• 한국기계가공학회지
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• 제21권5호
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• pp.1-8
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• 2022

Fused deposition modeling (FDM), based on stacking a continuous filament of polymer or composite materials, is well matured and is thus widely used in additive manufacturing technology. To advance FDM-based 3D printing technology, the mechanical properties of additively manufactured composite materials must be improved. In this study, we proposed a novel FDM 3D printing process using metal wire-polymer composites, enabling enhanced mechanical properties. In addition, we developed a new type FDM filament of copper wire wrapped in nylon material for stable 3D printing without thermal damage during the printing process. After FDM printing of the copper wire-nylon composite filament, we conducted a tensile test to investigate the mechanical behavior of the printed composite materials. The experimental results confirmed that the tensile strength of the 3D-printed metal wire-polymer composites was higher than that of the conventional single polymer material. Thus, we expect that the FDM printing process developed in this study may be promising for high-load-bearing applications.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2001년도 춘계학술발표대회 논문집
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• pp.189-192
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• 2001

Resin transfer molding process has been widely used in the automobile industry, because the product with large area can be manufactured easily and the cost for the manufacturing is lower than that of compression molding and hand lay up method. Since RTM process is suitable for large bus housing panels, in this work, the composite housing panel was manufactured by RTM process and the mechanical properties, surface quality and the condition of manufacturing process were studied.

• International Journal of Aerospace System Engineering
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• 제1권1호
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• pp.21-28
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• 2014

In this study, an investigation on mechanical properties of flax natural fiber composite is performed as a precedent study on the design of eco-friendly structure using flax natural fiber composite. The Vacuum Assisted Resin Transfer Molding-Light (VARTML) manufacturing method is adopted for manufacturing the flax fiber composite panel. The VARTML is a manufacturing process that the resin is injected into the dry layered -up fibers enclosed by a rigid mold tool under vacuum. In this work, the resin flow analysis of VARTM manufacturing method is performed. A series of flax composite panels are manufactured, and several kinds of specimens cut out from the panels are tested to obtain mechanical performance data. Based on this, structural design of chemical storage tank for agricultural vehicle was performed using flax/vinyl ester. After structural design and analysis, the resin flow analysis of VARTM manufacturing method was performed.

• Journal of the Korean Wood Science and Technology
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• 제23권2호
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• pp.55-69
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• 1995

The primary objective of this research was to investigate optimum manufacturing condition of thin composite panels composed of sawdust, polyethylene film and polypropylene net. At the study the experiment was designed to make thin board in which sawdust offers effectiveness as core composing material, polyethylene as adhesive with added urea resin, and polypropylene as stiffness and flexibility in the composition panel. 100 types of thin composite panels were manufactured according to press-lam and mat-forming process of various hot pressing conditions(pressure, temperature and time). They were tested and compared with control boards on bending properties(MOR, MOE, SPL, WML), internal bond strength, thickness swelling, linear expansion and water absorption. At the same time the visual inspections of each types of panels were accomplished. The physical and mechanical properties of composite types passed by visual inspection were analyzed by Tukey's studentized range test. From the statistical analysis, the optimum manufacturing condition of thin composite panels were selected. Compared with two manufacturing processes, mat-forming process performed better than press-lam process in all tested properties. The optimum manufacturing conditions resulted from the experiment and statistical analysis were able to determine as following: the press temperature was shown the most good result at 130$^{\circ}C$ in mat forming process and 140$^{\circ}C$ press lam process, the press time 4 min in both processes, but the press pressure was 25-10kg/$cm^2$ in mat forming and 15k/$cm^2$ press lam process.

• 한국CDE학회논문집
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• 제3권4호
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• pp.274-282
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• 1998

A feature is a local shape of a product directly related to the manufacturing process. The feature plays a role of the bridge connecting CAD and CAM. In the process planning for he CAM, information on manufacturing is required. To get the a manufacturing information from CAD dat, we need to recognize features. Once features are recognized, they are used as an input for the process planning. In this paper, we thoroughly investigate the composite features, which are generated by interacting simple features. The simple features in the composite feature usually have precedence relation in terms of process sequence. Based on the reason for the precedence relation, we classify the composite features for the process planning. In addition to the precedence relation, approach direction is used as an input for the process planning. In the process planning, the number of set-up orientations are minimized whole process sequence for the features are generated. We propose a process planning algorithm based on the topological sort and breadth-first search of graphs. The algorithn is verified using sample products.

• 한국기계가공학회지
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• 제21권2호
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• pp.137-143
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• 2022

Composite materials, being light-weight and of high mechanical strength, are increasingly used in various industries such as the aerospace, automobile, sporting-goods manufacturing, and ship-building industries. Recently, manufacturing of composite materials using 3D printers has increased. 3D-printed composite materials are made in free-form and adapted for end-use by adjusting the fiber content and orientation. However, research on the machining of 3D printed composite materials is limited. The aim of this study is to develop a machine learning method to select machining conditions for machining of 3D-printed composite materials. The composite material was composed of Onyx and carbon fibers and stacked sequentially. The experiments were performed using the following machining conditions: spindle speed, feed rate, depth of cut, and machining direction. Cutting forces of the different machining conditions were measured by milling the composite materials. PCA, a method of machine learning, was developed to select the machining conditions and will be used in subsequent experiments under various machining conditions.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2001년도 춘계학술발표대회 논문집
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• pp.172-175
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• 2001

The co-cured Joining method, which is regarded as an adhesively bonded Joining method, is an efficient joining technique because both curing and bonding processes for the composite structures can be achieved simultaneously. It requires neither surface treatment onto the composite adherend nor an additional adhesive joining process because the excess resin, which is extracted from composite materials during consolidation, accomplishes the co-cured Joining process. Since the adhesive of the co-cured joint is the same material as the resin of the composite adherend, the analysis and design of the co-cured joint for composite structures are simpler than those of an adhesively bonded joint, which uses an additional adhesive. In this paper, effects of the manufacturing parameters, namely surface roughness, stacking sequence of the composite adherend, and manufacturing pressure in the autoclave during curing process, on the tensile load bearing capacity of the co-cured single lap joint will be experimentally investigated.

• International Journal of Aerospace System Engineering
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• 제4권1호
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• pp.9-12
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• 2017

In this study, an investigation on mechanical properties of flax natural fiber composite is performed as a precedent study on the design of eco-friendly structure using flax natural fiber composite. The Vacuum Assisted Resin Transfer Molding-Light (VARTML) manufacturing method is adopted for manufacturing the flax fiber composite panel. The VARTML is a manufacturing process that the resin is injected into the dry layered-up fibers enclosed by a rigid mold tool under vacuum. In this work, the resin flow analysis of VARTM manufacturing method is performed. A series of flax composite panels are manufactured, and several kinds of specimens cut out from the panels are tested to obtain mechanical performance data. Based on this, structural design of chemical storage tank for agricultural vehicle was performed using flax/vinyl ester. After structural design and analysis, the resin flow analysis of VARTM manufacturing method was performed.

• 한국기계가공학회지
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• 제17권5호
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• pp.137-142
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• 2018

With the development of the electronic-materials industry, multi-functional metal-composite materials with high thermal conductivity and low thermal expansion must be developed for high reliability and high life expectancy. This paper is a preliminary study on the manufacturing technology of gas reaction control composite material, focusing on the prediction of the equivalent thermal properties of Al-AlN composite materials. Numerical equivalent property values are obtained by using finite element analysis and compared with theoretical formulas. Al-AlN composite materials should become the optimal composite material when the proportion of the reinforcing phase is less than 0.5.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2003년도 춘계학술발표대회 논문집
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• pp.169-172
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• 2003

Manufacturing process for autonomic microcapsules was introduced and autonomic microcapsules were manufactured by varying with various manufacturing process variables. Urea-formaldehyde resin was used for the wall of microcapsules and DCPD (dicyclopentadiene) was used for the self-healing agent. The characteristics of these microcapsules was evaluated through a particle size analyaer, an optical microscope, and a TGA. The various manufacturing process variables, such as pH and agitation speed of the emulsified solution, were considered to focus in this study. According to the results, the particle size distributions were affected on the agitation speed of the emulsified solution, and the thermal stability was influenced by pH of the emulsified solution.