The Difficulties of Scheduling Around the Assumption that Everyone, and Everything Will Work Exactly as Planned
In the previous article (2 of 5), we talked about planning our daily drive. We introduced the concept of using a time buffer to account for the unexpected. We also talked about the threat of incurring penalties in case our planning fails to deliver us to work on time.
What are the implications of this thought exercise for manufacturing scheduling?
- The first scenario has no time buffer built into the plan. As such, Scenario 1 is suggestive of those manufacturers who schedule around the assumption that everyone, and everything will work exactly as planned.As almost every commuter and manufacturer knows, this practice will likely result in frequent missed arrivals and due dates. The threat of losing customers upset about their late shipments will be very high.
- The second scenario provides a reasonable amount of time buffer to help us plan for the unexpected. Most manufacturers aim for this kind of operation. The manufacturer will be able to satisfy most of its customers, most of the time.The caveat is that over time, you should anticipate that customer expectations will move the bar ever higher. For that reason, you can’t afford to be complacent. You should look for ways to improve your production scheduling practices and accelerate turn-around times before new competitors emerge to threaten your business’ viability.
- The third scenario features a very long time buffer. This scenario describes those manufacturers who allot generously for variability. While this does give the individual driver the most protection from being late, it may introduce too many cars too early, creating more traffic slowdowns in the process. While this is easy to see on California highways, it also happens just like that in a manufacturing shop floor – too much Work in Process (WIP) slows things down. So, overall we need to strike a balance – how much buffer time versus how much “traffic” (work/jobs) do we release?
The manufacturer has customers who, for any number of reasons, must have their jobs delivered on time. Missed due dates are a threat to the business’ survival. Your competitive advantage is dependent upon your ability to continuously improve your shop floor scheduling practices.
In the next article (4 of 5), we’ll track the progress of our drive. The exercise will help us appreciate more fully the importance of using time buffers to improve our drive, if not your manufacturing businesses’ on time efficiency. As should be evident by now, learning how to improve your production scheduling is critical to your firm’s competitiveness – and ultimately, your bottom-line profitability.
How great is the threat of missed due dates? Does your plant deliver on time, most of the time? Are your customers tolerant of long turn-around times? What sort of time buffers are you using, too long, or too short? How can you tell?