• The Korean Journal of Ceramics
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• 제4권4호
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• pp.377-381
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• 1998

Wear behaviors of unidirectionally oriented $Si_3N_{4w)/Si_3N_4$ composites, sintered at different temperatures with different alignments of whiskers, have been studied in parallel and perpendicular sliding directions with respect to the orientation of the whiskers by using a ball-on-disk reciprocating sliding apparatus. The results show that wear rate in parallel direction is much greater than that in perpendicular direction. With decreasing alignment of the whiskers, the wear rate decreases in parallel sliding direction and increases in perpendicular direction. With increasing sintering temperature, the wear rate increases obviously in both parallel and perpendicular directions.

• 드라이브 ㆍ 컨트롤
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• 제10권1호
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• pp.56-60
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• 2013

• Tribology and Lubricants
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• 제30권2호
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• pp.116-123
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• 2014

The objective of this study is to model and simulate the nonlinear lubrication performance of the sliding part between the piston and cylinder wall in a hydrostatic swash-plate-type axial piston pump. A numerical algorithm is developed that facilitates simultaneous calculation of the rotating body motion and fluid film pressure to observe the fluid film geometry and power loss. It is assumed that solid asperity contact, so-called mixed lubrication in this study, invariably occurs in the swash-plate-type axial piston pump, which produces a higher lateral moment on the pistons than other types of hydrostatic machines. Two comparative mixed lubrication models, rigid and elastic, are used to determine the reaction force and sliding friction. The rigid model does not allow any elastic deformation in the partial lubrication area. The patch shapes, reactive forces, and virtual local elastic deformation in the partial lubrication area are obtained in the elastic contact model using a simple Hertz contact theory. The calculation results show that a higher reaction force and friction loss are obtained in the rigid model, indicating that solid deformation is a significant factor on the lubrication characteristics of the reciprocating piston part.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.207-208
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• 2002

In the present study, the friction and wear properties of boundary lubricated textured surfaces were investigated. The capability of textured surfaces to feed lubricant into the interface of a sliding contact and to isolate wear partices was studied and related to the properties of the textured surfaces. Well-defined surface textures were produced by lithography and anisotropic etching of silicon wafers. Different widths and distributions of parallel groves were manufactured and subsequently the wafers were PVD coated with thin wear resistant TiN or DLC coatings, retaining the substrate texture. The surfaces were evaluated in reciprocating sliding against a ball bearing steel ball under starved or boundary lubricated conditions.

• 제어로봇시스템학회논문지
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• 제7권5호
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• pp.399-406
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• 2001

This paper presents a dynamic modeling and a sliding mode controller for the high-speed/high-accuracy position control system. The selected target system is the wire bonder assembly which is used in the semiconductor assembly process. This system is a reciprocating one around the pivot point that consists of VCM(voice coil motor) as an actuator and transducer horn as a bonding tool. For the modeling elements, the sys-tem is divided into electrical circuit, magnetic circuit and mechanical system. Each system is modeled using the bond graph method and united into the full system. Two major aims are considered in the design of the controller. The first one is that the horn must track the given reference trajectory. The second one is that the controller must be realizable by using the DSP board. Computer simulation and experimental results show that the designed sliding mode controller provides better performance than the PID controller.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.807-810
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• 1995

The effects of weae particles on the friiction and wear behavior of metals in dry sliding conditions are presented. The tribological test were performed using pure metal specimens which were selected based on their degrees of compatibility and hardness ratio. Friction and wear experiments were conducted using both pin-on-disk and reciprocating pin-on-plate type tribotesters to investigate the effect of motion history. Experimental results show that in the case of dry sliding the frictional behavior observed during pin-on-disk test differed form that of pin-on-reciprocator test for the given set of material pairs. The friction coefficient and wear rate were found to be higher for the pin-on-disk tests. It is suspected that the sliding motion of the pin affects the wear particle dynamics, which in turn influences the frictional behavior. The effect of material pair properties seemed to be relatively smaller than that of wear particles. The results of this paper is expected to aid in the design of mechanical systems for best tribological performance.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 추계학술대회논문집 - 한국공작기계학회
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• pp.83-89
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• 2000

This paper presents a dynamic modeling and a sliding mode controller for the high-speed / high-accuracy position control system. Selected target system is the wire bonder head assembly which is used in semiconductor assembly process. This system is a reciprocating one around the pivot point that consists of VCM(voice coil motor) as a actuator and transducer horn as a bonding tool. For the modeling elements, the system is divided into electrical circuit, magnetic circuit and mechanical system. Each system is modeled by using the bond graph method and united into the full system. Two major aims are considered in the design of the controller. The first one is that the horn must track the given reference trajectory. The second one is that the controller must be realizable by using the DSP board. Computer simulation and experimental results show that the designed sliding mode controller provides better performance than the PID controller.

• 한국공작기계학회논문집
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• 제15권4호
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• pp.39-43
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• 2006

A computer-controlled micro tribotester has been developed to investigate the friction and wear characteristics of thin coatings, which can be applied to silicon-based materials. In the developed system, a step motor gives a reciprocating movement and an electromagnet applies a load between a ball and a plate specimen. Test results confirmed that the application of load in the range of $0.03{\sim}1.8N$ and with a sliding speed of $4.44{\sim}7.70mm/s$ was successfully accomplished. Advantages of the developed micro tribotester are: (1) realization of micro load and displacement applicable to micro electromechanical systems(MEMS) using DC motor and electromagnet (2) continuously variable load and reciprocating speed; and (3) high reliability, which allows for unattended use for long periods.

• Tribology and Lubricants
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• 제18권2호
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• pp.143-146
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• 2002

The effects of contact configuration and kinematic motion on the wear of ultrahigh molecular weight polyethylene (UHMWPE) were investigated. Two different contact configurations were adopted for wear testing under the two different kinematic motions with un-irradiated UHMWPE specimens. Wear of UHMWPE pins against the linear reciprocating stainless steel disks was 8% higher than that against the uni-directional repeat pass rotating disks. Wear of UHMWPE disks moving in the linear reciprocating motion against stainless steel ball was 37% higher than that moving in the uni-directional repeat pass rotating motion. The results in this study show that the contact configuration and kinematic motion of sliding definitely affect the wear of UHMWPE through the differences in the contact stress states of UHMWPE.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2001년도 제33회 춘계학술대회 개최
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• pp.100-104
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• 2001

The effects of contact configuration and kinematic motion on the wear of ultrahigh molecular weight polyethylene (UHMWPE) were investigated. Two different contact configurations were adopted for wear testing under the two different kinematic motions with un-irradiated UHMWPE specimens. Wear of UHMWPE pins against the linear reciprocating stainless steel disks was 8% higher than that against the uni-directional repeat pass rotating disks. Wear of UHMWPE disks moving in the linear reciprocating motion against stainless steel ball was 37% higher than that moving in the uni-directional repeat pass rotating motion. The results in this study show that the contact configuration and kinematic motion of sliding definitely affect the wear of UHMWPE through the differences in the contact stress states of UHMWPE.