Design of an Electrically Assisted Manufacturing Process

2014 ◽  
pp. 245-253
Author(s):  
Wesley A. Salandro ◽  
Joshua J. Jones ◽  
Cristina Bunget ◽  
Laine Mears ◽  
John T. Roth
Keyword(s):  
Manufacturing Process ◽  
Electrically Assisted ◽  
Electrically Assisted Manufacturing

A Process Comparison of Simple Stretch Forming Using Both Conventional and Electrically-Assisted Forming Techniques

2010 ◽  
Author(s):  
Joshua J. Jones ◽  
Laine Mears
Keyword(s):  
Sheet Metal ◽  
Manufacturing Process ◽  
Electrical Current ◽  
Stretch Forming ◽  
Forming Process ◽  
Process Comparison ◽  
Directional Flow ◽  
Direct Electrical Current ◽  
Electrically Assisted ◽  
Electrically Assisted Manufacturing

A common manufacturing process typically used to create large surface contours in sheet metal is stretch forming. With this process, the ability to create geometrically accurate parts and smooth surfaces is achievable, yet there are certain limits when considering the achievable elongation of the material and the inability to produce sharp contours in the sheet metal. Present research using Electrically-Assisted Manufacturing (EAM) has shown that applying direct electrical current to the workpiece during the forming process can increase the formability and reduce springback of the material, while also lowering the required forming forces. Seeing the advantageous qualities of EAM, this study examines the use of EAM for a simple stretch forming process. Specifically, this research examines this stretch forming process with regards to how the location where the electrical current is applied to the material affects the process, the achievable forming depth without fracture, and the application direction of the current. Overall results displayed that the directional flow of electrical current and the application location did not affect the obtained forming forces or forming depths using EAM.

Force Controlled Electrical Pulse Assisted Forming

2020 ◽  
Author(s):  
Tyler J. Grimm ◽  
Amit B. Deshpande ◽  
Laine Mears ◽  
Jianxun Hu
Keyword(s):  
Control Systems ◽  
Stress Level ◽  
Stress Reduction ◽  
Power Supply ◽  
Electrical Current ◽  
Strain Rates ◽  
Control Approach ◽  
Electrically Assisted ◽  
Minimum Stress ◽  
Electrically Assisted Manufacturing

Abstract Electrically-assisted manufacturing refers to the direct application of electrical current to a workpiece during a manufacturing process. This assistance results in several benefits such as flow stress reduction, increased elongation, reduced springback, increased diffusion, and increased precipitation control. These effects are also associated with traditional thermal assistance. However, for over half a decade it has been argued whether or not these observed effects are due to electroplasticity, a term which describes effects that cannot be fully explained through resistive heating. Several theories have been proposed as to the mechanism responsible for these purported athermal effects. Conflicting results within literature have enabled this debate over electroplasticity since its discovery in the mid 20th century. While the effects of electrically-assisted manufacturing are clearly characterized throughout literature, there is a lack of research related to control systems which may be used to take advantage of its effects. Typically, control systems are developed using an empirical approach, requiring extensive testing in order to fully characterize the stress-strain behavior at all conditions. Additionally, current research has primarily focused on reducing flow stresses during electrically-assisted processes without regard for the strength of the material subsequent to forming. Therefore, there is a strong need for a control system which can quickly be deployed for new materials and does not significantly reduce the subsequent strength of the material. Herein, a novel control approach is developed in which electrical pulses are triggered by a predetermined stress level. This stress value would be set according to the manufacturer’s stamping die strength. Once the material reaches this stress value, current is deployed until a minimum stress level is reached. At that point, the electricity is turned off and the material allowed to cool; at that stage the stress begins to elevate and the cycle continues. This approach does not require extensive pre-testing and is robust to a range of strain rate. This type of implementation can also be adapted to different levels of capability. For example, since the current is controlled by force and not by time, a low-current power supply will stay on for each pulse longer than a power supply with higher capabilities; however, each will achieve a similar effect. This study investigates the effect of several different minimum stress levels and strain rates. The strain rates chosen are relatively similar to common stamping process. This system was experimentally tested using 1018 CR steel. This control approach was found to be a successful method of maintaining a desired stress level.

A Review of Electrically-Assisted Manufacturing With Emphasis on Modeling and Understanding of the Electroplastic Effect

2017 ◽  
Vol 139 (11) ◽  
Author(s):  
Brandt J. Ruszkiewicz ◽  
Tyler Grimm ◽  
Ihab Ragai ◽  
Laine Mears ◽  
John T. Roth
Keyword(s):  
Fuel Economy ◽  
Elastic Recovery ◽  
Fuel Efficiency ◽  
High Strength ◽  
Carbon Steels ◽  
Metallic Materials ◽  
Low Carbon ◽  
Electroplastic Effect ◽  
Electrically Assisted ◽  
Electrically Assisted Manufacturing

Increasingly strict fuel efficiency standards have driven the aerospace and automotive industries to improve the fuel economy of their fleets. A key method for feasibly improving the fuel economy is by decreasing the weight, which requires the introduction of materials with high strength to weight ratios into airplane and vehicle designs. Many of these materials are not as formable or machinable as conventional low carbon steels, making production difficult when using traditional forming and machining strategies and capital. Electrical augmentation offers a potential solution to this dilemma through enhancing process capabilities and allowing for continued use of existing equipment. The use of electricity to aid in deformation of metallic materials is termed as electrically assisted manufacturing (EAM). The direct effect of electricity on the deformation of metallic materials is termed as electroplastic effect. This paper presents a summary of the current state-of-the-art in using electric current to augment existing manufacturing processes for processing of higher-strength materials. Advantages of this process include flow stress and forming force reduction, increased formability, decreased elastic recovery, fracture mode transformation from brittle to ductile, decreased overall process energy, and decreased cutting forces in machining. There is currently a lack of agreement as to the underlying mechanisms of the electroplastic effect. Therefore, this paper presents the four main existing theories and the experimental understanding of these theories, along with modeling approaches for understanding and predicting the electroplastic effect.

scholarly journals Electrically-Assisted Manufacturing for Reduction in Forging Forces of Bearing Steels

2020 ◽  
Vol 48 ◽  
pp. 349-357
Author(s):  
Christopher D. Lang ◽  
C.R. Hasbrouck ◽  
Austin S. Hankey ◽  
Paul C. Lynch ◽  
Bryan D. Allison ◽  
...  
Keyword(s):  
Bearing Steels ◽  
Electrically Assisted ◽  
Electrically Assisted Manufacturing

The Microstructural Effects on Magnesium Alloy AZ31B-O While Undergoing an Electrically-Assisted Manufacturing Process

2009 ◽  
Author(s):  
Timothy A. McNeal ◽  
Jeffrey A. Beers ◽  
John T. Roth
Keyword(s):  
Deformation Process ◽  
Microstructural Analysis ◽  
High Strength ◽  
Strength Properties ◽  
High Demand ◽  
Electrically Assisted ◽  
Magnesium Alloy Az31b ◽  
Microstructural Effects ◽  
Lightweight Alloys ◽  
Electrically Assisted Manufacturing

In today’s industry, the need for lightweight alloys with high strength properties is growing. More specifically, magnesium alloys are in high demand. Unfortunately, magnesium’s limited formability hinders its broad range applicability. Previous research has discovered that the tensile formability of this alloy can be increased using electrical pulsing during the deformation process, referred to as Electrically-Assisted Manufacturing (EAM). Although this method increases a material’s formability (i.e. lowers flow stress, increases elongation, and reduces springback), a detailed analysis is required to further evaluate the effects of electricity on the material’s microstructure. The research herein will examine the microstructure of Magnesium AZ31B-O specimens that were deformed under uniaxial tension while electrically pulsed with various pulsing parameters (i.e. different current density/pulse duration combinations). This microstructural analysis will focus on how EAM affected grain size, grain orientation, and twinning. The microstructure of the following different specimen types will be compared: deformed EAM specimens, deformed non-pulsed baseline specimens, and undeformed non-pulsed “as received” specimens.

Applications of Electrically Assisted Manufacturing

2014 ◽  
pp. 255-311
Author(s):  
Wesley A. Salandro ◽  
Joshua J. Jones ◽  
Cristina Bunget ◽  
Laine Mears ◽  
John T. Roth
Keyword(s):  
Electrically Assisted ◽  
Electrically Assisted Manufacturing

Influence of Continuous Direct Current on the Microtube Hydroforming Process

2016 ◽  
Vol 139 (3) ◽  
Author(s):  
Scott W. Wagner ◽  
Kenny Ng ◽  
William J. Emblom ◽  
Jaime A. Camelio
Keyword(s):  
High Pressures ◽  
Tube Hydroforming ◽  
Electrical Current ◽  
Deformation Energy ◽  
Recrystallization Temperature ◽  
Machining Processes ◽  
Electrically Assisted ◽  
Stainless Steel 304 ◽  
Hydroforming Process ◽  
Electrically Assisted Manufacturing

Research of the microtube hydroforming (MTHF) process is being investigated for potential medical and fuel cell applications. This is largely due to the fact that at the macroscale the tube hydroforming (THF) process, like most metal forming processes, has realized many advantages, especially when comparing products made using traditional machining processes. Unfortunately, relatively large forces compared to part size and high pressures are required to form the parts so the potential exists to create failed or defective parts. One method to reduce the forces and pressures during MTHF is to incorporate electrically assisted manufacturing (EAM) and electrically assisted forming (EAF) into the MTHF. The intent of both EAM and EAF is to use electrical current to lower the required deformation energy and increase the metal's formability. To reduce the required deformation energy, the applied electricity produces localized heating in the material in order to lower the material's yield stress. In many cases, the previous work has shown that EAF and EAM have resulted in metals being formed further than conventional forming methods alone without sacrificing the strength or ductility. Tests were performed using “as received” and annealed stainless steel 304 tubing. Results shown in this paper indicate that the ultimate tensile strength and bust pressures decrease with increased current while using EAM during MTHF. It was also shown that at high currents the microtubes experienced higher temperatures but were still well below the recrystallization temperature.

Thermo-Mechanical Investigations of the Electroplastic Effect

2011 ◽  
Author(s):  
Wesley A. Salandro ◽  
Cristina Bunget ◽  
Laine Mears
Keyword(s):  
Cold Work ◽  
Electrical Energy ◽  
Thermal Softening ◽  
Manufacturing Processes ◽  
Electroplastic Effect ◽  
Forming Load ◽  
Commercially Pure ◽  
Electrically Assisted ◽  
Grade 5 ◽  
Electrically Assisted Manufacturing

Recent development of Electrically-Assisted Manufacturing processes proved the advantages of using the electric current, mainly related with the decrease in the mechanical forming load and improvement in the formability when electrically-assisted forming of metals. The reduction of forming load was formulated previously assuming that a part of the electrical energy input is dissipated into heat, thus producing thermal softening of the material, while the remaining component directly aids the plastic deformation. The fraction of electrical energy applied that assists the deformation process compared to the total amount of electrical energy is given by the electroplastic effect coefficient. The objective of the current research is to investigate the complex effect of the electricity applied during deformation, and to establish a methodology for quantifying the electroplastic effect coefficient. Temperature behavior is observed for varying levels of deformation and previous cold work. Results are used to refine the understanding of the electroplastic effect coefficient, and a new relationship, in the form of a power law, is derived. This model is validated under independent experiments in Grade 2 (commercially pure) and Grade 5 (Ti-6Al-4V) titanium.

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