µm at a growth rate of 0.52 μm/hr using molecular beam epitaxy (MBE). The crystallinity of thin (37-nm) MBE-grown GaP layers was also compared with thin GaP layers grown by migration-enhanced epitaxy (MEE). The MBE growth procedure was shown to postpone relaxation of the epitaxial GaP layers up to a thickness of ∼250 nm. Detailed analysis of high-resolution X-ray diffraction patterns and comparison with cross-sectional transmission electron micrographs clarified the defect formation mechanism. Thin GaP layers showed very low defect densities except for anti-phase boundaries, whereas substantial threading defects predominated in the thicker, noticeably relaxed structures.

Improved semipolar green InGaN/GaN quantum wells on asymmetrically grown (112̄2) GaN templates and their correlations

Asymmetric island sidewall growth (AISG) is employed to reduce the threading defect density and to modify the surface/interface properties of semipolar GaN templates and InGaN/GaN quantum wells (QWs).

In Situ Site-Specific Gallium Filling and Nanograin Growth for Blocking of Threading Defects in Semipolar (112̅2) GaN

Undesirable nonuniformly distributed defects and mixed (1103) and (1122) phases during the growth of semipolar GaN films on m-plane sapphire substrates have been known to exist. In our study, we developed an interface-modification technique to achieve in situ site-specific Ga filling, nucleation, and nanograin growth, which efficiently blocked threading defects there. We have identified the mechanism governing the site-specific Ga filling and nanograin growth into Ga-rich islands based on surface atomic structures and theories of Gibbs free energy. Using the interface modification, we have achieved high-quality semipolar (1122) GaN films that enjoy merits of a very low basal-plane stacking fault density of ∼9 × 103 cm–1, a low threading dislocation density of ∼9 × 107 cm–2, and the strong band-edge-emission-dominated luminescence.

Deep-Ultraviolet Emitting AlGaN Multiple Quantum Well Graded-Index Separate-Confinement Heterostructures Grown by MBE on SiC Substrates

Deep-ultraviolet emitting structures based on Al 0.65 Ga 0.35 N/Al 0.8 Ga 0.2 N multiple quantum wells (MQWs), embedded in compositionally graded Al x Ga 1-x N films in the form of graded-index-separate-confinement heterostructure, were grown by molecular beam epitaxy. The graded AlGaN layer blocked threading defects (TDs) in the vicinity of the AlN/AlGaN heterointerface, resulting in a reduction of the TDs in the active layer. The intensity of the transverse-magnetic polarized amplified spontaneous emission spectra with peak emission at 270 nm was found to increase linearly with the number of QWs. Furthermore, while the peak intensity for devices with a single QW varies linearly with the pump fluence, it varies superlinearly for larger number of QWs, suggesting light amplification by stimulated emission. These results are consistent with numerical simulations, which indicate that the confinement of the optical mode in this device structure increases with the number of QWs and simultaneously the threshold under optical pumping decreases with increasing of the number of QWs. Finally, the band structure simulations indicate that the device is in the form of a p-n junction due to polarization-induced p- and n-doping in the compositionally graded Al x Ga 1-x N films on either side of the MQWs, and, thus, could be used for the development of an electrically pumped deep-ultraviolet laser by further optimizing the structures.

Investigation of water splitting using III‐N structures

Specifics of the water photoelectrolysis in KOH‐base aqueous solution using GaN‐based structures as working electrodes are studied. The structures were grown by HVPE and MOCVD techniques on sapphire substrates. In highly Si‐doped HVPE‐grown GaN layers (ND−NA ∼ 3 × 1018 cm−3) a barrier at the E1 offset potential dominates the current–potential (I–E) characteristics. The same dominant E1 offset potential was observed in MOCVD‐grown GaN/InGaN nanopillar structures after the treatment. The Debye screening effect in high‐concentration of KOH electrolyte (20–40 wt.%) that reduces the potential barrier was observed clearly in the defectless nanopillar structures. The corrosion process is initiated in the top p‐type layers via channels associated with threading defects and can penetrate deeply into the structure. It further proceeds in a lateral direction in n‐type layers forming voids and cavities in the structure. The H2 production rate of 0.3–0.6 ml cm−2 h−1 was measured for n‐GaN‐based structure in KOH electrolyte under the Xe‐lamp illumination (concentration factor ×15).