• 한국정밀공학회지
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• 제29권4호
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• pp.367-372
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• 2012

The biggest factors that lower the machining accuracy are thermal deformation and chatter vibration. In this article, we introduce the study case of technology that can automatically compensate the errors of these factors of a machine during processing on the machine tool's CNC(Computerized Numerical Controller) in real time. This study is related to the detection and compensation of thermal deformation and chatter vibration that can compensate for faster and produce processed goods with more precision by autonomous compensation. In addition, this study is related to the active control of vibration during machining, monitoring of cutting force and auto recognition of machining axes origin. Thus, we attempt to introduce the related contents of the development we have made in this article.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.677-682
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• 2007

Recently, a precision stage is widely used in the fields of the nano technology. In this paper, the precision stage which consists of linear motor, vision system, light source system and controller, is designed and developed for nano imprint machine. Stiffness design considering resonance frequency is important for the precision stage. A virtual machine simulation is useful for machine development the early design stage. Kinematic and dynamic simulations of XYZ stage are performed. To consider the resonance frequency and vibration effects flexible multibody dynamics are utilized with FE modeling of the structural components.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1992년도 추계학술대회 논문집
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• pp.249-254
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• 1992

Hydrostatic Bearings have been applied to ultra high precision machine tools and precision instruments, because of their low friction characteristic, high load carrying capacity and high moving accuracy at all range of speed. In regard to realizing the Hydrostatic Bearing, various restrictors such as capillary, orifice, diaphram valve, spool valve, and etc can be used. However, their stiffness and flexibility are not sufficient in practical use for ultra precision machine tool elements. In this study dynamic equations were derived and the dynamic characteristics were simulated for both orifice and flow control servo valve. Simulation was carried out on the condition that static and sinusoidal dynamic loads were applied to the table of CNC jig Boring machine. The simulation results indicate the improvement of the performance of the Bearing system when flow control servo valve has been used as restrictor of Hydrostatic Bearing.

• 한국정밀공학회지
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• 제19권7호
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• pp.64-70
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• 2002

The positioning system fur the ultraprecision machine tool should have nanometer order of positioning resolution. For the purpose of achieving that resolution, various feed drive devices have been proposed and currently hydrostatic lead screw and friction drive are paid attention. It is reported that an angstrom resolution can be achieved by using twist-roller friction drive. So we have manufactured ultraprecision feeding system driven by the twist-roller friction drive and perform performance assessment for problem definition and solution finding. As a result, we found that the twist-roller friction drive is mechanically suitable for ultraprecision positioning but some considerations are needed to get higher resolution.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.162-166
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• 1996

This paper presents a position control of ultra-precision machine tool post using piezoelectric material. A stack-type piezoelectric actuator Is employed in a hinge-type tool holder. An assumed linear transfer function of the practical nonlinear plant is established through the comparison of transfer functions and step responses in the experiments and the simulations. Several types of feedforward/feedback controllers are designed via computer simulations using the assumed linear transfer function. The position tracking control experiments are undertaken to show the control efficiency of each controller.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.46-51
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• 2002

A grinding technology is very essential to finish the surface of IT and BT industrial application parts such as wafer, optical connection part and lenses etc. However the finding machine has bead depended on imports. Especially, it is completely imported for machining high precision part relevant to domestic electric and communicational industries. The amount to import grinding machine is about $110milions. It takes about 35% of total import amount of all the machine tools. A domestic finder manufacturer is a very small-scaled bussinessman and research facilities is poor. Recently, it is increasing to demand high speed and precision grinding technology because it brings cost down and value added up. Its further study will be something related to inteligent grinding system fur value added and high precision part. It will make domestic grinding technology to its advanced country level.

• 한국정밀공학회지
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• 제34권1호
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• pp.35-39
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• 2017

We used a construction method using a CNC milling machine, where free-formed molds were made by cutting EPS (Expanded PolyStyrene) foam with the CNC machine, to build free-formed buildings. CNC milling is off-the-shelf technology that can easily cut EPS foam; however its production cost is too high and the time to manufacture an EPS mold is too long. This paper proposes a novel cutting machine with a fast and cost effective mechanism to manufacture EPS concrete molds. Our machine comprises a cutter and Cartesian coordinate type moving mechanism, where the cutter cuts EPS foam using a hotwire in the shape of '$\sqcap$' and is capable of adjusting its cutting angle in real-time while keeping its cutting width. We proved through cutting experiments on the CNC machine that cutting time was greatly shortened compared to the conventional method and that the resulting concrete mold satisfied manufacturing precision.

• 한국정밀공학회지
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• 제31권5호
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• pp.431-439
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• 2014

Recently, a demand for precision 5-axis machine tools is significantly increasing, and the maintenance of machine tool accuracy becomes more important. it is very difficult to evaluate to accuracy of 5-axis M/C in the production site since it needs expensive measuring equipment and skilled engineer. On the other hand, evaluation items of 5-axis M/C are not systematically organized in the existing KS and ISO standards. In this study, the evaluation items for 5-axis M/C were derived systematically and a test workpiece was developed to evaluate the machine tool accuracy more easily. The error sources of machine tool can be estimated by machining and measuring of the test workpiece. The correlation between the machine tool accuracy and the accuracy of machined test workpiece was analyzed. As a result, the accuracy of machined test workpiece represented the accuracy of machine tool and the error sources very effectively.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.672-675
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• 2005

To imprint 70-nm wide line-patterns, we used a newly developed ultraviolet nanoimprint lithography (UV-NIL) process in which an elementwise patterned stamp (EPS), a large-area stamp, and pressurized air are used to imprint a wafer in a single step. For a single-step UV-NIL of a 4' wafer, we fabricated two identical $5'\times5'\times0.09'(W{\times}L{\times}H)$ quartz EPSs, except that one is with nanopatterns and the other without nanopatterns. Both of them consist of 16 small-area stamps, called elements, each of which is $10\;mm\;\times\;10\;mm$. UV-curable low-viscosity resin droplets were dispensed directly on each element of the EPSs. The volume and viscosity of each droplet are 3.7 nl and 7 cps. Droplets were dispensed in such a way that no air entrapment between elements and wafer occurs. When the droplets were fully pressed between ESP and wafer, some incompletely filled elements were observed because of the topology mismatch between EPS and wafer. To complete those incomplete fillings, pressurized air of 2 bar was applied to the bottom of the wafer for 2 min. Experimental results have shown that nanopatterns of the EPS were successfully transferred to the resin layer on the wafer.

• 한국정밀공학회지
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• 제6권2호
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• pp.47-57
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• 1989

This paper aims at describing a series development of the electrical machine, by using the Similarity Theory. The character of the electrical machine defined as the Four Terminal Network of the electrical and mechanical energy transmission system, and the analogy theory of the modelmachine can be developed by the Four Termianl System. Also the Restriction Parameter and Disturbance Parameter can be founded by the comparative data of the developed machine that is the character of the theory and measurement.