Selecting a Product Family
One point to understand clearly before starting is the need to focus on one product family. Your customers care about their specific products, not all your products. So you will not be mapping everything that goes through the shop floor. Unless you have a small, one-product plant, drawing all your product flows on one map is too complicated. Value stream mapping means walking and drawing the processing steps (material and information) for one product family from door to door in your plant.
Identify your product families from the customer end of the value stream. A family is a group of products that pass through similar processing steps and over common equipment in your downstream processes. In general, you should not try to discern product families by looking at upstream fabrication steps, which may serve many product families in a batch mode. ite down clearly what your selected product family is, how many different finished part numbers there are in the family, how much is wanted by the customer, and how often.
Note: If your product mix is complicated you can create a matrix with assembly and steps equipment on one axis, and your products on the other axis (see below).
Assembly Steps & Equipment
A Product Family