Striving For Perfection: Preventing Defects by Preventing Errors
Striving For Perfection: Preventing Defects by Preventing Errors.
In very simplistic terms, a defect is most instances is caused by the occurrence of an error. This can be human error, such as inserting a component into an assembly jig in the incorrect position, by entering the wrong program number into a PLC, forgetting to include a component into a assembly machine to make an assembly and the list goes on.
A simple example (as I am a simple minded person) would be a manufacturing process where the machine operator places a component into a machine where it can be welded to another component. This sounds simple enough but, the machine operator can put the component in the wrong way, use the wrong component or forget to put the component into the machine before actuating the process. Many (non-defect prevention minded) companies will blame the machine operator for this, write them up, scream at them and tell them what a bad person that they are. This merely means that it will eventually happen again. Good (defect prevention minded) companies will have already thought of these occurring and will devices, fixtures, sensors, etc…. in place to not allow the machine operator to make the error. This is the ideal situation (error prevention). The next level of effectiveness would be to detect the error or the resulting defect at the source where it occurred and prevent it from leaving the operation where it was created. Following this level would be downstream detection through more sensors, or devices, etc… that does prevent the customer from receiving the defect but does nothing to keep the company from absorbing the costs of either scrap or rework.
It stands to reason then, that anything that we can do that prevents errors will result in either zero or very few defects in my view. The question is, how does an organization go about putting in place a culture and process for error or defect prevention? My hallucination is, that this starts at the top of the organization. After all, top management is ultimately accountable for the culture that exists in an organization by what they teach, reinforce, talk about and provide resources for in any company.
There are many great tools for identifying potential sources of defects in a process, such as a PFMEA, suggestion systems and work based improvement teams or Kaizens. If top management however, does not promote, require and reinforce this culture it does not happen on its own.
What does an organization do to promote a defect prevention, quality minded culture? They can do things like training all employees on this concept of “error = defect = dissatisfied customer” chain and have clearly defined duties and roles in this process. This also means that the senior level management needs to have the same beliefs that these efforts and resources to have this sort of a culture are worth the costs (ROI). They can look for the use of and potential new ideas for error-proofing methods in the plant. They can have metrics that reflect these important activities, talk about them to employees, reward employees for coming up with and implementing these methods. They can implement effective pre-launch PFMEA processes and after launch have regular meaningful reviews of them.
If the employees in the plant do not see that this is important and not a priority of top management, they will feel that they must just “do their best with what they have”, which is a formula for a low morale, low quality culture type of an organization and eventually the customers will also feel this.
Who’s Job Is It?
This is subject to how an organization is setup, but there are some very common roles that I have encountered over the years. I will lay these out below by typical position in a typical manufacturing organization:
Operator/ Line Worker:
- Study the process they are running and try to identify ways that they can do it incorrectly.
- Make suggestions on how to make the process better.
Foreman/ Area Lead:
- Conduct audits of the error-proofing process.
- Provide training on error-proofing/ mistake proofing.
- Talk about it (individually and at dept meetings)
Manager/ Senior Management
- Establish targets and goals centered around these activities.
- Hold everyone accountable.
- Talk about it, (individually and at company meetings).
Here is to prevention!