1960년대 경제개발 5개년 계획의 시작과 함께 우리나라 과학기술의 발전을 위한 투자가 본격화되었고, 과학기술 혁신이 정부정책의 가장 중요한 시책으로 부각되었다. 지난 40 여 년간 우리나라 과학기술은 선진기술의 모방에서 출발하여 효율적으로 단계별 성장을 거치면서 2000 년대에는 세계수준의 지식 및 기술을 창출할 수 있는 토대가 마련되었다. 본 발표에서는 한국과학기술의 현주소와 향후 전망을 분석하여 국내 연구개발의 방향을 조명해 보고자 한다. 1982년 특정연구개발사업을 시작으로 국가적 차원에서 목표설정 및 연구개발 자원을 전략적으로 집결하여 다양한 국가 연구개발 사업들이 수행되어 왔다. 그 후 20여년이 지난 현재 20개 부처에서 200 여개의 국가 연구개발사업이 추진되고 있으며, 이러한 연구개발사업의 성과로서 DRAM, TFT-LCD, CDMA 등 첨단 분야에서 세계 최고 수준의 국제경쟁력을 갖춘 기술들이 다수 확보되었다. 주력 산업인 IT산업, 자동차, 철강, 조선, 섬유 등도 기술혁신에 의한 국제 경쟁력 강화로 수출이 확대되면서 우리 경제의 견인차 역할을 하고 있다 최근 10년간 연구개발 투자규모는 3배 이상 증가하여 2000년 기준으로 세계 8위의 투자규모를 달성하였으며, 민간의 연구개발 투자 비중도 크게 늘어나 민간주도형 연구개발체제로 전환되게 되었다. 2001년에 이르러서는 총연구비 투자규모가 15조 이상으로서 이는 전체 GDP의 ∼3% 에 해당되는 수치이며 선진국 수준에 육박하고 있음을 짐작 할 수 있다. 지식기반사회를 선도하여 국가 경쟁력을 높이기 위해 정부는 연구개발 투자를 계속 확대할 정책을 시도하고 있으며 창의적 과학기술인력의 양성 체제 구축 및 효율적인 활용에도 적극 투자하고 있다. 과학기술부는 과학기술혁신의 중추적 역할을 담당하고 있으며 현재까지 20,000여개이상의 과제를 수행하여 국가경쟁력 강화에 크게 기여하여왔다. 정부는 국내외 과학기술 환경변화가 심한 21세기를 맞이하여 새로운 기회와 도약을 위하여 과학기술 중심국가 건설이라는 새로운 비전을 제시하게 되었다. vision 2025를 통해 2025년까지 21세기 첫 4반세기 동안 과학기술 경쟁력을 세계적인 수준으로 끌어올려 과학기술에 기반을 둔 선진국 진입을 실현하고자 다양한 정책적 대응을 물색하고 있다. 세계 시장규모, 전략적 중요성 등을 토대로 한 10대 산업을 육성하기 위하여 과학기술부는 기술수요조사를 바탕으로 49개 주요기술을 도출하여, 과학기술 일류 국가 실현, 국민소득 2만불 달성이라는 국가적 슬로건을 내걸고 “차세대 성장동력” 창출을 위한 범정부차원의 기획과 연구비의 집중투자를 추진하고 있다.

In hot forming process of the backward end-bulkhead of a pressure hull, the blank diameter and the tool clearance are the critical factors which influence wrinkling defect, forming load and shape completeness of the product. Two F.E.A softwares with the elasto-plastic material model and rigid plastic model were utilized to predict the occurrence of wrinkling defect. Tool clearance was determined by considering the increase of blank thickness, die strength and the stretching effect. Heat treatment condition after the hot forming to recover the original properties of the material was estabilished by specimen-based heat treating experiment.

The articulated piston that was used to more powerful diesel engine was composed by Al casted skirt part and steel forged crown part. this paper has the target to design the forging process of crown part. The parameters of piston design and forging process design were gotten based on work experience, experimental data, approximately calculated data and finite element analysis. Preform design parameter decided using the Taguchi method. Through this research, could design optimal shape of preform and produce prototype of the articulated piston

The improvement of dimensional accuracy for forged part is one of major goals in cold forging industry. There are many problems in controlling the dimension only by the trial-and-error, especially for a precision forged gear. A FEM analysis has been used in developing the forging technology. However, FE techniques have to be reconfirmed for predicting accurately the dimension of forged part. In this study, the effects of elastic characteristics and temperature changes are investigated by the comparisons between experimental and FEA in cold forging. When FE models related with elastic characteristics are considered as reality, FE results could predict the part dimension within the range of 10 $\mu\textrm{m}$. And if temperature also is considered really, the predicted dimensions are well coincided with the experimental down to about 5$\mu\textrm{m}$.

In metal working, cold forging that has profit to satisfy dimension accuracy is using in various manufacturing products. Recently, most of the interest thing is precision forging of gear. Gear forging product is more strength than broaching gear, and it has many advantages with reduction of factory expenses. The reason of difficulty to improve accuracy of gear dimension compare to another products is the dimension accuracy is very high, approximately 10$\mu\textrm{m}$, and because die of involute teeth and elastic strain of forged tool differ from standard curve. This paper represent quantitative analysis of die and teeth of forged tool, namely difference of curves, with experiments and analyze the factor of dimension gap, finally, will design compensated involute curve.

Steam Generator has been manufactured by welding process after partial manufacturing of various steel forgings such as shell, head and tube sheet. Usually, these steel forgings are made by open die forging process. After steel melting and ingot making, open die forging has been carried out to get a good quality which means high soundness and homogeniety of the steel forgings by using high capacity hydraulic press. This paper introduced open die forging development status of the large steel forgings which is used for the steam generator of 1,400MW next generation nuclear power plant.

To develop bevel gear dies that have characteristics of high precision and enough life time, the technology of die manufacturing and design which increase the resistance of wear and fatigue is essentially needed. Here in the study, we have investigated several materials for dies and electrode. And, the most economical and suitable electrode material has been selected through the characteristic analysis of electrode materials such as copper, graphite and chromium copper. With the help of CAD/CAM/CAE, the total manufacturing system of high precision electrode for bevel gear has been established.

Hot-forging Process and die design was made for a large-scale compressor wheel of Ti-6Al-4V alloy with 2-D FE analysis. The design integrated the geometry-controlled approach and dynamic materials modelling(DMM). In order to obtain the processing contour map of Ti-6Al-4V alloy based on DMM, compression tests were carried out in the temperature range of 915$^{\circ}C$ to 1015$^{\circ}C$ and the strain range of 10$\^$-3/s$\^$-1/ to 10s$\^$-1/. In the die design of the compressor wheel using the rigid-plastic FE analysis, forging dimensional accuracy, the capacity of the forging machine and defect-free forging were considered as main design factors. The microstructure of hot forged wheel using the designed die showed a typical alpha-beta structure without forging-defects.

The continuous casting is primarily a heat-extraction process in which the heat transfer at various cooling zones profoundly influences quality of products. So development of numerical model is necessarily needed for more specific and clear investigations upon heat transfer mechanism at mold and secondary cooling zones. In this study, heat transfer coefficients which shows the characteristic of heat transfer mechanism in mold are calculated for more exact analysis with temperatures measured in bloom mold using optimal algorithm, and finally the validity of cooling conditions at secondary cooling zone which is actually used at field for 30 Ton bloom type continuous casting of 0.187%C is investigated. From the results of solidification analysis, the characteristic of bloom mold shows good agreements with that of previously studies by other authors and optimized cooling conditions for 0.187%C are presented.

Rotor in small-medium induction motor has been usually manufactured by aluminum diecasting. In order to improve efficiency of induction motors, however, it is desirable that pure aluminum is replaced by high electrical conductivity copper alloy. For this purpose, a rotor is thixoformed with Cu-Ca alloy. Thermomechanical processing(TMP) is carried out to modify the semi-solid microstructure of the alloy and final microstructures and filling defects of thixoformed Cu- rotors are investigated. The characteristics of thixoformed Cu-rotor such as motor efficiency and torque are compared with those of Al rotor.

Semi-solid forming is the process of stirring alloy during solidification, making the mixture of liquid and solid, solidifying it, reheating it to the solid-liquid coexistent temperature, and then injecting this semi solid slurry into dies. In the semi-solid die casting process, it is very important to find out the correlation of injection condition, microstructure and mechanical properties. Especially, an improper injection condition is the main cause of liquid segregation and non-homogeneous mechanical properties due to the difference of solid fraction according to the position of the products. To ensure the database requisite to the semi-solid die casting product, it is essential to acquire the mechanical properties considering liquid segregation to the injection condition. In this study, the effect of injection condition on liquid segregation, formability, microstructure and mechanical properties in a thin product was investigated.

The authors have settled general modular design by analyzing related literatures, but general modular design are too massive to be applicable to all process devices. So, the common parts have to be selected, applied, and modified for the devices. We have chosen the dry pulverizing/mixing device for example. We have elected the target modules of this device such as flange, hinge, bolt, nut coupling. The remote assembling and disassembling possibilities of the selected modules have been analyzed from the viewpoints of visibility, interference, approach, weight and so on. We have presented final modular design proper to the target modules. The modular designs which have adopted the modular property been analyzed. The modular design points are comprised of common and unique points. Some points are common for several devices, such as bolt, flange and so on. Others are unique for each device, such as power transmission coupling. The experimental devices have been modified by these modular design points and the design drawings have been presented.

Heat treatment is one of the critical manufacturing processes that determine the quality of a product. This paper presents experimental and analytical results for the quench of a ring gear in stagnant oil. The goal of this study is to develop heat transfer predicting model in an overall analysis of the quenching process. Thermal conductivities which are dependant on temperatures and convection coefficients which are obtained by inverse method are used to develop the accurate heat transfer model. The results of heat transfer model have a good agreement with experimental results.

Almost all injection molds have multi-cavity runner system for productivity and are designed with geometrically balanced runner system in order to minimize filling imbalance between cavity to cavity during processing. However, filling imbalances have been observed though geometrically balanced runner lay-out are used. Generally, these filling imbalances are due to thermal unbalance, viscosity, characteristic of polymers and so on. These kinds of filling imbalances has already been reported by Beaumont[1] since 1997. In this study, we presented filling imbalaces in balanced runner that has unnary branch type lay-out through experimental tests. As a result of experiments, we could present the processing conditions for the balanced filling in geometrically balanced runner that has unnary branch type lay-out

Glass molding is an advantageous method to manufacture glass micro optical components. However, it is difficult to make tungsten carbide core for glass molded micro optics way. We have developed novel method to fabricate tungsten carbide core for glass molding of glass micro optical components. Silicon masters were fabricated by micro machining. Tungsten Carbide cores were fabricated by forming, sintering and coating. Finally we fabricated glass molded V-groove with pitch of 192$\mu\textrm{m}$ and glass microlens way with lens diameter of 36∼225$\mu\textrm{m}$ by the present method.

Transcribability of pit or land groove structures in replicating an optical disk substrate greatly affects the performance of a high-density optical disk. However, a solidified layer, generated during the polymer filling, deteriorates transcribability because the solidified layer prevents the polymer melt in filling the sub-micro patterns. Therefore, the development of the solidified layer during filling stage of injection molding must be delayed. For this delay, passive heating by insulation layer has been used. In the present study, to examine the development of the solidified layer delayed by passive heating, the flow of polymer melt with passive heating was analyzed. Passive heating markedly delayed the development of the solidified layer, reduced the viscosity of the polymer melt, and increased the fluidity of the polymer melt in the vicinity of the stamper surface with the sub-micro patterns. As a result, we predict that passive heating can improve transcribability of an optical disk substrate. To verify our prediction, we fabricated an optical disk substrate by using passive heating of a mold and measured the transcribability.

In this paper, The optimum design of a die shape has been carried out the FEM analysis of a pilger mill process considering various factors. The pilger mill forming process consists of a pair of rotating die which has appropriate surface shape. The important design parameters of the pilger mill are the feed rate and the profile of grooved die. Optimum design procedure was performed in order to investigated effects on the forming load and the deformed shape of material depending on the die radius profile. Profile of the die surface for the optimum design were suggested with the linear, the cosine and the quadratic curve considering a physical forming process. The surface of each die was modeled using the 3DAutoCAD and the analysis of pilger forming process was performed using the LS-DYNA3D. The optimum profile of the die shape for the pilger mill was determined to the quadratic profile. Since the analysis results provide that the model of the quadratic profile gives the lowest forming load and a proper deformed shape.

Nano-scratch tests were performed on PMMA thin films spin-coated on a Si substrate using an atomic force microscopy (AFM) with loads ranging from 10nN to 100nN. At low applied loads, a ridge pattern was formed on the PMMA surface. No wear particles were observed during the pattern-forming mild wear. At high applied loads, severe wear occurred accompanied by wear particles. The film with the highest hardness showed the highest wear resistance. Friction force generated during the Scratching was closely related with surface deformation of the film.

Recently, various bulk metallic glasses (BMG's) haying good mechanical and chemical properties were developed. BMG's can easily be deformed in the supercooled liquid region, via viscous flow mechanism. In our previous work, we evaluated the deformation behavior and some other basic properties of Z $r_{41.2}$ $Ti_{13.8}$C $u_{12.5}$N $i_{10}$B $e_{22.5}$ alloy. In this study, we investigated the micro forming of Z $r_{41.2}$ $Ti_{13.8}$C $u_{12.5}$N $i_{10}$B $e_{22.5}$ alloy. The process condition was chosen based on the viscosity data from TMA, and superalloy and Si wafer with micro patterns on the surface were used as forming die. The alloy showed good replication of the patterns. However, some stripe patterns, resembling scratches, appeared on the deformed alloy surface. These scratches can be reduced or eliminated by polishing before forming.ing.ore forming.ing.

Globally, the various machine components, as in electronics and communications, are demanded to being high-performance and micro-scale with abrupt development of the fields of computers, mobile communications. As this current tendency, production of the parts that must have high accuracy, so called milli-structure, are accomplished by the method of top-down, differently as in the techniques of MEMS, NANO. But, in the case of milli-structure, production procedure is highly costs, difficult and demands more accurate dimension than the conservative forming, processing technique. In this paper, forming analysis of the micro-former as the milli-structure are performed and then calculate the punch force etc. This information calculated is applied to decide the forming capacity of micro-former and design the process of forming stage, dimension of dies in another forming bodies. And, for the better precise forming analysis, elasto-plastic analysis is to be performed, then the consideration about effect of elastic recovery when punch and die are unloaded, have to be discussed in change of dimensions.

Recent electronic equipment becomes smaller, more functional, and more complex. According to these trends, LTCC(low temperature co-fired ceramic) has been emerged as a promising technology in packaging industry. It consists of multi-layer ceramic sheet, and the circuit has 3D structure. In this technology via hole formation plays an important role because it provides an electric path for the packaging interconnection network. Therefore via hole quality is very important for ensuring performance of LTCC product. Via holes are formed on the green sheet that consists of ceramic(before sintering) layer and PET(polyethylene Terephthalate) one. In this paper we found the correlation between hole quality and process condition such as ceramic thickness, and tool size. The shear behavior of double layer sheet by micro hole punching which is different from that of single layer one was also discussed.

The sheet metal shearing process is normally used in the precision elements such as semi-conductor components. In precision elements, burrs usually reduce the quality of machined parts and cause interference, jamming and misalignment during assembly procedures and because of their sharpness, they can be safety hazard to personnel. Furthermore, not only burrs are hard to predict and avoid, but also deburring, the process of removing burrs, is time-consuming and costly. In order to get the burr-free parts, therefore, we developed the precise burr measuring system using the laser. Using the X-Y precious table, we used vertical measuring method. Through the laser measurement system, we gain the minute analog signal, so this signal was amplified by the electric circuit. Finally, we gained the realtime burr data using A/D converter, PC. By introducing the novel laser measuring method which employing vertical measurement mechanism, we could get fast and precious burr data. Through the experiments, the accuracy of the developed system is proved. The burr height measured during the punching process can be used for automatic deburring and in-situ aligning.

Hem quality can be determined mainly by turn-down and roll-in. Turn-down, that is created by the elastic recovery, can't be easily detected and measured since it is usually as small as 0.03 m. This study is focused on the precise evaluation of the hemming defects through analytical and experimetal approaches, and on the investigation of the influence of process parameters on the final hem quality. Implicit finite element analysis of plane-strain hemming process is performed by using a commercial code ABAQUS/Standard. Experiment and measurement is also carried out for steel and aluminium sheet metals, and the results are compared with those of analysis.

Warm deep drawing which is one of the new forming technologies to improve formability of sheet metal is applied to the cylindrical cup drawing of Mg-alloy sheet metal. In experiments the temperature of die and blank holder is varied from room temperature to $300^{\circ}C$, while the punch is cooled by circulation of coolant to increase the fracture strength of workpiece on the punch corner area. Test material chosen for experiments is AZ31 magnesium sheet metal. Teflon film as a lubricant is used on both sides of a workpiece. The limit drawing ratio as well as thickness distributions of drawn cups are investigated and validity of warm deep drawing process is also discussed.

A new form-joining process with the aid of an adhesive is proposed in which an epoxy adhesive is applied to a sheet metal pair, and before it cures the pair is clinched to cause the geometric constraint in the form of a protrusion. In order to reduce the forming load and the height of protrusions, a new die and punch set with a very small clearance was devised to reduce the depth of drawing and the forming load. Taguchi method was employed to find the optimal values of design parameters. To implement each case of the orthogonal array, the finite element method was used. The experiments showed that on the tensile-shear test, the bonding strength of the new form-joining process with an epoxy adhesive is approximately the same as that of the resistance spot welding; and in comparison with the other two form-joining processes with an epoxy adhesive, the height of protrusions was reduced by more than 65 percent and the forming load by 50 percent.

The U-draw bending operation is known as a representative test method for springback evaluation of sheet metals since the sheet in U-draw bending operation undergoes stretching, bending and unbending deformations occurred at read stamping process. In this study, a simplified approach was proposed for predicting springback and side-wall curls in U-draw bending operations, using moment-curvature relationships derived for sheets undergoing stretching, bending and unbending deformation.

Asymmetric rolling, in which the ratio of the rotation rates of the upper and lower rolls was 2, has been used to introduce an intense plastic shear strain for the purpose of grain refinement and developing shear deformation textures through the sheet thickness to improve the strength and plastic strain ratio of AA1050 aluminum alloy sheets. The alloy sheets were rolled at room temperature without lubrication. The textures and microstructures of the sheets were investigated by x-ray diffraction and electron back-scattered diffraction (EBSD) analyses with emphasis on effects of combinations of rot ling directions.

Recrystallization textures of ferritic stainless steel sheets of STS 430, the crystallographic texture was modified by means of cross rolling and subsequent annealing. The conventional normal rolling led to the formation of ｛334｝＜483＞ in the final recrystallization texture. Cross rolling in the present work was performed by a 45$^{\circ}$rotation of RD around ND. After recrystallization annealing the cross-rolled samples displayed stronger｛111｝//ND orientations. The cross rolled sample displayed a higher resistance against ridging.

Sandwich sheet samples comprising AA1050/AA1050/AA1050, AA3003/AA1050/AA3003, AA3003 AA3003 AA3003. AA1050/AA3003/AA1050, SUS430/AA3003/SUS430, AA3003/SUS430/AA3003 and SUS430/SUS430/SUS430 were cold rolled in order to clarify the evolution of strain states md textures in the sandwich samples. To investigate the effect of stacking sequences of the samples on strain and texture, the relative contribution of each layer to the total reduction was measured and textures of the mid-layer sheet of sandwich samples were determined.

The drawbead is an important part in sheet metal forming for automotive part and its effect is affected by various process parameters. Therefore in this study, drawbead friction test was performed at various process parameters - panels (cold rolled and galvanized sheet steel), lubricants (having three different viscosities), bead materials(steel, iron) and surface treatment of bead (Cr plating). Circular shape bead has been used for the test. The results show that friction and drawing characteristics were mainly influenced by the nature of zinc coating, viscosity of lubricants, surface treatment of a bead and hardness of coated layer.

In order to evaluate spring-back behavior in automotive sheet forming processes, a panel shape idealized as a SS-rail has been investigated. After spring-back kas been predicted fer SS-rails using the finite element analysis, results has been compared with experimental measurements for three automotive sheets. To account for hardening behavior such as the Bauschinger and transient effects in addition to anisotropic behavior, the combined isotropic-kinematic hardening law based on the Chaboche type single-surface model and a recently developed non-quadratic anisotropic yield function have been utilized, respectively.

In order to achieve reliable but cost-effective crash simulations of stamped parts, sheet forming process effects were incorporated in simulations using the ideal forming theory mixed with the 3D hybrid membrane/shell method, while the subsequent crash simulations were carried out using a dynamic explicit finite element code. Example solutions performed for forming and crash simulations of I- and S-shaped rails verified that the proposed approach is cost-effective without sacrificing accuracy. The method required a significantly small amount of additional computation time, less than 3% for the specific examples, to incorporate sheet forming effects to crash simulations. As for the constitutive equation, the combined isotropic-kinematic hardening law and the non-quadratic anisotropic yield stress potential as well as its conjugate strain-rate potential were used to describe the anisotropy of AA6114-T4 aluminum alloy sheets.

In order to examine the springback of aluminum alloy sheets, AL1050 and AL5052, in the warm forming which forms the sheet above room temperature, the stretch bending and draw bending tests in various working temperatures were carried out. While the springbacks of AL5052 and AL1050 are tremendously reduced over 150$^{\circ}C$ in the stretch bending test, the springbacks in the draw bending test are rapidly reduced in 150$^{\circ}C$-200$^{\circ}C$ for AL5052 and 200$^{\circ}C$-250$^{\circ}C$ for AL1050. Using the FEM program, the forming and springback processes are analyzed. Though springback amounts of analysis result are slightly bigger than those of experiment, they showed the same trend in the decreasing springback as the forming temperature increases.

Sheets of aluminum alloy 1050 were asymmetrically cold rolled in a rolling mill with different roll speeds. In order to promote the shear deformation during asymmetrical rolling, cold rolling without lubrication was performed. The variation of the shear strain state during asymmetrical rolling was tackled by means of FEM calculations. Asymmetrical rolling gave rise to the development of pronounced residual shear strain gradients throughout the thickness layers.

The remeshing algorithm using the constrained Delaunay method adapted to the mesh density map is developed. In the finite element simulation of forging process, the numerical error increases as the process goes on. However, it is not desirable to use a uniformly fine mesh in the whole domain. Therefore, it is necessary to reduce the analysis error by constructing locally fine mesh at the region where the error is concentrated such as die corner. In this paper, the point insertion algorithm is used and mesh size is controlled by using a mesh density map constructed with a posteriori error estimation. And an optimized smoothing technique is adapted to have smooth distribution and improve the quality of the mesh.

The large deformation at cryogenic temperature would be one of the effective methods to produce large bulk UFG materials. The effects of annealing temperature 150∼300$^{\circ}C$, on microstructure and mechanical properties of the sheets received 85% reduction at cryogenic temperature were investigated. In comparison with those at room temperature. Annealing of 5083 Al alloy deformed 85%, at 200$^{\circ}C$ for an hour, results in the considerable increase of tensile elongation without the great loss of strength and the occurrence of equiaxed grains less than 300nm in diameter.

Instrumented indentation tests have been used for estimating material properties. In order to analyze deformation characteristics with various factors, the unloading stiffness should be properly determined from the elastic behaviour. In general, the unloading stiffness is obtained from shifted power functions fitting to indentation unloading curves. But, the functions give often a poor representation of actual data. In this study, control conditions for fitting unloading curves by shifted power functions were investigated. The current efforts may provide useful information about unloading process and valid unloading stiffness.

Thermomechanical behavior of Al-Mg-Si alloys have been studied to investigate the effect of microstructural features such as pre-existing substructure and distribution of particles on the deformation characteristics. The controlled compression tests have been carried out to get the basic information on how the alloy responds to temperature, strain amount and strain rate. Then hot forging of Al-Mg-Si alloys has been carried out and analyzed by the comparison with the compression tests. Microstructural features after forging have been discussed in terms of the thermomechanical response of Al-Mg-Si alloys. As already well mentioned, we have found that the deformation of Al-Mg-Si at the elevated temperature brought the recovered structure on most conditions. In a certain time, however, abnormally large grains have been found as a result of deformation assisted grain growth, which means that hot forging of Al-Mg-Si alloys could lead to a undesirable microstructural variation and the consequent mechanical properties such as fatigue strength.

Strip samples of AA 3103 were deformed by Continuous confined strip shearing (CCSS). The CCSS process was designed to provide a repeated shear deformation in metallic sheet materials. CCSS led to the formation of characteristic shear textures comprising a pronounced｛111｝＜uvw＞ orientations. The intensity of the deformation texture hardly increased with increasing number of CCSS passes. EBSD equipped in a FESEM with a high beam current revealed the formation of fine grains even after annealing for the recrystallization.

Equal channel angular pressing (ECAP) provides an efficient procedure for introducing an ultrafine grain size into a material. In this study, ECAP were conducted on IF-steel to investigate the effect of friction and processing temperatures on the deformation characteristics of the samples. Due to the blocking effect of the previously pressed samples residing in the exit channel, the shear pattern (especially on the bottom region) changes.

A finite element-based, integrated process model is presented for a three dimensional, coupled analysis of the thermal and mechanical behavior of type 304 stainless slab during hot charge rolling (HCR) and cold charge rolling (CCR) processes. The validity of the proposed model is examined through comparison with measurements. The susceptibility on micro-crack initiation or propagation due to the thermal stress in these two different process conditions was examined. The model's capability of revealing the effect of diverse process parameters is demonstrated through a series of process simulation.

An Fe-25Cr steel was oxidized in Ar at 973K with or without external stesses of 30~35Mpa. A 0.1 ${\mu}{\textrm}{m}$ thick Cr$_2$O$_3$scales was formed during pre-treatment in Ar. Cracking on the oxides scales commenced at the alloy grain boundary by the end of second creep stage, arrayed almost perpendicular to the direction of the tensile directions. On the contrary, a scale formed in $N_2$-0.1%SO$_2$shows poor adherence on the metal substrate. In this case, the strength of materials is much lower than in Ar

The results from a systematic study of the response of a Ti-6Al-4V alloy under quasi-static and dynamic loading at different strain rates and temperatures are presented. It has been shown that the work-hardening rate decreased as the strain rate and the strain increased. The correlations and predictions using modified KHL (Khan-Huang-Liang) viscoplastic constitutive model are compared with those from JC (Johnson-Cook) model and experimental observations. Overall, KHL model correlations and predictions compared much more favorably than the corresponding JC model predictions and correlations.

An automatic surface construction method based on B-spline surface and scalar field theory is proposed to generate the extrusion die surface of complicated sections in this paper. The isothermal lines and stream lines designed in the scalar field are introduced to find the control points which are used in constructing B-spline surfaces. Intersected points between the isothermal lines and stream lines are used to construct B-spline surfaces. The inlet and outlet profiles are precisely described with B-spline curves by using the centripetal method for uniform parameterization. The extrusion die surface is generated by using the cubic curve interpolation in the u- and v-directions. A quantitative measure for the control of surface is suggested by introducing the tangential vectors at the inlet and outlet sections.

Plastic injection mould have two kinds of trouble, one is in mould another in injection parts. Most of defects of the former take the cause in a design like in structure and working, the later weld line, transforming, sink mark, burning, flow mark, scratching, shading, black hole and so on. Most of problems of the later is difficult for making a clear definitely the reason of defects because of complexible. The purpose of this paper is to improve the quality of plastic injection mould and parts with inquiring the counter plan and rouble of the part of Flat TV Front Cover by flow control method and gas- assisted injection moulding. For minimizing defects from injection moulding parts, this paper was investigated with using computer aided injection mold filling simulations. Based on these numerical results, I established guidelines mould design and injection processing condition. As a results I got the improve of quality, minimizing surface defects moulded parts and troubles in mould.

The purpose of this work is to find an appropriate welding approach for rotor assembly of a marine turbocharger. The friction welding and laser welding of dissimilar materials, IN713LC and SCM440 were investigated. The quality of the welded joints obtained from two welding processes was evaluated by microstructure observation, micro-hardness and tensile tests. The friction welded joint indicated a good bonding structure in the weld interface. On the other hand, the laser welded joint showed the weld defects and non-welded area in the weld interface.

Weld line in injection molded part is one of the defect in injection molding process. Weld line deteriorates not only appearance quality but mechanical property. In this study weld line strength has been examined according to the injection operational conditions, materials and mold designs. PC and PP were used, and four different specimens were used in this experiment. Weld line strength decreased as injection temperature increases for PC. It was more dependent on mold temperature than injection temperature for PP Among the four different specimens, uneven thickness specimen showed the highest weld line strength.

Due to the lighter weight and the higher freedom of design than metals plastics have been spot lighted in a wide number of applications. In the making plastic parts injection-molding process is one of the most general methods. During the injection molding process, filling-packing-cooling process, plastics have exposed to several external stresses and then plastic parts injected have molding effects which are known as anisotropic properties, orientation, and residual stress. Those molding effects are often shown as unexpected phenomena which are warpage, strength decrease, stiffness reduction, etc. In case of glass fiber filed plastics these effects are more significant than the ufilled ones. Therefore the molding effects have to be considered in the parts design using glass fiber reinforced plastics. We have developed the interface program in order to consider the molding effects in structural analyses of plastic parts using Heirarchical structural searching and layer handling in direction of thickness algorithm. The advantages of this program are the freedom of FE mesh between molding and structural analysis, the variable layer to the thickness direction of parts and the conveniences of data transferring and checking

Recently, the market share of the thin-film-transistor liquid-crystalline-display (TFT-LCD) is growing rapidly in display device market. The backlight unit is used as a light source of TFT-LCD module. A light-guide is one of several important components of backlight unit. The manufacturing technology and optical system design of the light guide is very sensitive to quality and cost of the TFT-LCD module. In the present study a new manufacturing method which is called as direct surface forming(DSF) has been tested under various conditions. The result of this test, V-groove pattern shows different shapes depends on the temperature of mold surface, contact time of mold and depth of V-groove.

This paper is concerned with pressure welding, which has been known as a main bonding mechanism for the cold and warm clad forming. Bonding characteristics of pressure welding between the copper and aluminum plates are experimentally investigated. Experiments are performed at the cold and warm temperature range with the variation of important factors such as magnitude of pressure, surface roughness of Cu and Al plates, and pressure holding time. It could be concluded that the bonding criterion might be given as a function of bonding pressure and surface roughness for the cold and warm temperature ranges.

In the roll forming process, a sheet or strip of metal is continuously and progressively formed into a desired cross-sectional profile by feeding it through a series of forming roll. Accordingly, it is important to maintain the material properties of the initial sheet and deform uniformly during the roll forming. The roll forming process was estimated in consideration of some factors such as material properties, strip thickness, roll diameter, roll velocity, and the deformation of the material that influence the forming length. The hydroforming technology has been recognized as a new technique in manufacturing industry, especially in automotive industry. The formed pipe in used in hydroforming process is manufactured by the roll forming. The formability during hydroforming is very sensitive to the state of pipes which are made by roll forming. Particularly the amount of hardening during roll forming affects the formability. Therefore, it is necessary to design the optimum roll flower to reduce the local hardening. In this paper, optimum roll flower which has uniform strain distribution through sheet width was obtained by comparing strain distribution in various roll flower. Finite element analysis(FEA) is performed to estimate the strain distribution related to hardening by roll forming. A numerical analysis is carried out by SHAPE-RF.

A bumper comprises a bumper face, a bumper beam for distributing the load from the impacts applied to the bumper face and reinforcing the bumper, an absorber member interposed between the bumper face and the bumper beam, and a pair of bumper stays which secure the bumper beam to the vehicle body. A conventional bumper stay structure is assembled into several stamped parts, so several processes are needed and the structure is complicated. In this study the bumper stay is applied to the tubular hydroforming which is known to have several advantages such as the reduction of the number of the process and the part weight. The thickness distribution of the tube after hydroforming and the internal energy at the event of the a compression are mainly considered to evaluate the hydro-formability and energy absorption performance.

Deformation surrounding the hole in the tube during the hydro-piercing process has been investigated in this study. The tube is expanded and internally pressurized between upper and lower dies, and a piercing punch is driven forcefully through a cross passage in the die and through the wall of the tube. The pressurized fluid within the tube provides support to the wall of the tube during a piercing step to form a hole in the tube having less deformation surrounding the hole in the tube. The deformation area may be fully retracted to a substantially flat form or partially retracted to a countersunk form. In this study, a mathematical model that can predict deformation surrounding the hole has been proposed and experimentally verified by actual hydro-piercing test.

The productivity of hydroforming process can be increased by combining pre-forming process and post-forming process such as the bending, piercing and the embedding process. Therefore in this study, integrated studies on the hydro-embedding technology have been performed by analyzing the deformed mode of the tubes and the optimal process parameters. In the case of the embedding test the characteristics of the embedded parts, such as the shape of the screw tip, screw thread and shape of thread were investigated at various process conditions. To measure the clamping force between the embedded part and the tube, special measuring device was used.

This research conducted milling tests to study effects of cutting environment conditions of ball end mills on the characteristics of hard milling process. KP4 steels and STD11 heat treated steels were used as the workpiece and WC-Co ball end mill tools with TiAIN coated were utilized in the cutting tests. Dry cutting without coolant and semi-dry cutting using botanical oil coolant were conducted and MQL (Minimum Quantity Lubricant) device was used to spray coolant. Cutting forces, tool wear and surface roughness were measured in the cutting tests. Results showed that dry cutting of KP4 and hardened STD11 specimens produced better surface quality and wear performance than MQL spray cutting did.

In this study, main works are focused on investigating the stress distribution at the interface between a rotor core and Cu bar when a punch is applied into the body of Cu bar. A parametric study with dimensional changes of core slot was performed numerically to identify what factors are dominant in producing high contact forces in the interface. As analysis results, it was found that core slot length was a dominant factor in increasing contact force at the interface between a rotor core and Cu bar.

In this study, to develop a flash-less die for forming of shoe-outsole, experiments and forming analysis were carried out. In order to reduce the extra-materials, of feet method and mass distribution method are used in the preform design. To improve the accuracy of contact surface of dies, the contact status of dies are measured by using the pressure film. The vertical pressing die structure and the guide-gutter system have been developed for the discharge of extra-materials and re-pressing. By the investigation, flash of shoe-outsole was considerably reduced.

Semi-solid processing is now becoming of great interest for the production of various parts by pressure die casting. Many advantages are associated with this forming process at the condition that the forming operation is performed under appropriate conditions. The thixoforming process, which needs a suspension of a globular, non-dendritic solid phase in the liquid phase, is characterized by three major steps. The first step is casting of billets with a microstructure suited for thixoforming. The second step is reheating of slugs cut from these billets. The third step is injection of the semi-solid slugs into a die. In this paper, the horizontal reheating machine to obtain the optimal conditions suitable for semiu-solid die casting process was used and applied to extrusion material. It is estimated the possibility of application on semi-solid die casting with extrusion material through various results.

In the extrusion process, the working material is forced to flow through a die with the desired profile. In general, the width of an extruded section is limited to about an inch less than the diameter of the round billet. But through the lip die, material is spreaded to produce a wider extruded section than the diameter of round billet. In this study, the extrusion process of an aluminum plate using the lip die is investigated. The width of the extruded plate is 450mm that is formed from the round billet with a diameter of 250mm. The flow characteristic through the lip die is considered to produce the wide-extruded plate with a small billet using rigid plastic FE analysis. Based on the result of FE analysis, new designs of lip die are proposed.

There is a growing interest to replace the commercial steels with non-heat treated steels, which does not involve the spheroidization and quenching-tempering treatment. However, Non-heat treated steels should satisfy high strength and good formability without performing heat treatment. Therefore, it is important to investigate optimum materials showing a good combination of strength and formability after the drawing process. In this study, Dual-Phase Steels were studied as candidate materials for non-heat treated steels, which have different martensite morphologies and volume fractions obtained through heat-treatment of intercritical quenching (IcQ), intermediate quenching (ImQ) and step quenching (SQ). The mechanical properties of DP steels were measured by tension and compression tests. Also, the cold formability of three DP steels which have similar tensile strength value was investigated by estimating the deformation resistance and the forming limit. The deformation resistance which is important factor in determining die life was estimated by calculating the deformation energy. And the forming limit was estimated by measuring the critical strain revealing crack initiation at the notch tip of the specimens.

High-temperature superconduction materials(Bi2223) possess electrical/electronic and magnetic properties. Because high-temperature superconduction materials is a ceramic powder, that can not be produced singlehandedly. So Ag sheathed Bi-2223 wire was produced by drawing process using powder-in-tube(PIT) method. This superconductor has many difficulties to produce. The main difficulty is that the mechanical properties of the ceramic powder are very different from those of the Ag sheath. Bi2223 high-temperature superconductivity have a single filament drawing process, and multi-filament drawing process. This study analysed multi-filament drawing process by FEM, a defects during multi-filament drawing was studied by FEM.

It was investigated that the "ㄱ" type angle product could be bended with a curvature during extrusion by extru-bending process. The bending process for the "ㄱ" type angle product can be developed by the hot metal extru-bending machine with the two punches moving in the different velocity. Because of non-symmetry of product, it is important to design the ruled surface contour of dies cavity for the welding and bending with two billets. So it is designed that the multi-hole container has two non-symmetric holes and non-symmetric contour of dies entrance. The results of the experiment show that "ㄱ" type angle product can be bended by the extrusion process and that the curvature of the product can be controlled by the velocity of punch and that the defects such as the distortion of section and the thickness change of the product and the folding and wrinkling of the product did not happen after the bending processing by the extrusion bending machine.

The microstructural changes of Al-Zn-Mg-Cu alloy containing Sc during hot extrusion and post heat treatment is investigated. Two kinds of Al-Sc alloys with different alloying elements (B1, B2) are hot extruded to make I-shape bars at 380$^{\circ}C$, then the bars are solution treated at 480$^{\circ}C$ for 2hrs followed by artificial aging at 120$^{\circ}C$ for 24hrs. The interior microstructure of as extruded bar consists of elongated grains, however, fine equiaxed grains are mainly observed around surface. The microstructural gradient suggests that different restoration process can proceed during the hot extrusion. For B1 and B2, different grain growth behaviors are found around the surface during the post heat treatment. Rapid grain growth behavior around the surface is discussed related with the crystallographic orientation of the grain.

The bending phenomenon during extruding one product using four billets can be obtain by the difference of hole diameters in the multi-hole container. The difference of hole diameter caused the difference of billet amount inserted in the die cavity. As results, it can bend during extruding products by the different amount of two billets and by the cohesion of billets in the porthole dies cavity. And the bending curvature can be controlled by the size of holes and billets. The experiments using aluminium material had been done for the rectangular and square curved tube product. The results of the experiment show that the curved aluminum tube product can be bended by the extru-bending process without the defects such as the distortion of section and the thickness change of the wall of tube and the folding and wrinkling. The curvature of product is affected by shape of cross section and the difference of billet diameters. It is known that the welding and extruding and bending can be done simultaneously in the die cavity when a rectangular hollow curved tube would be extruded by porthole dies using four different size billets made of aluminum material.

The occurrence of ductile fracture is the working limit of many metal forming processes. It is necessary to predict the criteria and to apply the condition in a process design. Over the years. the way for clarifying conditions have been studied and presented. However such a way needs lots of experiments and analysis. In this study, in order to determine the critical damage value of a used material Cu 4N, it was performed a tensile test and FEM analysis by using DEFORM 2D. For applying the obtained critical damage value it was also performed a upsetting test by using DEFORM 2D. The way of determining a critical damage value which is presented in this study will make possible to find easily it which is one of the working limit factor. And the way of determining a critical damage value will make possible to find in multi-pass drawing process.

Design of drawing dies used in real industrial environments. It was designed by CAD software in many small & medium companies, but many products require various types, and sizes. Therefore, many companies are required to reduce process time and design mistakes. In this paper, for the automatic design of drawing dies, Design process considered that easy to team and use. which are used with Visual LISP/DCL language in a commercial CAD package, AutoCAD. It has adopted GUI in design system, and has applied DCL language. The system is based on the knowledge base system which is involved a lot of expert's know-how We have built database of design type and detail sizes. The automatic design system requires basic product type and sizes. Then the system accesses to the database and find out sizes by comparing with input parameters and generate drawing dies file.

In current study, Nanocomposites are reinforced with carbon nanofiber, carbon nanotube and SiC, etc. Since the nano reinforcements have the excellent mechanical, thermal and electrical properties compared with that of existing composites, it has lately attracted considerable attention in the various areas. Cu have been widely used as signal transmission materials for electrical electronic components owing to its high electrical conductivity. However, it's size have been limited to small ones due to its poor mechanical properties. Until now, strengthening of the copper alloy was obtained either by the solid solution and precipitation hardening by adding alloy elements or the work hardening by deformation process. Adding the alloy elements lead to reduction of electrical conductivity. In this aspect, if carbon nanofiber is used as reinforcement which have outstanding mechanical strength and electric conductivity, it is possible to develope Cu matrix nanocomposite having almost no loss of electric conductivity. It is expected to be innovative in electric conducting material market. The unidirectional alignment of carbon nanofiber is the most challenging task developing the cooer matrix composites of high strength and electric conductivity. In this study, the unidirectional alignment of carbon nanofibers which is used reinforced material are controlled by drawing process and align mechanism as well as optimized drawing process parameter are verified via numerical analysis. The materials used in this study were pure copper and the nanofibers of 150nm in diameter and of 10∼20$\mu\textrm{m}$ in length. The materials have been tested and the tensile strength was 75MPa with the elongation of 44% for the copper. it is assumed that carbon nanofiber behave like porous elasto-plastic materials. Compaction test was conducted to obtain constitutive properties of carbon nanofiber Optimal parameter for drawing process was obtained by analytical and numerical analysis considering the various drawing angles, reduction areas, friction coefficient, etc. The lower drawing angles and lower reduction areas provides the less rupture of co tube is noticed during the drawing process and the better alignment of carbon nanofiber is obtained.

Porthole die extrusion is the method which put the billet in the container and push it between die hole by ram. This method make it possible that product manufacture which have complex shape of area with excellent induction of area, in addition that this is economical. So this method is used as the basic manufacturing method of many industrial materials. The subject of this research is the forming technology development of heat sink which is being produced by extrusion process in my country. Flow condition of extrusion for heat sink, and metal flow of billet in the die are estimated by the means of rigid-plasticity finite element method.

In order to generate the extrusion die surface of non-symmetric H- and U-shaped sections, an automatic surface construction method based on B-spline surface and scalar field theory is proposed in this study. The isothermal lines and stream lines designed in the scalar field are introduced to find the control points which are used in constructing B-spline surfaces. Intersected points between the isothermal lines and stream lines are used to construct B-spline surfaces. The inlet and outlet profiles are precisely described with B-spline curves by using the centripetal method for uniform parameterization. The extrusion die surface is generated by using the cubic curve interpolation in the u- and v-directions. A quantitative measure for the control of surface is suggested by introducing the tangential vectors at the inlet and outlet sections.

Nano-imprint lithography(NIL) is a polymer embossing technique, capable of transferring nano-scale patterns onto a thin film of thermoplastics such as polymethyl methacrylate(PMMA) using this parallel process. Feature size down 10 nm have been demonstrated. In NIL, the pattern is formed by displacing polymer material, which can be squeeze flow of a viscous liquid. Due to the size of the pattern, a thorough understood of the process through experiments may be very different. Therefore we nead to resort to numerical simulation on the embossing process. Generally, there are two ways of numerical simulation on nano-scale flow, namely top-down and bottom-up approach. Top-down approach is a way to simulate the flow assuming that polymer is a continuum. On the contrary, in the bottom-up approach, simulation is peformed using molecular dynamics(MD). However, as latter method is not feasible yet. we chose the top-down approach. For the numerical analysis, two dimensional moving grid was used since the moving grid can predict the flow front. Effects of surface tension as well as the slip at the boundary were also considered.

Molecular dynamic simulations of nano indentation on single-crystal silicon (100) surface were performed using diamond indentor. Silicon substrate and diamond indentor were modeled diamond structure with Tersoff potential model. Phase transformation of silicon, incipient plastic deformation, change of incident temperature distribution are investigated through the change of potential energy distribution, displacement-load diagram, the change of kinetic energy distribution and displacements of silicon atoms. Phase transformation is highly localized and consists of a high-density region surrounding the tip. Axial load linearly increased according to the indenting depth. Number of atoms with high kinetic energy increased at the interface between substrate and indentor tip.

The dynamics of fluid flow through nanomachines is completely different from that of continuum. In this study, molecular dynamics simulations were performed for the flow of helium, neon, argon inside carbon(graphite) nanotubes of several sizes. The fluid was introduced into the nanotube at a given initial velocity according to given temperature. Diffusion coefficients were evaluated by Green-Kubo equation derived from Einstein relationship. The behaviour of the fluid was strongly dependent on the density of fluid and tube diameter, not on the tube length. It was found that the diffusion Coefficients increased With decreasing the density of molecules and increasing the diameter and temperature.

To estimate the residual stresses in the thin film and surface coatings, combined method based on nanoindentation and finite element (FE) analysis was developed. A simple equation for estimating the residual stress was composed of the hardness and the parameters which can be driven from the nanoindentation loading and unloading behaviors. FE analysis on the nanoindentation procedure under the various residual stress levels was performed to determine the parameters that included in the equation. The equation showed a good coincidence between the estimated residual stresses and those for the FE analysis. Thus the proposed method was considered as a useful method for estimating the residual stresses in the thin film without stress free specimen.

Damping systems have been widely used to various industrial structures and are mainly hydraulic and pneumatic devices nowadays. In this work, a novel damping system based on the colloidal suspension in the field of nanotechnology is investigated. The colloidal suspension consists of Iyophobic working fluid and hydrophobic-coated porous particle. The mechanism of mechanical energy dissipation in damping system based on the colloidal suspension with nano-porous particles is different from that of the existing hydraulic damping system. The absorbed energy of the damping system using colloidal suspension can be calculated through the mechanical equilibrium condition by the superficial tensions of liquid-gas Interface in the hydrophobic surface in nano-porous particles. The results from an analytic approach have a reasonable agreement with experimental results.

In nanomachining processes, chemical effects are more dominant factor compared with physical deformation. For example, during the nanoscratch on a silicon surface in the atmosphere, micro protuberances are formed due to the mechanochemical reaction between the diamond tip and the surface. On the contrary, in case of chemically stable materials, such as ceramics or glasse, the surface protuberance are not formed. The purpose of this study is to understand effects of the mechanochemical reaction between tip and surfaces on deformation behaviors of hard-brittle materials. Nanometerscale elasoplastic deformation behavior of single crystal silicon (100) was characterized with the surface protuberance phenomena, and compared with that of borosilicate (Pyrex glass 7740).

In this study, application of SAM (self-assembled monolayer) to nano replication process as an anti-adhesion layer was presented to reduce the surface energy between the nano mold and the replicated polymeric nano patterns. The electron beam lithography was used for master nano patterns and the electorforming process was used to fabricate the nickel nano stamper. Alkanethiol SAM as an anti-adhesion layer was deposited on metallic nano stamper using solution deposition method. To analyze wettability and adhesion force of SAM, contact angle and LFM (Lateral Force Microscopy) were measured at the actual processing temperature and pressure for the case of nano compression molding and at the actual UV dose for the case of nano UV molding. It was found that the surface energy due to SAM deposition on the nickel nano stamper markedly decreased and the quality of SAM on the nickel stamper maintained under the actual molding environments.

The hot embossing process has been mentioned as one of major nanoreplication techniques. This is due to its simple process, low cost, high replication fidelity and relatively high throughput. As the initial step of quantitating the embossing process, simple parametric study about embossing time have been carried out using high-resolution masters which patterned by the DRIE process and laser machining. Under the various embossing time, the viscous flow of thin PMMA films into microcavities during Compression force has been investigated. Also, a study about simulating the viscous flow during embossing process has planned and continuum scale FDM analysis was applied on this simulation. With currently available test data and condition, simple FDM analysis using FLOW3D was made attempt to match simulation and experiment.

Recently, demand of digital products with optoelectronic device is increasing rapidly. A microlens array is applied to improve optical efficiency on optoelectronic device, and it is usually fabricated by photolithography and reflow process after planarization layer coating process. UV molding process is more suitable for mass production of high quality microlens array than photolithography and reflow process. In the present study, microlens array was fabricated on the simulated optoelectronic device with planarization layer by aligned UV molding process. The shape of replicated microlens was measured, and the section image of molded part was examined.

This paper presents the fabrication possibility of the micro actuator which uses a micro-thermal bubble, generated by a micro-heater under pulse heating. The micro-actuator is consist of three plate. The lower plate includes the channel and chamber are fabricated on high processability silicon wafer by the DRIE(Deep Reactive ion Etching) process. The middle plate includes the chamber and diaphragm, and the upper plate is the micro-heater. The micro-heater designed non-uniform width and results in periodic generation of stable single bubbles in D.I water. The single bubble appears precisely on the narrow part of the micro-heater and control is recorded.

As a trial of application of hydrostatic pressure in micro fomring, burr-free punching has been conducted by means of hydro-mechanical procedure. Even though it is in beginning stage, result of the hydro-mechanical punching is promising. Hydrostatic pressure helps delay fracture initiation and makes it possible to get clean shearing surface. Without any burr on both side of sheet, smooth holes are archived as intended. To verify the significance of hydro-mechanical punching, conventional punching is performed under similar conditions and relatively larger portion of fracture surface is detected in the punching hole. Despite the quality of sidewall is not good enough, it might be possible to make the hole shaped upright, reduce the roll-over radius and minimize the fracture surface by optimizing process parameters.

Laser direct writing process is developed 3rd harmonic Diode Pumped Solid State Laser with the near visible wavelength of 355 m sensitive polymer is irradiated by UV laser and developed using polymer solvent to obtain quasi-3D. It is important to reduce line width for image mode waveguides, so some investigations will be carried out in various conditions of process parameters such as laser power, writing speed, laser focus and optical properties of polymer. This process could be to fabricate a single mode waveguide without expensive mask projection method. Experimentally, the patterns of trapezoidal shape were manufactured into dimension of 8.4 mm width and 7.5 mm height. Propagation loss of straight waveguide measured 3 dB/cm at 1,550 nm.