• 제목/요약/키워드: Manufacture process

검색결과 1,592건 처리시간 0.03초

공정능력지수 $C_p$에 대한 효율적인 가설검정 (Better Statistical Test for Process Capability Index $C_p$)

  • 조중재;임수덕
    • 품질경영학회지
    • /
    • 제34권3호
    • /
    • pp.66-72
    • /
    • 2006
  • The process capability indices are widely used to measure the capability of the process to manufacture items within the specified tolerance. Most evaluations on process capability indices focus on point estimates, which may result in unreliable assessments of process performance. The index $C_p$ has been widely used in various industries to assess process performance. In this paper, we propose new testing procedure on assessing $C_p$ index for practitioners to use in determining whether a given process is capable. The provided approach is easy to use and the decision making is more reliable. Whether a process is clearly normal or nonnormal, our bootstrap testing procedure could be applied effectively without the complexity of calculation. A numerical result based on the proposed approach is illustrated.

Copper thickness and thermal reliability of microvias produced by laser-assisted seeding (LAS) process in printed circuit board (PCB) manufacture

  • Leung, E. S.W.;Yung, W. K.C.
    • International Journal of Quality Innovation
    • /
    • 제2권2호
    • /
    • pp.69-92
    • /
    • 2001
  • The laser-assisted seeding (LAS) process has potential to replace conventional electroless copper plating in Printed Circuit Board (PCB) manufacturing since it combines the steps of laser drilling and plating into one single process. In the LAS process, the single extra LAS step can metallize a microvia. Thus, the process steps can be greatly reduced and the productivity enhanced, but also the high aspect ratio microvias can be metallized. The objectives of this paper are to study the LAS copper thickness within PCB microvias and the thermal reliability of the microvias produced by this process. It was found that results were satisfactory in both the reliability test and also the LAS copper thickness which both comply with IPC standard, the copper thickness produced by the LAS process is sufficient for subsequent electro-plating process. The reliability of the microvias produced by LAS process is acceptable which are free from any voids, corner cracks, and distortion in the plated copper.

  • PDF

폐석고로부터 시멘트와 유산제조 및 기반응촉진제 탄소의 무연탄 대체에 관한 연구 (Study of manufacturing of portland cement and sulfuric acid from waste gypsum and the utilization of anthracite coal other than cokes as reaction promotor)

  • 이석우
    • 시멘트
    • /
    • 통권30호
    • /
    • pp.44-50
    • /
    • 1969
  • To manufacture portland cement and sulfuric acid from gypsum has long been established in Europe. As sulfur, more Precisely sulfuric acid, is getting around shortage, it boosts hunt for alternate sources and for new fertilizer process. As the result, all

  • PDF

다단계 냉간 압연된 고탄소강 와이어의 미세조직 및 기계적 특성에 미치는 패스스케줄의 영향 (Effect of Pass Schedule on the Microstructures and Mechanical Properties of Multi-step Cold Rolled High Carbon Steel Wires)

  • 우동혁;이욱진;박익민;박용호
    • 한국재료학회지
    • /
    • 제21권6호
    • /
    • pp.320-326
    • /
    • 2011
  • Flat rolling of wire is an industrial process used to manufacture electrical flat wire, medical catheters, springs, piston segments and automobile parts, among other products. In a multi-step wire flat rolling process, a wire with a circular crosssection is rolled at room temperature between two flat rolls in several passes to achieve the desired thickness to width ratio. To manufacture a flat wire with a homogeneous microstructure, mechanical and metallurgical properties with an appropriate pass schedule, this study investigated the effect of each pass schedule (1stand ~ 4stand) on the microstructures, mechanical properties and widths of cold rolled high carbon steel wires using four-pass flat rolling process. The evolutions of the microstructures and mechanical properties of the widths of cold rolled wires during three different pass schedules of the flat rolling process of high carbon wires were investigated, and the results were compared with those for a conventional eight-pass schedule. In the width of cold rolled wires, three different pass schedules are clearly distinguished and discussed. The experimental conditions were the same rolling speed, rolling force, roll size, tensile strength of the material and friction coefficient. The experimental results showed that the four-pass flat cold rolling process was feasible for production of designed wire without cracks when appropriate pass schedules were applied.