Posts Tagged ‘capacity constraint resources’

We looked earlier at identifying constraints, noting that it is fairly intuitive to observe that the constraint by definition is the weak link in the system.  How do we improve the throughput at the constraint without unduly increasing the expense or cost of doing so?

The answer lies in finite scheduling – The Rope, of Drum-Buffer-Rope thinking – in order to balance the flow (throughput) of our system.  The idea is to control the flow of production through the plant in order to meet sales (market) demand, with the least amount of manufacturing lead time, expense and inventory costs.

Modern MRP software can handle this for you.  In our experience over the years, we’ve seen many manufacturers with a high level of urgency regarding Scheduling.  Often, it’s the first thing they look at when evaluating an MRP system, but the last thing they implement – and for good reason.  Truly tight scheduling simply asks so much of the operators and managers.  We often guide clients to a rough-cut or gross requirements scheduling solution: it’s more important to get the order right, than schedule the shop down to the gnat’s behind – especially since attempts to do so are rarely successful.

All that being said however, The Theory of Constraints (TOC) school of thought, first introduced in Goldratt’s The Goal focuses on five steps to implementing an effective scheduled throughput, which I quote verbatim below.  For a fine (if lengthy) overview go here.

1. Identify the system’s constraint(s).
2. Decide how to exploit the system’s constraint(s).
3. Subordinate everything else to the above decisions.
4. Elevate the system’s constraint(s).
5. If, in the previous steps, a constraint has been broken, return to step one, but do not allow inertia to cause a system’s constraint.

The Rope provides for proper release to the manufacturing flow process, or as put by others, it aids in subordinating all else to the system’s constraint(s).  It’s your schedule.

Broadly speaking, you start by identifying all constraints within the system.  Make these the focus of your attention.  From these, derive your planning, scheduling and control of resources.  Once you’ve identified your capacity constraint resources (your CCRs, or your bottlenecks), schedule orders through them according to the capacity of the resource and market demand (your due date requirements). 

This schedule (or Rope), in effect is a looping-back to the Drumbeat of your demand. 

Next article, a little more info on Scheduling…

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