• Korean Journal of Materials Research
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• v.9 no.1
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• pp.18-24
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• 1999

This study was performed to observe the surface roughness and microstructural change of the grinding surface of plasma sprayed $Cr_2$$O_3$coating layer. The experimental condition were particle size of diamond grinding stone, depth of cut, rotating speed and coolant feed. As a results, the grinding conditions influencing on the surface roughness and microstructure were depth of cut and the particle size of diamond grinding stone. In addition to the conversion of brittle-ductile fracture of grinding surface on depth of cut is $5~10\mu\textrm{m}$ and rotating speed was 100 r.p.m after grinding

• Journal of the Korean Society for Precision Engineering
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• v.17 no.2
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• pp.89-96
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• 2000

This paper describes the characteristic of die finishing to obtain smooth surface using electro-chemical grinding after cutting process. Electro-chemical grinding is possible under lower load and tool wear comparing with those in the mechanical grinding. Conventionally, if the metal bonding material of the grinding wheel is directly t contacted with workpiece, the current is circulated without electrolytic phenomena. Sometimes, electrical discharge is occurred between tool and workpiece. To cope with this problem, the metal-resin bonded pellet was used in this study. This pellet is composed of optimal volume of metal and resin powders and its characteristics are changable with the each volume of powders. Finally, high efficient die finishing is realized using metal resin bonded pellet in electro-chemical grinding.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.6
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• pp.192-198
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• 2000

This paper presents multi degree analysis of self-exited vibration of grinding system including spindle and workpiece rotational effect. The governing equations are derived by applying the finite element method to structure of spindle and workpiece rotor and by estimating the grinding force. Vibration analysis is carried out for external cylindrical plunge grinding. Displacement of workpiece and grinding force is simulated with machining time. Using this model, effects of characteristics of spindle bearing and major grinding conditions on chatter growth rate are predicted. Some of results are compared with those of other previous model and show good agreements.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.3
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• pp.21-27
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• 1997

This paper aims to clarify the effects of grinding conditions in form grinding of Sr-ferrite with the electro-plated diamond wheel. The main conclusions obtained were as follows. (1) The flexural strength and surface roughness of ferrite became the best at the peripheral wheel speed of 1700 m/min. (2) In the case of the depth of cut larger than 0.4mm, crack layers is induced in the ground surface, and the fracture type of chips exhibits slight ductile mode in the depth of cut smaller than 0.2mm. (3) Whe the depth of cut exceeds 0.6mm, the wheel life becomes extremely severe due to the large chipping and brack- age in the diamond grains. However, at the depth of cut .leq. 0.05mm, the diamond grain shows abrasive wear. (4) The decrease of flexural strength and the increase of surface roughness is in proportion to the increase of the feed rate. (5) Most effective nozzle setting angles with various delivery conditions of the grinding fluid, such as nozzle position .PHI. , flow rate Q, etc., were made clear.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.61-64
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• 1995

Grinding has been adapted as a finishing process,which can carry out form and surface integrity at the same time. Recently, high efficient and precise grinding technique is required bacause the needs for functional parts such as silicon wafer,ceramic,and electric materials are increasing. Accordingly, the development of grinding wheel appropriate to that purpose is very important. So, in this paper we newly developed a diamond grinding wheel by applying the superior characteristics of spheroidal graphite of the cast iron sintered product. Especially, a electric resistance sintering method was applied in which rapid heat treatment is possible. Finally, we have achieved successful results that the grinding wheel has high hardness,durability and grinding ability,and satisfies above conditions.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.1
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• pp.20-25
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• 2012

A Crankshaft multi grinding machine is developed for manufacturing of high precision crankshaft. The grinding head part of the developed machine should be moved precisely during grinding of work materials. In this paper, structural and modal analysis for the crankshaft multi grinding machine is carried out to check the design criteria of the machine. The analysis is carried out by FEM simulation using the commercial software. The machine is modeled by placing proper shell and solid finite elements. The results of structural and modal analysis confirmed that the structural characteristics of grinding machine and the structural safety are considered secure.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.405-409
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• 2003

We explored a new rough grinding technique on optics materials such as Zerodur. The facility used is a NANOFORM-600 diamond turning machine with a custom grinding module and range of diamond resin bond wheel. The grinding parameters such as workpiece rotation speed depth of cut and feed rate were altered while grinding the workpiece surfaces of 20m in diameter. Surface roughness is measured by Form Talysurf series2. Our target is to define grinding conditions producing the surface roughness better than 0.02${\mu}{\textrm}{m}$ Ra and the form accuracy of around 0.2${\mu}{\textrm}{m}$ PV.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.4 no.1
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• pp.13-17
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• 2005

We explored a new rough grinding technique on optics materials such as Zerodur. The facility used is a NANOFORM-600 diamond turning machine with a custom grinding module and a range of diamond resin bond wheel. The grinding parameters such as workpiece rotation speed, depth of cut and feed rate were altered while grinding the workpiece surfaces of 20mm in diameter. Surface roughness was measured by Form Talysurf series2. Our target is to define grinding conditions producing the surface roughness smaller than $0.2{\mu}m$ Ra.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.85-86
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• 2010

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.11
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• pp.1596-1602
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• 2012

Eight rice cultivars grown in Korea were analyzed to investigate the quality of flour prepared using wet and dry grinding methods. The hardness of the kernel was related with starch damage following dry grinding but not following wet grinding. Although Chenmaai had the hardest steeped kernel, its flour exhibited minimal starch damage, a lower water absorption index (WAI), and a smaller difference between the RVA properties of wet and dry ground flour. However, Seolgan and Suweon517 are soft grains, and their flours had more starch damage and a higher WAI. In general, soft kernels produce better grinding characteristics. However, our wet grinding results indicated that grain hardness was not the main factor affecting the grinding characteristics. Even Chenmaai, with its hard kernels, had good grinding characteristics, whereas the softer kernels of Seolgan and Suweon517 did not show the appropriate grinding characteristics.