The Supply Process

Overview

The supply process is the process used to create the product or service that a company sells. Modeling the supply process uses the standard tools for process modeling in general.

Drawing a Process Flow Diagram

Supply process diagrams typcially use the following conventions.

• Activities are represented by a square. Activities can be viewed as mini processes that are represented as a single (black box) unit.
• Arrows represent a output of one element and input into another
• Inventory is drawn as a triangle and represents a static amount of some good

Process Capacity

Capacity is the ability of a process to produce a given amount of output over a given amount of time. The capacity of a process is dependent on the capacity of the individual acitivities that composes the process.


Bottlenecks : One of the primary reasons that a process capacity is below its maximum is the presence of bottlenecks. A bottleneck is an activity in the process for whcih its output becomes inputs to other processes in the chain and for which the downstream processes often sitting idle waiting for the bottleneck process to create enough output for them to begin.

A simple way to identify bottlenecks is to draw the process diagram, and then note the activities are being run conituously versus the activities that are only being run sporadically.

(For more information, see Theory of Constraints)

Branches and Critical Path : many processes split into sub-processes called branches. Branching in a process

Bathtub Modeling

Bathtub Models are a type of dynamic model used to model a series of flows (inputs and outputs) between nodes in a diagram. They can be modeled as discrete time processes or in continuous time using differential equations.