• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.659-660
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• 2011

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.963-966
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• 2000

Abrasive jet machining(AJM) process is similar to the sand blasting, and effectively removes hard and brittle materials. AJM has applied to rough working such as deburring and rough finishing. As the needs for machining of ceramics, semiconductor, electronic devices and LCD are increasing, micro AJM was developed, and became the inevitable technique to micromachining. This paper describes the performance of the micro AJM in micro groove cutting of glass. Diameter of hole and width of line in this groove cutting is 80${\mu}{\textrm}{m}$. Experimental results showed good performance in micro groove cutting in glass, but the size of machined groove was increased about 2~4${\mu}{\textrm}{m}$. therefore, this micro AJM could be effectively applied to the micro machining of semiconductor, electronic devices and LCD parts.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.6
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• pp.95-101
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• 2011

Micro-abrasive jet machining(${\mu}AJM$) using mask is a fine machining technology which can carve a figure on a material. The mask should have holes exactly same as the required figure. Abrasive particles are jetted into the holes of the mask and it collide with the material. The collision break off small portion of the material. And the ${\mu}AJM$ nozzle should move all over the machining area. However, in general the carving shape is modeled as in a bitmap figure, because it often contains characters. And the mask model is also often modeled from the bitmap image. Therefore, the machining path of the ${\mu}AJM$ also efficient if it can be generated from the bitmap image. This paper suggest an algorithm which can generate ${\mu}AJM$ tool path directly from the bitmap image of the carving figure. And shows some test results and applications.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.10
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• pp.178-183
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• 2001

Abrasive jet machining(AJM) process is similar to the sand blasting and effectively removes hard and brittle materials. AJM has applied to rough working such as debarring and rough finishing. As the need for machining of ceramics, semiconductor, electronic devices and LCD are increasing, micro AJM is developed, and has become the inevitable technique to micromachining. This paper describes the performance of the micro AJM in micro grooving of glass. Diameter of hole and width of line in grooving is 80${\mu}{\textrm}{m}$. Experimental results showed good performance in micro grooving of glass, but the size of machined groove increased about 2~4${\mu}{\textrm}{m}$. With the fine tuning of masking process and compensation of film wear. this micro AJM could be effectively applied to the micro machining of semiconductor, electronic devices and LCD.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.1
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• pp.138-144
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• 2008

Micro-machining of a brittle material such as glass, silicon, etc., is important in micro fabrication. Particularly, micro-abrasive jet machining (${\mu}-AJM$) has become a useful technique for micro-machining of such materials. The ${\mu}-AJM$ process is mainly based on the erosion of a mask which protects brittle substrate against high velocity of micro-particle. Therefore, fabrication of an adequate mask is very important. Generally, for the fabrication of a mask in the ${\mu}-AJM$ process, a photomask based on the semi-conductor fabrication process was used. In this research a rapid mask fabrication technology has been developed for the ${\mu}-AJM$. By scanning the focused UV laser beam, a micro-mask pattern was fabricated directly without photolithography process and photomask. Two kinds of mask patterns were fabricated using SU-8 and photopolymer (Watershed 11110). Using fabricated mask patterns, abrasive-jet machining of Si wafer were conducted successfully.

• Korean Journal of Medicinal Crop Science
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• v.26 no.5
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• pp.391-400
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• 2018

Background: Atractylodes radix is a well-known medicinal crop having many physiological effects. This study was conducted to select useful Atractylodes japonica ${\times}$ Atractylodes macrocephala (AJM) cultivars by comparing anti-oxidative and anti-inflammatory efficacies. Methods and Results: Seven extracts from AJM cultivars were used to treat lipopolysacchride (LPS)-treated BV2 cells, and the effects on cell viability and inhibition on reactive oxygen species (ROS) and nitric oxide (NO) production were analyzed. In vitro scavenging activities of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and peroxynitrite ($NOO^-$) radicals were also investigated. Contents of total phenol, atractylenolide I, and atractylenolide III in the AJM extracts were measured using high performance liquid chromatography (HPLC) or spectrophotometry. The experiments show that none of the seven extracts was cytotoxic above 89.2% at $20-250{\mu}g/m{\ell}$. Extracts of Gowon, Dawon, Sangchul, and Huchul inhibited ROS generation in a dose-dependent manner, and Sangchul extract showed the highest inhibition on ROS production. All the AJM extracts showed effective inhibitory activity after on NO release in the LPS-treated BV2 cells, and Sangchul extract showed the highest activity. Sangchul extract had the most potent scavenging activities for $NOO^-$ and had some DPPH radical scavenging effect. Sangchul extract also had the highest content at total phenol and atractylenolide I content. Atractylenolide III was not detected in the AJM extracts. Conclusions: The results suggested that Sangchul was the most useful anti-oxidative and anti-inflammatory resource among the AJM cultivars.

• Journal of the Semiconductor & Display Technology
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• v.10 no.3
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• pp.35-42
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• 2011

This paper describes the characteristics of high speed grinding and the influence of wheel surface speed V and a grindability of the grinding materials. The various fine ceramics pieces was ground by metal and vitrified bonded diamond wheel. The surface roughness of fine ceramics(Zirconia($ZrO_2$), Silicon Carbide(SiC), Silicon Nitride($Si_3N_4$), Alumina($Al_2O_3$)) decreases from $0.05{\mu}m(R_{max})$ to $0.025{\mu}m(R_{max})$ when the wheel speed at grinding point increases the wheel speed. Relation between the temperature at grinding point and surface roughness was linear. Abrasive jet machining(AJM), a specialized from of shot blasting, is considered one of the most helpful micro machining methods for hard and brittle materials such as glasses and ceramics by constant pressure grinding.