• Journal of Industrial Technology
• /
• v.22 no.A
• /
• pp.119-125
• /
• 2002

In Kwangjin industrial company, mill is operating for the foundry sand production at the rate of 25t/hr from quartzite. Foundry sands fall into four distinct categories: silica sand, lake sand, bank sand, and natural molding sand. Silica sand is a general term used to describe crushed, washed, graded, dried, and cooled clay-free sands. This study was conducted for the investigation of the foundry sand productivity and the life span of the hammer according to the material quality. The life time of hammer from several manufacturer were compared in order to find out the grinding efficiency of the various hammer material. In the result of tests, the life time of high-Mn hammer was 10.5 hours while that of high-Cr was 19.5 hours. The life time in case of typical worn shape hammers was about 12 hours and the average time of a blowhole hammer was about 6.5 hours.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.37 no.2
• /
• pp.105-108
• /
• 2018

Recently matured silkworm powder was developed by RDA. In this study, the effect of pulverizing method on the particle size of matured silkworm powder was examined. FESEM was performed to observe the morphology and to measure the particle size of silkworm powder. Particle morphology of air-jet mill pulverized powder was round and smooth, however, those of roller-mill and hammer-mill pulverized mature silkworm was more harsh and square. Particle size was varied with pulverizing technique as follows; $1.1{\mu}m$ (air-jet mill), $10{\mu}m$ (roller mill), and $120{\mu}m$ (hammer mill), respectively. A proximate analysis results of air-jet mill powder showed that crude protein, crude lipid, crude fiber, and ash was 73%, 12%, 1.95%, and 3.4%, respectively. According to our results, air-jet mell technique might be used to make a tiny matured silkworm powder.

• Journal of the Mineralogical Society of Korea
• /
• v.23 no.3
• /
• pp.219-225
• /
• 2010

Optimal grinding condition was examined by changing only the size of screen opening with fixing other factors to produce coal fines of particle sizes required for circulating fluidized bed gasifier. At least 85 wt% of the coal particles should fall into the size range of 0.045~1.0 mm for efficient gasification. In this study, hammer mill was used to grind Chinese low rank lignite coal following grinding condition designed by Taguchi method. The analysis of signal to noise ratio showed that optimum grinding condition for the gasifier was 3 mm in primary screen size and 1.3 mm in secondary screen size on the 95% level of significance.

• Resources Recycling
• /
• v.11 no.2
• /
• pp.28-35
• /
• 2002

A study on the grinding characteristics of metal components in printed circuit boards (PCBs) scrap by a swing-hammer typeimpact mill was conducted. The PCBs scrap crushed to sizes less than 3 mm were pulverized to liberate metal components by the impact mill. The effect of rotation speed of hammer on the grinding characteristics was investigated. The particle size distribution and degree of liberation of metals such as copper and solder were measured. The effect of rotation speed and particle size on the shape sorting of metal Particles from milled PCBs was investigated using an inclined vibrating Plate. At the hammer speed of 61.3 m/s about 80% of the copper particles became larger than 297 $\mu$m while 90% of solder particles was smaller than 297 $\mu$m. In the shape sorting method, the recovery location becomes shorter as the rotation speed of hammer increases. The recovery location for particles larger than 297$\mu$m was shorter than for particles sized between 149$\mu$m and 297$\mu$m. As the recovery location becomes shorter, KI value increases towards unity while $\phi_{c}$ value decreases towards unity indicating the more roundness of metal particles.

• Journal of the Korean Wood Science and Technology
• /
• v.51 no.1
• /
• pp.23-37
• /
• 2023

One type of biomass that has promising potential for bio pellet production is spent coffee grounds (SCGs). However, previous studies have shown that SCGs in bio pellets cause a lot of smoke. Therefore, they need to be mixed with a material that has a higher calorific value to produce better quality pellets. One material that can be used is pine wood because it has a natural resin content that can increase the calorific value. The aim of this study was to examine the quality of bio pellets produced with SCGs and pine wood charcoal at different particle sizes. The charcoal was ground using either a hammer mill (HM) or a ball mill (BM). Pine wood charcoal was mixed with SCGs at ratios of SCGs to pine wood charcoal of 4:6 and 6:4 by weight, respectively, and the adhesive used a tapioca with a composition ratio 5% of the raw material. The bio pellets were produced using a manual pellet press. The quality of the bio pellets was assessed based on Indonesian National Standard (SNI) 8021-2014, and the physical observations include flame length, burning rate, and compressive strength. The average water content, ash content, and calorific value of the bio pellets were in accordance with SNI 8021-2014, but the density and ash content values were below the standard values. The BM variation of bio pellets had a higher compressive strength than the HM variation, and the 4:6 BM variation had the longest burning time compared with 4:6 HM.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.12 no.6
• /
• pp.159-166
• /
• 2013

In order to develop the optimum shape of an MQL carbide end-mill suitable for high speed machining of wing ribs which are a detailed part of larger wing structures, using a new material Al-Li alloy, a new MQL carbide end-mill is created that has various quantities of holes, hole sizes, and hole locations. A theoretical machining graph is generated using the hammer test and FRF simulation, and a machining test is performed in order to verify the machining stability in the high speed machining area. The optimum configuration of the MQL carbide end-mill is also presented through comparing the chattering, machining noise and cutting conditions, including the maximum cutting depth, rpm, and feed rate per teeth, for each cutter.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2013.05a
• /
• pp.211-211
• /
• 2013

Ru-Cr은 차세대 반도체 메모리(RAM, MRAM, FeRAM), 헤드(MR, TMR), 캐피시터의 웨이퍼 등에 전극층이나 시드층 형성을 위해 스퍼터링 타겟으로 제조되며, IT산업이 발달함에 따라 수요가 증가하고 있다. 기존의 스퍼터링 타겟은 산처리와 주조와 같은 습식법이 주를 이루었으나, 긴 제조시간과 강산사용의 위험성화 강산폐유의 처리가 문제되고 있다. 최근에는 습식공정을 보완하기 위한 건식법의 연구가 진행 중이며, 합금소재에 대한 건식법의 연구가 필요하다. 본 연구에서는 폐 Ru-Cr 금속합금 스퍼터링 타겟을 Hammer-mill, jet-mill 등 건식으로 분쇄하고 RF-Plasma를 이용하여 소결에 용이한 구형, 고순도 Ru-Cr금속합금분말을 제조하였다.

• Korean Journal of Agricultural Science
• /
• v.10 no.2
• /
• pp.334-344
• /
• 1983

This study was conducted to investigate the variables affecting the performance of hammer mills by the theoretical and dimensional analysis, and evaluate the power requirements of hammer mills for farm use in Korea. From the theoretical analysis, 16 variables affecting the performance of hammer mills were defined. In order to develop the mathematical relationships among the variables, the dimensional analysis was made for power requirements and $12{\pi}$ parameters were obtained. For the evaluation of the power requirements of hammer mills, approximate rates of grinding for 1HP, 3HP, 5HP, 6HP, 8HP, and 10HP were analyzed. Then, the fineness of grinding recommendation and average feeding rate of grain for livestock which is native cattle, dairy cattle, beef cattle, swine, broilers, and layers, were estimated. Finally number of livestock feeding shelled corn and barley were estimated from the above for one hour's hammer mill operation having the various power requirements. From this study it is known that 5HP is considered as an enough power for feed grinding of any kinds of livestock of Korean farm, as far as the grinding capacity is concerned.

• Resources Recycling
• /
• v.26 no.4
• /
• pp.71-78
• /
• 2017

This study investigated the recovery of metallic aluminium in the black dross generated from used beverage can recycling process with crushing mechanism such as compression and impact. The as-received Al black dross had a spherical shape, and its size was about 10~40 mm. Also, The X-ray diffraction pattern showed that the main contents of black dross are composed of halite (NaCl), sylvite (KCl), spinel ($MgAl_2O_4$) and corundum ($Al_2O_3$). A metallic aluminium recovery test was performed using jaw crusher and hammer mill having different crushing mechanism. It was analysed that Jaw crushing process can separate into metallic aluminium and non metallic constituents. However, hammer milling process shows significant difference on the separation results. It was found that jaw crushing process was effective for recovery of metallic aluminium in the black dross than that of hammer milling process.

• Resources Recycling
• /
• v.5 no.3
• /
• pp.37-43
• /
• 1996

The recovery of metals from printed circuit board(PCBs) scraps was investigated by utilizing a shape sorting method.After all electronic parts mounted on the board were removed. PCBs were pulverized to particles smaller than 1 mm by aswing hammer type impact mill in order to liberate metal components. Metals were separated from nonmetalliccomponents by an inclined vibrating plate (IVP). The metal separation efficiency was measured as a function of vihrationintensity and inclined angle. The maximum efficiency was obtained when IVP was operated at the vibration intensity(Kv)of 1.40 and the inclined angle of 10". The grade of the metal components was recovered from PCBs exceeding 90% byusing IVP.0% by using IVP.