Drawing Height Research Articles

Uniform thickness in the process of ore-mixed characteristics of particles passing through experimental research

The nature of fine particulate matter is caused by the deterioration of the lean ore loss index and the important influence factors of a mine disaster accident. In this paper, fine moraine particles and coarse-grained ore from the Pulang Copper Mine are studied. The flow of fine particles in mixed particles under the condition of uniform ore drawing was studied by using the laboratory 3D physical model test method. This experiment explored the flow of hybrid particles in the system and characteristics of the particle size of fine particles passing through, and suggested a transit index to quantify the draining effect of fine particles. The experimental results show the following: ①Hybrid particles in the flow system of fine particulate matter under their own gravity use mixed ore particles flow in the process of formation of the pore to implement down through sports. ②The fine particles with the particle sizes of 2.5–1.25 mm, 1.25–0.63 mm, 0.63–0.315 mm, and 0.315–0.16 mm all have the flow-through characteristics, and the smaller the particle size, the more significant the flow-through degree. ③The cumulative ore drawing height of fine particles with different particle sizes increases, while the permeability index of the appropriate discharge decreases. ④The relative motion of coarse and fine particles is the internal control factor that leads to the flow of fine particles. The more significant the relative motion of coarse and finely mixed particles is, the more pores are randomly generated in the particle flow system and the larger the pores are, resulting in the more obvious fine particle flow effect. This study provides some theoretical reference value for revealing the flow-through characteristics of the fine particulate matter in the mixed particle flow system. At the same time, it has practical engineering significance for ore lean loss index control and mine disaster accident prevention and control in caving mining.

Experimental investigation of the effect of specially manufactured blank (SMB) materials on deep drawing

Deep drawing, one of the sheet metal forming processes, has a large area of use in industry. In the deep drawing, sheets having a fixed thickness are usually deep drawn. In general, there are some limitations, which prevent the part from being drawn at the desired depth, in the deep-drawing processes. Some of these consist of the increase in the sheet thickness towards the end of the part, being exposed to ironing, increasing wrinkles, exposure of the material to deformation hardening, and as a result, the fractures occur in the drawn part. Many special methods have been developed to increase the drawing height. One of them is to use blanks having machined edges. In the present study, the edges of the blank material were thinned by using the turning process at certain angles to avoid the above-mentioned negative effects. In this study, Al-1050 aluminum alloy with a thickness of 2 mm and machined edges of 1°, 2°, 3°, and 4° were used. The results were compared with the unmachined blanks. The highest drawing height was obtained with the blank having a 1° machined edge and 95 mm diameter. In addition, the power (approximately 7–31%) needed for deep drawing and material weight were reduced with the help of the deep-drawing process applied by using a specially manufactured blank.

Cryogenic formability of a solution-treated aluminum alloy sheet at low temperatures

• A newly-designed digital image correlation (DIC) testing device at cryogenic temperatures was developed. • The cryogenic FLDs and FLSDs of the solution-treated Al-Cu-Mn alloy sheet were experimentally obtained. • The cryogenic FLD and FLSD ductile fracture models were determined to predict the drawing limits of the Al-Cu-Mn alloy sheet. In this paper, the analysis of the necking and limit strains of a solution-treated aluminum alloy sheet at extreme low temperatures is performed using a newly-designed test apparatus equipped with the digital image correlation (DIC) device. The forming limit diagram (FLD) and forming limit stress diagram (FLSD) ductile fracture models were used to predict the drawing limit and fracture resistance capacity of an Al-Cu-Mn alloy sheet under complex stress at room temperature (RT) and -160 °C. It was found that the FLD 0 value at -196 °C increased to 0.32 as compared to 0.23 at RT. The Al-Cu-Mn alloy sheets at -160 °C and -196 °C were found to have significantly higher limit strains than those at RT. The drawing height and limit major strain at the round corner of the cryogenic deep-drawn cups were found to be increased by 21.3 % and 9.7 %, respectively, as compared to those at RT. Moreover, a larger necking amount and higher fracture resistance of the Al-Cu-Mn alloy sheet could be achieved during cryogenic deformations. The obtained cryogenic FLDs and FLSDs can be used to accurately predict the damage evolution and failure occurrence for the forming of complex-shaped aluminum alloy components at low temperatures.

Study on formability and failure modes of steel/CFRP based FMLs consisting of carbon fiber reinforced polymer prepreg and steel sheet

Due to the potential application need of the automotive and transportation industry for Fiber metal laminate parts made of steel sheets and carbon fiber reinforced polymer (i.e., Steel/CFRP based FML parts), the related combined forming process of FML parts has attracted extensive attention in the last decades. In order to design and fabricate the qualified Steel/CFRP based FML auto parts with various plane stress states, it is vital to thoroughly understand the formability and failure modes of Steel/CFRP based FMLs under various forming states and process conditions. Accordingly, in the present work, a series of deep drawing experiments were designed and conducted on Steel/CFRP based FML specimens with various width to embody their special forming features under different stress states. By considering the limit drawing height at fracture for the evaluation indicator of the forming limit of FMLs, authors studied systematically the influence of key process conditions such as lay-up scheme, stamping speed and the number of plies in the carbon fiber reinforced polymer prepreg (i.e.,CFRP prepreg) core on the formability and failure modes of FML specimens with various forming states. The research results are expected to provide a reliable data source for establishing the accurate forming limit criterion of FMLs and optimizing lay-up schemes.

Large ellipsoid parts manufacture using electromagnetic incremental forming with variable blankholder structure

Large ellipsoid parts are prone to wrinkle when forming by using traditional stamping. Aiming to solve the wrinkling problem in large parts, the EMIF method with a variable blank holder is proposed in this paper. The numerical simulation has shown that the sheet material near the blank holder is, as a consequence of stamping, subjected to circumferential compressive stress. When the drawing height was 100 mm, the sheet metal was notably wrinkled. In the electromagnetic forming (EMF) process, the sheet region facing the coil becomes thinner. However, the sheet metal thickness corresponding to the coil edge increases with the increase in forming height. If the EMF forming height is 150 mm, the sheet, which is in contact with the smooth mold, is deformed without a wrinkle. Compared to traditional stamping, the EMF can significantly reduce the sheet metal wrinkling, improving the deformation height of the sheet metal smooth area.

Simulation and Experimental Investigation of Granular Medium Forming Technology on Titanium Alloy Sheet at 500 °C

To investigate and verify the degree to which the forming properties of low plasticity materials are improved at room temperature using the granular medium forming (GMF) process at 500 °C, a coupled Eulerian–Lagrangian unit calculation model was established and a special mold was designed to conduct a GMF experiment for titanium alloy sheets under different-shaped pressing blocks. Then, using a three-coordinate measuring machine, the sizes of the outer contours of the parts formed at room temperature were measured, and the results showed that the bottom of the parts maintained a smooth surface during the drawing process. As the drawing height increased, the radius of curvature of the cambered surface gradually decreased. By measuring the wall thickness of the parts at different positions from the central axis using a caliper, the wall thickness distribution curves of these parts were obtained, which showed that the deformations of the bottom of the formed parts were uniform and the uniformity of the wall thickness distribution was good. By comparing the GMF experimental data at 500 °C with traditional deep drawing experimental data, it was found that the GMF technology could improve the forming properties of low plastic materials such as titanium alloys.

Deep drawing behavior of IN625 alloy under the influence of different process parameters

The Ni-Cr based IN625 alloy has been extensively used in critical applications of aerospace and nuclear industries. Various components have been manufactured using sheet metal forming processes. In the present work, the deep drawability of material has been examined under the influence of different process parameters such as temperature, punch speed, lubrication, and blank holding pressure using the processing window. The deep drawability has been analyzed in three different zones, namely, safe, wrinkling, and fracture. The limit drawing ratio increased by 7.12 % on increasing the temperature from 300K to 673K. The thickness distribution across the deep-drawn component plays a crucial role in examining the quality and life of it. Therefore, in this context, a detailed analysis of different process parameters over the drawn cup’s thickness distribution has been done. The minimum thickness was obtained near the punch corner or the cup junction region of the deep drawn cup. The uniformity in the thickness distribution and drawing height also increased with the forming temperature and decrease in punch speed. Additionally, two different yield criteria, namely, Hill 1948 and Barlat 1989, have been analyzed and further used for the numerical analysis using the user material subroutines in Abaqus software. The results predicted using Barlat 1989 yield criterion more closely followed the experimental results as the average absolute error obtained is well within the 5% of the acceptable limit.

Description of stress-strain response and evaluation of the formability for Al-Cu-Mg alloy under the impact hydroforming

This study aims at investigating on the descriptions of stress-strain response and the assessment of formability for Al-Cu-Mg alloy under impact hydroforming (IHF). IHF process effectively combines the advantages of the flexible liquid and the impact impulse. The formability of low plastic materials can be increased by using IHF process. The elongation of Al-Cu-Mg alloy can even be more than 50 % compared with the quasi-static forming means (27 %∼30 %) if the strain rate was on the level of 5000/s. The stress-strain curve is characterized with S-shape. It is found that the strain hardening rate decreases linearly at the stage III, increases linearly at the stage IV and decreases non-linearly at the stage V. The deformation mechanism is the interaction of dislocation accumulation and dynamic recovery under the transmission from non-sheared to sheared precipitation when the strain rate is on the level of 3000/s∼5000/s. A modified Kocks-Mecking model was established to describe the mechanical property of AA 2B06. In addition, the high strain rate formability was evaluated by the new means which revealed the relationship between the impact energies, deep drawing height ratios and the deep drawing ratios by using the finite element modelling of the solid liquid coupling.

A novel deep drawing process for aluminum alloy sheets at cryogenic temperatures

Abstract To overcome the low drawability of aluminum alloy sheets at room temperature (RT), a novel deep drawing process at cryogenic temperatures is proposed. Uniaxial tensile tests were carried out at RT, −130 °C, −150 °C, −160 °C and −196 °C, respectively, and the desired temperature of cryogenic deep drawing was obtained. Based on a newly-designed cryogenic deep drawing system, deep drawing experiments of an Al-Cu-Mn alloy sheet were conducted at different cryogenic temperatures. The material flow, drawing ratio, drawing load, thickness distribution and Vickers microhardness of the drawn cups at both RT and cryogenic temperatures were discussed in detail. It was found that the deep drawability was significantly enhanced as the temperature decreased to −160 °C. The limiting drawing ratio at RT was 1.80, while that at −160 °C increased by 15.6% to 2.08. Similarly, the average cup height (89.5 mm) at −160 °C was found to be 50.2% higher than that at RT (59.6 mm). The cryogenically drawn cups exhibited slight localized thinning, uniform thickness distribution, and a large drawing height and drawing load. In addition, the enhancement of the deep drawability was illuminated via microstructural observations of the fracture morphology and dislocation evolution at cryogenic temperatures.

A novel method to evaluate the high strain rate formability of sheet metals under impact hydroforming

In this study, a novel method was proposed to evaluate high strain rate (HSR) formability of Al-Cu-Mg 2B06-O sheets by impact hydroforming (IHF). IHF was suitable to manufacture hard-to-form sheets, since it combined the advantages of flexible liquid and impact impulse loading. Both 2D and 3D HSR formability curves were established to describe the relationship between impact energy, drawing height ratio (DHR) and deep drawing ratio (DDR). Moreover, the novel evaluation method was realized by finite element (FE) modeling using fluid-structure interaction (FSI) algorithm. FSI modeling was used to deal with the interaction of structure solid and flexible fluid. This evaluation means of FE modeling characterized with guiding production practice, saving evaluation costs, improving efficiency compared with corresponding experiments. The results obtained from FE modeling were in a remarkable agreement with those obtained from IHF experiments in the aspects of part shape, failure feature, thickness distribution. FE modeling showed that the limit deep drawing ratio (LDDR) and limit drawing height ratio (LDHR) were 1.99 and 1.04, respectively when the blank was completely deep drawn into the cavity of the die in one step only. FE modelling is proved to be reliable and efficient to estimate high strain rate formability of low formability metal sheets.

Flow property of ore from multiple drawpoints and evolution law of the isolation layer

ABSTRACTA physical laboratory experiment and a numerical simulation were used to study the flow property of ore and the evolution law of the isolation layer. The relationships among the drawing ore mass and drawing height, moving law of the drawbody, and evolution law of the isolation layer were revealed. The results showed the following: the amount of drawing ore from each drawpoint first increased slowly and exponentially and then increased linearly with the increase in drawing height. The trends of all curves were consistent with each other. The drawbody was approximately ellipsoid in shape. Moreover, adjacent bodies were staggered and different degrees of loss were seen. The isolation layer interface approximately maintained its initial level at first and then descended slowly during the initial period. After the isolation layer had descended to a certain depth, it began to form a wavy pattern until the end of ore drawing.

Theories and experiments on effects of acoustic energy field in micro-square cup drawing

A vibration-assisted uniaxial tension experimental setup was designed to study the stress-strain relationship induced by ultrasonic excitation, and an acoustic-plastic constitutive model was developed and calibrated based on dislocation density evolution under experimental data. Also a prediction model for the drawing height of micro-square cups in vibration-assisted plastic deformation was investigated based on the dangerous section stress theory and the acoustic-plastic constitutive model. The prediction model was validated by designing a finite element model and an experimental deep drawing system under various working conditions, in which 200-μm-thick stainless steel 304 was excited by ultrasonic vibration at frequency 19.891 kHz and different amplitudes. It was found the predicted drawing height of micro-square cups agreed well with the experimental results, indicating the prediction model was able to accurately predict the drawing height of micro-square cups during vibration-assisted metal micro-forming.

Psychometric properties of clock and pelvic drawings in Parkinson's disease: A validity and cross-sectional study.

Parkinson's disease (PD) is characterized by visuospatial and body schema deficits. People with PD often exhibit hypometric movements and graphic hypometria (i.e., small drawing dimensions). The goal of the current study was to explore graphic-metric representation in people with PD by assessing pelvic and clock drawing dimensions (i.e., height and width) and by investigating associations between pelvic drawing dimensions and participant characteristics. Twenty people (16 males, 4 females; M age: 65.75±10.13years) with idiopathic PD (Hoehn &Yahr Stages I-III) volunteered to participate in this study. Draw Your Pelvis and Clock Drawing tests were used for assessing drawing dimensions, which were then correlated with PD severity, stage and duration, cognitive level, side of symptoms onset, and pelvic schema score. Bivariate and multiple linear regression analyses were also used. Excellent (.844-.999) interrater reliability was shown for measuring pelvic and clock drawing dimensions. Pelvic drawing dimensions did not significantly (P>.05) differ in magnitude, whereas clock drawing height was significantly (p<.01) greater than width, both suggesting graphic dysmetria (i.e., distorted graphic dimensions). Pelvic drawing width was negatively associated with PD severity and stage, was positively associated with pelvic schema score, and predicted all three parameters. Measuring pelvic drawing dimensions, and specifically pelvic drawing width, holds potential as an adjunct diagnostic measure in PD assessments and for detecting pelvic schema deficits or misperceptions. This test can be used by physical therapists in the clinic for assessing disease severity, stage, and pelvic schema in people with PD. The knowledge gained from this study contributes to a greater understanding of graphic-metric representation and associated deficits in people with PD. Future studies should explore the relationship between pelvic drawing dimensions and pelvic mentally imaged estimates, and their role in motor planning, control, and execution in people with PD.

Experimental investigations of the electromagnetic pulse-assisted incremental drawing of aluminum alloy

During the drawing process, when the radial tensile stress is greater than the limit of the sheet metal’s bearing capacity, the workpiece will rupture. In order to succeed in forming the cylindrical part, it is necessary to reduce the radial tensile stress, or even change the tensile stress into compressive stress. In the current study, electromagnetic pulse-assisted incremental drawing (EMPAID) technology was used to form the cylindrical part, which can generate magnetic force on the flange material, which pushes them to flow into the die cavity. The drawing coil with different turns matching the determined corner coil and different auxiliary coils were used to conduct the experiments. When the two-turn drawing coil, one-turn corner coil, and two-turn auxiliary coil were used, after multiple times of discharge and micro-shaping, the limit of the drawing height of the formed part increased to 42.86 mm, which was 2.16 times of the limit drawing height obtained using the conventional drawing. Using the three-turn drawing coil combined with the corner coil and four-turn auxiliary coil to carry out the experiments, the cylindrical part’s maximum drawing height reached 63.72 mm. Meanwhile, the flange area was almost completely converted into the cylinder wall. When the dense winding auxiliary coil was used to conduct the experiments, the maximum forming depth was only 25.24 mm. The experimental results showed that during the forming process, majority of the flange material was pushed into the die cavity due to the action of magnetic force. Due to this reason, the thinning of the forming part can be suppressed. If the magnetic force generated by the drawing and auxiliary coils matched reasonably, then the depth of the formed part can be improved significantly.

“Will you draw me a pelvis?ˮ Dynamic neuro-cognitive imagery improves pelvic schema and graphic-metric representation in people with Parkinsonʼs Disease: A randomized controlled trial

BackgroundBody schema (i.e., the mental representations of the body), vital for motor and cognitive functions, is often distorted in people with Parkinsonʼs disease (PD). Deficits in body, and especially pelvic, schema can further exacerbate motor and cognitive deficits associated with PD. Such deficits, including those in graphic and metric misjudgments, can manifest in drawing tasks. Mental imagery is a recommended approach for PD rehabilitation with potential for ameliorating body schema. ObjectiveTo investigate the effect of a two-week dynamic neuro-cognitive imagery (DNI) training versus in-home learning and exercise control (learning/exercise) on pelvic schema and graphic representation (i.e., drawing height and width). DesignTwenty participants with idiopathic PD (Hoehn&Yahr I-III; M age: 65.75 ± 10.13) were randomly allocated into either a DNI or a learning/exercise group. Participants were asked to complete the “Draw Your Pelvisˮ test in which they drew their pelvis at pre- and post-intervention. Drawings were assessed for pelvic schema score and drawing dimensions (i.e., height and weight). InterventionDNI anatomical and metaphorical imagery focusing on pelvic anatomy and biomechanics. ResultsNo difference (p > .05) was detected at baseline between drawn pelvis height and width. Following intervention, improvements were greater in the DNI group for pelvic schema (p < .01), drawn pelvic width (p < .05) and width-height difference (p < .05). ConclusionsThis study suggests that DNI could serve as a rehabilitation path for improving body schema in people with PD. Future studies should explore DNI mechanisms of effect and the effect of enhanced pelvic schema on motor and non-motor deficits in this population.

Multi-scale, multi-depth lithography using optical fibers for microfluidic applications

This paper proposes and demonstrates a method for multi-scale, multi-depth three-dimensional (3D) lithography. In this method, 3D molds for replicating microchannels are fabricated by passing a non-focused laser beam through an optical fiber, whose tip is immersed in a droplet of photopolymer. Line width is adjustable from 1 to 980 µm using eight kinds of optical fibers with different core diameters. The height of line drawing can be controlled by adjusting the distance between the tip of the optical fiber and a substrate. The surface roughness (Ra, Rz) of a single line and plane was evaluated. The method was employed to fabricate a 3D mold of a microchannel containing tandem chambers, which was then successfully replicated in PDMS. Multi-scale, multi-depth 3D lithography can provide a simple, flexible tool for producing PDMS microfluidic devices.

Electromagnetic pulse-assisted incremental drawing forming of aluminum alloy cylindrical part and its control strategy

This paper explores a compound forming method of the cylindrical drawing by using the servo press forming combined with the electromagnetic pulse-assisted incremental drawing. The method comprises four steps: the punch press pre-drawing, electromagnetic pulse-assisted incremental drawing, punch shaping, and the final continuous punch drawing. By applying the four steps sequentially, the good drawing performance was achieved, and the maximum drawing height was of 3.4 times compared with that of the conventional punch drawing process, without changing the diameter of the punch. During the electromagnetic pulse-assisted incremental drawing process, the drawing coils, the corner coils, and the upper and bottom auxiliary coils generate the electromagnetic pulse force to help achieve the drawing of the metal sheet. The electromagnetic pulse-assisted incremental drawing step and the punch press deforming step were alternately carried out. In the electromagnetic pulse drawing step, by applying a two-time discharge using 13 and 14 kV in turn, the height of the drawing was improved, and the thinning rate of sheet metal was reduced. The application of the servo press and the computer numerical control system in the electromagnetic pulse-assisted incremental drawing process can effectively improve the processing efficiency and provides technical basis for the intelligent control of the electromagnetic pulse-assisted incremental drawing process.

Superplasticity and Micro-arrayed Deep-Drawing Behavior of Ni-Co/GO Nanocomposite

In this article, Ni-Co/GO nanocomposite was fabricated by AC pulse electrodeposition method. The room temperature strength tests and the superplasticity of the nanocomposite were investigated by the tensile tests. A 5 × 5 micro-arrayed deep-drawing die was designed to explore the feasibility of micro-forming. The as-deposited material has a narrow grain size distribution with a mean grain size of 50 nm. The addition of GO as a reinforcing phase can effectively enhance the room temperature tensile strength of the nanocomposite, but reduce the plasticity. When adding GO to the plating bath, a maximum elongation of 467% was observed for the specimen with a GO content of 0.01 g/L at 773 K and a strain rate of 1.67 × 10−3 s−1 by tensile tests. Micro-arrayed deep-drawing tests were subsequently performed with male die diameter of 0.58 mm and female die diameter of 0.8 mm. The experimental relative drawing height values were measured and compared with the deep-drawing parts without GO additive. It is found that the micro-arrayed deep-drawing with rigid male die at high temperature was feasible and forming parts with good shape could be got. The thickness distribution analysis of the deep-drawing parts showed that wall thickness changed ranging from 53 to 95 μm, and the thickness reduction at the punch fillet is the most obvious.

Analysis of Dominant Process Parameters in Deep-Drawing of Paperboard

The application of the wrinkle measuring method described in Muller et al. (2017) and the subsequent evaluation algorithm of a range of deep-drawn samples were used to determine the influences and interdependencies of blankholder force, tool temperatures, and drawing height on the formation of wrinkles in paperboard. The main influences were identified and quantitatively evaluated. For the given experimental space, a regression function was derived and validated in further experiments. It was shown that a quadratic regression was superior to the previously used linear regression. The findings were discussed and compared with the results of similar experiments from past publications. Special attention was given to the wrinkles formed and the resulting quality of the formed paperboard cups. The restrictions of the data acquisition from the measuring method that was used and limitations of the model were presented to demonstrate the reliability of the results.

Advances on Geometrical Limits in the Deep Drawing Process of Paperboard

The geometrical limits of the deep drawing process of paper to advanced shapes are not known. This report examines the technological limits of convex elements of the base shape in relation to the drawing height and shows the material behavior in the bottom radius of 3D shapes with regard to special material properties. In the bottom radius, non-compressed wrinkles occurred due to the in-plane compression, but wrinkles were reduced by an increased blank holder force or tool temperatures and improved extensibility or in-plane compressive strain. The forming ratio during deep drawing (drawing height related to base diameter) was increased to a value of more than 1 by a blank holder force, which increased with the drawing height such that the initial blank holder force was reduced concurrently. Straight sections in the base shape reduced the risk for ruptures in the edge radii of rectangular shapes, producing a forming ratio in these radii of 2.5. The forming ratio was further supported by a pattern of creasing lines at the blanks with a radial orientation and a number near the expected maximum number of wrinkles. The spring-back at rectangular shapes mainly depended on the drawing height and edge radius.