Tham khảo tài liệu 'quality management and six sigma part 11', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Defining Placement Machine Capability by Using Statistical Methods 193 XY Matrix Prioritization matrices are used to help to decide upon the order of importance of a list of items Breyfogle 2003 . XY matrix is one of them and will take into account not only how often things might happen but also the severity of the effect it will create. Fig. 10 shows XY matrix on placement process key input variables. Prioritization matrices are often completed by the selected project team. Fig. 10. XY matrix on placement process key input variables showing the relative importance and effect of each input variable X on response variable Y pickup and placement error . SOP Standard Operating Procedure C Controllable N Noise. X s from Measure Phase From measure phase three X s were identified and prioritized for the project scope by the six sigma project team. 1 R C sequence Placement sequence of resistors R and capacitors C this X is to be further studied 2 Feeder condition Elimination of X by using calibrated error-free feeder 3 Machine condition capability Elimination of X by using maintained calibrated machine . machine is in good condition but what machine placement sigma level from PAM-board is required this X is to be further studied 194 Quality Management and Six Sigma 5. The ANALYSE phase A DOE was performed with a dedicated HD-board test PWB. Picture of HD board is seen in . The HD boards were first solder paste printed with a modern high-accuracy stencil printing machine. Then 0402 resistors and capacitors were placed on the boards by machines having placement sigma levels of 1 2 3 and 4 respectively. Totally four HD-boards were produced one for each placement sigma level. Components were placed only on modules 1 and 3 of the HD-board panel see . Resistors and capacitors were placed on modules 1 and 3 using different placement sequence which is described in . AOI inspection was performed immediately after placement and totally 20 200 .
