• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.653-654
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• 2013

• Journal of the Korean Society for Precision Engineering
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• v.30 no.9
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• pp.1001-1006
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• 2013

Projection-based stereolithography is divided into constrained-surface and free-surface type according to controlling liquid layer. The constrained-surface type has a uniform layer thickness due to the use of a projection window, which covers the pattern generator such as liquid crystal display. However, the adhered resin on the projection window causes trouble and requires great separation force when the cured layer is separated from the window. To minimize the separation force, we developed a system to measure the separation force. The influence of material covering the pattern generator and the resin temperature is investigated in the system. Several structures according to the resin temperature and the velocity of z-axis elevation are compared. As a result, the fabrication condition to minimize the separation force reduces the process time.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.10
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• pp.917-923
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• 2015

3D Printing has a great advantage for its capabilities in manufacturing complicated structures in a reasonable manufacturing time, and thus is widely used in various fields. Due to the high cost of the equipment and material, a fairly acceptable equipment, the Projection Stereolithography Apparatus (PSLA), has been developed, using the projection pattern approach for the purpose of quick manufacturing. We evaluated its surface quality, as compared with that of other systems. The result is the development of a high-performance, low-cost 3D Printer and its operating software, using LCD and UV LED. Working materials for an optimal manufacturing are suggested in the research, along with some suggestions of basic approaches for enhancing the accuracy and quality of the manufactured structures.

• Journal of Venture Innovation
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• v.3 no.2
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• pp.95-109
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• 2020

The source of value-added creation in modern times has been transformed from material to man's value-added generating power, and ownership of the means of production has been converted from a particular landlord, capitalist to a person with value-added capacity, and a system of capital participation is needed beyond the profit-sharing system or performance incentive system in which workers of an enterprise participate in simple profits if they significantly increase the added value of the company. It is also necessary to introduce our private stock system as a means of addressing the problem of capital bias and for the stable development of capitalism. The purpose of Employee Stock Ownership Plans is to improve the economic and social status of workers and promote labor-management cooperation by allowing workers to acquire and hold shares of the stock company in which the employee ownership association is established through the employee ownership association, but the reality is that our stock ownership system has failed to achieve its purpose due to insufficient protection against the employee. In terms of welfare, the acquisition of our company shares should include active government support for the welfare of workers' ownership on a social welfare level rather than on the logic of the capital market, and in terms of investment, it would not be appropriate to apply the regulation for investor protection to see workers' acquisition of our company shares as 'investment' in the view of workers' willingness to own shares on the stock market. Therefore, as a way to support and deregulate employee's stock acquisition, 1. Expanding direct support, such as tax support, 2. As employee's stock ownership association is being discussed as a division's nature, it is less effective in terms of various management, not investment, and 3. Those who own stocks with 1% of the company's shares and 300 million won in face value will be classified as major shareholders. As a way to reduce the risk of management of our company owners and cooperative funds, As a measure to reduce the risk of management of our company owners and cooperative funds, only our employee shareholders' association shall manage the fund in a long-term deposit, and even though our employee's stock is managed by the association or company after the end of the deposit period, the management of each employee shall be allowed and In terms of improving the utilization of our company's stock and fund, 1. Employee's stockholders are prohibited from lending during the deposit period, but it is necessary to improve profitability by allowing them to borrow under strict restrictions, 2. It is necessary to make the use of the employee's welfare funds available for the preservation of losses, and to stipulate the redemption obligations of unlisted companies in order to improve the redemption system of our company.