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

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.19 no.8
• /
• pp.8-14
• /
• 2020

In the air current pulverizing type grinding method, the blade wings fitted inside a casing are rotated at a high speed to generate a cornering air current, which facilitates the collision of materials with one another, leading to the pulverizing phenomenon. In contrast to mechanical grinding, grit pulverizing leads to fine grinding and less acid waste and degeneration of the material. Moreover, this approach prevents the loss of nutritional value, while allowing the milling grain to have an excellent texture. However, the existing air current pulverizing type machines consist of prefabricated blades, which cannot be rotated at a speed higher than 5,000 rpm. Consequently, the grinding process becomes time consuming with a low productivity. To overcome these problems, in this study, the shape and structure of the air current pulverizing type wings were optimized to allow rapid grinding at more than 8,000 rpm. Moreover, the optimal design for the ripening parts for the air current pulverizing type device was determined by performing a computational fluid dynamics analysis based on airflow analyses to produce machinery that can grinding materials to the order of micrometers.

• Journal of the Korean Society of Safety
• /
• v.5 no.1
• /
• pp.31-39
• /
• 1990

In this paper, the influence of the table speed, metal removal rate and grinding fluid on long wheel workpiece contact zone at high effect grinding was investigated by theoretical analyses and measuring the temperature, and discussed by the temperature distribution in grinding surface layer. Main results obtained are as follows, 1) Rega.dless of the table speed, the temperature gap of the workpiece(heat influx) is about 6-8 times as high in dry condition as in wet condition. 2) Good grinding condition can be obtained owing to the effect of grinding fluid without any burning defect under the condition of the metal removal rate(1.0mm$^3$/mm.s) in case of wet grinding. 3) When the depth from the surface layer is about 1.25-1.5mm under the condition of the slow table speed, surface temperature goes up higher as the table speed slows down, because long contact time is laked at the surface layer. 4) In case of the same metal removal rate, the lower the table speed becomes, the higher the surface temperature is, because grinding depth has a far more influence on wheel workpiece contact zone than the table speed.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.1289-1293
• /
• 2005

We will improve tools performance without the change of a tools' physical shape, if we process mirror like finishing on the surface of cutting tools. Because cutting tools' shapes are very complex, the general method of polishing can't be polished. So we will apply new method of polishing which is magnetic fluid grinding technique. Magnetic fluid grinding technique can polish complex shape's workpiece by pressing the surface of workpiece with magnetic and abrasive grains in magnetic field. Therefore we developed the polishing equipment to improve the performance of cutting tools and experimented on various polishing conditions to determine the polishing conditions of cutting tools.

• Journal of Mechanical Science and Technology
• /
• v.15 no.3
• /
• pp.351-356
• /
• 2001

In the surface grinding operations, the grinding fluid cannot be supplied sufficiently in the cutting zone. Temperature generated in the cutting zone increases rapidly and causes thermal damage such as burning on the surface of a workpiece. To reduce thermal damage, the intermittent grinding wheels, which have an excellent cooling effect, have been applied. This paper describes machining characteristics by using intermittent grinding wheels. The grinding force of the intermittent wheels has been simulated by the SIMULAB, which is a program for simulating dynamic systems. Using the intermittent grinding wheels, the characteristics of grinding force, temperature, surface roughness, and geometric error have been evaluated experimently.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.14 no.5
• /
• pp.1-6
• /
• 2005

Machining is a one of the broadly used manufacturing process to produce the parts, products and various molds and dies. The environmental impact due to aerosol generation via atomization process is a major concern associated with environmental consciousness. This paper presents the experimental results to analyze the characteristics of cutting fluid aerosol generation in grinding process. Experimental results show that the generated fine aerosol which particle size less than 10micron appears near worker's breath zone under given operational conditions. The aerosol concentration is much higher enough to affect human health risk with its generated aerosol quantities. This quantitative analysis can be provided the basic knowledge f3r further research for environmentally conscious machining technology developments.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2005.05a
• /
• pp.282-287
• /
• 2005

This paper presents the experimental results to analyze the characteristics of cutting fluid aerosol generation in grinding process. Machining is a one of the broad manufacturing process to produce the parts, products and various molds and dies. The environmental impact due to aerosol generation via atomization process is a major concern associated with environmental consciousness. Experimental results show that the generated fine aerosol which particle size less than 10 micron appears near worker's breath zone under given operational conditions. The aerosol concentration is much higher enough to affect human health risk with its generated aerosol quantities. This qualitative analysis can be provided the basic knowledge for further research for environmentally conscious machining technology developments.

• 제어로봇시스템학회:학술대회논문집
• /
• 1991.10b
• /
• pp.1677-1680
• /
• 1991

Machining is a bottleneck in robot application technologies because of uncertainty of position/form, poor reliability of robot function and low reaction speed of robot to changes of surroundings, But in grinding automation with relatively low machining speed it is feasible to integrate of sensor signal in machining. In this paper strategy for robotic grinding with F/T sensor will be presented and with that the experimental results will be discussed. F/T sensor signal in grinding of strategy weld seam are transferred to PC, which plays a role as cell computer and transform F/T data to robot position and/or orientation, speed correction data according to programmed algorithm. The possibility and boundary of robotic grinding with F/T sensor intergration is discussed.

• 연구논문집
• /
• s.28
• /
• pp.59-71
• /
• 1998

The ELID(electrolytic in-process dressing) grinding method is a new precision grinding technique with the special electrolytic in-process dressing by metal bonded grinding wheel, fluid, and power supply. It is possible to make a efficient precision machining of hard and brittle materials such as ceramics, hard metals, and quenched steels by using this method, In this study, a new efficient precision grinding method with ELID was attempted for application to the machining and finishing processes of cylindrical structural components. And, we try to develop the cylindrical grinding technique for mirror surface of ceramics, tungsten carbide and SCM steel, and for the high efficiency grinding of machined parts, for example, ball screw shaft. Electrical characteristics of three different wheel grit sizes of #325, #2000 and #4000 were investigated experimentally. ELID grinding method is proved to be useful for mirror surface generation and efficient machining.

• Journal of the Korean Society of Safety
• /
• v.11 no.3
• /
• pp.10-19
• /
• 1996

Grinding temperature and thermal deformation(dimensional error) are studied theoretically and experimentally. The propose of this research is clarified loading phenomena and residual stress In order to guide nozzle's efficiency. The main results to be obtained are as follows ; 1) When grinding condition Is high efficient grinding, FEM program is developed about grinding heat and dimensional error. 2) Thermal deformation depend on temperature distribution is in good agreement with experimental results in case of little grinding energy flux but is comparatively in good agreement with in case of large (3.5$\times$10$^{6}$ J/m). 3) In terms of high efficient grinding at field(table speed 4m/min), grinding fluid (dilution 5/100) obtained a good workpiece quality and decreased a grinding temperature. 4) A surface roughness, dimensional error, residual stress and loading phenomena with guide nozzle are decreased and these results obtained a good workpiece quality.