• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2009년도 춘계학술대회 논문집
• /
• pp.1019-1020
• /
• 2009

• 한국정밀공학회지
• /
• 제29권8호
• /
• pp.824-833
• /
• 2012

The shrinkage and the warpage of the moulded part are influenced by the design of the product and injection mould. In a flat part with a partly thick volume, the warpage of the flat part is created from the difference of the shrinkage between thin and thick regions. The warpage of the flat part with a partly thick volume can be reduced by a proper design of the cooling system in the injection mould. The goal of this paper is to design properly cooling channels of injection mould to manufacture a flat part with a partly thick volume. The conformal cooling channel is adopted to improve cooling characteristics of a region with the thick volume. The linear cooling channels are assigned to the other region. The proper design of the conformal cooling channels is obtained from three-dimensional injection molding analysis for various design alternatives. The moulding characteristics of the designed mould with both conformal and linear cooling channels are compared to those of the mould with linear cooling channels from viewpoints of temperature, shrinkage and warpage of the moulded part using numerical analysis. Injection mould with both conformal and linear cooling channels for the flat part with a partially thick volume is fabricated. In addition, injection moulding experiments are performed using the fabricated mould. From the results of the injection moulding experiments, it has been shown that the designed mould can successfully fabricate the flat part with a partially thick volume.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2007년도 춘계학술대회A
• /
• pp.1243-1248
• /
• 2007

In recent, rapid manufacturing (RM) technology is widely used to develop an injection mould with a high performance. The objective of this paper is to develop the injection mould with a high productivity using a hybrid RM technology combining Laser-aided Direct Metal Tooling process with a machining process. The geometry decomposition has been utilized to improve the speed of the manufacturing for the mould. Mould with conformal cooling channels has been designed to improve cooling characteristics. Several experiments have been carried out to evaluate characteristics of the mould manufactured from the hybrid RM technology. In addition, injection molding tests have been performed to examine the performance of the manufactured mould. The results of the injection molding tests have been shown that a cooling time and the injection time of the designed mould are reduced to one-fifth and one-second that of the mould with convention cooling channels.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2010년도 추계학술대회 논문집
• /
• pp.883-884
• /
• 2010

• Journal of Welding and Joining
• /
• 제32권4호
• /
• pp.10-14
• /
• 2014

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.

• 대한기계학회논문집A
• /
• 제35권12호
• /
• pp.1647-1653
• /
• 2011

일반적으로 사출금형의 사출주기는 플라스틱 제품의 냉각 시간에 크게 좌우되는 데, 냉각회로를 적용하여 조절할 수 있다. 금형의 냉각회로는 전통적으로 기계가공을 통하여, 직선형상만을 생성할 수 있었지만, 최근 적층조형 방법의 개발로 코어 형상을 따라가는 형상적응형 냉각회로를 생성할 수 있게 되었다. 한편 금형의 다이 재질로 열저항력이 크고, 치수변화가 적은 H13 스틸이 널리 사용되고 있지만, 열전도율이 낮기 때문에 냉각효율은 높지 않다. 이러한 점에서 열전달 효율을 극대화 시킬 수 있는 방법으로 H13 스틸과 구리(Cu)를 기능적으로 혼합한 기능성 경사 복합재(FGM)를 적층조형을 이용하여 냉각회로에 적용하는 방안이 검토되고 있다. 이러한 시도로서 본 논문에서는 H13 스틸과 Cu 간의 FGM을 이용한 형상적응형 냉각회로의 모델링 방법을 제안하고자 한다.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2007년도 춘계학술대회 논문집
• /
• pp.721-722
• /
• 2007

• Design & Manufacturing
• /
• 제12권3호
• /
• pp.36-41
• /
• 2018

Metal 3D printing is very useful for making the injection molds containing complex conformal cooling channels. The most important issue of the 3D printed molds is cost and life cycle. However, powder bed fusion (PBF) methods are vulnerable to fatigue loading because of the presence of pores and rough surfaces. In the present study, the fatigue test was performed to obtain fatigue analysis input data for predicting the durability of a 3D printed injection mold core. The metal 3D printer used to manufacture the specimen was OPM250L from Sodick, and the metal powder material was maraging steel. The ultrasonic fatigue testing method was adopted for the fatigue test. A key advantage of the ultrasonic fatigue method is that $10^8{\sim}10^9$ long cycle test data or more could be obtained within a relatively short period. Based on the results of the experiment, the effect of heat treatment was negligible. However, there was an apparent difference in durability depending on the presence or absence of the surface treatment.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2006년도 추계학술대회 논문집
• /
• pp.193-194
• /
• 2006