Stability is a major issue in manufacturing. Parts need to be made to specifications to allow an easy assembly of final products. Unstable behaviors generate quality problems that customers must deal with later.

Yet there are often so many consecutive steps that a slight misalignment at one will impact the entire production line. Read on to see four challenges to stability, and how to address them.

1. A Problem of Tolerance

It is often not possible to completely eliminate variations so tolerances that are tight are difficult to deal with and increase final costs. If this aspect is not fully taken into consideration right from the very beginning, during the design stage, manufacturing plants will struggle to achieve the expected performance.

As supply chains often extend over several countries and suppliers compete to get orders from larger groups, a key criteria to rank suppliers is their ability to stay well within specifications as far as critical parameters are considered.

2. Stability = Competitive Advantage

Companies constantly encourage their suppliers to better control the stability of their processes. Costs related to lack of stability will increase whenever they are passed on from vendor to vendor and then to the final customer as defects are detected much later in the manufacturing process.

This is why a reliable, predictable supplier can gain a major advantage over the competition, establishing long term profitable relations with large customers.

3. Collaboration by Departments is Essential

Stability improvement often involves solving complex problems, to identify the few critical factors that really affect variability and separate them from the trivial many.

Solving such problems will often involve the collaboration from several departments:

  • Production
  • Quality
  • Design
  • Etc.

…that generally tend to have differing perceptions regarding stability problems.

To improve the situation, individuals may try to implement their own ad hoc solutions that will differ from team to team.

Typically, these include Excel files with calculations and methods that have not been validated company-wide. 

This will obviously tend to reduce the level of cohesiveness.

4. Standardization vs. Human Nature

Sharing ideas across teams, working together to look for potential solutions to complex issues, based on data and facts, using robust and powerful methods to identify the major sources of variations and reduce their impact, requires standardized and validated tools.

Unfortunately, there are natural human tendencies that cause problems and confusion for teams:

  • Jumping to solutions before a problem and its scope have been fully defined.
  • Moving on too quickly to the next problem to be solved, without making sure that initial gains are maintained in time after the previous improvement project has been completed.
  • Suggesting potential solutions based primarily on subjective conjectures rather than on actual data and hard evidence.
  • Starting to analyze data without checking that the data can really be trusted including the way the data has been collected and measured.

To avoid all of these common pitfalls, relying on a methodology with a proven track record help teams share a common view.

For example, the DMAIC methodology has standardized stages such as Define, Measure, Analyze, Improve and Control.