Surface Quality of Extruded Sidewall in Cold Backward Cup Extrusion with Low-Frequency Torsional Oscillation

2021 ◽  
pp. 217-225
Author(s):  
Ryo Matsumoto ◽  
Seiji Takatsuka ◽  
Hiroshi Utsunomiya
Keyword(s):  
Surface Quality ◽  
Torsional Oscillation ◽  
Low Frequency

Effects of Electromagnetic Field and Lubricate Condition on the Surface Quality of Aluminum Alloy Billet during LFEC Processing

2012 ◽  
Vol 268-270 ◽  
pp. 378-381
Author(s):  
Fu Qu ◽  
Jian Zhong Cui
Keyword(s):  
Electromagnetic Field ◽  
Aluminum Alloy ◽  
Surface Quality ◽  
High Surface ◽  
Low Frequency ◽  
High Surface Quality ◽  
Electro Magnetic ◽  
Lubricate Condition

The microstructures of the aluminum billets could be improved markedly by low-frequency electro-magnetic casting (LFEC) processing. In fact, the low-frequency electromagnetic field (LFEF) also has favorite effect on the surface quality of billet. However, few public reports on the surface quality of LFEC aluminum billets could be found. Therefore, a new crystallizer together with a kind of lubricant was designed aiming at lowing surface turning quantity, and the effects of casting velocity, electromagnetic condition and lubrication on the surface quality of aluminum billets were investigated. The results indicate that LFEF together with the lubricate condition would be responsible for the surface quality of the billets, and the high surface quality billets could be achieved by optimizing the casting conditions.

Modeling of surface roughness for manufactured thin-walled structure

2018 ◽  
Vol 233 (4) ◽  
pp. 1216-1223 ◽  
Author(s):  
Jixiong Fei ◽  
Bin Lin ◽  
Shuai Yan ◽  
Mei Ding ◽  
Jin Zhang ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Dynamic Deformation ◽  
Low Frequency ◽  
Experimental Results ◽  
Superposition Method ◽  
Milling Force ◽  
Machined Surface ◽  
Thin Walled

Deformation of thin-walled structure during machining will influence the surface quality of the final part. Present article investigates this problem and develops a method to predict the surface roughness of the machined surface. To achieve this, the prerequisite is to obtain the dynamic deformation along the milling path. To calculate it accurately, the workpiece is simplified as thin-walled shell and the milling force is simplified as moving input. An expression of the dynamic deformation of the whole structure, which under the excitation of moving milling force, is derived by solving the vibration equation using modal superposition method. Then, the deformation along the milling path is computed by substituting the path coordinates into the expression. The deformation along the milling path is filtered to remove its low-frequency and mid-frequency signals before it is used to evaluate the surface roughness of the machined surface. At last, several machining cases are implemented to demonstrate the proposed method. The experimental results match well with the predicted results. From the predicted and experimental results, it is founded that the deformation during processing is the main reason leading to the poor surface quality of the flexible machined workpiece.

Direct Chill Casting of Φ500mm ZK60 Magnesium Alloy Billets under Low Frequency Electromagnetic Field

2011 ◽  
Vol 686 ◽  
pp. 26-29
Author(s):  
Zhi Qiang Zhang ◽  
Qi Chi Le ◽  
Jian Zhong Cui
Keyword(s):  
Electromagnetic Field ◽  
Magnesium Alloy ◽  
Surface Quality ◽  
Low Frequency ◽  
Direct Chill ◽  
Hot Tearing ◽  
Direct Chill Casting ◽  
Chill Casting ◽  
Zk60 Magnesium Alloy

Effects of low frequency electromagnetic field on surface quality, microstructure and hot-tearing tendency of direct chill casting of Φ500mm ZK60 magnesium alloy billets were investigated. The results show that with the application of the low frequency electromagnetic field, the surface quality of Φ500mm ZK60 magnesium alloy billets has been markedly improved, and the depth of cold fold is decreased. In the conventional direct chill casting, the microstructures of the billet, especially at the center, are coarse. The distribution of the grain size is non-uniform throughout the billet. From the edge to the center, the microstructure gradually changes from fine to coarse in all billets. However, under the low frequency electromagnetic casting, the microstructures of the billet is significantly refined, the distribution of the grains size is relatively uniform from the billets edge to the billets center. And it also shows that the hot-tearing tendency of direct chill casting Φ500mm ZK60 magnesium alloy billets under low frequency electromagnetic field is significantly reduced.

Effect of Combined Electromagnetic Field on Microstructure and Surface Quality of (Al2O3+Al3Zr)P/Al Composites

2010 ◽  
Vol 152-153 ◽  
pp. 1387-1390
Author(s):  
Hong Ming Wang ◽  
Gui Rong Li ◽  
Yu Tao Zhao ◽  
Zhao Zhang
Keyword(s):  
Electromagnetic Field ◽  
Surface Quality ◽  
High Frequency ◽  
Aluminum Matrix ◽  
Low Frequency ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
High Frequency Electromagnetic Field ◽  
Average Size

In the experiment Al-Zr(CO3)2 components were utilized to in situ synthesize the Al2O3, Al3Zr reinforced aluminum matrix composites. Low frequency and high frequency electromagnetic fields were combined and introduced into the fabrication of particulates reinforced aluminum matrix composites. The average size of particulate and grain size of matrix were refined to 0.5~1μm and 20~40μm separately. The particulates distributed uniformly in matrix. The Lorenz force improved the kinetic condition and accelerated the nucleation of endogenetic particulates. At the meniscus of solidifying billet the high frequency electromagnetic field was applied. The surface quality of billet was enhanced obviously.

Dynamics of the processes in metal machining

1998 ◽  
Vol 2 ◽  
pp. 115-122
Author(s):  
Donatas Švitra ◽  
Jolanta Janutėnienė
Keyword(s):  
High Frequency ◽  
Machine Tools ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Low Frequency ◽  
Metal Cutting Machine ◽  
Cutting Machine ◽  
Metal Machining

In the practice of processing of metals by cutting it is necessary to overcome the vibration of the cutting tool, the processed detail and units of the machine tool. These vibrations in many cases are an obstacle to increase the productivity and quality of treatment of details on metal-cutting machine tools. Vibration at cutting of metals is a very diverse phenomenon due to both it’s nature and the form of oscillatory motion. The most general classification of vibrations at cutting is a division them into forced vibration and autovibrations. The most difficult to remove and poorly investigated are the autovibrations, i.e. vibrations arising at the absence of external periodic forces. The autovibrations, stipulated by the process of cutting on metalcutting machine are of two types: the low-frequency autovibrations and high-frequency autovibrations. When the low-frequency autovibration there appear, the cutting process ought to be terminated and the cause of the vibrations eliminated. Otherwise, there is a danger of a break of both machine and tool. In the case of high-frequency vibration the machine operates apparently quiently, but the processed surface feature small-sized roughness. The frequency of autovibrations can reach 5000 Hz and more.

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