With the advent of lean-six sigma era, an extensive use of analytic tools such as control charts is required in the field of manufacturing. In relation to statistical quality control (SQC) or process control (SPC), the Korean standards have undergone a meaningful change. In this study, the theoretic backgrounds for evaluating the control limits in connection with the variable control charts are examined in view of better understanding the related constants and coefficients. This paper is intended to help the quality control practitioners understand the mathematical backgrounds by comparing related quality control constants and also to encourage them to make use of and to take the advantage of the variable control charts which are very useful for implementing the concept of lean-six sigma in many industrial sites.

1. 서 론
 2. 계량형 관리도
  2.1 관리도
  2.2 범위에 의한 모 표준편차의 추정
  2.3 분산에 의한 모 표준편차의 추정
  2.4 불편화 상수 c2와 c4의 관계
  2.5 상수의 계산
 3. x- R 관리도
  3.1 x 관리도
  3.2 R 관리도
 4. x-S 관리도
  4.1 x 관리도
  4.2 s 관리도
 5. x-S 관리도
  5.1 x 관리도
  5.2 S 관리도
  5.3 관리한계의 변화
  5.4 범위의 상대 효율성
 6. 결론 및 제언
 Acknowledgements
 References

• 안해일(서경대학교 산업공학과) | Haeil Ahn Corresponding Author