• Journal of Powder Materials
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• v.18 no.1
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• pp.35-40
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• 2011

LAS-system ceramic powder, spodumene ($Li_2O{\cdot}Al_2O_3{\cdot}4SiO_2$), was successfully synthesized by a chemical solution technique employing PVA(polyvinyl alcohol) as an organic carrier. The PVA content affected the microstructure of porous precursor gels and the crystalline development. The optimum PVA content contributed to homogeneous distribution of metal ions in the precursor gel and it resulted in the synthesis of glass free $\beta$-spodumene powder having a specific surface area of $7.57\;m^2/g$. The agglomerated $\beta$-spodumene powders were also enough soft to grind to fine powders by a simple ball milling process. The microstructures of the densified powder compacts were strongly dependant on the minor phases of spodumene solid solution and amount of liquid phase, which were formed from the inhomogeneous precursors.

• Journal of the korean Society of Automotive Engineers
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• v.12 no.5
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• pp.60-75
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• 1990

Advanced Ceramics have some excellent prosperities as the material for the mechanical component. It is, however, very difficult to grind ceramics with high efficiency because of their high strength, hardness and brittleness. In this study, various machining experiments are carried out to obtain the basic knowledge of grinding High Strength Ceramics with high efficiency and precision for the purpose of application to Automobile parts. Advanced Engineering Ceramics such as Si$_{3}$N$_{4}$, SiC, ZrO$_{2}$, $Al_{2}$O$_{3}$ are ground with diamond wheels using conventional grinding machine. Results obtained in this study provide some useful informations to attain the high efficiency grinding of Advanced Ceramics.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.8-13
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• 1996

A relatively new non-traditional finishing process called Abrasive Flow Machining(AFM) is being used to deburr, polish and radius workpiece or produce compressive residual stresses by flowing an abrasive-laden viscoelastic compound across the surface to be machined. This paper presents the effects of AFM on surfaces of tool steel produced by EDM and W-EDM. Using AFM, white layer produced by EDM is erased almost equally and the amount of metal removal is significantly affected the initally machined surface condition of workpiece. The dimension of workiece is enlarged and its surface roughness is improved as AFM time is increased. The optimal AFM time can be established from the experimental results. It is considered that the grinding method lide AFM is useful to grind complex or slim geometry of workpiece even. Scanning Electron Microscopy(SEM) was used to study the surface characteristics of the workpiece before and after AFM.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.796-799
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• 2000

The concern of environmental problems by using coolant required the recycling technologies of used coolant and development of environmental-firiendly coolant Some methods have been developing. Those are the dry grinding with compressed cold air and grinding with misted coolant. The farmer is effective in the cooling effect, but has not the performance of lubrication. Otherwise, the latter can satisfy both of them and also decrease the environmental pollution. This paper tried to analyze the cooling effect and surface integral of coolant, compressed cold air, mist through measuring the temperature of grind point and grinding force. Especially, the grinding method with misted coolant according to parameters was done. So, the finding method with misted coolant proved to be effective as one of methods to decrease the environmental pollution.

• Journal of Technologic Dentistry
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• v.22 no.1
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• pp.57-67
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• 2000

The 2 key bridge system has been developed to make crownless bridges without damaging sound teeth. Strong bridge work of single or multiple pontics is possible for replacing both anterior and posterior teeth. It is incresingly considerde to be unacceptable, by dentists as well as patients, to fully grind down healthy elements in order fit a conventional bridges. Because this technique uses a combination of hole and adhesive fitting, it has a number of adventages over etched bridges and conventional bridges: - In comparison with conventional bridges, hardly and healthy dental tissue is sacrificed - Due to the lack of crown edges there is no periodontal pressure, as is the case with conventional bridges - The treatment procedure is straight forward and involves less time than conventional bridges. - The treatment is largely resiverable and repairable

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1995.10a
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• pp.76-81
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• 1995

MgO single crystal is widely used as a the material of high temperature resistance, but is difficult to grind because of brittleness and crack generation. Therefore, superabrasive diamond wheel is required for mirror like grinding of this material. This study describes a newly proposed optimum in-process electrolytic dressing system for carrying out effective dressing of superbrasive diamond wheel. Using this system the grinding surface of MgO single crystal was improved, the grinding force was very l9ow and crack was removed. In conclusion, this system is good to obtain the efficient grinding and mirror-like grinding without crack of MgO single crystal.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.2
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• pp.165-170
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• 2012

The resin bonded diamond wheel is used to grind the difficult-to-cut materials. Traditionally, the resin bonded diamond wheel is manufactured without any pores due to the characteristics of resin bond. In this study, two porous resin bonded diamond wheel were made and the grinding characteristics were compared with traditional nonporous ones. The experimental results indicate that the porous resin bond diamond wheel require less grinding forces and powers.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.158-162
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• 2006

A lot of pieces of iron plate are used to build a ship. The states of cutting surface of iron are however bended or ununiformly cuttled by cutting machine. These may cause bad Quality of painting, and shorter lifetime of iron by rust. In this paper, a new approach of grinding force control method which teaching of robot is not required is proposed to avoid long preparation time of robot and to improve the productivity. The way used in this paper is just like a blind man works through the road with stick only.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.10
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• pp.182-186
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• 1999

Structural ceramics such as $Al_2O_3$, SIC, and $Si_3N_4$ are difficult to grind materials because of their high hardness and brittleness. They are normally ground in brittle mode, but it is possible to be ground in ductile mode depending upon the grinding conditions. In this paper an experimental investigation has been carried out to see the relationship between the grinding energy and grinding mode. It has been found that the ductile mode grinding consumes more grinding energy than the brittle mode grinding. Thus, the grinding conditions of the higher specific grinding energy leads to the plastic deformation in the ground surface of workpiece and results in the better surface finish.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.119-124
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• 1994

Morden industrial society pursues unmanned system and automation of manufacturing rocess. Abreast with this tendensy, prodution of goods which requires advaned accuracy is increasing as well. According to this, the work sensing time of dressing by monitoring and diagnosis the condition of grinding, which is the representative way in accurate manufacturing, is a important work to prevent serios damages which affect grinding process or products by wearing wheel. Computer vision system is composed, so that grind wheel wurface was acquired by CCD camera and the change of cutting is composed. Then we used autometic threshoding technique from histogram as a way of deviding cutting edge which is used in manufacturing from the other parts. As a result, we are trying to approach unmanned system and sutomation by deciding more accurate time of dressing and by visualizing behavior of grinding wheel by marking use of computer vision.