• Transactions of Materials Processing
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• v.26 no.5
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• pp.277-285
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• 2017

Vehicle weight reduction is a known strategy to improve fuel efficiency and strengthen exhaust gas regulation. The use of high strength steel can satisfy safety, efficiency, emission, manufacturability, durability, and cost requirements. However, springback of high strength steel results in undesired shape defects. Springback is one of the most important issues of high strength steel for many applications in an automobile. Servo press has various capabilities to improve defects, process conditions, and productivity problems when forming a high strength steel. Especially, servo press can be set to function with variable slide motion in a single operation. In this study, the effect of servo press slide motion on 980MPa high strength steel was investigated through U-bending test.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.5
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• pp.881-888
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• 2022

Servo presses are used in variety of ways in industry throughout the production and assembly lines of machine parts. The bottom of the servo press is fixed to a bed or a tabletop, and the press cylinder continuously operates under vertical upward loads. In this research, a static structural analysis was performed by simplifying 3D model of the servo press, and the maximum deformation was applied to the clamp and bolt. The maximum value of Von Mises stress was reported in this paper. The result was used to calculate the safety factor, and it was confirmed that the design was conservative.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.813-814
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• 2013

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.252-252
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• 2000

The Resistance Spot Welding (RSW) has been considered as an inherently safe and reliable method far joining metals, and has been widely employed, especially in automobile body assembly shops, as a manufacturing process. In recent years, the requirement for more sophisticated quality control procedures has considerably grown in the mass production industries. The object of the application of servo control to spot welding gun is the improvement of quality control in the spot welding, one of conventional industrial areas. The important factors affecting welding qualities (shear strength, nuggest size, indentation depth) are welding current, welding time, and gun press force. Welding current and welding time are controlled by welding timer. But, the conventional welding guns using compressed air are out of control in changing gun press forces in welding process. In this paper, a servo gun welding system having a AC servo motor and a PC control system is presented. The main object of this paper is to estimate the influence of gun press force changes in the welding process (press time -> welding time -> hold time) to welding qualities, and to evaluate welding qualities in real time, by recognizing the patterns of gun press forces changed in the welding process and comparing with the standard patterns.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.819-820
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• 2013

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.821-822
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• 2013

• Journal of Advanced Navigation Technology
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• v.18 no.3
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• pp.248-252
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• 2014

In this paper, press and nut runner used in press-fit or tightening the bolts and nuts at assembling process of automobile parts companies continually demand accuracy and improved productivity. Simultaneous control of production systems through synchronization configuring of the combination multi press-fit system developed multi servo press system using the low-speed serial communication. As a result, the accuracy and the productivity is improved and product quality improvement could be achieved.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.829-830
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• 2013

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.2
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• pp.206-215
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• 2013

In this paper, a synchronization control technique of dual-servo motor driven press system is proposed. An independent cascade PID control technique has been applied to the conventional press system for advancement of control stability. However, it is not easy to reduce synchronous error using the independent cascade PID control technique when some different load disturbances are involved in each motor. The eccentric error of the slide caused by the problem degrade the control performance of the BDC(Bottom Dead Center). In order to achieve reduction of the synchronous error between two servo motors and accurate position control simultaneously, a new control scheme comprised with cascade PID control loop and cross-coupling loop is proposed. In simulation using Matlab SIMULINK, the AC servo system is designed. The control performance of proposed technique is compared with conventional control technique to the model of AC servo system. Also, the sub-scale model of dual-servo motor driven press system which can replicate the slide motion is constructed for experimental verification for the performance of the proposed control technique. The cross-coupling control technique reveals more precise and stable performances in the position and synchronization controls.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.817-818
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• 2013