• Journal of the Korean Society for Precision Engineering
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• v.32 no.5
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• pp.423-429
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• 2015

Linear motion (LM) ball guides have good accuracy and high efficiency. They are widely applied for precision machinery such as machine tools, semiconductor fabrication machines and robots. However, friction force incurs heat between the balls and grooves. Thermal expansion due to the heat deteriorates stiffness and accuracy of the LM ball guides. For accurate estimation of stiffness and accuracy during the linear motion, friction models of LM ball guides are required. To formulate accurate frictional models of LM ball guides according to load and preload conditions, rolling and viscous frictional analyses have been performed in this paper. Contact loads between balls and grooves are derived from Hertzian contact analysis. Contact angle variation is incorporated for the precision modeling. Viscous friction model is formulated from the shear stress of lubricant and the contact area between balls and grooves. Experiments confirm validity of the developed friction model for various external load and feedrate conditions.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.445-448
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• 2004

Linear motor is very rapidly substituted for rotary motor and ball screw for precision positioning applications because of its characteristics such as high speed, no backlash and simplicities. A precision positioning system which is composed of linear motion(LM) guide and linear motor is widely used since it has easy controllable property but this system has low accuracy problem caused by friction of the LM guide. In this study, a scanning type XY stage is manufactured and some experiments is performed to improve the accuracy of the stage.

• Journal of Ocean Engineering and Technology
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• v.19 no.4 s.65
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• pp.15-20
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• 2005

This paper presented the development of a new experimental and numerical technique for the investigation of slamming impact. The in-house code was developed, based on the boundary element method. The application of commercial code was attempted using FLUENT. Pneumatic cylinder and LM-guide were introduced to closely simulate the free fall phenomenon. It was demonstrated that the proposed experimental and numerical studies can be useful tools in investigating slamming phenomenon.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.973-977
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• 2004

A pneumatic cylinder used to sliding seal which seal the element one to another in relative motion. It is difficult to accuracy control because of adhesion phenomenon. To confirm this phenomenon, it is carried to friction force test and analysis for bellows type rodless cylinder. In the rodless cylinder of this type, friction force test is very important. Through the theoretical analysis of shock absorber obtained the optimal design of bellows type rodless cylinder. As the result of the friction force test, LM Guide type is suitable for work under low friction force.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.1
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• pp.21-26
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• 2000

This paper describes a positioning system for ultra-precision that will be utilized in semiconductor manufacturing field and precision machinery. This system is composed with laser scale unit with 10nm resolution, ball screw with LM guide, brushless DC servo motor, vibration isolator and is equipped in chamber for continuous measuring environment. The dynamic of table, the problem of servo control and the traceability for micro step motion are described. These data will be applied for getting more stable system with 50nm resolution.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.708-713
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• 2000

This paper reviews the concepts of the snake motion which can be often observed on the bodies moving along guide rails. A simple modelling is proposed in order to analyze the snake motion of the cross head assembly and force and moment equilibrium equations are established. It is determined the critical conditions at which snake motion just brings about. Some possible methods to reduce or prevent snake motion are discussed in detail.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.10a
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• pp.180-180
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• 2003

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.2
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• pp.199-206
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• 2016

Linear motion (LM) ball guides with rolling contact are core units of feed-drive systems. They are widely applied for precision machinery such as machine tools, semiconductor fabrication machines and robots. However, the friction force induced from LM ball guides generates heat, which deteriorates positioning accuracy and incurs changes of stiffness and preload. To accurately analyze the effects and apply the results to precision machine design, mathematical modeling of the friction force is required. In this paper, accurate formulation of the friction force due to rolling, viscous, and slip frictions is conducted for LM ball guides. To verify the reliability of the developed friction model, experiments are performed under various assembly, load and velocity conditions. Effects of frictional components are analyzed through the formulated friction model.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.135-138
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• 2011

As a basic research for the development of Korean lunar lander, propulsion system development for ground test is in progress. Thrust for descent is 200 N class. Design target is 220 N in vacuum thrust at 100 g/s flow rate, 200 psi chamber pressure. For ground test, thrust measurement system using LM guide was developed and test was performed. The result shows 160 N thrust in atmosphere condition at 210 psi chamber pressure.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.42-45
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• 2012

As a basic research for the development of Korean lunar lander, propulsion system development for ground test is in progress. Design target is 220 N in ground thrust at 130 g/s flow rate, 200 psi chamber pressure. For the performance improvement, two type injector and catalyst bed was designed. For ground test, thrust measurement system using LM guide was developed and test was performed. The result shows 214.1 N thrust in atmosphere condition at 126.6 g/s flow rate.