X̄-R Chart — Paint Film Thickness
Twenty subgroups of five dry-film-thickness readings in microns, catching a starved-bell subgroup with rule 1 and reporting Cp 1.22 against Cpk 0.94 — a process that is precise enough but centred too low.
Make it your own.
title "Dry film thickness — topcoat booth 1"
chart xbar-r
unit "microns"
spec lsl: 60 usl: 100 target: 80
# Five gauge readings per body, taken at the fixed audit points.
group 81.1 89.3 76.4 79.6 76.9
group 86.8 80.8 67.6 80.0 85.3
group 73.9 75.3 85.9 76.9 69.3
group 73.6 65.8 76.7 70.8 72.8
group 79.2 73.2 80.6 76.3 76.7
group 82.5 70.1 79.4 77.1 73.1
group 73.7 85.0 69.6 78.0 80.0
group 78.1 70.3 75.3 77.9 81.7
group 76.0 63.2 72.2 76.2 81.0
group 70.2 77.8 75.0 76.0 77.7
group 66.0 75.2 73.8 78.4 76.2
group 77.1 74.9 76.5 76.5 65.1
# Bell 3 starved — paint feed pressure dropped for one body.
group 58.8 68.4 66.7 61.8 59.8
group 70.5 70.0 72.3 86.2 80.9
group 78.8 66.5 75.6 72.4 79.5
group 82.0 84.5 71.8 70.6 77.5
group 81.8 75.3 82.9 73.9 82.1
group 85.0 70.7 73.7 72.9 73.1
group 69.8 76.9 79.6 74.8 76.5
group 69.6 74.4 81.4 76.3 71.7