Time scale for Xbar-R Chart

Stat > Control Charts > Variables Charts for Subgroups > Xbar-R > Scale > Time

Specify a time scale for the x-axis.

Label the x-axis with the number of the subgroup.
Label the x-axis with values from a column. In Stamp columns (1-3, innermost first), enter up to three columns that contain date/time, numeric, or text values for the scale.