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.

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.

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.

scholarly journals Interactions between feed system and process in production of preforms as linked micro parts

2018 ◽  
Vol 190 ◽  
pp. 15004 ◽  
Author(s):  
Philipp Wilhelmi ◽  
Christine Schattmann ◽  
Christian Schenck ◽  
Bernd Kuhfuss
Keyword(s):  
Laser Energy ◽  
Melting Process ◽  
Feed System ◽  
Output Rate ◽  
Cold Forming ◽  
Part Quality ◽  
Melt Pool ◽  
Multi Stage ◽  
Micro Parts ◽  
The Individual

This contribution deals with interactions between feed system and process in the production of preforms as linked parts, which is the first step of a multi-stage process chain for cold forming of micro parts. Due to the interconnection of the parts, the feed system is not only used for part transport, but also for the positioning during the generation of the preforms by laser rod melting. Thereby, the influence of the feed system on the production is more significant. Absorbed laser energy melts a wire, so that a melt pool is formed. While the wire is fixed on one side, the other side is fed into the melt pool whose volume increases. The production can be divided in the steps of preheating, active melting, solidification and transportation. The positioning takes place in parallel to the melting. Until now, the increase of the output rate was based especially on the consideration of the melting process and higher feed velocities. In this contribution, the interactions between feed and process are analyzed with the goal of further increasing the output rate. For that reason, the positioning behavior and its influence on the geometry of the produced preforms are analyzed. Finally, a method is presented, which unites the steps of transportation, preheating and melting. It is shown, that by a favorable coordination of the individual process steps, a further increase of the output rate is achievable without significantly worsening part quality.

scholarly journals Strengthening of Copper by Using RCS Process and Optimization Through Taguchi Method

2019 ◽  
pp. 187-193
Author(s):  
Jwala Sudheer Reddy ◽  
U. Mahaboob Basha ◽  
L. Balasubramanyam ◽  
S. Jithendra Naik
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Severe Plastic Deformation ◽  
Optimization Technique ◽  
High Strength ◽  
Ultrafine Grain ◽  
Taguchi Optimization ◽  
Fine Grained ◽  
Safety And Reliability ◽  
Micro Parts

Severe plastic deformation (SPD) Processes is to be determined as metal forming processes in which a very large plastic strain is imposed on a bulk process in which to make an ultra-fine-grained metal. Generating an ultrafine grained metal is to allow lightweight parts by using high strength metal for the safety and reliability of micro-parts and for eco-friendly, is the main intention of SPD Processes. In Severe plastic deformation processes (SPD), repetitive corrugation and straightening (RCS) are one of the new technical processes, in which the grain size is reduced to ultrafine grain size then the strength of copper is going to be increased by using this process in this project. The Taguchi optimization technique is utilized with conventional orthogonal array L9, in which to determine the process parameters are statistically significant on hardness. Finally, the verification test was carried out to investigate optimization enhancements.

Briefing of CSC and its R & D Activities for Metal Forming

2014 ◽  
Vol 626 ◽  
pp. 576-582
Author(s):  
Shyi Chin Wang
Keyword(s):  
Aluminum Alloys ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Technology Innovation ◽  
High Speed Steel ◽  
High Strength ◽  
Cold Forming ◽  
Research Activities ◽  
Work Rolls

China Steel Corporation was founded in 1971 being the largest integrate steel mill in Taiwan. After several stages of expansion projects, its crude steel production has reached 16.5 million tons annually. CSC has made consistent efforts on its technology innovation mainly carried out by two R & D departments. One of the major tasks of its R & D activities is to establish the advanced technologies for the manufacturing better steels and aluminum alloys as well as product application technology for downstream users. This presentation will mainly brief the research activities of CSC in the field of metal forming including rolling, sheet metal forming and thermal mechanical simulations carried out at Gleeble 3800. Work rolls with continuously variable crown (CVC) were applied to produce hot-rolled strips having precise profile and flatness. Lubrication rolling technology with high speed steel rolls was developed to diminish the wearing of work rolls at hot strip mills. The campaign life of rolling cycle was greatly prolonged. Computer-aided engineering (CAE) simulation technology of sheet metal forming has been established which proved to be an effective way to deal with the sever spring back and breakage of the cold forming of high strength steel automobile parts. Hot stamping has also been developed to support the technology innovation of CSC’s downstream customers. Flow stress and microstructure evolution during hot rolling for aluminum alloys were investigated using a Gleeble 3800 simulator. Both high strength AA5182 for can end and low earing AA3104 for can body aluminum sheets have been successfully developed.

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.

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