Spaghetti diagram is a method that uses a continuous line to trace the path and distance traveled of a particular object or person throughout a process. It is most commonly illustrated on a floor map diagram that contains the entire process you are evaluating; i.e. a manufacturing floor, hospital floor, office layout, etc. The purpose of this Lean Six Sigma tool is to expose inefficient process layouts, unnecessary travel distance between process steps and overall process waste.
Why Do I Need a Spaghetti Diagram?
A spaghetti diagram, also known as spaghetti chart, spaghetti model, or spaghetti plot, is a particular tool for determining the distance traveled by (usually) man or (in some cases) material. Hence, a spaghetti diagram can help you if you want to reduce the distance traveled by either parts or people. Obviously, this works best for an repetitive environment where the work repeats in the same or similar style multiple times.
This allows you to then analyze and optimize the distances. The benefit can be either faster delivery or the same delivery with less effort.
How to do it:
Start by either printing out or drawing a diagram of the floor plan of the area that contains the process you’re evaluating. Identify the object/person you wish to track and its starting point (or Step #1 of your process) on the map. Start your line and replicate the actual flow of your object/person on the map and continue the line until the completion of the process (your last step). A common mistake in a spaghetti diagram is drawing the line through walls; do not do this, as this does not realistically represent the actual flow of the object/person. If you did it right, you’ll notice that the line will most likely look like a piece of spaghetti, which is where its name is derived from.
When you start, note the start time on the diagram. While he walks through the factory, mark his route with a pen on a layout of the factory. I usually use a colored pen on an ideally not colored layout (just use a gray-scale printer). You can also add arrows to indicate directions. Whenever I observe him doing something worth remembering, as, for example, searching, making mistakes, or doing other types of waste, I also make a quick note on the layout. This can also include times and will come in handy later on for the improvement. Do not skip any parts, even if it becomes messy (unless the worker needs a toilet break)
After you complete the observation, write down the end time so you have the interval observed. If you take breaks, note the start and end of the breaks. Congratulations, you have completed a spaghetti diagram.