Critical control parameters Strongly affect performance of the system IPDT can control(select)the value Complex systems have hundreds of critical control parameters Fault trees help IpdT to identify Note: IPDT is Integrated Product Development Team C Don Clausing 1998 人 16881 Fig 6
Critical control parameters • Strongly affect performance of the system • IPDT can control (select) the value • Complex systems have hundreds of critical control parameters • Fault trees help IPDT to identify Note: IPDT is Integrated Product Development Team © Don Clausing 1998 16.881 Fig. 6
Fault tree for paper feeder FAIL TO FEED SINGLE SHEET MISFEED MULTIFEED JAM DAMAGE BIG WEAK OVERLAP SLUG SEPARATION ArGe SMALL LOW WEAK SMALL FRICTION WRAP RETARD BELT RETARD DIFFERENCEI ANGLE FRICTION TENSION RADIUS INITIAL WEAR μ T R pp Identification of critical parameters -both control and noise C Don Clausing 1998 人 16881 Fig. 7
Fault tree for paper feeder FAIL TO FEED SINGLE SHEET MISFEED MULTIFEED JAM DAMAGE BIG SLUG WEAK SEPARATION OVERLAP SMALL WRAP ANGLE INITIAL WEAR WEAK BELT TENSION LOW RETARD FRICTION LARGE FRICTION DIF FERENCE SMALL RETARD RADIUS ∆µ pp α 0 α t µ rp T R Identification of critical parameters – both control and noise © Don Clausing 1998 16.881 Fig. 7
Critical parameters at base of tree Both control and noise parameters Example of control factors Roll radius Belt tension Example of noise factor: paper-to-paper friction,up-p C Don Clausing 1998 人 16881 Fig 8
Critical parameters at base of tree • Both control and noise parameters • Example of control factors: – Roll radius – Belt tension • Example of noise factor: paper-to-paper friction, µp-p © Don Clausing 1998 16.881 Fig. 8
Noises Affect performance -adversely IPDT cannot control-examples Ambient temperature Power-company voltage Customer-supplied consumables IPDT must apply large magnitudes of noise early in the development schedule C Don Clausing 1998 人 16881
Noises • Affect performance – adversely • IPDT cannot control – examples: – Ambient temperature – Power-company voltage – Customer-supplied consumables • IPDT must apply large magnitudes of noise early in the development schedule © Don Clausing 1998 16.881 Fig. 9
Role of control factors Values of control factors determine response Many combinations of control-factors values will give same value for response One of these combinations will give the least sensitivity to undesirable variations(noises) Improvement is achieved by searching through the combinations of control-factors values to find the one that gives best performance C Don Clausing 1998 人 16881 Fig. 10
Role of control factors • Values of control factors determine response • Many combinations of control-factors values will give same value for response • One of these combinations will give the least sensitivity to undesirable variations (noises) • Improvement is achieved by searching through the combinations of control-factors values to find the one that gives best performance © Don Clausing 1998 16.881 Fig. 10