• Proceedings of the KWS Conference
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• 2000.04a
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• pp.178-180
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• 2000

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.2 no.2
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• pp.67-74
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• 2003

This paper presents the development of the Inspection machine for SMD mounted on cream solder of PCB. There are mounting errors of SMD such as misalignment, missing part, wrong orientation, wrong polarity and so on. The main hardware of the system consists of a machine vision part and a motion control part. Operating software has been developed in GUI environment to help user convenience. The Inspection Jobs consist of two procedures, that is, creation of the inspection reference data and automatic inspection. The Inspection reference data has a tree structure of linked list including PCB information, blocks, components, windows, and inspection methods. This paper presents versatile inspection methods which include a section length method, a projection method and histogram method. Therefore, user can choose the suitable procedure for various components. Finally, the automatic Inspection procedure using the reference data checks the mounting errors of components.

• Proceedings of the KWS Conference
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• 2000.04a
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• pp.174-177
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• 2000

• Journal of the Korea Society of Computer and Information
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• v.27 no.11
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• pp.115-121
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• 2022

In surface mount technology (SMT), the screen printer, which is an equipment for applying solder cream, has a lot of poor coating as the pad becomes smaller. To solve this problem, a jet printer is being used recently. However, if the nozzle at the end of the valve applied to the jet printer head is not cleaned, solder cream remains or an error occurs. To prevent this, the nozzles should be cleaned periodically. In this paper, a more stable cleaning method than the existing technology is presented for the stable application of solder cream on a jet printer. In this method, cut a 35mm wide mujin cloth, wrap it in a roll, and rotate it with a DC geared motor on the other side to clean it. As a result, it was confirmed that the solder paste was not left on the nozzle surface and was well wiped when cleaning with about 2,000 dotting cycles.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.1
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• pp.37-42
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• 2012

LIFT (laser-induced forward transfer) is an advanced laser processing method used for selectively transferring micron-sized objects. In our study, this process was applied in order to deposit solder balls in microsystem packaging processes for electronics. Locally melted solder paste could be transferred to a rigid substrate using laser pulses. A thin glass plate with a solder cream layer was used as a donor film, and an IR laser pulse (wavelength = 1070 nm) was used to transfer a micron-sized solder ball to the receptor. Mass balance and energy balance were applied to analyze the shape and temperature profiles of the solder paste drops. The transferred solder bumps had measured diameters of 30-40 ${\mu}m$ and thicknesses of 50 ${\mu}m$ in our experiment. The limits and applications of this method are also presented.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.605-608
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• 1996

The aim of this thesis is to develop a SMT-components placement inspection system equipped with a visual sensor. The visual sensor, which consists of a camera and 2-layer LED illuminator, developed to inspect the component placement state such as missing, shift, flipping, polarity and tomb-stone. on PCB in the reflow-process. In practical applications, however, it is too hard to classify component from images mixed pad on PCB, cream solder paste and component. To overcome the problem, this thesis proposes the 2-layer illumination method and the heuristic image processing algorithms according to inspection type. To show the effectiveness of the proposed approach, a series of experiments on the inspection were conducted. The results show that the proposed method is robust to visual noise and variations in component conditions.

• Clean Technology
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• v.10 no.2
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• pp.61-72
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• 2004

In this study, aqueous/semi-aqueous cleaning agents which consist of organic solvent, surfactant, cosurfactant, and water were developed by changing formulation parameters such as organic solvent type and contents, surfactant type and contents, and cosurfactant/surfactant(A/S) ratio, etc.. And physical properties and flux removal of the formulated cleaning agents have been evaluated. Also, the performance of oil-water separation from the rinse water contaminated during the cleaning process was evaluated for its recycling. The formulated cleaning agents in this work expected to have good penetration because of their low viscosity and low surface tension values of 30.2~32.5 dyne/cm. The flux removal with the terpene type cleaning agent was higher than that with hydrocarbon type cleaning agent and two commercial products (CPA(commercial product A), CPB(commercial product B)). And the performance of oil-water separation by gravity settling from the rinse water contaminated with formulated cleaning agent and soils was shown to be very good. The cleaning agents developed in this work were applied to surface mounting technology(SMT) cleaning process for manufacturing electronic parts at L electronic company. As a result, the newly developed cleaning agents showed two times better cleaning speed for removal of solder cream than the conventional ond containing ethanol and IPA(isopropyl alcohol). In addition, malodor and VOC problems generated by the previous organic cleaning agents have been solved in the manufacturing field through introduction of the non-volatile and environmental-friendly cleaning agents to the field.

• Journal of Platform Technology
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• v.8 no.1
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• pp.24-32
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• 2020

This paper designed and manufactured a chip mounter based on 3D printer technology that can be used for educational research or sample production to disseminate chip mounter, a core technology of SMT line. A stepper motor with open loop control is used for low cost drive design. The shortcomings of the motor's vibration and disassembly caused by the use of the step motor were compensated by the Micro-Step control method. In the chip mounter experiment, the gerber file was generated on the small chip mounter, printed at the actual size, and the solder cream was printed on the HASL-treated PCB in the same manner as the sample board fabrication. As a result of the experiment, unlike the 2012 micro components, parts such as SOIC and TQFP that require correction are twice as long as the component mounting time, but it can be confirmed that they are mounted relatively accurately. In addition, as a result of repeatedly measuring the error of the initial position 10 times, it was confirmed that a relatively small error of about 0.110mm occurs.