Lean Value Stream Mapping (VSM) is a methodology to help reveal the waste in processes and then prioritize lean projects to eliminate that waste in a way that has the most beneficial impact on the overall system. Lean VSM is not a tool meant to analyze variability or dynamics in a process. Lean VSM is meant to be a static analysis of a snapshot in time, with a representation of average data. However, some limited benefit may be realized by representing parallel paths in a Lean VSM, given that the scope is still within the context of one product or product family (Value Stream) and keeping a relatively static nature to the data.
In a Lean VSM diagram a process step may be placed vertically oriented above or below another process step. iGrafx automatically detects this orientation and will select the process step with the longest Processing Time (labeled Total C/T in the default Lean VSM template) to be represented on the Lean Timeline. Thus the boxes with the largest Processing Time will be represented on the Lean Timeline. Note that this may be different than the longest path represented because the longest processes may be alternating between paths.
The notion of longest Processing Time also applies if a shape is horizontally stretched long enough to be vertically oriented above or below multiple sequential shapes along another path. In this case the Processing Time for each of those shapes will be evaluated against the one stretched shape and the longest Processing Time will be represented on the Lean Timeline.
If it is desirable to analyze paths separately, then selected process steps on certain 'paths' may have their Timeline Type set to be 'Not on Timeline', so that they do not show up on the timeline and affect the calculations for the 'path' that you define. You may instead use multiple timelines if the parallel paths are sufficiently different to essentially constitute separate family of products or separate processes with vastly different times. Finally, you may also export/import data to/from Excel to do calculations on a given set of shapes if you want to do more complex calculations for parallel paths.
To set a shape to not be on the timeline:
- Display the Properties of the shape (e.g. right-click and choose Properties).
- Click on the Lean Data page on the left-hand side of the Properties dialog box, if it is not already chosen.
- In the Timeline Type drop-down menu near the bottom of the dialog box, set it to 'Not on Timeline'.
Set the 'Not on Timeline' Timeline Type for each shape that you do not want to be on the timeline.
To use multiple timelines and / or export/import of data to/from Excel, see the iGrafx Help system (Help menu > iGrafx Help).