Electromagnetic Embossing of Optical Microstructures

2016 ◽  
Vol 4 (2) ◽  
Author(s):  
Lasse Langstädtler ◽  
Lars Schönemann ◽  
Christian Schenck ◽  
Bernd Kuhfuss

Electromagnetic forming (EMF) is a high-speed forming process that is already established in the macroworld. Due to its advantages like high deformation rate and cheaper tools, it is introduced to microforming. In this research, the replication of prismatic optical microstructures is investigated. EN AW-1050A (Al99.5) micrometal sheets with a thickness of 50 μm and 300 μm are electromagnetically micro-embossed. With this technique, it is possible to successfully replicate triangular cross section micro V-grooves of 86.6 μm in width and 24.1 μm in depth with an average surface roughness of Sa = 44 nm. The microstructures of the embossing tool are generated by diamond micro chiseling (DMC), a novel machining process to produce microstructures with discontinuous geometry, like miniature cube corner retro reflectors and V-grooves with well-defined endings.

2014 ◽  
Vol 792 ◽  
pp. 115-120 ◽  
Author(s):  
Pál Rácz ◽  
Nándor Göbl ◽  
Daniel Horváth ◽  
Athanasios G. Mamalis

Electromagnetic forming is a high speed forming process, wherein the forming pressure is created by high energy density electromagnetic pulse. Besides direct shaping there are other application areas as well, so electromagnetic plastic forming is a potential field of creating joints between tube and rod-like components. Connecting components of dissimilar materials is an increasing demand in the manufacturing process of structures in the automotive industry. The application of new technologies, such as electrodynamic, especially electromagnetic forming, is a possible method to satisfy these demands. The article summarizes the most important fundamentals of electromagnetic forming; in particular, tube-rod joints, the main types of such joints; interference-fit and form-fit joints are described. Experiments, which were carried out producing tube-rod joints with electromagnetic forming, are also introduced. A new type of form-fit joints for tube-rod connections has been developed, which can withstand not only tensile loads but also torsion. Experiments and mechanical tests have proved the applicability of this kind of joints.


Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 611
Author(s):  
Ambarish Kulkarni ◽  
Vispi Karkaria ◽  
Milankumar Nandgaonkar ◽  
Sandeep P. Patil ◽  
Bernd Markert

The high-speed forming process is the key to attaining difficult and irregular profiles on ductile materials. In the present work, we proposed the all-atom model of the gas detonation forming process, wherein molecular dynamics (MD) simulations were performed on the aluminum workpiece at different loading speeds similar to the various pressure values in the process. The deformation response of an aluminum workpiece for a wide range of loading speeds, 0.1–8 Å/ps, was investigated. The dome-height, failure patterns, and formability of the aluminum workpiece were examined for these loading speeds. We obtained an inverse relationship between the formability of the aluminum workpiece and the applied loading speed. Moreover, in this work, the influence of the different percentage of defects in the workpieces on the mechanical behavior was investigated. We observed that at lower speeds (< 2 Å/ps), the deformation is observed throughout the workpiece starting from the point of contact in the middle and that is contrary to the deformations observed due to the higher loading speed where localized deformations occur due to creation of slipping planes. We also found that the internal voids lead to the rearrangement of atoms to facilitate the movement of slipping planes leading to better formability compared to the no-void workpieces. This work helps to get a fundamental understanding of deformation behavior in the high-speed forming process with and without defects in the aluminum workpiece at the nanoscale.


2013 ◽  
Vol 554-557 ◽  
pp. 741-748 ◽  
Author(s):  
Joao Pedro M. Correia ◽  
Saïd Ahzi

Electromagnetic forming is a non-conventional forming process and is classified as a high-speed forming process. It provides certain advantages as compared to conventional forming processes: improved formability, high repeatability and productivity, reduction in tooling cost and reduction of springback and of wrinkling. However, various process parameters affect the performance of the electromagnetic forming system. Finite element simulations are very useful to optimize a process because they can reduce time and costs. With the aim of investigating the effects of the process parameters on the deformed blank geometry, finite element simulations of an electromagnetic sheet bulging test have been performed in this work. Furthermore the role of first impulse of discharged current is also investigated.


2014 ◽  
Vol 592-594 ◽  
pp. 894-898
Author(s):  
K. Sriram ◽  
Karibeeran Shanmuga Sundaram ◽  
P. Arumugam

Forming processes are defined as to modify the shape of a work piece by deforming it, without the removal of material. To overcome a number of longstanding problems in conventional forming methods such as low production rates, difficulty in forming light weight components etc., an alternate approach of electromagnetic forming process is introduced. Electromagnetic forming (EMF) is a high speed forming process used to form thinwalled work pieces (usually sheets and tubes) that have high electrical conductivity, such as aluminium, copper etc. Electromagnetic tube compression processes, the design of an experimental set up for electromagnetic tube compression process are discussed in detail in this paper


2021 ◽  
Vol 871 ◽  
pp. 80-86
Author(s):  
Ya Nan Wei ◽  
Fei Fei Zhang ◽  
Bo Wei ◽  
Hui Xu ◽  
Kai He

Electrohydraulic forming (EHF) is a kind of high speed forming process, which deforms the metal by shock wave through instantaneous discharge of high voltage in water. Compared with the traditional forming methods, this high speed forming process can greatly improve the formability of the materials. There are many processing factors that affect the forming efficiency and performance of the electrohydraulic forming process, one of which is the discharge voltage between the electrodes. In this paper, three electrohydraulic forming experiments with various die shapes were carried out under various discharge voltage conditions. And the bulge height and axial length of the aluminum alloy A6061 tubes under different conditions were compared. Besides, finite element numerical simulation was also performed to quantitatively investigate the deformation history of the tube.


2012 ◽  
Vol 217-219 ◽  
pp. 2187-2193 ◽  
Author(s):  
Mohammad Yeakub Ali ◽  
A. R. Mohamed ◽  
Banu Asfana ◽  
Mohamed Lutfi ◽  
M. I. Fahmi

This paper presents the vibration and surface roughness issue of poly methyl methacrylate (PMMA) workpiece produced by micro end milling using integrated multi-process machine tools DT 110 (Mikrotools Inc., Singapore) with control parameter; spindle speed, feed rate, and depth of cut. The vibration was measured using accelerometer, DYTRAN Instrument and the average surface roughness Ra was measured using Wyko NT1100. The optimum solution for minimum average vibration is 64.3 Hz with spindle speed 3000 rpm, feed rate 2 mm/min, and depth of cut 1.5 μm. However, the optimum solution for minimum average surface roughness, Ra is 0.352 μm with spindle speed 2000 rpm, feed rate 2 mm/min, and depth of cut 1.5 μm. The micro end milling parameters are suitable to machine PMMA to get good precision surface roughness. The analysis revealed that the feed rate and depth of cut is the most influential parameter on vibration during machining process meanwhile for average surface roughness, Ra spindle speed is the most influential parameter.


Author(s):  
Kishor Kumar Gajrani ◽  
Rokkham Pavan Kumar Reddy ◽  
Mamilla Ravi Sankar

In machining process, cutting fluids are used to reduce the tool–chip interface temperature and forces, but it causes various health hazards to machine operators as well as increases the associated costs. To improve machining sustainability, researchers are trying to reduce or eliminate cutting fluid usage during machining by various other techniques (development of better tool material, bio-cutting fluids, use of vegetable oils, near-dry machining, process optimization, surface coatings, etc). In recent years, several researchers applied controlled surface modification (surface texturing/engineering) at the tool–chip interface to improve the tribological properties in the machining performance. In the present study, first mechanical microtextures (MµT) are created on the rake surface, and its structural stability is compared with an untextured/virgin cutting tool. The static structural analyses show a negligible effect of mechanical microtextures on the strength of the cutting tool. Afterwards, MµT cutting tools are coated using molybdenum disulphide (MoS2) solid lubricant (i.e. coated MµT, C-MµT). Subsequently, the machining performance studies of C-MµT were carried out to show its advantages over two other types of cutting tools (UC, MµT). Performance of C-MµT is improved by mechanical microtextures (due to the reduction in the actual contact area between tool–chip interfaces) and proper lubrication of the tool–chip contact area. Thus, due to the reduced contact area and formation of lubricant layer by MoS2 at the tool–chip interface, C-MµT experiences 23.75% lower tool–chip interface temperature, 41.06% reduction in the cutting force, and produces 14.37% less workpiece center line average surface roughness ( Ra) compared to untextured cutting tool. C-MµT experiences 9.55% lower tool–chip interface temperature, 19.02% reduction in the cutting force, and produces 5.34% less workpiece center line average surface roughness compared to the MµT cutting tool. Hence, C-MµT cutting tools are the viable alternative to untextured cutting tools.


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