• Journal of Powder Materials
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• v.26 no.6
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• pp.508-514
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• 2019

In the development of advanced ceramic tools, material improvements and design freedom are critical in improving tool performance. However, in the die press molding method, many factors limit tool design and make it difficult to develop innovative advanced tools. Ceramic 3D printing facilitates the production of prototype samples for advanced tool development and the creation of complex tooling products. Furthermore, it is possible to respond to mass production requirements by reflecting the needs of the tool industry, which can be characterized by small quantities of various products. However, many problems remain in ensuring the reliability of ceramic tools for industrial use. In this study, alumina inserts, a representative ceramic tool, was manufactured using the digital light process (DLP), a 3D printing method. Alumina inserts prepared by 3D printing are pressurelessly sintered under the same conditions as coupon-type specimens prepared by press molding. After sintering, a hot isostatic pressing (HIP) treatment is performed to investigate the effects of relative density and microstructure changes on hardness and fracture toughness. Alumina inserts prepared by 3D printing show lower relative densities than coupon specimens prepared by powder molding but indicate similar hardness and higher fracture toughness values.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.05a
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• pp.106-109
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• 2001

The use of ceramic inserts in hot extrusion dies offers significant technical and economic advantages over other forms of manufacture. These potential benefits can however only be realized by optimal design of the tools so that the ceramic inserts are not subjected to stresses that lead to their premature failure. In this paper, process simulation and stress analysis are thus combined during the design, and a data exchange program has been developed that enables optimal design of the dies taking into account the elastic deflections generated in shrink fitting the die inserts and that caused by the stresses generated in the process. The stress analysis of the dies is used to determine the stress conditions on the ceramic insert by considering contact and interference effects under both mechanical and thermal loads. The results are compared with the experimental ones for verification.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.655-659
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• 2002

This study is performed to develop the Si$_3$N$_4$ based ceramic inserts. Si$_3$N$_4$with addition of SiC and A1$_2$O$_3$ is investigated to determine the possibility to be a new tool. The tool life of Si$_3$N$_4$ insert with more than 20wt% SiC is shorter than commercial Si$_3$N$_4$ insert during machining both heat treated SCM440 and gray cast iron. Even though SiC has higher hardness than Si$_3$N$_4$, its chemical affinity to the iron on high temperature may causes deteriorat ion of tool life. To the contrary, Si$_3$N$_4$insert with A1$_2$O$_3$ shows increase of tool life up to 300% compared to the commercial Si$_3$N$_4$insert. It may attribute to the high temperature stability of A1$_2$O$_3$. Further study will be focused on the optimization of ceramic inserts with the composition of Si$_3$N$_4$and A1$_2$O$_3$.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.9
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• pp.118-124
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• 2002

The use of ceramic inserts in hot extrusion dies offers significant technical and economic advantages over other forms of manufacture. In this paper, process simulation and stress analysis are thus combined during the design, and a data exchange program has been developed that enables optimal design of the dies taking into account the elastic deflections generated in shrink fitting the die inserts and that caused by the stresses generated in the process. The shrink fit analysis has been performed that enables optimal design of the dies taking into account the elastic deflections which generated in shrink fitting the die inserts and that caused by the stresses generated in the process and by using DEFORM software for process analysis. This data can be processed as load input data for a finite element die-stress analysis. Process simulation and stress analysis are thus combined during the die design. The stress analysis of the dies is used to determine the stress conditions on the ceramic insert by considering contact and interference effects under both mechanical and thermal loads. The results are compared with the experimental ones for verification.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.3
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• pp.9-17
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• 2000

The use of ceramic inserts in steel forging tools offers significant technical and economic advantages over other materi-als of manufacture. These potential benefits can however only be realised by optimal design of the tools so that the ceramic insert are not subjected to stresses that led to their premature failure. In this paper the data on loading of the tools is determined from a commercial forging simulation package as the contact stress distribution on the die-workpiece interface and as temperature distributions in the die. This data can be processed as load input data for a finite-element die-stress analysis. Process simulation and stress analysis are thus combined during the design and a data exchange program has been developed that enables optimal design of the dies taking into account the elastic detections generated in shrink fitting the die inserts and that caused by the stresses generated in the forging process. The stress analysis of the dies is used to determine the stress conditions on the ceramic insert by considering contact and interference effects under both mechanical and thermal loads. Simulation results have been validated as a result of experimental investigation. Laboratory tests on ceramic insert dies have verified the superior performance of the Zirconia and Silicon Nitride ceramic insert in order to prolong maintenance life.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.1
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• pp.32-37
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• 2002

The use of hexagonal ceramic inserts for copper extrusion dies offers significant technical and economic advantages over other forms of manufacture. In this paper the data on the loading of the tools is determined from a commercial FEM package as the contact stress distribution on the die-workpiece interface and as temperature distributions in the die. This data can be processed as load input data for a finite element die-stress analysis. Process simulation and stress analysis are thus combined during the design and a data exchange program has been developed that enables optimal design of the dies taking into account the elastic deflections generated in shrink fitting the die inserts and that caused by the stresses generated in the process. The stress analysis of the dies is used to determine the stress conditions on the ceramic insert by considering contact and interference effects under both mechanical and thermal loads.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2001.11a
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• pp.111-114
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• 2001

Optical transmitter and receiver are the essential components for optical communication. For these components, butterfly type packages are used which are comprised of metal housing, multilayer ceramic inserts, lead and window. In this study, 2.5 Gbps DFB(Distributed -Feedback) LD(Laser Diode) package was fabricated and characterized. Metal housing showed good thermal conductivity (200W/mK) and well matched TCE(6.7ppm/K) with GaAs chip. Ceramic inserts also showed good VSWR(Voltage Standing Wave Ratio) characteristics(<2.0). By brazing technology, all the elements were combined and sealed. RF characteristics of the package mounted on the PWB was also tested.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.04a
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• pp.72-77
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• 2001

The use of hexagonal ceramic inserts for copper extrusion dies offers significant technical and economic advantages over other forms of manufacture. In this paper the data on the loading of the tools is determined from a commercial FEM package as the contact stress distribution on the die-workpiece interface and as temperature distributions in the die. This data can be processed as load input data for a finite element die-stress analysis. Process simulation and stress analysis are thus combined during the design, and a data exchange program has been developed that enables optimal design of the dies taking into account the elastic deflections generated in shrink fitting the die inserts and that caused by the stresses generated in the process. The stress analysis of the dies is used to determine the stress conditions on the ceramic insert by considering contact and interference effects under both mechanical and thermal loads.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.11
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• pp.760-766
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• 2008

The characteristics of heat transfer and pressure drop of several different porous materials which can be used as inserts inside solar volumetric air receivers were experimentally investigated. Generally, porous materials were inserted into solar volumetric air receivers to increase the thermal performance. In the present work, honeycomb (diameter: 100 mm, thickness: 30 mm), laminated mesh (diameter: 100 mm, thickness: 1 mm) are considered as the inserts for the experiment. The experimental apparatus consists mainly of a cylindrical ceramic duct as a receiver and an electric heater as an energy source. This system is an intake open loop, which used as air of working fluid. The temperatures inside the ceramic tube are measured by thermocouples, which are installed at each layer of the porous materials. The pressure-drop experimental apparatus is fabricated alike the above experimental equipment. An acrylic tube is used like as the ceramic tube, which has the same specifications of the ceramic tube. The pressure drop of porous materials inserted in the acrylic tube is measured between front and rear of those by transmitter. The results show that the laminated mesh surpasses the honeycomb of heat transfer and pressure drop increase as the porous material thickness and Reynolds number.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.4 no.3
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• pp.67-76
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• 1995

An experimental study of hot machining has performed to improve the machinability of Inconel718. This experiment used plasma are for heating materials and Whisker0reinforce aluminum oxide ceramic tool insert. An assembled plasma heating system are described and experimental results from both conventional and plasma hot machining of Inconel 718 are compared. The experiments with plasma heating demonstrated the following effectiveness. 1)The cutting force was reduced with increasing surface temperature of workpiece from 450$^{\circ}C$ up to 720$^{\circ}C$ as much as approximately from 20 to 40%. 2) Surface roughness(Ra) was improved by as much as a factor 2 in case of one pass cutting with new ceramic tool inserts.3) The depth of cut notch were at promary cutting tool was significantly reduced.