scholarly journals Diamond-Like-Carbon Coated Dies for Electromagnetic Embossing

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4939
Author(s):  
Marius Herrmann ◽  
Björn Beckschwarte ◽  
Henning Hasselbruch ◽  
Julian Heidhoff ◽  
Christian Schenck ◽  
...  
Keyword(s):  
Physical Vapor Deposition ◽  
High Speed ◽  
Thin Sheet ◽  
Surface States ◽  
Die Design ◽  
Initial Surface ◽  
Force Transmission ◽  
Sheet Surface ◽  
Aluminum Sheets ◽  
Die Materials

Electromagnetic forming is a high-speed process, which features contactless force transmission. Hence, punching operations can be realized with a one-sided die and without a mechanical punch. As the forces act as body forces in the part near the surface, the process is especially convenient for embossing microstructures on thin sheet metals. Nevertheless, the die design is critical concerning wear like adhesion. Several die materials were tested, like aluminum, copper as well as different steel types. For all die materials adhesion phenomena were observed. To prevent such adhesion an a-C:H-PVD (Physical Vapor Deposition)-coating was applied to steel dies (X153CrMoV12) and tested by embossing aluminum sheets (Al99.5). By this enhancement of the die adhesion was prevented. Furthermore, the die surface was structured with tribology-effective patterns that were generated by micro hard milling. The embossing quality was topographically analyzed with respect to different initial surface states of the sheets. It was identified that thicker sheets facilitate better embossing results. Moreover, the initial sheet surface has a decisive influence on the embossing quality, whereby the characteristic of the topography showed different susceptibility on the initial sheet surface state.

Morphology of Edge Cracks of Rolled Magnesium Alloy Sheet

2014 ◽  
Vol 922 ◽  
pp. 469-474 ◽  
Author(s):  
Sho Manabe ◽  
Hiroshi Utsunomiya ◽  
Tetsuo Sakai ◽  
Ryo Matsumoto
Keyword(s):  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
High Speed ◽  
Heating Temperature ◽  
Thin Sheet ◽  
Contact Length ◽  
Alloy Sheet ◽  
Different Temperatures ◽  
Edge Cracks ◽  
Critical Reduction

Magnesium alloys show low deformability at low temperature because of hcp structure and inactiveness of basal slip. Manufacturing of thin sheet is difficult in industries. Some approaches, such as small-draft multi-pass rolling, intermediate annealing, isothermal rolling and high-speed rolling were proposed to overcome the deformability. However, small edge cracks are still formed on the sheet. In this study, rolling speed of 1000m/min was employed to warm-roll AZ31B magnesium alloy in a single pass at different temperatures. The edge cracks formed after the rolling were classified into three main groups: minor, regular and zigzag edge cracks. ‘Crack contact length’ are introduced to explain the morphology of edge cracks. The results show that the critical reduction for crack initiation depends on the pre-heating temperature. The spacing between edge cracks increases linearly with the crack contact length regardless of roll diameter, speed and reduction. It is suggested that this approach is useful to understand the formation mechanism of edge cracks and to evaluate the rollability of magnesium alloys.

Effective Stripper-Holding on High Speed Precision Blanking of Electronic Machine Parts

2005 ◽  
Vol 6-8 ◽  
pp. 805-808
Author(s):  
F. Sekine
Keyword(s):  
Mechanical Model ◽  
High Speed ◽  
Thin Sheet ◽  
Dimensional Accuracy ◽  
New Method ◽  
Important Process ◽  
Sheet Metals ◽  
Progressive Dies ◽  
Machine Parts

The blanking of thin sheet metals using progressive dies is an important process on production of precision electronic machine parts. As a model of IC leadframe, an I-shaped and an Lshaped models were blanked and influences of blanking conditions on dimensional accuracy of blanked lead were examined. Furthermore, a mechanical model is proposed to explain the affect of the blanking conditions on product accuracy. In these days, more fine leads are required as electronic machines become more precise and accurate. It must be treated that leads are firmly held for blanking leadframes accurately. In this paper, an effective method of stripper holding leads strongly are discussed and a new method using newly designed stripper is proposed. Consequently the effect of it on lead accuracy is proved.

Seam Welds Modeling and Mechanical Properties Prediction in the Extrusion of AA6082 Alloy

2008 ◽  
Vol 367 ◽  
pp. 125-136 ◽  
Author(s):  
Lorenzo Donati ◽  
Luca Tomesani
Keyword(s):  
Mechanical Properties ◽  
High Speed ◽  
Fem Simulation ◽  
Die Design ◽  
Welding Parameters ◽  
Middle Section ◽  
3D Fem ◽  
Strain And Strain Rate ◽  
Mechanical Properties Prediction ◽  
Temperature Time

This work summarizes the outcome of recent research by the authors on modeling the formation of seam welds in aluminum extrusion and on evaluating the related mechanical properties on the final products. A profile with a seam weld in the middle section was produced with different die designs in order to investigate the relation between die design and local welding parameters, such as contact pressure, temperature, time of contact, strain and strain rate paths. The local welding conditions were evaluated by complete thermo-mechanical 3D FEM simulation of the processes. Specimens were extracted from the profiles and tensile tested, the resulting mechanical properties being discussed with respect to the local welding conditions. The possibility to adopt criteria for assessing the welding quality is discussed, together with the effect of high speed damage cracking.

Simulation on the Thixocasting Process of the Turbocharger Impellers and Selection of the Viscosity Models

2014 ◽  
Vol 217-218 ◽  
pp. 219-224 ◽  
Author(s):  
Fan Zhang ◽  
Xiao Gang Hu ◽  
Da Quan Li ◽  
You Feng He ◽  
Xiao Jing Xu ◽  
...  
Keyword(s):  
Solid Fraction ◽  
High Speed ◽  
High Viscosity ◽  
Shrinkage Porosity ◽  
Die Design ◽  
Semisolid Slurry ◽  
Filling Process ◽  
Viscosity Models ◽  
Defect Control ◽  
Porosity Defects

The thixocasting technology is chosen to produce the turbocharger impellers as it is capable of producing castings with high precision dimension, free of oxide and shrinkage porosity defects and therefore long service life. The thixocasting turbocharger impellers have the similar mechanical property to those produced by forging and machine processes, but much less costs. In the thixocasting process, the semisolid slurry with certain solid fraction is injected into mould at a high speed. Since high viscosity and thixotropic characteristics, the semisolid slurry reveals unique flow condition and characteristics in the filling process. So, its very desirable for the die design, process optimization, and defect control to visualize the high-speed filling process of semisolid slurry by numerical simulation. In this paper, several commonly used viscosity models for semisolid slurry are analysed. The Power law cut-off model (PLCO) model is selected to simulate the filling process in the thixocasting process of the impellers of 319s alloy, compared with actual results by partial filling testing. The causes of the casting defects are also analysed, indicating that the simulation results can accurately reproduce the filling process of semisolid slurry, and PLCO model is a successful choice for simulating the filling process of semisolid slurry with high solid fraction.

scholarly journals Threading Performance of Different Coatings for High Speed Steel Tapping

Coatings ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 464
Author(s):  
Alain Gil Del Val ◽  
Fernando Veiga ◽  
Octavio Pereira ◽  
Luis Norberto Lopez De Lacalle
Keyword(s):  
Tool Life ◽  
Vapor Deposition ◽  
Physical Vapor Deposition ◽  
High Speed ◽  
Cutting Speed ◽  
High Speed Steel ◽  
Tialn Coating ◽  
Tool Performance ◽  
Thread Profile ◽  
Increase Tool Life

Threading holes using tapping tools is a widely used machining operation in the industry. This manufacturing process involves a great tool immersion in the part, which involves both friction and cutting. This makes the use of coatings critical to improving tool life. Four coatings are used based on Physical vapor deposition (PVD) technology—TiN, TiCN, TiAlN and TiAlN+WC/C are compared to uncoated tool performance. The effect of various coatings on the life of M12 × 1.5 tapping tools during threading of through holes 20 mm deep, in GG25 casting plates, dry and applying cutting speed of 50 m/min. The end-of-life criterion has been established based on a cutting torque of 16 N-m. Taking the uncoated tap as a basis for comparison, it is observed that coatings based on PVD technologies increase tool life doubling in the most advantageous case with the TiAlN coating. PVD type coatings provide better protection to wear at cylindrical area of the tool, where the thread profile is finished, than uncoated taps. The teeth located in the cone-cylinder transition zone of the taps suffer the most wear regardless of the coating. However, taps coated with TiAlN+WC/C wear level values is lowest of all the coatings tested, which indicates a strong reinforcement in these teeth.

Rapid Synthesis of Nanostructural Intermetallics and their Bulk Properties

1996 ◽  
Vol 457 ◽  
Author(s):  
S. M. Pickard ◽  
A. K. Ghosh
Keyword(s):  
Grain Size ◽  
Physical Vapor Deposition ◽  
High Speed ◽  
Single Phase ◽  
Deposition Process ◽  
Indentation Hardness ◽  
Rotational Rate ◽  
Fine Grain ◽  
Compositional Variability ◽  
Nano Grains

ABSTRACTA rapid physical vapor deposition process (PVD) utilizing a high speed rotating substrate and small substrate-to-source spacing has been used to produce bulk sheet of Ti-Al alloys in the compositional range Ti-12% Al to Ti-75% Al1 at a rate of 1–3 μm/minute. Microstructural architectures produced by the method comprise of either fully homogenous phase mixtures of nano-grains, or nanolaminated material, depending on the substrate rotational rate, with lower rotational rate producing a layered microstructure. Defect populations within the as-deposited material are characterized by TEM and SEM, and hot pressing consolidation of the as-deposited material, which retains a grain size < 1000 nm, has been investigated. While indentation hardness of α2+γ(2 phase) alloys exceeded 7 GPa, brittle failure occurred in the elastic regime at nominally lower tensile stress than that for conventionally produced alloys containing Nb and Cr as solute elements. α2+γ alloys can exhibit tensile elongations of more than 100% at 850°C with retention of fine grain size. Elevated temperature failure occurs by the formation of voids in regions of compositional variability in the composite where single phase α2-Ti3Al structure was present.

The Thermal Effect of Unconventional Cutting Technologies on Steel DIN 1.7102

2020 ◽  
Vol 994 ◽  
pp. 78-87
Author(s):  
Pavel Stoklásek ◽  
Aleš Mizera ◽  
Miroslav Manas ◽  
Martin Ovsik
Keyword(s):  
Thermal Effect ◽  
High Speed ◽  
New Technologies ◽  
Electrical Discharge Machining ◽  
Thin Sheet ◽  
Cutting Edge ◽  
Steel Sheets ◽  
Complex Shapes ◽  
Cut Surface

New technologies known as unconventional technologies make it possible to cut complex shapes at high speed and with relatively high precision. In many cases, especially in the case of thin sheet, created parts produced do not require any further treatment by post-machining. Knowledge of the accompanying phenomena, such as the heat-affected zone (HAZ) or the surface quality of the cutting edge, is necessary, for example, to assess further machining of material in these areas (e.g. drilling and reaming holes or finishing operations on the cutting edge). In this study, the thermal effect of four unconventional cutting technologies – laser, plasma, wire electrical discharge machining (wire EDM) and waterjet cutting on the cut surface of steel sheets is investigated. Steel 1.7102 (DIN 54SiCr6) was chosen for purpose of this study. The width of the HAZ and the nanohardness beneath the cut surface were analyzed.

scholarly journals Metallurgical and Mechanical Characterization of High-Speed Friction Stir Welded AA 6082-T6 Aluminum Alloy

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4211 ◽  
Author(s):  
Anton Naumov ◽  
Iuliia Morozova ◽  
Evgenii Rylkov ◽  
Aleksei Obrosov ◽  
Fedor Isupov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Welding Speed ◽  
Welded Joints ◽  
High Speed ◽  
Structural Characteristics ◽  
Tensile Fracture ◽  
Friction Stir ◽  
Microhardness Distribution ◽  
Aluminum Sheets

The objective of this study was to investigate the effect of the high welding speed on the mechanical properties and their relations to microstructural characteristics of butt friction stir welded joints with the use of 6082-T6 aluminum alloy. The aluminum sheets of 2.0 mm thick were friction stir welded at low (conventional FSW) and high welding speeds (HSFSW) of 200 and 2500 mm/min, respectively. The grain size in the nugget zone (NZ) was decreased; the width of the softened region was narrowed down as well as the lowest microhardness value located in the heat-affected zone (HAZ) was enhanced by HSFSW. The increasing welding speed resulted in the higher ultimate tensile strength and lower elongation, but it had a slight influence on the yield strength. The differences in mechanical properties were explained by analysis of microstructural changes and tensile fracture surfaces of the welded joints, supported by the results of the numerical simulation of the temperature distribution and material flow. The fracture of the conventional FSW joint occurred in the HAZ, the weakest weld region, while all HSFSW joints raptured in the NZ. This demonstrated that both structural characteristics and microhardness distribution influenced the actual fracture locations.

Shearing Edging Investigation in High-Speed Blanking Process Applying Precision Progressive Die

2013 ◽  
Vol 668 ◽  
pp. 460-464
Author(s):  
Zhen Yuan Huang ◽  
Feng Ruan
Keyword(s):  
Surface Roughness ◽  
High Speed ◽  
Orthogonal Experiment ◽  
Thin Sheet ◽  
Progressive Die ◽  
Small Complex ◽  
Thin Sheet Metal ◽  
The One ◽  
Blanking Process

The high-speed blanking process applying precision progressive die represents the one of the highest level of today’s stamping technology, mainly is used for the production of the ultra-thin, small, complex electronic components. An orthogonal experiment scheme with three factors (including blanking clearance, surface roughness of the die, stamping speed) was established in this paper based on the actual production. The high-speed blanking process experiment applying precision progressive die was carried out base on this scheme. The quality of the shearing edging of blanking parts was used to evaluate the different influence degree of three factors. The result showed that the surface roughness of the die affected the quality of the shearing edging more than that of the other two. The higher the die surface accuracy, the better the quality of the shearing edging. The result also showed that the high speed can reduce the quantity of the burr of the blanking of the ultra-thin sheet metal.

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