• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.171-172
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• 2006

The effect of the preparation factors, such as the feeding mode and rate of raw materials, the reaction temperature and the surfactant on the size distribution of molybdenum trioxide particle were investigated by orthogonal test. The optimum conditions for the preparation of $MoO_3$ precursors are as following; opposite feeding fast, reaction temperature of $60^{\circ}C$ and adding dispersant.

• Journal of Welding and Joining
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• v.19 no.5
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• pp.481-485
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• 2001

Laser cladding processing allows rapid transfer of heat to the material being processed with minimum conduction into base metal. The effect of $CO_2$ laser cladding with high viscosity mixed powders was investigated. High viscosity mixed powder consists of bronze powder and flux that is used at a high temperature condition. The mixed powder has a high viscosity that it can be easily pasted over a curved or slope substrate. The device for mixed powder was designed and manufactured. It consists of the high viscosity mixed powder feeding system, the preheating system and the shielding gas system which prevents the clad layer from being oxidized. The results of experiment indicated that the feed rate of high viscosity mixed powder was important for later cladding with mixed powder feeding. The high viscosity mixed powder and substrate must be preheated to prevent porosity from breaking at the clad layer. The experimental result shows that the high viscosity mixed can be applied for laser cladding process.

• Journal of Korea Society of Industrial Information Systems
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• v.8 no.3
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• pp.105-110
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• 2003

The purpose of this paper is to development of micro particle powder feeding systems for the reduction of air leakage of the feeding system. Most of the powder-granule supply systems using compressed air supply have a large amount of air leakage interference. The results of this study lead to reduce air leakage rate by over 50% and to save production cos by. 60%.

• Proceedings of the KWS Conference
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• 2004.05a
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• pp.144-145
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• 2004

Submerged arc welding technique using metal powder as supplementary filler metal has been studied. Forward feeding was used, and the deposit rate was increased by 50%. Good bead appearance, soundness and mechanical properties were obtained with feed rate of 120g/min..

• Proceedings of the KWS Conference
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• 1996.10a
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• pp.3-15
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• 1996

The formation of a thicker hard alloyed layer have been investigated on the surface of aluminum cast alloy (AC2B) by PTA overlaying process with Cr, Cu and Ni motel powders under the condition of overlaying current 125-200A. overlaying speed 150 mm/min and different powder feeding rate 5-20 g/min. In addition the characteristics of hardening and wear resistance of alloyed layer here been examined in relation to the microstructure of alloyed layer. Main results obtained were summarized as follows: 1) There was an optimum overlaying condition to get a good alloyed layer with smooth surface. This good layer became easy to be formed as increasing overlaying current and decreasing powder feeding rate under a constant overlaying speed. 2) Cu powder was the most superior one in metal powders used due to a wide optimum overlaying condition range, uniform hardness distribution of Hv250-350, good oar resistance and freedom from cracking in alloyed layer with fine hyper-eutectic structure. 3) On the contrary, irregular hardness distribution was usually obtained in Cr ar Ni alloyed layers of which hardness was increased as Cr or Ni contents and reached to maximum hardness of about Hv400-850 at about 60wt%cr or 40wt%Ni in alloyed layer. 4) Cracking occurred in Cr or Ni alloyed layers with higher hardness than Hv250-300 at mere than 20-25wt% of Cr or Ni contents in alloyed layer. Porosity was observed in all alloyed layers but decreased by usage of spherical powder with smooth surface.

• Journal of Powder Materials
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• v.11 no.3
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• pp.224-232
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• 2004

Ni-diamond composite powders with nickel layer of round-top type on the surface of synthetic diamond (140/170 mesh) were prepared by the electroless plating method (EN) with semi-batch reactor. The effects of nickel concentration, feeding rates of reductant, temperature, reaction time and stirring speeds on the weight percentage and morphology of deposited Ni, mean particle size and specific surface area of the composite powders were investigated by Atomic Adsortion Spectrometer, SEM-EDX, PSA and BET. It was found that nucleated Ni-P islands, acted as catalytic sites for further deposition and grown into these relatively thick layers with nodule-type on the surface of diamond by a lateral growth mechanism. The weight percentage of Ni in the composite powder increased with reaction time, feeding rate of reductant and temperature, but decreased with stirring speed. The weight percentage of Ni in Ni-diamond composite powder was 55% at 150 min., 200 rpm and 7$0^{\circ}C$ .

• Journal of Ginseng Research
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• v.9 no.2
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• pp.186-192
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• 1985

In order to observe the effect of defatted ginseng which is made by extracting fat from ginseng using petroleum ether during the growth and the starvation, the powder of defatted ginseng was added to the basal diet by 25% and 50% respectively, and the mixtures were fed for 4 weeks to just weanling white female rat which weighed 78-82 g. As for the diet initake, there was not showed any meaningful difference between the defatted ginseng powder fed group and the control group (to which was fed just - the basal diet not including defatted ginseng powder), but the protein intake for the former group appeared to be reduced (P<0.02-0.01) compared to the control group. As for the growth rate, that of the defatted ginseng powder fed group appeared higher (P<0.02) than that of the control group in 1 week after feeding, but since after 2 weeks, there was not showed meaningful difference between the two groups. As for the weight-reduction rate by starvation, that of the 25% defatted ginseng powder fed group showed just 79.6% (P<0.05) of the control group's in 5 days after feeding, but the rate of the 50% defatted ginseng powder fed group appeared 119.3% of the control group's. As for the required time from the beginning of starvation to the death, it was resulted that the higher the rate of defatted ginseng addition is, the shorter the time becomes (P<0.05)

• Journal of Welding and Joining
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• v.15 no.5
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• pp.92-103
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• 1997

The purpose of this study is to improve the wear resistance and hardness of Al alloy by making a formation of the thick surface hardening layers. The thick surface hardening layers were formed by PTAW(Plasma Transferred Arc Welding), with the addition of metal powders (Cu), ceramics powders (NbC, TiC), and mixture powders (Cu+NbC) in Al alloy (A1050, A5083). Mechanical properties of overlaid layers (wear resistance, hardness) were investigated in relation to the microstructure. The results obtained are summarized as follows: The depth of penetration was increased with increasing powder feeding rate. It is considered that these increase were due to the thermal pinch effect by the addition of powders, especially, for the Cu powders, were due to the heat of reaction with the matrix. The hardness and wear resistance of overlaid layers were improved with increasing powder feeding rate. For the Cu powders, it is considered that these increase were due to the increase of the formation of ${\theta}(CuAl_2)$ phase with increasing feeding rate of Cu powers.

• Laser Solutions
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• v.18 no.3
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• pp.1-5
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• 2015

A 3D printer based on laser powder deposition (LPD), also known as DED (direct energy deposition), has been developed for fabricating metal parts. The printer uses a ytterbium fiber laser (1070nm, 1kW) and is equipped with an Ar purge chamber, a three-dimensional translation stage and a powder feeding system composed of a powder chamber and delivery nozzles. To demonstrate the performance of the printer, a tapered cylinder of 320mm in height has been fabricated successfully using Ti-6Al-4V powders. The process parameters including the laser output power, the scan speed, and the powder feeding rate have been optimized. A 3D printed test specimen shows mechanical properties (yield strength, ultimate tensile strength, and elongation) exceeding the criteria to employed in a variety of Ti alloy applications.

• Proceedings of the KIEE Conference
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• 1997.07b
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• pp.527-529
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• 1997

In this paper, a system to control feeding rate by fuzzy controller was developed and tested in the various raw material of the powder gram state. The designed fuzzy controller for feeding rate control system is proved robust performance under parameter variation and load disturbance effect which is caused by the kind and quantity of various raw material.