DED방식의 적층가공을 통한 금형으로의 응용사례 및 효과

김우성,홍명표,김양곤,서창희,이종원,이성희,성지현,Kim, Woosung,Hong, Myungpyo,Kim, Yanggon,Suh, Chang Hee,Lee, Jongwon,Lee, Sunghee,Sung, Ji Hyun 대한용접접합학회 2014 대한용접·접합학회지 Vol.32 No.4

Laser aided Direct Metal Tooling(DMT) process is a kind of Additive Manufacturing processes (or 3D-Printing processes), which is developed for using various commercial steel powders such as P20, P21, SUS420, H13, D2 and other non-ferrous metal powders, aluminum alloys, titanium alloys, copper alloys and so on. The DMT process is a versatile process which can be applied to various fields like the mold industry, the medical industry, and the defense industry. Among of them, the application of DMT process to the mold industry is one of the most attractive and practical applications since the conformal cooling channel core of injection molds can be fabricated at the slightly expensive cost by using the hybrid fabrication method of DMT technology compared to the part fabricated with the machining technology. The main objectives of this study are to provide various characteristics of the parts made by DMT process compared to the same parts machined from bulk materials and prove the performance of the injection mold equipped with the conformal cooling channel core which is fabricated by the hybrid method of DMT process.

고체 추진제의 연소속도 증진 방안 연구

이선영(Sunyoung Lee),홍명표(Myungpyo Hong),이형진(Hyoungjin Lee) 한국추진공학회 2017 한국추진공학회 학술대회논문집 Vol.2017 No.5

본 연구에서는, 고연소속도 고체 추진제 개발을 위하여 금속연료인 Al 과 Zr이 도입된 HTPB/AP계 추진제의 연소특성에 대한 연구를 수행하였다. 고체 추진제의 연소특성은 연소속도와 압력지수로서 평가하였으며 연소속도 증진을 위한 연소촉매제로서 Butacene을 적용하여 추진제를 제조하였다. Al과 Zr이 도입된 추진제가 성능 및 연소 특성이 향상되었음을 보였다. In this study, we carried out the study on the combustion characteristics of HTPB/AP propellants with Al and Zr as fuel metal in order to develop the solid propellant with high burning rate. The major combustion characteristics of propellant were investigated as measuring of the burning rate and pressure exponent, and the HTPB/AP solid propellants were prepared with introducing Butacene as burning rate catalyst for the enhancement of burning rate. The propellant with Al and Zr was demonstrated the improvement of propellant performance and combustion characteristic.

Carbon black이 충전된 라이너 특성 연구

김정은(Jeongeun Kim),류태하(Taeha Ryu),홍명표(Myungpyo Hong) 한국추진공학회 2014 한국추진공학회지 Vol.18 No.2

In this study, the viscosity of carbon black filled HTPB liner, mechanical properties and bonding force between propellant and liner were investigated. It is difficult to apply carbon black filled HTPB liner to the motor case in using a horizontal centrifugal casting because of its high viscosity. This problem is solved as a ageing premix at 60℃. The viscosity of premix is drastically decreased from 464 to 200 poise after 6days ageing.

HTPB/AP계 고체 추진제의 연소속도 증진 방안 연구

이선영(Sunyoung Lee),류태하(Taeha Ryu),홍명표(Myungpyo Hong),이형진(Hyoungjin Lee) 한국추진공학회 2017 한국추진공학회지 Vol.21 No.4

In this paper, in order to control the burning rate and pressure exponent of HTPB/AP/Al based propellant for the improvement of performance, the effect of the size ratio of AP particles and various contents of Butacene as burning catalyst on combustion properties was investigated. In the propellant formulation with both 28 ㎛ Al of 23% and Butacene of 3%, the burning rate and pressure exponent were increased with increasing the contents of 9 ㎛ AP particles. And the burning rate was increased with increasing the contents of Butacene with showing the relatively low pressure exponent in the propellant containing Butacene. However, the significant variations of pressure exponent by contents of Butacene were not observed.

HTPB 바인더를 이용한 미 경화 추진제의 연소 특성

김낙현(Nakhyun Kim),김정은(Jungeun Kim),홍명표(Myungpyo Hong) 한국추진공학회 2016 한국추진공학회지 Vol.20 No.1

In this study, we examined the burning rate of the uncured propellant (with and without a curing agent application) in order to inspect the process of the HTPB solid propellant. The burning rate of the uncured propellant, that did not contain the curing agent, was approximately 9.7 mm/s at 1000 psi. In relation to the curing time, the burning rate was constant. The propellant, with the curing agent application, was approximately 8.1 mm/s showed a tendency of slowing as it burned. When the cure reaction rate was low, in accordance to the time, there were small changes in burn rate. However, when the cure reaction rate was high, the difference in burning rate was increased. The burning rate of a fully-cured propellant was approximately 6.8 mm/s, which appeared to be the lowest in order.

HTPB 바인더를 이용한 미 경화 추진제의 연소 특성

김낙현(Nakhyun Kim),김정은(Jungeun Kim),홍명표(Myungpyo Hong) 한국추진공학회 2015 한국추진공학회 학술대회논문집 Vol.2015 No.11

본 연구에서는 HTPB를 적용한 고체추진제의 공정간 검사를 위해 경화제를 넣기 전과 넣은 후의 미경화 추진제의 연소속도를 검토하였다. 그리고 경화제를 넣기 전 미 경화 추진제의 연소속도는 압력 1000psi에서 약 9.7mm/s 정도이며, 경화시간에 따른 연소속도 변화는 없었다. 경화제가 들어간 미 경화 추진제의 연소속도는 약 8.1mm/s로 시간에 따라 느려지는 경향을 보였다. 경화반응 속도가 느린 미 경화 추진제는 시간에 따라 연소속도가 서서히 느려졌으며, 경화반응 속도가 빠른 미 경화 추진제는 연소속도가 빠르게 느려지는 것을 확인할 수 있었다. 그리고 완전히 경화된 추진제의 연소속도는 약 6.8mm/s 정도로 가장 느린 것으로 나타났다. In this study, we examined the burning rate of the uncured propellant (with and without a curing agent application) in order to inspect the process of the HTPB solid propellant. The burning rate of the uncured propellant, that did not contain the curing agent, was approximately 9.7mm/s at 1000psi. In relation to the curing time, the burning rate was constant. The propellant, with the curing agent application, was approximately 8.1mm/s showed a tendency of slowing as it burned. When the cure reaction rate was low, in accordance to the time, there were small changes in burn rate. However, when the cure reaction rate was high, the difference in burning rate was increased. The burning rate of a fully-cured propellant was approximately 6.8mm/s, which appeared to be the lowest in order.

HTPB 뱃취별 추진제 특성 연구

김정은(Jeongeun Kim),류태하(Taeha Ryu),홍명표(Myungpyo Hong) 한국추진공학회 2015 한국추진공학회 학술대회논문집 Vol.2015 No.11

추진제의 주 바인더로 사용하고 있는 폴리부타디엔 계열인 HTPB(Hydroxyl Terminated Polybutadiene)는 합성 뱃취에 따라 바인더 및 추진제의 경화 속도에 영향을 미치는 현상을 보였다. 이에 본 연구는 HTPB의 서로 다른 뱃취를 사용하여 반응속도에 영향을 줄 수 있는 다양한 분석을 통하여 경화되는 시간에 따른 점도 상승을 확인하고, 추진제에 적용하였을 때 미치는 영향에 대해 연구하였다. In this study, we used four kind of HTPBs (Hydroxyl Terminated Polybutadiene), as a binder of the propellant, which are fabricated by different batch and/or condition, and investigated their chemical, viscosity build-up, mechanical properties of HTPB binder. We also applied the binders to the propellant and studied the effect of HTPB binder on the mechanical and viscosity build-up properties of propellant.

무노즐 부스터 적용을 위한 HTPB/AP/Zr계 고체 추진제의 연소속도 증진 연구

이선영(Sunyoung Lee),류태하(Taeha Ryu),홍명표(Myungpyo Hong),이형진(Hyoungjin Lee) 한국추진공학회 2017 한국추진공학회지 Vol.21 No.2

The study for the combustion characteristics of propellants for nozzleless boosters was carried out. The metal fuels of Al and Zr were introduced into solid propellant formulations in order to enhance the density-specific impulse and the high burning rate with low pressure exponent was investigated as the major combustion characteristic of propellant to design nozzleless boosters. The burning rate of Zr-containing propellant was higher than Al-containing propellant and, 13 ㎛ Zr-containing propellant exhibited the burning rate of 35 mm/s (at 1000 psi)and pressure exponent of 0.3282. The benefit of using Al and Zr-containing propellant into nozzleless boosters was demonstrated in these results.

HTPB 바인더가 추진제에 미치는 영향

김정은(Jeongeun Kim),류태하(Taeha Ryu),홍명표(Myungpyo Hong),이형진(Hyoungjin Lee) 한국추진공학회 2017 한국추진공학회 학술대회논문집 Vol.2017 No.5

추진제의 주 바인더로 사용하고 있는 폴리부타디엔 계열인 HTPB(Hydroxyl Terminated Polybutadiene)는 합성 뱃취에 따라 바인더 및 추진제의 경화 속도에 영향을 미치는 현상을 보였다. 이에 각기 다른 뱃취에서 합성된 HTPB의 바인더 특성 분석을 통해 추진제에 적용하여 경화반응 속도 및 기계적 특성을 확인하였다. 최종적으로 이러한 추진제의 경화 반응속도가 추진제 물성에 영향을 미치며, 우수한 물성의 추진제를 제조하기 위해서는 적절한 수준의 바인더의 경화 반응이 필요한 것으로 분석되었다. The polybutadiene-based HTPB used as the propellant main binder influences the curing reaction rate of the binder and propellant depending on the synthetic batch. The properties of HTPB synthesized in different batches were analyzed and applied to propellants to evaluate the curing reaction rate and mechanical properties. Finally this reaction can also affect mechanical properties of propellant. And the results suggest that proper degree of curing reaction is necessary to obtain better mechanical properties of propellant.

Carbon Black이 충전된 라이너 특성 연구

김정은(Jeongeun Kim),류태하(Taeha Ryu),홍명표(Myungpyo Hong) 한국추진공학회 2013 한국추진공학회 학술대회논문집 Vol.2013 No.12

본 연구에서는 HTPB에 보강제로 Carbon black이 충전된 라이너의 점도, 기계적 특성, 추진제와의 접착력을 고찰하였다. Carbon black이 충전된 라이너는 점도가 높아 수평원심 주조 방법으로 라이닝에 문제가 있었으나, 프리믹스를 60℃에서 숙성시킴으로써 프리믹스의 초기 점도는 464poise에서 6일 숙성 시 200poise로 점도를 대폭 감소됨에 따라 해결할 수 있었다. In this study, the viscosity of carbon black filled HTPB liner, mechanical properties and bonding force between propellant and liner were investigated. It is difficult to apply carbon black filled HTPB liner to the motor case in using a horizontal centrifuge lining process because of its high viscosity. This problem is solved as a ageing premix at 60℃. The viscosity of premix is drastically decreased from 464 to 200 poise after 6days ageing at 60℃.