• Transactions of Materials Processing
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• v.12 no.6
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• pp.558-565
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• 2003

Rotary swaging is one of the incremental forming process which is a chipless metal forming process for the reduction of cross-sections of bars, tubes and wires. In the present work, the rotary swaging machine and dies were designed to investigate the formability of TDS(Tube Drive Shaft) used in automotive industry. The process variables such as the speed of forming, the shape of the formed materials and the reduction of area were also estimated to study experimental analyses of rotary swaging process using the materials of 34Mn5 and S45C. From experimental results, it was found that the process variables affected the quality of TDS in terms of hardness, the precision of products and the surface roughness. The hardness after swaging approved to be Increased with the increase in the reduction of diameter. And it was found that the grain size became smaller and the elongated grains were formed in the axis direction.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.1
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• pp.77-84
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• 2012

Numerical performance analysis of the vane-roller integral type swing compressor was conducted. The swing compressor has been investigated for the highly efficient air conditioning system. Performance analysis results of the swing compressor were compared with those of a conventional rotary compressor. Mechanical and gas losses of a swing compressor were larger than those of a rotary compressor. However in case of mass flow rate from the discharge port, the swing compressor was about 6.68% higher than the rotary compressor. Hence the EER, the cooling capacity and the compressor work of the swing compressor were about 3.71%, 6.69% and 2.90% higher than the rotary compressor respectively.

• Journal of Biosystems Engineering
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• v.37 no.5
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• pp.279-286
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• 2012

Purpose: This study has been conducted to investigate the applicability of motion analysis of tillage blade for estimation of tillage characteristics of crank-type and rotary-type rotavators. Methods: The interrelation between tillage traces from motion analysis and field test results including rotavating depth, pulverizing ratio and inversion ratio at the same work conditions were analyzed for both crank-type and rotary-type rotavators. The work conditions include working speed of prime mover tractor and PTO speed of rotavators. For the motion analysis, joint conditions of main connecting component were specified considering the actual working mechanism of rotavator. Results: There were important correlations for the trend between motion analysis and field test results. Conclusions: Although further study is needed for applying motion analysis to estimate the accurate tillage related parameters such as rotavating depth, the soil pulverizing ratio and inversion ratio, it could be used to compare the tillage characteristics of various rotavators quickly and simply.

• Journal of Environmental Health Sciences
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• v.18 no.1
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• pp.6-11
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• 1992

This study was carried out to investigate exposure level, size distribution, and respirable mass fraction of airborne coal dust and heavy metal concentration of respirable coal dust at each work site in coal briquet factory from July 1991 to September 1991. Geometric mean of total dust concentration was 10.88mg/m$^{3}$ at storage shop, 8.22mg/m$^{3}$ at pulverize shop, and 3.79mg/m$^{3}$ at rotary press shop, respectively, but those at storage and pulverize shop were higher than TLV. Geometric mean of respirable coal dust concentration wat 1.03mg/m$^{3}$ at storage shop, 0.78mg/m$^{3}$ at pulverize shop, and 0.55mg/m$^{3}$ at rotary press shop, respectively, which were lower than TLV Aerodynamic 50% cutoff diameter of the suspended coal dust was 5$\mu$m at rotary press shop and 6.8$\mu$m at storage shop, ranged to thoracic particulate defined by ACGIH, and deposited in the region of repiratory system. The mass fraction rate of respirable dust to the total coal dust was 26.2% at rotary press shop, 18.8% at storage shop, and 13.8% at pulverize shop, respectively. Heavy metal concentrations of the respirable coal dust were 0.028mg/m$^{3}$ ib Fe, 0.0081mg/m$^{3}$ in Cu, and 0.0039mg/m$^{3}$ in Pb.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.364-367
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• 2007

Typical seamless tube production methods are an extrusion and a rotary tube piercing. The rotary piercing process is more competitive than the extrusion process form view point of productivity, quality, and flexibility. It consists of twin rolling mills, a pair of disc or flat guides, and a plug. Twin rolling mills are skewed with proper angles in two directions. A round billet is progressively fed forward and rotated due to the rotation of twin rolling mills. Internal crack initiation and growth at central area of the billet are gradually progress because of the repeating actions of tension and rotation. Design variables in the rotary piercing rolling process are the feed angle, the cross angle, the reduction ratio, and the position of plug. In this work, a rotary tube piercing machine was developed and parametric studies on design variables were carried out using finite element analysis. The Brozzo ductile fracture criterion was utilized to determine an internal crack initiation.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.5
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• pp.1041-1053
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• 1993

A theoretical model to predict the triangular chip formation in cutting with a self-propelled rotary tool is developed. The model is based on the model of transient chip formation in two dimensional orthogonal cutting. The predicted results are found to be in good agreement with the experimental observations and suggest that transient charcteristics of work material, which depend on both cutting conditions and material properties, have the significant influence on triangulation.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.6
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• pp.2100-2108
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• 1991

A hear transfer model was developed to calculate the temperature distribution in the rotary kiln incinerator of municipal solid waste. The thermo-gravimetric characteristics of waste and the gas-to-waste heat transfer coefficient were determined by comparing the experimental results and model prediction. With this, heat transfer rates by existing heat transfer mechanisms were calculated to be compared each other. The effects of treatment capacity, calorific value of waste, and flow rate and temperature of combustion air on the temperature distribution in the rotary kiln incinerator were predicted by the model developed in this work.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.964-968
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• 2003

Hermetic rotary compressor is one of the most Important components for air conditioning system since it has a great effect on both the performance and the noise and vibration of He system. Noise and vibration of rotary compressor is occurred due to gas pulsation during compression process and unbalanced dynamic force. In order to reduce noise and vibration. it is necessary to identify sources of noise and vibration and effectively control then. Many approaches have been tried to identify noise sources of compressor. However, compressor noise source identification has proven to be difficult since the characteristics of compressor noise are complicated due to the interaction of the compressor parts and gas pulsation. In this work, Statistical Energy Analysis has been used to trace the energy flow in the compressor and identify transmission paths from the noise source to the sound field.

• Journal of Korean Society for Quality Management
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• v.47 no.3
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• pp.437-451
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• 2019

Purpose: The purpose of this study is to improve the quality of the PGM system by improving the structure and production process of slip-ring rotary joint for radar. Methods: The improvement measures for each cause are established through failure analysis of broken items. Specifically, changing in the housing to improve the heating system. Changing the transportation method to prevent damage to equipment during transport. Changing work process of the attenuator ring to prevent damage. etc. Results: The results of this study are as follows; improving the heating system reduces heat generated by the attenuator by about 7 degrees and obtain additional temperature margins. Reduction of defect rate because of adding X-band rotary joint run-out measurement test, ESS of slip-ring rotary joint and Transportation improvement(reinforced flight boxes, tube protection, etc). Getting stable VSWR values by improving work process of attenuator overheating due to a bad bonding process. Conclusion: Through this study, improvements were made to slip-ring rotary joint that failed repeatedly for various reasons. As a result of the application of the improvements, the same fault does not occur until now, so we can see that the quality of PGM has improved.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.07a
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• pp.22-28
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• 2000