Why Having One Production Schedule is Not Enough

If you’re running APS scheduling, then you must know that one production schedule will probably not meet all your business needs

If you’re running Advanced Planning and Scheduling (APS), then you must know that one production schedule will probably not meet all your business needs.  You can test this assertion by selecting which of the following requirements are important to your business:

1. Ability to effectively establish production due dates to drive the supply chain
2. Ability to predict when work will be completed in light of current factory loading
3. Ability to evaluate load versus capacity as part of a periodic management review

If you answered yes to all three, then that means that you need THREE production schedules.  Yes, you read that right … Three production schedules.

Three Types of Production Schedules

Each of the requirements listed above corresponds to a different type of production schedule some of which are described in my book, Lean MRP.  These schedules, respectively, can be referred to as:

1. BASELINE Schedule: Used to establish stable production due dates and work priorities necessary for reliably meeting customers’ delivery requirements.  It is important that these scheduled due dates be initially established subject to capacity constraints so that they may be realistically achieved.
2. PROJECTED Schedule: Used to provide estimated completion dates (ECDs) useful for updating management and customers on projected completions.  These estimates should be updated regularly to reflect the impacts of shop floor loading.
3. CAPACITY Schedule: Used for load versus capacity reporting.  This is helpful for manufacturing management to support equipment and staff planning.

What Happens in Practice

This is probably the first time you’ve heard of having three different production schedules.  Other consultants or software providers may speak of the ability to maintain separate “what-if” schedules but how they are put to use is the key.  The concept of have having an offline schedule scenario that staff can use to test different scheduling strategies accomplished through drag-and-drop scheduling may sound compelling to some but it is rarely (i.e., close to never) effective in practice.  In fact, I am begging you NOT to do it.

I contend that the best use of multiple scheduling scenarios is to implement the three production schedule types described previously and let them run, run, … run free ... with minimal manual interference from production schedulers, analysts, supervisors, or expeditors.

You spent a lot of money on a scheduling system so why not let it do the work for you?

When the system is enabled to work more optimally, a broad swath of your organization will very probably be liberated from the symptoms of high blood pressure, anxiety, feelings of helplessness, and general bad feelings that permeate so many manufacturing organizations engaged in poor production scheduling practices.

Nowhere is this felt more than in industries where there is a large number of part numbers with deep bills of materials in a job shop environment.  Examples include aerospace, medical devices, industrial equipment manufacturing, food co-packing, and contract manufacturing.

Volatility is the Enemy

Many manufacturers experience schedule volatility, which then renders the schedule itself useless as an essential element of an effective manufacturing control system.  A schizophrenic system that cannot make up its mind as to what is needed when is indeed no system at all.  It’s important to understand that many (i.e., most) ERP users implement production scheduling in a way that inadvertently creates feedback loops that impede on-time performance, grow WIP inventory, and lengthen lead times.

The use of multiple production schedules provides a way to short-circuit these feedback loops in a way that enables a meaningful manufacturing control system conducive to on-time performance and satisfies all three of the business objectives outlined at the beginning of this discussion.

The following video provides a quick introduction that illustrates what is really going on: