• 한국표면공학회지
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• 제53권4호
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• pp.144-152
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• 2020

In the manufacturing process of joining of aluminum alloy and polymer, the strength of the metal-polymer joining is greatly influenced by the nanostructure of the oxide film. In this study, we investigated the dependence of joining strength on the thickness, structure, pore formation and surface roughness of the formed film. After the two-step anodization process, the surface oxide layer became thinner and rougher resulting in higher joining strength with the polymer. More specifically, after the two-step anodization, the surface roughness, Ra increased from 2.3 to 3.2 ㎛ with pore of three-dimensional (3D) nanostructure, and the thickness of the oxide film was thinned from 350 to 250 nm. Accordingly, the joining strength of the aluminum alloy with polymer increased from 23 to 30 MPa.

• Journal of Welding and Joining
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• 제31권4호
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• pp.23-27
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• 2013

Laser heat source was used for automotive interior and exterior parts to reduce weights. Typically, 900's nm wavelength of laser has been widely used for polymer joining, however, the transmittance of the laser beam thorough clear polymers such as PMMA or PC has been an issue to overcome. To solve this issue, 1,940nm laser was applied on the clear polymer for the better absorption and 900nm laser beam was used for main laser for the joining. Conventional Gaussian or Elliptical heat source approximation has limitation in polymer which had deeper skin depth where major laser beam absorbs. To accurately simulate the physical laser beam absorption and joining optical properties were experimentally measured for the computer FEM simulation. The simulation results showed close correlation between theoretical and experimental results. The developed laser process is expected to increase productivity and gap closing which can cause failure of joining in laser material processing.

• 한국재료학회지
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• 제31권3호
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• pp.122-131
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• 2021

In the fabrication of joined materials between anodized aluminum alloy and polymer, the performance of the metal-polymer joining is greatly influenced by the chemical properties of the oxide film. In a previous study, the dependence of physical joining strength on the thickness, structure, pore formation, and surface roughness of films formed on aluminum alloys is investigated. In this study, we investigated the effect of silane coupling treatment on the joining strength and sealing performance between aluminum alloy and polymer. After a two-step anodization process with additional treatment by silane, the oxide film with chemically modified nanostructure is strongly bonded to the polymer through physical and chemical reactions. More specifically, after the two-step anodization with silane treatment, the oxide film has a three-dimensional (3D) nanostructure and the silane components are present in combination with hydroxyl groups up to a depth of 150 nm. Accordingly, the joining strength between the polymer and aluminum alloy increases from 29 to 35 MPa, and the helium leak performance increases from 10-2-10-4 to 10-8-10-9 Pa ㎥ s-1.

• 한국기계가공학회지
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• 제21권2호
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• pp.87-93
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• 2022

The demand for metal-polymer joining technology have been increasing, especially in the industrial fields of automotive and aerospace, which require the manufacturing of various lightweight parts. Conventional joining processes have technical hurdles on aspects such as thermal degradation, need for chemical surface treatment, or complicated process settings. These issues can be alleviated by employing interlocking structures for the metal-polymer joined interface. In this study, we joined 3D-printed metal and polymer parts, which were featured with 3D-printed interlocking structures at their interface. By using high frequency induction heating, the joined region could be locally heated to reduce the thermal degradation and distortion of polymer parts. In addition, through the adjustment of interface morphologies and compression conditions, the polymer flow could be optimized to completely fill the interlocking grooves on metal parts, thereby achieving high joining strength. This suggests feasible guidelines for manufacturing metal-polymer joined structures involving 3D-printed architectures.

• 한국분말재료학회지
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• 제15권1호
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• pp.58-62
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• 2008

Reaction bonded silicon carbide (RBSiC) is an important engineering ceramic because of its high strength and stability at elevated temperatures, and it is currently fabricated using reasonably cheap manufacturing processes, some of which have been used since the 1960s. However, forming complicated shapes from these materials is difficult because of their poor workability. The purpose of this work is to join the reaction-bonded SiC parts using a preceramic polymer as joint material. The manufacturing of ceramic material in the system Si-O-C from preceramic silicon containing polymers such as polysiloxanes has attained particular interest. The mixtures of preceramic polymer and filler materials, such as SiC, Si and MoSi, were used as a paste for the joining of reaction sintered SiC parts. The joining process during the annealing in Ar atmosphere at $1450^{\circ}C$ were described. The maximum strength of the joints was 63 MPa for the specimen joined with 10 vol.% of $MoSi_2$ and 30 vol.% of SiC as filler materials. Fracture occurred in the joining layer. This indicates that the joining strength is limited by the strength of the joint materials.

• 한국정밀공학회지
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• 제9권1호
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• pp.66-74
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• 1992

The joining processes of aluminum alloy tubes and polyurethane cores by electromagnetic impulsive compression are studied. The influences of various geometrical factors (the length of joined part, the thickness of tube, and the clearance between tube and core) and the process factors(the discharged energy and the number of discharge)are examined experimentally and discussed. And the magnetic pressure in metal/polymer joining is calculated and is compared to the pressure in metal/metal joining. The following results are obtained: (1) The joining strength is dependent upon the residual radial strain of the polyurethane cores. (2) The joining strength increases as discharged energy and the number of discharge increase, but decreases as the clearance, thickness and joining length of tube increases. (3) In the case of metal/polymer joining energy loss is increased and the value of magnetic pressure is less than that in the case of metal/metal joining.

• Journal of Welding and Joining
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• 제32권2호
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• pp.63-69
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• 2014

Dual laser heat sources were used for polymer based material joining. An infrared camera and thermocouple DAQ system were used to correlate the temperature distribution to computer simulation. A 50 degree tilted pre-heating laser source was acting as a heating source to promote the temperature to minimize thermal shock by the following a welding heat source. Based on the experimental result, the skin depth was empirically estimated for computer simulation. The offsets of 3mm, 5mm and 10mm split by weld and preheat were effectively used to control the temperature distribution for the optimal laser joining process. The closer offset resulted in an excessive melting or burning caused by sudden temperature rising. The laser power was split by 50%, 75% and 100% of the weld power, and the best results were found at 50% of preheating. To accurately simulate the physical laser beam absorption and joining optical properties were experimentally measured for the computer FEM simulation. The simulation results showed close correlation between theoretical and experimental results. The developed dual laser process is expected to increase productivity and minimize the cost for the final products.

• 한국레이저가공학회지
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• 제17권4호
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• pp.14-19
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• 2014

Laser beam was applied on the boundary of the polyurethane and biodegradable polyacetate polymers. The distributed laser passed through the polyurethane layer and heated the polyacetate layer, then the soften acetate was squeezed thorough the 1mm square slots of polyurethane for the mechanical joining. The surface roughness ranging between $0.28{\mu}m$ and $3.06{\mu}m$ had almost no effect on joining strength, but the optical properties of HD (High Definition) and UHD (Ultra High Definition) mode affected laser beam transmittance. The optimum laser power was found to be between 8watt and 10watt with 500mm/min of scanning speed. The joining boundary was characterized by optical and SEM analysis. Based on the experiment and characterization results, the laser energy was effective for the polymer joining and efficiency of joining.

• Journal of Welding and Joining
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• 제34권4호
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• pp.23-27
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• 2016

A 3D printed metal part and thermal plastic polymer part were joined by direct laser irradiation. The 3D metal part was fabricated by using DED(Direct Energy Deposition) with STS316 material. The experiment was carried out through no patterned metal surface, 3D metal printed surface and micro laser patterned surface. The most secure joining quality was obtained at the laser micro patterned surface specimen and the counterparts of polymers were PLA and PE based thermo plastics. The applied laser power was 350Watt and the distance of patterns was maintained at $150{\mu}m$. The laser line width was optimized at $450{\mu}m$ and the laser micro pattern depth was $180{\mu}m$ for the best joining quality. Based on the result analysis, the possibility of laser material joining for metal to polymer was proposed and multi-material joining will be possible in 3D laser direct material fabrication.

• 한국레이저가공학회지
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• 제18권4호
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• pp.6-11
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• 2015

Specially designed and 3D printed samples were prepared and joined by a diode laser source. To increase the strength of joining and reliability of samples, the surface was patterned by using a 3D printer. The joining surface was prepared as hemispherical shape with no-patterns, 0.5mm pitch, 0.75mm pitch and 1mm pitch. The optical properties of samples were measured by using an integrated sphere where classical Kubelka-Munk theory and modified Richard-Mudgetts theory for the analysis applied. Scanning speed was set at 500mm/min and laser power was varied between 9 and 10watts for the preliminary joining characteristic analysis.