• 한국정밀공학회지
• /
• 제33권3호
• /
• pp.191-198
• /
• 2016

Traceability is essential in modern automotive manufacturing. Among existing technologies, RFID is the most promising choice for this purpose. However, due to the harsh conditions of production lines, especially in the paint shop, automobile OEMs would require expensive dedicated RFID tags and readers, which are incompatible with standard RFID technologies. Unlike the manufacturing industry, the logistics industry uses UHF label tags for track and trace, which provides high performance and a low price. Recently, this technology has improved to the extent that it can be used in harsh conditions such as on metal parts or in liquid. Herein, we assess the technical, operational, and economic feasibility of UHF label-tag technology for seamless end-toend traceability. Based on prototyping, lab/field tests, and cost-benefit analysis, we have proven that the single disposable UHF tags can successfully replace the problematic and expensive tags used in most domestic automobile OEMs today.

• 한국해양공학회지
• /
• 제28권2호
• /
• pp.177-184
• /
• 2014

Heavy duty coating is playing an important role in the field of heavy industry in the development of the shipbuilding and plant industries. Heavy duty coating has the very important function of protecting steel under serious corrosive conditions. The airless tip used for heavy duty coating is an essential part that determines the spray pattern of the paint. This research investigated the injection properties of three airless tips(numbers 521, 523, and 525) by using particle image velocimetry(PIV). The velocity and turbulent intensity according to pressure change with each tip type were investigated by using PIV. If the pressure is greater, the turbulent intensity becomes stronger and the break up of particles becomes bigger as the tip number gets smaller. The velocity is the fastest in the center and decreases in the radial direction.

• Corrosion Science and Technology
• /
• 제11권1호
• /
• pp.15-19
• /
• 2012

Both electrogalvanized and hot-dip galvanized steel sheets have been finally produced via organic-inorganic surface coating process on the zinc surface to enhance corrosion resistance and afford additional functional properties. Recently, POSCO has been developed a variety of chromate-free coated steels that are widely used in household, construction and automotive applications. New organic-inorganic hybrid coating solutions as chromate alternatives are comprised of surface modified silicate with silane coupling agent and inorganic corrosion inhibitors as an aqueous formulation. In this paper we have prepared new type of hybrid coatings and evaluated quality performances such as corrosion resistance, spot weldability, thermal tolerance, and paint adhesion property etc. The electrogalvanized steels with these coating solutions exhibit good anti-corrosion property compared to those of chromate coated steels. Detailed components composition of coating solutions and experimental results suggest that strong binding between organic-inorganic hybrid coating layer and zinc surface plays a key role in the advanced quality performances.

• 한국기계가공학회지
• /
• 제11권6호
• /
• pp.183-188
• /
• 2012

This study was carried out to design the spray nozzle tip for airless spray coating. Airless spray coating is the process of coating an object with a liquid spray of paint or other fluid. The nozzle tip controls the fluid flow rate and creates back pressure in the system. The nozzle tip also defines the spray pattern by the size and shape of the orifice. The spray pattern of nozzle tip was investigated numerically using ANSYS CFX ver. 14.0. It was observed that performance result of designed nozzle tip was correspond well, compared with that of GARCO nozzle tip.

• 산업경영시스템학회지
• /
• 제36권3호
• /
• pp.95-108
• /
• 2013

The problem of constrained sequencing of a set of jobs on a conveyor system with the objective of minimizing setup cost is investigated in this paper. A setup cost is associated with extra material, labor, or energy required due to the change of attributes in consecutive jobs at processing stations. A finite set of attributes is considered in this research. Sequencing is constrained by the availability of conveyor junctions. The problem is motivated by the paint purge reduction problem at a major U.S. automotive manufacturer. We first model a diverging junction with a sequence-independent setup cost and predefined attributes as an assignment problem and this model is then extended for a more general situation by relaxing the initial assumptions in various ways.

• 대한금속재료학회지
• /
• 제49권6호
• /
• pp.448-453
• /
• 2011

Pre-aging heat treatment after solution heat treatment (SHT) of Al-0.4 wt%Mg-1.2 wt%Si-0.1 wt%Mn alloy sheets for auto-bodies was carried out to investigate the effect of pre-aging and its conditions on the bake-hardening response. Mechanical properties were evaluated by a tensile and Vickers hardness test. Microstructural observation was also performed using a transmission electron microscope (TEM). It was revealed that pre-aging treatments play a great role in the bake-hardening response. In addition, it was found that the sphere-shaped nanosized clusters that can directly transit to the needle-shaped ${\beta}$" phase during the paint-bake process, not being dissolved into the matrix, are formed at 343 K. The result, reveals that the dominant factor of the bake-hardening response is the pre-aging temperature rather than the pre-aging time.

• Journal of Welding and Joining
• /
• 제34권1호
• /
• pp.21-25
• /
• 2016

The automotive vehicle is made through the following processes such as press shop, welding shop, paint shop, and general assembly. Among them, the most important process to determine the quality of the car body is the welding process. Generally, more than 400 pressed panels are welded to make BIW (Body In White) by using the RSW (Resistance Spot Welding) and GMAW (Gas Metal Arc Welding). Recently, as the needs of light-weight material due to the $CO_2$ emission issue and fuel efficiency, new joining technologies for aluminum, CFRP (Carbon Fiber Reinforced Plastic) and etc. are needed. Aluminum parts are assembled by the spot welding, clinching, and SPR (Self Piercing Rivet) and friction stir welding process. Structural adhesive boning is another main joining method for light-weight materials. For example, one piece aluminum shock absorber housing part is made by die casting process and is assembled with conventional steel part by SPR and adhesive bond. Another way to reduce the amount of the car body weight is to use AHSS (Advanced High Strength Steel) panel including hot stamping boron alloyed steel. As the new materials are introduced to car body joining, productivity and quality have become more critical. Productivity improvement technology and adaptive welding control are essential technology for the future manufacturing environment.

• 접착 및 계면
• /
• 제12권1호
• /
• pp.34-42
• /
• 2011

자동차용 도장시스템으로 새롭게 대두되고 있는 roll coating process는 비친환경적이면서도 생산성이 떨어지는 기존의 습식도장공정을 완전 대체할 수 있는 기술로 알려져 있다. Pre-painted 강판 시스템에서 도막 유연성 및 강도 등의 구현을 위하여 경화거동뿐만 아니라 내식성 및 성형가공성, 유변학적 거동 등의 평가가 매우 중요하다. 본 연구에서는 pre-painted system에 적용하기 위하여 polyester 수지를 수산화기 및 분자량 변성을 통하여 합성한 후, 경화거동 및 딥드로잉, 인장력, 유변특성 등을 평가하였다. 40 (mg KOH-/mol)정도의 수산화기를 갖는 N-0375-40 system이 유연성 및 도막강도, 경화거동 등의 가장 우수한 물성을 나타내었다.

• 열처리공학회지
• /
• 제30권3호
• /
• pp.117-126
• /
• 2017

The variation in microstructure and mechanical properties during heat treatment was examined in a series of 0.27% C-1.5% Mn-1.0% Cr steels with silicon contents in the range of 0 to 1.0 wt%. It was found that addition of 0.5%~1.0% silicon increased both tensile strength and impact toughness through solid solution strengthening and microstructural refinement. 0.27% C-1.0% Si-1.5% Mn-1.0% Cr steel showed tensile strength of 1,700 MPa in the as-quenched condition and the steel revealed a full martensitic structure even after air cooling from $900^{\circ}C$ to room temperature, showing air hardening characteristics. Tempering at $150^{\circ}C$ which corresponds to the typical paint-baking temperature after painting of body in white, slightly decreased the tensile strength and increased elongation, but substantially increased the impact toughness compared to the as-quenched steel.

• KSTLE International Journal
• /
• 제2권1호
• /
• pp.80-84
• /
• 2001

The purpose of this paper is to show the result from the study to improve the formability and appearance which is important in the cold rolled strip, the coated strip and prepainted strip. Furthermore, to give appropriate surface roughness, shape of work roll for temper mill is also important. The strip has a greater peak counts and homogeneous roughness. This makes the prepainted surface smooth and consistent in appearance with good image clarity. Therefore, the surface roughness of the work roll is very important. The reason that surface roughness of the work roll is transferred to the strip surface is the rolling farce and tension at the temper rolling or cold rolling. This study is classified in order to get an accurate and homogeneous roughness. There are few papers published in this field, because its importance is not known and the proper operation of the machine is not generally well known. This paper investigates the correlation between strip surface roughness and the surface of the work roll. After studying the surface roughness and shape according to the texturing method for roll surfaces at temper rolling, the findings were as follows. Irregular surface roughness can be compensated with several paint coatings, but this also makes the quality deteriorate and manufacturing costs go up.