Tapping Operations Research Articles

Microstructural and fatigue characterization of 316L stainless steel subjected to flow drilling and tapping: comparison with machined threads

Despite extensive research on the plastic deformation of materials to enhance their fatigue resistance, the influence of the flow tapping process on the fatigue resistance of drilled and tapped bars remains poorly understood. Herein, the fatigue performance of flow-drilled (friction-drilled) and flow-tapped 316L stainless steel bars was experimentally analyzed and compared with that of conventional material-shearing-based drilling and tapping operations. The effect of flow processes on the material properties was evaluated via microhardness tests and microstructural analyses. The results indicated that the hardness near the holes produced via flow forming was 62 % higher than that of the base metal. Moreover, grain refinement and plastic deformation were observed beneath the thread surfaces. Metallographic observations revealed the occurrence of craters and folds at the crest of the flow-formed threads. Following the ASTM F382-17 standard, four-point bending fatigue tests were performed at three stress amplitudes with a stress ratio of 0.1. No noteworthy differences were observed when the maximum bending moments applied were at 75 % and 60 % of the bending moment at yield. However, when the maximum bending moment applied was limited to 50 % of the bending moment at yield, the average fatigue life of the specimens with machined threads was longer than that of their flow-formed counterparts. Fractographic observations were used to identify the crack initiation regions and elucidate the underlying fracture mechanisms. For both types of specimens, failure originated at the crest of the first thread, beneath the surface of the maximum tensile stress. The flow-processed specimens exhibited secondary cracks at the root of the threads, where grain refinement also occurred. This study provides robust empirical evidence that using flow-forming processes to thread 316L stainless steel does not systematically improve the fatigue resistance of the material surrounding the holes. Furthermore, by optimizing the flow process and eliminating discontinuities, the threading process proposed herein could help improve the fatigue resistance of orthopedic implants.

From natural abundant silk to TENG; from biowaste to carbon supercap: A natural sustainable approach of active energy storage

Integrating an energy harvester and energy storage into a single unit, without connecting any external source, has gathered substantial attention for its ability to convert and store energy in a single device. This study introduces an innovative, self-sustaining power cell called the self-power supercapacitor (SPSC). The SPSC consists of two triboelectric nanogenerators (TENG) and a carbon based supercapacitor cell sandwiched between two TENGs. The SPSC utilizes the energy produced by two TENGs and stores it directly in the supercapacitor, bypassing the requirement of power management circuits. This energy storage process is achieved using tribo-electrochemical methodology. The supercapacitor consists of activated porous carbon obtained from natural biowaste, infused with an ionic liquid electrolyte gel. Each TENG is constructed using a blend of naturally abundant Silk with PVA and PVDF as triboelectric components and exhibit a maximum voltage of 800 V with an instantaneous output power density of 598 mW/cm2. In addition, the self-power supercapacitor effectively gets charged to a voltage of 0.8 V after continuous tapping of 100 s Due to the huge active surface area of the activated carbon electrodes, the device attains a specific capacitance of 43.75 mF/cm2. The assessed specific energy and specific power of the assembled SPSC device were 3.89 mWh/cm2 and 666.67 mW/cm2, respectively when subjected to tapping operations. The self-power supercapacitor cell also has the ability to power a range of portable electronics, such as LED. This research evidences the competence of charging the supercapacitor of SPSC system using TENGs without the need for an external parameter.

Resin tapping of Atlantic pine forests: towards an optimized use of stimulant pastes over the season

Pine resin is a valuable non-wood forest product with an increasing interest in multiple industrial sectors. Resin-tapping activities also provide valuable ecosystem services in timber-oriented and highly productive pine forest of Atlantic regions, where little previous experience in resin-tapping is available. The objectives of this study were to determine the efficiency of different stimulant pastes and its variation with pine species, site conditions, seasonality and frequency of tapping interventions. We conducted parallel experiments using both conventional and micro-tapping techniques in mature pine stands in NW Spain. We tested four stimulants (control and Zeta, Cunningham and Salicylic pastes) and two groove frequencies (every 2 or 3 weeks). All stimulant pastes significantly increased resin yield compared to the control, being resin stimulation highly consistent across years, sites and species. In conventional resin tapping, resin yield was maximized with the Cunningham and Salicylic pastes while in micro-tapping Salicylic was the most outstanding stimulant treatment. According to the rapid decay of resin flow after wounding, total resin yield decreased with more spaced grooves. However, the reduction was low, and the global efficiency of the tapping operations are likely maximized with grooves applied every three weeks, which would allow increasing the number of tapped trees. Micro-tapping techniques were valuable for screening stimulant pastes and anticipating variation among sites in resin production. Altogether, the Salicylic paste is recommended, especially at the beginning of the resin campaign, when the effect of the pastes was maximized, and if tapping is conducted using closed atmospheres and containers.

How Do Adults with Dyslexia Recognize Spoken Words? Evidence from Behavioral and EEG Data

ABSTRACT Purpose In adults with dyslexia (DYS), the persistent influence of phonological deficits on spoken language processing has mainly been examined in either perceptual tasks or those tapping complex cognitive operations. Much less attention is devoted to spoken word recognition per se. Our study aimed to fill this gap. Method Adults with and without dyslexia (for both groups: N = 30, mean age = 21 years, 50% female, 100% white European) performed an auditory lexical decision task. Performance and ERP were recorded. Results Reaction times showed a lexicality effect in both groups although they differed in ERP responses to stimulus lexicality. Skilled readers showed the typical amplitude enhancement for pseudowords compared to words in a late phase of N400 (414-581msec) whereas DYS showed the opposite pattern in an earlier phase of N400 (246-413msec). Both groups showed a stronger negativity during pseudowords processing in the late post-lexical stage (582-800msec). Conclusions ERP data showed subtle differences between the two populations during the lexical stage of word recognition despite their comparable behavioral outcomes. We hypothesized that a stronger reliance on intact semantic knowledge might contribute to the general enhanced and sustained ERP responses to words in DYS across different phases of lexical processing, although confirmation is needed.

Конечно-элементное моделирование нарезания резьбы мет-чиком с целью прогнозирования ее приведенного среднего диаметра

The development of high-precision tapping operations involves predicting such accuracy. Very often, this requires expensive experiments. Numerical calculation methods, which have recently received wide application, make it possible to replace these experiments with computer simulations. However, this modeling is now mainly associated with determining the stresses and strength of tools, for which only the cutting tool itself and a fragment of the workpiece are modeled. This approach turns out to be unacceptable for predicting the machining accuracy, since the errors in the thread size and shape significantly depend on the actual movement of the tool, which, in turn, depends on the conditions of its fixing in the machine spindle. In this regard, the task concerns with not only the specified above technological system elements, but also an clamping tool. In addition, after calculating the thread surface of the part, it is necessary to calculate accuracy characteristics of this thread. It is these issues that are considered in this article: the results of finite element modeling of threading with a tap fixed in a tapping chuck of a floatingoscillating type are shown. The obtained graphs of axial force and torque correspond to the expected curves, both in its shape and in numerical values. The obtained thread point cloud made it possible to further calculate its virtual pith thread diameter, which turned out to be comparable with the corresponding tap diameter and the same thread size from the state standard. Thus, the above calculations show their realism and the possibility of application in the practice of designing thread-cutting operations.

Finite element simulation of stresses in cutting tools during tapping

Tapping is inherently more complex than other machining processes. The main reason for this complexity is that the chip removal process takes place in a closed environment. For this reason, in order to use the tap tools more efficiently, it is necessary to know the cutting conditions and the stresses that occur in the tool during cutting. In this study, holes of different diameters were drilled in the AISI 1050 material and threaded with M10 taps with three different geometries. Uncoated HSS and TiN coated HSS taps were used in the study. The tapping operations were carried out in dry conditions. The simulation conditions were chosen exactly the same as the experimental conditions. Stresses during tapping were analyzed using the Third Wave AdvantEdge program based on the finite element method (FEM). The tapping tools were modeled by reverse engineering method and then imported in the program. In general, the coating applied to the tools positively affected the stresses on the cutting tool.

The Development of Rubber Tapping Machines in Intelligent Agriculture: A Review

In the past decade, intelligent technologies have advanced rapidly, particularly due to improvements in automatic control, which have had a significant impact on forestry, as well as animal husbandry and the future of farm management. However, the degree of production and management mechanization in natural rubber plantations is low, especially since the methods of tapping still rely heavily on labor. The decrease of skilled rubber tappers and the increase in labor costs have led to the development of the mechanization of rubber tapping operations. The application of emerging intelligent agricultural technologies could provide an alternative in order to maximize the potential productivity of natural rubber. Based on this vision, we reviewed the literature on rubber tapping from the past decade for system implementation in rubber plantations. In this review, selected references on rubber tapping were categorized into several directions of research, including rubber tapping machines, the key technologies applied in tapping operations, and some related protective research, analyzing research works from 2010 to 2022 that focused on tapping methods. The review also discusses the application of intelligent agricultural technologies, such as the recognition of tapping trajectory and tapping path planning. A summary of challenges and future trends is also provided in this study. Based on the relevant research, the use of intelligent technologies in rubber tapping machines is still in its initial stage and has broad prospects. Through this study, we aim to provide a reference for researchers in the field of rubber tapping machines and thus to play a positive role in future rubber tapping.

Advances in Robotic Tapping and Plugging of Non-Ferrous Smelting Furnaces: The MIRS Robotic Tapping Machine.

The operation of a metallurgical furnace requires the safe opening and closing of the furnace taphole. In this operation, the molten phase in the furnace is allowed to flow through the tap-hole for transfer to a ladle or another vessel before the tap-hole needs to be safely closed. Until now, non-ferrous tapping operations have largely been performed by an operator. Safe operations around the tap-hole require good process control of the smelting furnace, the proper tap-hole design for the required duty, and high-quality, robust tapping equipment. This paper briefly describes a new robotic tapping and plugging machine for the slag tapping operation on a large copper flash smelting furnace. The operating features and performance aspects are also summarized. Studies that indicate the applicability of this technology in operations other than slag tapping at a flash furnace are described.

TH82. NOVEL DISEASE ASSOCIATIONS WITH SCHIZOPHRENIA GENETIC RISK REVEALED IN ∼400,000 UK BIOBANK PARTICIPANTS

This study aims at modeling the geometrical distortion induced by the heat flux generated after several drilling (D), reaming (R) and tapping operations (T). The thermal expansion over the time is estimated with the modeling of heat fluxes induced step by step during a sequence. The paper presents a method to identify heat fluxes induced into an AlSi7 aluminium workpiece during either a drilling, a reaming, or a tapping operation. These identifications have been performed with different diameters and shapes of tools using minimum quantity lubrication (MQL). A thin part having 22 holes has been manufactured by D+R+T. Its geometry has been controlled and the values have been compared with the values predicted by the model.

Modeling of geometrical thermal distortion induced by drilling, reaming, and tapping operations

This study aims at modeling the geometrical distortion induced by the heat flux generated after several drilling (D), reaming (R) and tapping operations (T). The thermal expansion over the time is estimated with the modeling of heat fluxes induced step by step during a sequence. The paper presents a method to identify heat fluxes induced into an AlSi7 aluminium workpiece during either a drilling, a reaming, or a tapping operation. These identifications have been performed with different diameters and shapes of tools using minimum quantity lubrication (MQL). A thin part having 22 holes has been manufactured by D+R+T. Its geometry has been controlled and the values have been compared with the values predicted by the model.

Velocity Measurement of Blast Furnace Molten Iron Based on Local Multi-Feature Correction Using Multi-Stage Filtered High-Speed Camera

Accurately measuring the velocity of molten iron at the taphole of a blast furnace is of great significance for safe tapping and reflecting the operating state of the blast furnace. The presence of dust-induced brightness changes and weakly textured areas on the surface of molten iron seriously affects the accuracy of the surface velocity field reconstructed by traditional methods. This paper presents a local multi-feature correction using multi-stage filtered high-speed camera to achieve high-precision measurement of the surface velocity field of molten iron. First, two sets of local molten iron features were extracted according to a theoretical analysis of the influence of dust-induced brightness changes and the molten iron texture on the accuracy of combined local-global approach with total variation regularization (CLG-TV) and digital image correlation (DIC). Then, a mixed semifuzzy approximation network based on the characteristics of local molten iron features is proposed to estimate measurement errors under the influence of brightness changes and weak textures. Finally, an ingenious decision maker is designed to determine a more accurate displacement field of the molten iron surface. Additionally, a designed multi-stage filtered high-speed camera is installed beside the taphole to provide good optical images of molten iron surface. Industrial experiments and applications illustrate that the proposed method can stably and accurately measure the molten iron velocity at the taphole and provide reliable guidance for tapping operations.

Epitaxy Enhancement of Piezoelectric Properties in P(VDF‐TrFE) Copolymer Films and Applications in Sensing and Energy Harvesting

AbstractWith the rapid development of wearable and flexible electronics, energy harvesting from the environment has attracted much attention. As one representative piezoelectric polymer, poly(vinylidene fluoride‐trifluoroethylene) [P(VDF‐TrFE)] is an expected candidate for mechanical energy harvesting and self‐powered mechanical sensors due to its flexibility and moderate piezoelectricity. However, low crystallinity and electroactivity limit its electric performance. Controllable modulation of microstructure and crystallization is one feasible measure to enhance piezoelectric property. Here the piezoelectric properties of epitaxial P(VDF‐TrFE) films which are fabricated via removable polytetrafluoroethylene template method are reported. Piezoelectric measurement between 50 and 800 Hz presents an averaged d33 coefficient of −40.7 pC N−1 for epitaxial film, ≈61% enhancement to that of non‐epitaxial one. Transverse piezoelectric experiment indicated that epitaxy process enhanced open‐circuit voltage and short‐circuit current outputs. Simple piezoelectric energy harvesters are prepared by depositing both epitaxial and nonepitaxial films on flexible polyimide substrates. Epitaxial film shows a maximum generated power density of 0.118 µW cm−2 and energy conversion efficiency of 0.81%, both of which are much larger than those from nonepitaxial film (0.047 µW cm−2 and 0.30%). Piezoelectric films are used to monitor bending, punching, twisting and finger tapping operations, where epitaxial film exhibited larger open‐circuit voltage responses than nonepitaxial one.

Changes of Multiphase Flow Patterns during Steel Tapping with Simultaneous Argon Bottom Stirring in the Ladle

Changes of unsteady multiphase fluid flow patterns of liquid steel during electric arc furnace-ladle tapping operations, with simultaneous argon bottom injection, are simulated using interfacial tracking computing techniques. The impinging steel jet interacts with the argon bubbling plume, suffering mutual bending effects, and imparting non-symmetric flows of liquid steel during the whole ladle filling time. At low bath levels, radial recirculating flows are generated and at high bath levels, these flows are substituted by vertical long flows generated by the permanent interaction between the impinging jet and the argon plume. Turbulence intensity increases as the bath level rises. Low bath levels are suitable for pre-melting and preheating ferroalloy particles. High bath levels of steel in the ladle, close to total ladle filling, are the most suitable conditions for thermal and chemical homogenizations. Argon gas forms an intermittent blanket over the air–liquid steel mix due to its higher density than air during the whole ladle filling time.

Experimental investigation of screwed joints capabilities for the CFRP composite laminates

The load-carrying capability of the screwed joints for the carbon fiber reinforced polymer (CFRP) composite laminates was investigated by compression and torsion tests. To this end, the M6, M8, M10, and M12 metric internal threads were obtained by tapping directly into the CFRP composite laminates. In order to avoid material damage, the milling and tapping operations were implemented using CNC controlled machine tools. Quasi-static compression and torsion tests were carried out on the simply tapped and Helicoil reinforced screwed joints in the universal tensile-press test machine under uniform test conditions. The applied force and torque values respect to the screw displacements were obtained. Based on the experimental outcomes, the load-carrying capability and failure mechanisms of screwed joints were evaluated. The SEM graphics were utilized to explain the failure mechanism of threads. The load-carrying capability of joints increased with increasing the joint size. Helicoil reinforced specimens showed significantly higher maximum failure load and torque values compared to simply tapped specimens. Although, Helicoil inserts were effective in improving load-carrying of screwed joint, analysis of Helicoil performance proved that the effectiveness of Helicoil decreased with an increase in metric screw size. The computed stripping strength values indicated that Helicoil reinforced screwed joint can be an alternative to riveted and adhesively bonded joints as a detachable joining technique for thick CFRP composite laminates.

Resin exudation profile, chemical composition, and secretory canal characterization in contrasting yield phenotypes of Pinus elliottii Engelm

In conifer stems, secretory canals synthesize and store resin for defense against herbivores and pathogens. Resin terpenes are used as raw material by an array of industrial sectors. Most forest stands operationally used in resin extraction are derived from seeds, showing high genetic variation, which reflects in yield. The objective of this study was to identify adult slash pine (Pinus elliottii Engelm.) trees of high yield of resin in a short timeframe by resin mass flow rate analysis, aiming at the establishment of elite forests for tapping prior to its start. In addition, the anatomical basis of resin yield was investigated by examining the correlation between parameters such as number, shape, area and internal volume of wood canals with resin production. Monoterpene composition in resin of high and low yielding trees was also compared. The resin flow-based selection method was reliable for resin yield phenotype detection, confirming this property in trees formerly identified as being of high and low resin production by conventional tapping. The reverse test for identification of high and low yield resin features in previously untapped younger plants was in good agreement with their yields after subsequent standard tapping procedure. To evaluate and quantify the three-dimensional structure of resin canals, we used microCT scans. High yielding trees had more axial resin canals when compared with low yielding ones. Frequency of putative anastomosed canals and canal diameter were also superior in the former. Chemical analyses of resin monoterpenes revealed that the ratio of α-pinene/ β-pinene was lower in more productive trees, which also had more limonene in total terpenes compared with their low yield counterparts. Data support the use of short-term resin mass flow rate analysis as a tool to identify and select high yield trees for the establishment of elite slash pine forests for resin tapping operations. Strong correlation of the superesinous phenotype with canal density and structure was also evident.

Design and fabrication of a tool changing mechanism for cylinder block in a vertical milling machine

In inline three cylinder engine, cylinder block is an integrated structure comprising the cylinders, coolant passages, intake and exhaust passages and ports, and crank case. The cylinder block is mostly fabricated by casting process. The surface irregularities in the top face of the casted cylinder block causes improper seating of cylinder head and surface finishing becomes essential. Hence the casted cylinder block was machined with series of operations such as rough milling, face milling, finish milling, honing, line boring, drilling, tapping and reaming operations. In face milling operation, milling machine requires special cutting tools to remove the surface irregularities of the cylinder block. In the vertical milling machine, 12.6 kg cutting tool is fitted and removed by manually and it leads safety problems to the workers. The manual tool changing method increases the idle time of the machine and hence a tool changing mechanism is required to overcome the above said problems. In this present work, tool changing mechanism is designed and fabricated for a vertical milling machine to perform top face milling operation. Hence a semi-automatic mechanism is suggested to minimize the time of tool replacement. The solid model of the semi-automatic mechanism was modelled using SOLIDWORKS and the stress analysis of the components of the tool changing mechanism was performed using ANSYS Workbench. The manual tool changing method increases the idle time of the machine and hence a tool changing mechanism is required to overcome the above said problems. The cutting tool replacement time is reduced as 4.10 minutes from 11.05 minutes.

A Multi-Response Optimization of Thrust Forces, Torques, and the Power of Tapping Operations by Cooling Air in Reinforced and Unreinforced Polyamide PA66

The use of cooling air during machining is an environmentally conscious procedure, and its applicability to different processes is a research priority. We studied tapping operations, an important operation in the assembly process, using cooling air with unreinforced polyamide (PA66) and polyamide reinforced with glass fiber (PA66-GF30). These materials are widely used in industry, but their behavior with respect to tapping has not been studied. We analyze the outcomes regarding the thrust force, torque, and power at cutting speeds between 15 and 60 m/min. The experimental tests were executed using cooling air at 22 °C, 2 °C, and −18 °C in dry conditions. The M12 × 1.75 mm taps were high-speed steel, with cobalt as the base material and coatings of TiN and AlCrN. To identify the more influential factors, an analysis of variance was performed, along with multi-response optimization to identify the desirability values. This optimization shows that the optimum for PA66can be found in environments close to 3 °C, while the optimum for PA66-GF30 is found at the minimal temperature studied (−18 °C). Thus, cooling air can be considered an adequate procedure for tapping operations, to increase the sustainability of the manufacturing processes.

The force control and path planning of electromagnetic induction-based massage robot

Massage robot is considered as an effective physiological treatment to relieve fatigue, improve blood circulation, relax muscle tone, etc. The simple massage equipment quickly spread into market due to low cost, but they are not widely accepted due to restricted massage function. Complicated structure and high cost caused difficulties for developing multi-function massage equipment. This paper presents a novel massage robot which can achieve tapping, rolling, kneading and other massage operations, and proposes an improved reciprocating path planning algorithm to improve massage effect. The number of coil turns, the coil current and the distance between massage head and yoke were chosen to investigate the influence on massage force by finite element method. The control system model of the wheeled massage robot was established, including control subsystem of the motor, path algorithm control subsystem, parameter module of the massage robot and virtual reality interface module. The improved reciprocating path planning algorithm was proposed to improve regional coverage rate and massage effect. The influence caused by coil current, the number of coil turns and the distance between massage head and yoke were simulated in Maxwell. It indicated that coil current has more important influence compared to the other two factors. The path planning simulation of the massage robot was completed in Matlab, and the results show that the improved reciprocating path planning algorithm achieved higher coverage rate than the traditional algorithm. With the analysis of simulation results, it can be concluded that the number of coil turns and the distance between the moving iron core and the yoke could be determined prior to coil current, and the force can be controllable by optimizing structure parameters of massage head and adjusting coil current. Meanwhile, it demonstrates that the proposed algorithm could effectively improve path coverage rate during massage operations, therefore the massage effect can be improved.

A Comparative Study of Map Exploration Interfaces for Multi-Touch Tabletops

ABSTRACTWith the advent of multi-touch tabletops, software developers are creating innovative interfaces for applications such as interactive map systems. In this article, we summarized three representative interfaces from prevalent electronic map applications and literatures—gesture based, widget based, and hybrid, which supported both gestures and widgets—and then compared the effectiveness and the efficiency of these three interfaces by experiments. The results show that the hybrid interface had a better performance, requiring less task-completion time and operations, and causing less arm fatigue. The widget-based interface had the least distance traversed by fingers, but it required many tapping operations. The gesture-based interface was easier to learn compared to the widget-based interface, but the distance traversed during finger movements was the longest. Based on the findings from our experiments, we discuss the implications for the design of map exploration interfaces on multi-touch tabletops.

Influence of tool cooling on thrust forces in tapping operations of reinforced polyamide

The machining with compressed air cooling has been identified as an environmentally conscious process. Its good performance has been achieved in materials as titanium alloys or aluminum alloys, but composites have not been explored. This work presents a first study related to evolution of thrust forces during the tapping process in reinforced polyamide with glass fiber, in particular PA66-GF30, when the tool cooling is considered. The experimental methodology was carried out by tapping operations in plates of PA66-GF30, using a drilling center. The experimental tests were executed using compressed air cooling by means of a vortex-tube cooling, in dry. Taps are of high-speed-steel with cobalt as base material and with coating; their geometry and dimensions are M12x1.75 mm. Outcomes obtained confirm that the methodology is appropriate in the tapping process of PA66-GF30. The tool cooling provides a reduction of thrust forces, although it is conditioned by type of tap and the coating.