scholarly journals Reconfigurable Multipoint Forming Using Waffle-Type Elastic Cushion and Variable Loading Profile

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4506
Author(s):  
Mohammed Moheen ◽  
Adel Abdel-Wahab ◽  
Hany Hassanin ◽  
Khamis Essa
Keyword(s):  
Process Parameters ◽  
Fem Analysis ◽  
Thickness Variation ◽  
Variable Loading ◽  
Shape Deviation ◽  
Multipoint Forming ◽  
Base Radius ◽  
Manufacturing Techniques ◽  
Elastic Cushion ◽  
Reconfigurable Die

There is an increasing demand for flexible, relatively inexpensive manufacturing techniques that can accommodate frequent changes to part design and production technologies, especially when limited batch sizes are required. Reconfigurable multi-point forming (MPF) is an advanced manufacturing technique which uses a reconfigurable die consisting of a set of moveable pins to shape sheet metal parts easily. This study investigates the use of a novel variable thickness waffle-type elastic cushion and a variable punch-loading profile to either eliminate or minimise defects associated with MPF, namely wrinkling, thickness variation, shape deviation, and dimpling. Finite element modelling (FEM), analysis of variance (ANOVA), and the response surface methodology (RSM) were used to investigate the effect of process parameters pertaining to the cushion dimensions and type of loading profile on the aforementioned defects. The results of this study indicate that the most significant process parameters were maximum cushion thickness, cushion cut-out base radius, and cushion cut-out profile radius. The type of loading profile was found to be insignificant in all responses, but further investigation is required as the rate, and the thermal effects were not considered in the material modelling. Optimal process parameters were found to be a maximum cushion thickness of 3.01 mm, cushion cut-out base radius of 2.37 mm, cushion cut-out profile radius of 10 mm, and a “linear” loading profile. This yielded 0.50 mm, 0.00515 mm, 0.425 mm for peak shape deviation, thickness variation, and wrinkling, respectively.

scholarly journals Technological Shells in the Processes of Rolling Thin Sheets From Hard-To-Deform Materials

2021 ◽  
Author(s):  
Denis R Salikhyanov ◽  
Ivan Kamantsev
Keyword(s):  
Stress State ◽  
Tool Steel ◽  
Process Parameters ◽  
Fe Simulation ◽  
Rolling Force ◽  
High Hardness ◽  
Thickness Variation ◽  
Rolled Sheet ◽  
Total Reduction ◽  
Low Efficiency

Abstract The present work is devoted to the study of deformability of high-strength and hard-to-deform materials. Today the most promising technology for their forming is a rolling in a ductile shell also known as sandwich rolling. Despite the fact that the use of such technological shells allows to effectively reduce the rolling forces and soften the stress state, they have not got wide application in manufacturing practice due to the accompanying disadvantages. On the basis of finite element (FE) simulation, we carried out an all-around analysis of the effect of shell material on process parameters of method: rolling force, total reduction of hard-to-deform material, deformation inhomogeneity and thickness variation of rolled sheet, stress state scheme. Analysis of computer models allowed us to highlight the main reason for the low efficiency of the known method and propose a new design of technological shells. Preliminary FE-simulation of the rolling process of hard-to-deform material in the new technological shells showed an improvement in process parameters and method efficiency. Approbation was carried out via rolling U12 high-carbon tool steel (Russian analogue of DIN C110W2 tool steel), which has low plasticity and high hardness, on the rolling mill Duo 250 under laboratory conditions. Evaluation according to technological criteria – reducing the rolling force, increase of the total reduction and the deformation uniformity of hard-to-deform material, improvement of its deformability – showed the prospects of using proposed technological shells in manufacturing practice.

scholarly journals Investigation of a plain ball burnishing process on differently machined Aluminium EN AW 2007 surfaces

2018 ◽  
Vol 190 ◽  
pp. 11005 ◽  
Author(s):  
Marco Posdzich ◽  
Rico Stöckmann ◽  
Florian Morczinek ◽  
Matthias Putz
Keyword(s):  
Surface Roughness ◽  
Process Parameters ◽  
Process Development ◽  
Fem Simulation ◽  
Initial Surface ◽  
Shape Deviation ◽  
Finishing Process ◽  
Path Distance ◽  
Burnishing Process

Burnishing is an effective chipless finishing process for improving workpiece properties: hardness, vibration resistance and surface quality. The application of this technology is limited to rotationally symmetrical structures of deformable metals. Because of the multiaxial characteristics, the transfer of this force controlled technology on to prismatic shapes requires a comprehensive process development. The main purpose of this paper is the characterization of a plain burnishing process on aluminium EN AW 2007 with a linear moved, spherical diamond tool. The method of design of experiments was used to investigate the influence of different machined surfaces in conjunction with process parameters: burnishing force, burnishing direction, path distance and burnishing speed. FEM simulation was utilized for strain and stress analysis. The experiments show, that unlike the process parameters the initial surface roughness as 3rd order shape deviation does not have a significant influence on the finished surface. Furthermore a completely new surface is created by the process, with properties independent from the initial surface roughness.

Effect of Double Sided Process Parameters in Lapping Silicon Wafer

2013 ◽  
Vol 393 ◽  
pp. 259-265 ◽  
Author(s):  
Abdul Rahim Mahamad Sahab ◽  
Nor Hayati Saad ◽  
Amirul Abdul Rashid ◽  
Yusoff Noriah ◽  
Nassya Mohd Said ◽  
...  
Keyword(s):  
Silicon Wafer ◽  
Process Parameters ◽  
Integrated Circuit ◽  
Quality Standard ◽  
Wafer Surface ◽  
Thickness Variation ◽  
Total Thickness ◽  
Hard And Brittle Material ◽  
Total Thickness Variation ◽  
Lapping Machine

Silicon wafer is widely used in semiconductor industries for development of sensors and integrated circuit in computer, cell phones and wide variety of other devices. Demand on the device performance requires flatter wafer surface, and less dimensional wafer variation. Prime silicon wafer is hard and brittle material. Due to its properties, double sided lapping machine with ceramic grinding agent were introduced for machining high quality standard silicon wafers. The main focus is the silicon wafer with high accuracy of flatness; to reduce total thickness variation, waviness and roughness. In this paper the lapping experiment and analysis showed that the double sided lapping machine is able to produce total thickness variation less than 10 um at controlled process parameters within short processing time. Machining using low mode method reduced the total thickness variation (TTV) value. The lapping load and speed directly reflected the performance and condition of final silicon wafer quality.

FEM Analysis of Helical Rolling of Steel Balls

2013 ◽  
Vol 572 ◽  
pp. 525-528 ◽  
Author(s):  
Zbigniew Pater
Keyword(s):  
Process Parameters ◽  
Effective Strain ◽  
Fem Analysis ◽  
Helical Rolling ◽  
Damage Criterion ◽  
Advantages And Disadvantages ◽  
Roll Wear ◽  
Software Program ◽  
Steel Balls

In this paper, two helical rolling processes for producing balls with a diameter of 40 mm are compared – the traditionalrolling and wedge rolls rolling. The process analyses were performed using Simufact.Forming, a FEM-based software program, and the same process parameters were applied in the analyses. Based on the calculations results (the distributions of effective strain, damage criterion, roll wear as well as the variations of forces and rolling moments during the processes), advantages and disadvantages of the considered rolling methods could be presented.

Modeling and Analysis of Material Removal Characteristics in Silicon Wafer Double Side Polishing

2012 ◽  
Vol 516 ◽  
pp. 384-389
Author(s):  
Sang Jik Lee ◽  
Hyoung Jae Kim ◽  
Hae Do Jeong
Keyword(s):  
Integrated Circuits ◽  
Process Parameters ◽  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Thickness Variation ◽  
Modeling And Analysis ◽  
Profile Variation ◽  
Friction Energy ◽  
Wafer Edge

As advancing technologies increase the demand for yield and planarity in integrated circuits, wafers have become larger and their specifications more stringent. Flatness, thickness variation and nanotopography have emerged as important concerns in the wafering process. Double side polishing has been adopted as a solution to these problems. This paper focuses on the material removal characteristics and wafer profile variation during Si double side polishing. A polishing experiment to investigate Si removal characteristics according to process parameters was carried out in a single head rotary polisher equipped with a monitoring system for friction force. It was found that the material removal rate is related to friction energy rate, and the polishing state was transited and divided into three conditions according to pressure. On the basis of the experimental results, the wafer profile variation in double side polishing was modelled and simulated according to pressure. The friction energy was calculated to find the material removal amount across the wafer. With the conversion of calculated friction energy to the material removal amount, wafer profile variation was simulated. As a result, the wafer profile variation and its range were increased with a pressure increase, and originated from the position near the wafer edge.

Experimental Investigation of Temperature Distribution during Wire-Based Laser Metal Deposition of the Al-Mg Alloy 5087

2018 ◽  
Vol 941 ◽  
pp. 988-994 ◽  
Author(s):  
Martin Froend ◽  
Frederic E. Bock ◽  
Stefan Riekehr ◽  
Nikolai Kashaev ◽  
Benjamin Klusemann ◽  
...  
Keyword(s):  
Process Parameters ◽  
Large Scale ◽  
Substrate Material ◽  
Metal Deposition ◽  
Temperature Evolution ◽  
Laser Metal Deposition ◽  
Deposition Rates ◽  
Excessive Heat ◽  
Manufacturing Techniques ◽  
The Individual

Wire-based laser metal deposition enables to manufacture large-scale components with deposition rates significant higher compared to powder-based laser additive manufacturing techniques, which are currently working with deposition rates of only a few hundred gram per hour. However, the wire-based approach requires a significant amount of laser power in the range of several kilowatts instead of only a few hundred watts for powder-based processes. This excessive heat input during laser metal deposition can lead to process instabilities such as a non-uniform material deposition and to a limited processability, respectively. Although, numerous possibilities to monitor temperature evolution during processing exist, there is still a lack of knowledge regarding the relationship between temperature and geometric shape of the deposited structure. Due to changing cooling conditions with increasing distance to the substrate material, producing a wall-like structure results in varying heights of the individual tracks. This presents challenges for the deposition of high wall-like structures and limits the use of constant process parameters. In the present study, the temperature evolution during laser metal deposition of AA5087 using constant process parameters is investigated and a scheme for process parameter adaptions in order to reduce residual stress induced componential distortions is suggested.

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