Drawing Velocity Research Articles

Quantification characteristics of digital spiral analysis for understanding the relationship among tremor and clinical measures in persons with multiple sclerosis

BackgroundMultiple sclerosis (MS) is a degenerative neurological condition causing demyelination and neuronal loss. Tremor, a symptom of MS, is prevalent in 45.0–46.8% NARCOMS registrants. Although several tools to measure tremor exist, few outcomes are quantitative or regularly utilized clinically. New methodIntroduction of a novel adaptation of the digital spiral drawing to find a quick, sensitive, and clinically useful technique, to predict tremor in persons with MS (pwMS). Digital spiral measures included: Segment Rate (SEGRT), Standard Deviation (SD) of Radial Velocity (VSD-R), SD of Tangential Velocity (VSD-T), SD of Overall Velocity (VSD-O), Mean Drawing Velocity (MNV-O) and Mean Pen Pressure Acceleration (MNA-P). Digital spiral measures were compared with the manual Archimedes Spiral (AS) drawing and the following clinical measures: Finger-Nose Test (FNT), presence of visually observed intention tremor (VOT), Nine-Hole Peg Test (NHPT), and Box and Block Test (BBT). ResultsAll clinical measures utilized demonstrated significant relationships with all digital variables, except VSD-R. The forward-stepwise regression revealed BBT accounted for the most variance, followed by SEGRT.Comparison with Existing Methods: SEGRT is more sensitive in detecting VOT and better for quantifying tremor than AS. BBT and SEGRT are optimal predictive measures for tremor. ConclusionsSEGRT has stronger sensitivity and negative predictive value than AS in detecting VOT. All clinical measures (NHPT, FNT, BBT, and AS) were significantly associated with the digital variables (SEGRT, VSD-T, VSD-O, MNV-O, and MNA-P) except for VSD-R. After controlling for Patient Determined Disease Steps (PDDS), BBT and SEGRT are the best predictive measures for tremor.

Analysis and study of dieless drawing process for rod based on radial direction gradient slab method

Dieless drawing is one of the most advanced processing technologies. After heating and cooling, the diameters of the wires or rubes can be reduced without drawing dies. Comparing to the traditional drawing processes, the workpiece is no longer touched with the processing equipment. The production efficiency is increased while the consumption of energy is also saved. In this paper, the dieless drawing process will be researched based on the gradient slab method. All the significant parameters in this process will be taken into the consideration, such as drawing velocities, thermal properties, and temperature conditions and geometrical parameters of material. The effects of pairwise related parameters on the final area and temperature as well as deformation length will be shown in three-dimensional diagrams. A novel analysis model of dieless drawing will also be proposed based on vertical gradient slab method. This model will be seen as a strong theoretical support for studies of dieless drawing.

Mechanical Properties of PETG Fibres and Their Usage in Carbon Fibres/Epoxy Composite Laminates

This paper reports on a melt-spinning process of glycol-modified poly(ethylene terephthalate) PETG and regranulate of PETG. The effect of the processing temperature and winding reel velocity on the diameters of fibres was examined. It was observed with a scanning electron microscope that the surface of fibres produced from recycled PETG are thicker but smoother than fibres made of fresh PETG. Applying a higher drawing velocity helped to decrease the diameters, which were between 75-150 μm. Under static deformation, fibres showed different behaviour, with higher flexibility and lower strength observed for fibres made of PETG regranulate. Both types of fibre were chopped and added to carbon fibre reinforced polymers as interlayers to investigate their effect on mechanical properties. It was found that the flexural strength decreased in the presence of PETG fibres, while interlaminar shear strength improved, but only in the case of fresh PETG fibres.

Study on forming process and spring back control of high strength sheet based on Dynaform

The drawing process of a high strength steel part without blank holder force was numerically simulated based on Dynaform. In present investigation, the drawing velocity and velocity profile motion of punch was studied by simulating the drawing operation of high strength steel part. The results show that restricting drawing velocity and controlling velocity profile motion of punch could all reduce the spring back. The measure of restricting drawing velocity could reduce non-pressure forming spring back about 31% and Trapezoidal motion mode of punch is the most beneficial to reduce spring back.

Experimental Study on Fine Titanium Wire Drawing with Two Ultrasonically Oscillating Dies

This paper investigates the influences of ultrasonic vibration on the two-pass titanium wire drawing process through experiments conducted at different drawing speeds (99–480 mm/s) and under various ultrasonic amplitudes (5.63– $13.97~\mu \text{m}$ ). Ultrasonic vibrators were designed, analyzed, and manufactured to impose ultrasonic vibrations, along opposite directions, on the dies. Their dynamic characteristics were predicted by finite element analysis and subsequently measured using specific instruments. The interaction between the two vibrators, when driven by the same ultrasonic generator, resulted in the deviation of coupled resonant frequency (50–60 Hz) and the decrease in maximum output amplitudes (about 4 $\mu \text{m}$ ). A wire drawing equipment was developed to record the drawing forces under different experimental conditions, and the surface morphologies of the drawn wires were then inspected with a scanning electron microscope. Results show that increased ultrasonic amplitude contributes to greater drawing force reduction, whereas higher drawing speed brings about the reverse effect. At the lowest drawing speed and with the largest ultrasonic amplitude, the drawing force declined by over 50%. Both factors have influences on the surface finish of the drawn wires. However, higher drawing velocity (480 mm/s) with the moderate ultrasonic amplitude ( $9.69~\mu \text{m}$ ) turned out to be most effective in removing the surface defects of the wire products. This paper provides a low-cost, high-efficiency, and eco-friendly approach for the industrial production of fine titanium wires at room temperature.

Investigation of the influence of process parameters on adhesive wear under hot stamping conditions

Current challenges like increasing safety standards and reducing fuel consumption motivate lightweight construction in modern car bodies. Besides using lightweight workpiece materials like aluminum, hot stamping has been established as a key technology for producing safety relevant components. Producing hot stamped parts out of ultra-high strength steels offers the possibility to improve the crash performance. At the same time the weight of car structure is reduced by using thinner sheet thicknesses. In order to avoid oxide scale formation and ensure corrosion protection, AlSi coatings are commonly deposited on the sheet surfaces used for direct hot stamping. This workpiece coating has a critical impact on the tribological conditions within the forming process and, as a consequence, influences the quality of hot stamped parts as well as tool wear. AlSi coatings have been identified as major reason for adhesive wear, which represents the main wear mechanism in hot stamping. Within this study, the influence of the process parameters on adhesive wear are investigated in dependency of workpiece and tool temperatures, drawing velocities and contact pressures. The tribological behavior is analyzed based on strip drawing experiments under direct hot stamping conditions. The experiments are performed with AlSi coated 22MnB5 in contact with the hot working tool steel 1.2367. For analyzing the amount of adhesion on the friction jaws, the surfaces are characterized by optical measurements. The experiments indicate that higher workpiece temperatures cause severe adhesive wear on the tool surface, while an increase of drawing velocity or contact pressure led to reduced adhesion. The measured friction coefficients decreased with rising amount of adhesion and remained at a constant level after a certain adhesive layer was built up on the tool surface.

Experimental study on titanium wire drawing with ultrasonic vibration

Titanium and its alloys have been widely used in aerospace and biomedical industries, however, they are classified as difficult-to-machine materials. In this paper, ultrasonic vibration is imposed on the die to overcome the difficulties during conventional titanium wire drawing processes at the room temperature. Numerical simulations were performed to investigate the variation of axial stress within the contacting region and study the change of the drawing stress with several factors in terms of the longitudinal amplitude and frequency of the applied ultrasonic vibration, the diameter reduction ratio, and the drawing force. An experimental testing equipment was established to measure the drawing torque and rotational velocity of the coiler drum during the wire drawing process. The result indicates the drawing force increases with the growth of the drawing velocity and the reduction ratio, whether with or without vibrations. Application of either form of ultrasonic vibrations contributes to the further decrease of the drawing force, especially the longitudinal vibration with larger amplitude. SEM was employed to detect the surface morphology of the processed wires drawn under the three circumstances. The surface quality of the drawn wires with ultrasonic vibrations was apparently improved compared with those using conventional method. In addition, the longitudinal and torsional composite vibration was more effective for surface quality improvement than pure longitudinal vibration, however, at the cost of weakened drawing force reduction effect.

Defect Formation Mechanism and Influence of Processing Parameters on Surface Quality of Copper Clad Steel Composite Wires Prepared by Core-Cladding Continuous Casting

Copper clad steel (CCS) composite wires with the carbon steel core diameter of 8 mm and copper cladding thickness of 1 mm were prepared by core-cladding continuous casting method under argon protection. The effects of melt temperature, molten metal height and drawing velocity on the surface quality were investigated. The formation mechanisms of the surface defects were discussed. The results showed that CCS wires with good surface quality could be continuously fabricated at a melt temperature of 1120 to 1200°C, a molten metal height of 2 to 4 cm and a drawing velocity of 10 to 30 mm/min. Raising the melt temperature, increasing the molten metal height or decreasing the drawing velocity is in favor of improvements in the surface quality. Insufficient supplement of liquid copper during solidification shrinkage resulted in surface dimple. Transverse hot cracking and exposed steel defect appeared because the frictional force between cladding metal and mold was larger than the tensile strength of cladding metal under high temperature.

Continuous Casting of TiAlNb Alloys with Different Velocities by Mixing Binary TiAl Ingot and Nb Wire

A method of continuous casting is used and the research investigates microstructure and mechanical properties under different drawing velocity (R, mm/min). The results show that microstructure and composition measurement of different zones are uniform. The smallest grain size is 25.93 μm and formability is good with 0.5R. Compressive strength is higher with 0.5R and maximum value is 1697MPa. Fracture toughness with 0.5R improves about 35.7% which is 21.7MPa·m1/2. The fracture morphology is trans‐lamellar fracture and interface de‐lamination. The method is a feasible way to continuously cast the TiAl‐Nb alloys. The R is an important parameter to add high‐melting‐point element, which affects solidified temperature interval of solidification front and electromagnetic stirring.

The speed of reinfusion affects the vascular system during ozone major autohemotherapy

Ozone major autohemotherapy (O-MAHT) is a way of ozonetherapy administration consisting of drawing patient’s venous blood, mixing with oxygen/ozone, and reinfusing it into the vein. Some ozone therapists reported side effects during the O-MAHT, but the origin has not been described yet. We investigated the effect of blood drawing velocity during O-MAHT to see its effects on the vascular system and symptomatology. We administered O-MAHT to 11 subjects, and we interleaved fast and slow reinfusions. We monitored cerebral macrocirculation with transcranial Doppler (TCD) and tissue microcirculation with near-infrared spectroscopy (NIRS). Annoying symptoms appeared just during the fast reinfusion periods. NIRS and TCD parameters revealed vasoconstriction during fast reinfusion and improved metabolism during slow reinfusion. Overall, our investigation well discriminated fast from slow reinfusion velocity.

On numerical modelling of multi-rifled tube drawing

Abstract Production of precision seamless steel tubes in Zeleziarne Podbrezova is divided into several technological steps, with final cold drawing determining final tube dimensions. The drawing itself usually takes several drawing passes with intermediate heat treatment. For multi-rifled tubes, the last drawing pass utilizes a special, free-to-rotate plug with multiple helical grooving so to produce a helical rifling pattern on the inner surface of the tube. A crucial factor to meet stringent dimensional tolerances on rifling geometry is to determine proper input dimensions of the tube just before the final rifling pass. Also, drawing velocity is another key factor that not only determines the overall productivity but the quality of the rifling as well. Due to the high costs of plant trials in early stage of technology development, computer simulation approach can easily serve the purpose very well, thus saving us from laborious and costly pilot experiments. Numerical modelling software DEFORM-3D has been utilized in Zeleziarne Podbrezova for drawing technology development and optimization for T12 steel tubes with 28.6 × 6.3 mm (O.D. × W.T.) In particular, both input dimensions and drawing velocity were optimized while meeting rather strict dimensional requirements on tube rifling. Resulting tube & rifling dimensions were in good accordance with dimensions from experimental proofing trials, where the actual dimensions were obtained via 3D optical scanning of multi-rifled tubular samples.

Analytical modelling of dry-jet wet spinning

This paper introduces an analytical method for the analysis and design of a dry-jet wet spinning system. The 1-D mass conservation equation is used, and velocity distribution is assumed to derive a simple relationship among various spinning parameters. The effect of spinneret mass flow rate, solution density, spinneret structure including velocity and air-gap length, and drawing velocity on the dry-jet wet spinning was simulated using the proposed analytical model. Theoretical prediction of fiber diameter is obtained, which depends upon spinning conditions, solution properties, and spinneret structure. The theoretical results were verified by comparing experimental data with the numerical solution. It was found obviously that the theoretical prediction has comparable accuracy as that by numerical computation. The analytical model can be useful for preliminary design of a spinning process for fabrication of fibers with controllable diameter by adjusting parameters in spinning conditions.

Temperature modes and critical velocities when drawing the wire

When producing rod and wire wares, residual stresses are formed. This phenomenon is caused both by plastic deformation and by possible thermoplastic deformation, which appears due to contact heating the metal ware surface due to external friction forces. Undesirable residual stresses in surface layers affect the accuracy of metal wares and increase their failure probability, which is observed in the practice of drawing production. In this study, a procedure is proposed to determine the contact heating conditions from the formation prevention criteria of residual stresses. Based on thermoelasticity equations, temperature modes leading to the appearance of thermoplastic deformations are established. Critical values of the temperature difference between the drawing wire surface and the center, at which the wire surface layers transform into the plastic state with the subsequent formation of residual stresses, are determined. Limiting drawing velocities for a series of nonferrous metals (copper, zirconium, and titanium), which, if exceeded, will lead to undesirable residual stresses in the drawn wire, are determined. To increase the critical velocities, it is recommended to implement the hydrodynamic (fluid) friction mode conditions when producing metal wires.

A Study on Optimal Design of Process Parameters in Tube Drawing Process of Rectangular Parts by Combining Box–Behnken Design of Experiment, Response Surface Methodology and Artificial Bee Colony Algorithm

Tube drawing process is comprised of many factors that have great impact on the formed part quality and die life. In producing polygonal sections from round tube, due to accumulation of residual stress in corners, the final shape of the drawn part is to some extent different from what is expected. Therefore, selection of optimal combination of drawing parameters for enhancing the parts quality and die life is crucial. In the present paper, a complete multi criteria optimization procedure starting from numerical modeling, and leading to the search of robust optimal process parameters is proposed. A numerical model of tube drawing process of aluminum alloy for rectangular section is developed by means of ABAQUS and validated experimentally. Then a total set of 27 numerical tests are conducted based on four-factors and three levels Box–Behnken design to correlate empirical relationship between factors (i.e., die angle, bearing length, friction coefficient and drawing velocity) and responses (i.e., drawing force, linear and peripheral thickness distributions and dimensional error). Response surface model of each quality characteristic is obtained and analysis of variances is performed to check the adequacy of developed models. Finally the obtained RSM models are integrated with their weight factors and the objective function is formed. This function is then associated with artificial bee colony (ABC) algorithm to find factor combination regarding minimum drawing force and dimensional error, as well as maximum thickness distributions. Results indicate that the optimal result obtained through RSM–ABC is in agreement with those derived from simulations and confirmatory experiments.

The influence of the silicon dioxide barrier films on the laser ablation destruction of the glass composites with the films drown from the sols

The laser ablation destruction of the composites with nano dimensional oxide one- or two-layers films drown from the sols on a glass substrate has been studied. It has been shown that the laser ablation destruction threshold energy density depends on the number and chemical composition of the layers and the drawing velocity. The ablation threshold energy density of the two-layer composites finds out mainly a tendency to decrease at the 3.8 mm/s drawing velocity, but at the 5.8 mm/s one--to increase that can be explained by the films thickness decreasing and the low-melting components from the glass substrate diffusion due to the barrier films diminishing.

Temperature modes and critical velocities during wire drawing

Rod and wire product manufacturing is usually accompanied by residual stresses. The reason for this is both plastic deformation and potential thermoplastic deformation that occurs due to the contact frictional heating of metal surfaces. Undesirable residual stresses in the surface layers affect the accuracy and increase the probability of hardware destruction that can be observed in drawing product manufacturing. The authors of the article propose a method of determining the contact heating conditions based on the criteria of residual stress prevention. Temperature conditions causing thermoplastic deformations are determined according to thermoelasticity equations. Critical values are calculated for the temperature difference between the center and the surface of the stretched wire, at which the latter transits to a plastic state followed by residual stress formation. The limiting drawing velocities for a number of nonferrous metals (copper, zirconium, titanium) are defined. The excess of those top velocities will lead to undesirable residual stresses in the stretched product. It is proposed as a recommendation to increase the critical speed by creating hydrodynamic (fluid) friction conditions in metal products manufacturing.

Numerical and experimental study of the glass flow and heat transfer in the continuous glass fiber drawing process

The manufacturing process of glass fibers used for the reinforcement of composite materials consists in drawing a free jet of a molten glass at high temperature into fibers using a winder. This process is sensitive to numerous disturbances that can cause the fiber to break during the drawing process, and thus reduce the process efficiency. The underlying physics of the forming of a single fiber is investigated here through numerical simulations, and results are validated with measurements obtained on a dedicated experimental unit. Both a two-dimensional axisymmetric and a simplified one-dimensional model are used to simulate the high-temperature region before glass transition. The influence of key parameters and physical mechanisms on the internal stress is investigated through a sensitivity analysis. The simplified model is then used to identify the optimal operating window and to assess the impact of temperature inhomogeneities at the bushing plate. Results show that the initial region close to the tip is critical, and that a low cooling rate reduces the stress. Operating at high tip temperature, large drawing velocity and small tip radius is then found to be the best strategy to minimize the stress. Finally, it is shown that the heat pattern of the bushing plate is one of the most important causes for disturbance in the process.

Investigation of Influencing Parameters for Tribological Conditions in Dry Forming Processes

Environmental awareness and a growing demand for efficient resource utilization encourage the realization of lubricant-free forming processes. A first step in accomplishing dry sheet metal forming is to gain knowledge about the changing tribological conditions and to identify the relevant influencing parameters. The commonly used flat strip drawing test was selected to investigate the tribological conditions in the flange area of deep drawing processes. The influencing factors of contact pressure and varying drawing velocities were analyzed under dry and lubricated conditions. Additionally, the tool and workpiece surfaces were characterized. Besides lubrication, the contact pressure mainly determines the tribological conditions. In lubricated tests higher normal pressure reduces friction, whereas without lubrication higher pressure results in slightly increasing friction. A changing drawing velocity affects the friction when lubricant is applied. In dry experiments, no influence of velocity was found. Results of surface characterization reveal adhesion as main wear mechanism under dry conditions. Based on the investigated influence of the process parameters, an increase in process understanding for dry forming operations is derived.

Three Dimensional Finite Element Analysis of Wire Drawing Process

This work aims to analytically and numerically study the parameters affecting on the wire drawing process using a 3D finite element model and the effect of these parameters on drawing force. Three-dimensional finite element model using DEFORM-3D V6.1 was built to simulate this process. AL-1100 wire was drawn through a conical die with semi-die angle ( α = 6° , 8° , 8.5° , 9° , 9.5° , 10°,, 15° ), reduction ratio ( r = 0.1 , 0.15 , 0.2 , 0.25 , 0.3), friction coefficient ( µ = 0.1 , 0.08 , 0.075 , 0.07 , 0.065 , 0.06 , 0.05), bearing length ( BL= 0.5 , 0.75 , 1 , 1.25 , 1.6 ) mm, drawing velocity ( 5000, 7500, 10000, 12500, 15000, 17500, 20000)mm/sec. were taken in this study. Many simulations with different parameters were taken to capture the optimum die angle. The results show that the optimum die angle depends on reduction in area (α= 9.5°, 9.5°, 9.5°,10°, 10°) for reduction in area (r= 0.1, 0.15, 0.2, 0.25, 0.3). The drawing force estimated from finite element results was compared with that of analytical results and found in line with maximum error percentage of 4%. The results of finite element model were analyzed statistically using SPSS software in order to find the relationship between the above factors and drawing force.

Characterization of fine motor development: Dynamic analysis of children’s drawing movements

In this study, we investigated children’s fine motor development by analyzing drawing trajectories, kinematics and kinetics. Straight lines drawing task and circles drawing task were performed by using a force sensitive tablet. Forty right-handed and Chinese mother-tongue students aged 6–12, attending classes from grade 1 to 5, were engaged in the experiment. Three spatial parameters, namely cumulative trace length, vector length of straight line and vertical diameter of circle were determined. Drawing duration, mean drawing velocity, and number of peaks in stroke velocity profile (NPV) were derived as kinematic parameters. Besides mean normal force, two kinetic indices were proposed: normalized force angle regulation (NFR) and variation of fine motor control (VFC) for circles drawing task. The maturation and automation of fine motor ability were reflected by increased drawing velocity, reduced drawing duration, NPV and NFR, with decreased VFC in circles drawing task. Grade and task main effects as well as significant correlations between age and parameters suggest that factors such as schooling, age and task should be considered in the assessment of fine motor skills. Compared with kinematic parameters, findings of NFR and VFC revealed that kinetics is another important perspective in the analysis of fine motor movement.