Effect of Die Geometry Properties on Forming of Micro-Parts by Forward-Backward Extrusion of 6063 Aluminum Alloy

2014 ◽  
Author(s):  
N. Takatsuji ◽  
K. Dohda ◽  
T. Funazuka
Keyword(s):  
Grain Size ◽  
Size Effects ◽  
High Viscosity ◽  
Scale Level ◽  
Die Geometry ◽  
Dlc Coating ◽  
Test Pieces ◽  
Micro Parts ◽  
6063 Aluminum Alloy ◽  
Micro Features

The recent trend towards miniaturization of products and technology has boosted a strong demand for such metallic micro-parts with micro features and high tolerances. Conventional forming technologies, such as extrusion and drawing, have encountered new challenges at the micro-scale level due to the ‘size effects’ that tends to be predominant at this scale level. Friction is one of the predominant factors exercising strong effects in micro-forming. Previous studies varied grain size of the test pieces in order to examine size effects in micro-extrusion. In addition, the effects on the extrusion load, forming shape, as well as hardness of different grain sizes, die coatings and lubricants were compared. DLC coating has been proven effective as a die coating. Increasing grain size was effective with lubricants having high viscosity. In this study, the effect of different die Properties is compared and examined.

Influence of Tribological Condition on Construction of Minute Parts in Micro-Meso Extrusion of A6063 Alloy

2014 ◽  
Vol 966-967 ◽  
pp. 336-343 ◽  
Author(s):  
Norio Takatsuji ◽  
Kuniaki Dohda ◽  
Tatsuya Funazuka
Keyword(s):  
Grain Size ◽  
Size Effects ◽  
High Viscosity ◽  
Micro Forming ◽  
Scale Level ◽  
Grain Sizes ◽  
Dlc Coating ◽  
Test Pieces ◽  
Micro Parts ◽  
Micro Features

The recent trend towards miniaturization of products and technology has boosted a strong demand for such metallic micro-parts with micro features and high tolerances. Conventional forming technologies, such as extrusion and drawing, have encountered new challenges at the micro-scale level due to the ‘size effects’ that tends to be predominant at this scale level. Friction is one of the predominant factors exercising strong effects in micro-forming. Previous studies varied grain size of the test pieces in order to examine size effects in micro-extrusion. In addition, the effects on the extrusion load, forming shape, as well as hardness of different grain sizes, die coatings and lubricants were compared. DLC coating has been proven effective as a die coating. Increasing grain size was effective with lubricants having high viscosity. In this study, the effect of different die angles and lubricants is compared and examined.

Effects of Specimen Diameter on Microstructure and Microhardness of Hot Extruded AZ31B Magnesium Alloy

2014 ◽  
Vol 1004-1005 ◽  
pp. 158-162 ◽  
Author(s):  
Xiang Ting Hong ◽  
Fu Chen ◽  
Fei Chen ◽  
Wang Yu ◽  
Bo Rong Sang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Magnesium Alloy ◽  
Size Effects ◽  
Strain Distribution ◽  
Elevated Temperatures ◽  
Az31b Magnesium Alloy ◽  
Specimen Diameter ◽  
Average Grain Size ◽  
Micro Parts

Microstructures of metal micro parts after microforming at elevated temperatures must be evaluated due to mechanical properties depend on average grain size. In this work, the effects of specimen diameter on the microstructure and microhardness of a hot-extruded AZ31B magnesium alloy were studied. Obvious size effect on microstructure and microhardness of the alloy could be observed. The size effects could be explained by strain distribution and dislocation density differences between the two kinds of specimens.

Study of Size Effects on Deformation Behavior and Formability in Micro Metal Forming of Ti Foil

2012 ◽  
Author(s):  
Jie Xu ◽  
Bin Guo ◽  
Debin Shan ◽  
Baishun Li
Keyword(s):  
Grain Size ◽  
Flow Stress ◽  
Size Effects ◽  
Deep Drawing ◽  
Metal Forming ◽  
Deformation Behavior ◽  
Foil Thickness ◽  
Micro Scale ◽  
Micro Deep Drawing ◽  
Micro Parts

Micro forming technology becomes a promising approach to fabricate micro-parts due to its advantages of high productivity, low production cost, good product quality and mechanical properties, and near net or net shape characteristics. However, the deformation behaviors of material change and the so-called size effect occurs when the part dimension is decreased to micro-scale. To analyze the quality of micro-parts, the material flow stress, anisotropy, ductility and formability in micro-scale need to be considered. In the paper, micro tensile and micro deep drawing tests of Ti foils were used and the size effects on deformation behavior and formability of micro sheet metal forming were studied. The results show that the flow stress of Ti foils is related with foil thickness and grain size. The fracture behaviors also have been changed from shear dimple to slip separation with the decrease of foil thickness. The formability of micro deep drawing becomes worse with the decrease of micro cup dimension and the increase of grain size.

scholarly journals Investigation of Size Effects in Multi-Stage Cold Forming of Metallic Micro Parts from Sheet Metal

Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1561
Author(s):  
Martin Kraus ◽  
Marion Merklein
Keyword(s):  
Grain Size ◽  
Sheet Metal ◽  
Size Effects ◽  
Functional Integration ◽  
Ultrafine Grain ◽  
Cold Forming ◽  
Research Activities ◽  
Multi Stage ◽  
Micro Parts ◽  
Increasing Demand

Product miniaturisation and functional integration are currently global trends to save weight, space, materials and costs. This leads to an increasing demand for metallic micro components. Thus, the development of appropriate production technologies is in the focus of current research activities. Due to its efficiency, accuracy and short cycle times, microforming at room temperature offers the potential to meet the steadily increasing demand. During microforming, size effects occur which negatively affect the part quality, process stability, tool life and handling. Within this contribution, a multi-stage bulk microforming process from sheet metal is investigated for the materials Cu-OFE and AA6014 with regard to the basic feasibility and the occurrence of size effects. The results reveal that the process chain is basically suitable to produce metallic micro parts with a high repeatability. Size effects are identified during the process. Since several studies postulate that size effects can be minimised by scaling down the metallic grain structure, the grain size of the aluminium material AA6014-W is scaled down to less than one micrometre by using an accumulative roll bonding process (ARB). Subsequently, the effects of the ultrafine grain (UFG) structure on the forming process are analysed. It could be shown that a strengthened material state increases the material utilization. Furthermore, too soft materials can cause damage on the part during ejection. The occurring size effects cannot be eliminated by reducing the grain size.

scholarly journals Understanding Size Effects and Forming Limits in the Micro-Stamping of Industrial Stainless Steel Foils

Metals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 38
Author(s):  
Matthias Weiss ◽  
Peng Zhang ◽  
Michael P. Pereira ◽  
Bernard F. Rolfe ◽  
Daniel E. Wilkosz ◽  
...  
Keyword(s):  
Grain Size ◽  
Stainless Steel ◽  
Size Effects ◽  
Bipolar Plate ◽  
Forming Limits ◽  
Tool Profile ◽  
Steel Processing ◽  
The Individual ◽  
Stainless Steel Foils ◽  
Steel Foils

This study investigates the effect of grain size and composition on the material properties and forming limits of commercially supplied stainless steel foil for bipolar plate manufacture via tensile, stretch forming and micro-stamping trials. It is shown that in commercially supplied stainless steel the grain size can vary significantly and that ‘size effects’ can be influenced by prior steel processing and composition effects. While the forming limits in micro-stamping appear to be directly linked to the plane strain forming limits of the individual stainless steel alloys, there was a clear effect of the tensile anisotropy. In contrast to previous studies, forming severity and the likelihood of material failure did not increase with a decreasing channel profile radius. This was related to inaccuracies of the forming tool profile shape.

Scale-Dependent Crack Modeling for Investigation the Effect of Geometrically Necessary Dislocations in Micro/Nano Grain Size of Copper

2016 ◽  
Vol 15 ◽  
pp. 1-16 ◽  
Author(s):  
Amin Zaami ◽  
Ali Shokuhfar
Keyword(s):  
Grain Size ◽  
Stress Concentration ◽  
Strain Gradient ◽  
Stress Concentration Factor ◽  
Size Effects ◽  
Crack Tip ◽  
Length Scale ◽  
State Variables ◽  
Dependent Model ◽  
Homogeneous Strain

In this study, a scale-dependent model is employed to investigate the size effects of copper on the behavior of the crack-tip. This model includes the homogeneous and non-homogeneous strain hardening based on the wavelet interpretation of size effect. Introducing additional micro/nano structural considerations together with decreasing grain size, different size effects can be obtained. As the size dependency is not taken into account in conventional plasticity, an enhanced theory which is related to the strain gradient introduces a length scale will give more realistic representations of state variables near the crack-tip. Accordingly, the contribution of geometrically necessary dislocations (GNDs) activity on strengthening and stress concentration factor is identified in the crack-tip. Finally, the affected zone which is dominated by presence of GNDs is identified

Grain-Size Effects during Dynamic Recrystallization of Nickel

Metal Science ◽  
1974 ◽  
Vol 8 (1) ◽  
pp. 325-331 ◽  
Author(s):  
J. P. Sah ◽  
G. J. Richardson ◽  
C. M. Sellars
Keyword(s):  
Grain Size ◽  
Dynamic Recrystallization ◽  
Size Effects ◽  
Grain Size Effects

Modeling of Size Effects on the Flow Stress of Type 304 Stainless Steel and Application in Coining Process

2007 ◽  
Author(s):  
Gap-Yong Kim ◽  
Muammer Koc ◽  
Jun Ni
Keyword(s):  
Grain Size ◽  
Stainless Steel ◽  
Flow Stress ◽  
Size Effect ◽  
Size Effects ◽  
Specimen Size ◽  
304 Stainless Steel ◽  
Length Scales ◽  
Type 304 ◽  
Type 304 Stainless Steel

Application of microforming in various research areas has received much attention due to the increased demand for miniature metallic parts that require mass production. For the accurate analysis and design of microforming process, proper modeling of material behavior at the micro/meso-scale is necessary by considering the size effects. Two size effects are known to exist in metallic materials. One is the “grain size” effect, and the other is the “feature/specimen size” effect. This study investigated the “feature/specimen size” effect and introduced a scaling model which combined both feature/specimen and grain size effects. Predicted size effects were compared with experiments obtained from previous research and showed a very good agreement. The model was also applied to forming of micro-features by coining. A flow stress model for Type 304 stainless steel taking into consideration the effect of the grain and feature size was developed and implemented into a finite element simulation tool for an accurate numerical analysis. The scaling model offered a simple way to model the size effect down to length scales of a couple of grains and extended the use of continuum plasticity theories to micro/meso-length scales.

Sign in / Sign up

Export Citation Format

Share Document