The Challenge. Many production systems today contain ‘bottlenecks’ or constraints costing a company money. Do you still have significant bottlenecks in production at your facility?
The APICS dictionary defines a bottleneck as “a facility, function, department or resource whose capacity is less than the demand placed upon it.”
In other words, a constraint is an element or process in a system that prevents the overall output from reaching higher levels.
Theory of Constraints. Dr. Eliyahu M. Goldratt developed a philosophy that ‘all’ systems at any one time have only a small number of variables or constraints (perhaps as few as one) that effectively limit the output of a system.
With this in mind, there are ways to optimize a manufacturing system’s output. Likewise, once constraints are removed, a company can reduce its overall costs since more product will be moving through the production process in a shorter amount of time.
It follows that the company’s challenge is to see (and understand) the current state of the production system and then envision the future state allowing for higher output of the system.
Removing Constraints. The APICS dictionary defines ‘five focusing steps’ to help identify and remove bottlenecks or constraints in a system. They include,
- Identify the constraint – determine the throughput rate and the demand rate
- Exploit the constraint – maximize use of the constraint
- Subordinate the constraint – make effective use of the constraint the top priority
- Elevate the constraint – increase capacity of the constraint
- Once resolved, identify the new constraint.
One of the most difficult steps, in more complex processes, is identifying the initial constraint in the system.
‘Product flow’ diagrams, that pictorially describe the product and flow rate, can be of help in finding the point or points of constraint in a system.
The Bottom Line. Many production systems exhibit ‘bottlenecks,’ i.e., those elements whose capacity is less than the demand placed upon them. Dr. Goldratt’s theory of constraints stipulates that a system can have only one or, at most, several constraints limiting the systems output. Identifying and removing constraints increases the output of a system and helps reduce costs. APICS defines five steps that assist in removing constraints. Product flow diagrams help identify constraints in a system.