• Journal of Powder Materials
• /
• v.8 no.4
• /
• pp.239-244
• /
• 2001

To investigate the effect of process parameters on selective laser sintering of Cu/polyamide mixed powder, Cu/polyamide mixed powder was sintered by selective laser with changing laser power and scanning speed. The properties of sintered body were evaluated by measuring the density and tensile strength, and analysis of XRD, FT-Raman and microstructure. With an increase in the laser power, the density and ultimate tensile strength of sintered Cu/polyamide body increase and then decrease. The maximum values of the density and ultimate tensile strength were decreased with increasing laser scanning speed. These changes were concerned with the difference of irradiation energy of laser into the powder layer. It was considered that the change of the mechanical property of the sintered body with irradiation energy of laser is due to the changes of amount of copper particle and property of polyamide.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.18 no.7
• /
• pp.97-103
• /
• 2019

Mn+1AXn (MAX) phases are a family of nano-laminated compounds that possess unique combination of typical ceramic properties and typical metallic properties. As a member of MAX-phase, $Ti_2AlN$ bulk materials are attractive for some high temperature applications. In this study, $Ti_2AlN$ bulk with high density were synthesized by spark plasma sintering method. X-ray diffraction, micro-hardness, electrical and thermal conductivity were measured to compare the effect of material properties both $Ti_2AlN$ bulk samples and a conventional Ti-6Al-4V alloy. A femto-second laser conditions were conducted at a repetition rate of 6 kHz and laser intensity of 50 %, 70% and 90 %, respectively, laser confocal microscope were used to evaluate the width and depth of ablation. Consequently, the laser ablation result of the $Ti_2AlN$ sample than that of the Ti-6Al-4V alloys show a considerably good ablation characteristics due to its higher thermal conductivity regardless of to high densification and high hardness.

• Transactions of Materials Processing
• /
• v.18 no.3
• /
• pp.262-267
• /
• 2009

Selective laser sintering is a kind of rapid prototyping process whereby a three-dimensional part is built layer wise by laser scanning the powder. This process is highly influenced by powder and laser parameters such as laser power, scan rate, fill spacing and layer thickness. Therefore a study on fabricating Fe-Ni-Cr powder by selective laser sintering has been performed. In this study, fabrication was performed by experimental facilities consisting of a 200W fiber laser which can be focused to 0.08mm and atmospheric chamber which can control atmospheric pressure with argon. With power increase or energy density decrease, line width was decreased and line surface quality was improved with energy density increase. Surface quality of quadrangle structure was improved with fill spacing optimization.

• Proceedings of the Korean Society of Laser Processing Conference
• /
• 2006.11a
• /
• pp.90-95
• /
• 2006

• Proceedings of the KSME Conference
• /
• 2007.05a
• /
• pp.1383-1388
• /
• 2007

Accuracy and processing time are very important factors when the desired shape is fabricated with Selective Laser Sintering (SLS), one of Solid Freeform Fabrication (SFF) systems. In a conventional SLS process, laser spot size is fixed during laser exposing on the sliced figure. Therefore, it is difficult to accurately and rapidly fabricate the desired shape. In this paper, to deal with those problems an SFF system having ability of changing spot size is developed. The system provides high accuracy and optimal processing time. Specifically, a variable beam expander is employed to adjust spot size for different figures on a sliced shape. Finally, Design and performance estimation of the SFF system employing a variable beam expander are achieved and the mechanism will be addressed to measure the real spot size generated from the variable beam expander.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.9 no.1
• /
• pp.30-37
• /
• 2000

In this paper rapid prototyping and precision casting technology have been developed for the manufacturing of inlet gear box of an airplane, Rapid prototyping is a new prototyping technology that produces complicated parts directly from three-dimensional CAD data with a high efficiency and has been extensively applied to various manufacturing processes. In the present work Selective Lase Sintering(SLS) system is utilized in order to manufacture prototype of the inlet gear box. Prototyping technology using SLS is also investigated from the viewpoint of accuracy. Using the SLS master the casting products are manufactured through several processes such as : vacuum casting lost wax shell casting and investment cast-ing. The shrinkage characteristics of wax and cast iron in the casting procedures are considered and then reflected to the design procedure so that the accuracy of the product is improved consequently.

• Korean Journal of Materials Research
• /
• v.8 no.7
• /
• pp.628-633
• /
• 1998

단사정 HBO2 분막을 무기접착제로 이용하여 선택적 레이저 소결 기술을 적용시켜 알루미나-글래스 복합재료를 제조하였다. 만들어진 green SLS 시험편을 여러 온도에서 열처리하여 글래스-세라믹 복합재료를 얻었다. 글래스의 양이 많을수록 복합재료는 높은 밀도와 높은 굽힘강도를 보여주었다. 열처리 온도 $900^{\circ}C$에서 복합재료는 최대 밀도와 최대 강도를 나타낸다. 이것은 글래스의 낮은 점도로 인한 좋은 유동성 때문에 글래스의 재분배가 이루어졌기에 가능하다고 생각되어진다. 그리고 기공이 많은 열처리한 SLS 시험편에 콜로이드 실리카를 주입시켜 치밀화시켰다.

• Proceedings of the KWS Conference
• /
• 1999.10a
• /
• pp.218-219
• /
• 1999

• Proceedings of the KWS Conference
• /
• 1999.05a
• /
• pp.13-16
• /
• 1999

• Journal of Welding and Joining
• /
• v.26 no.4
• /
• pp.34-37
• /
• 2008