Coming to Terms

BY: DALE WICKER

In the manufacturing industry, and specifically in the area of Quality Management, many technical terms are used that people also use in everyday life. However, they don’t always have the same meaning. This can lead to misunderstandings and serious problems in production if team members can’t differentiate between everyday meanings and technical meanings.

WHAT MAKES A PROCESS ROBUST?
A few months ago, while leading The Center’s Manufacturing Skills Development class, I told students that we needed to ensure a robust process was in place. Most responded with head nods, indicating they understood. To be sure, I asked the room, “What does robust mean?”

The room suddenly became silent. “Uh, safe?” one student timidly replied. “Strong,” replied another. “Reliable!” shouted another. While all of these are correct in the proper context, they do not exactly fit the manufacturing definition. Rubbing my stomach, I told them my wife calls me robust, but that also was not the correct meaning I sought.

Finally, one student called out, “Consistent!” I responded, “That is almost it! But it needs further clarification. Let me explain…” In manufacturing, having a robust process means the process is insensitive to variation. Regardless of any variation present in the process, conforming products can still be made at the quantity and rate desired.

For example, if we have a process that is running around the clock with three different shifts, it is likely that variation will exist with operator change, tooling, equipment maintenance, raw material from various suppliers, utility fluctuations and temperature. These variations, called common cause variation, are expected and should be part of the manufacturing plan. They are normal fluctuations that will not impede our ability to manufacture and deliver good parts on time. Meaning, the process is robust!

PUTTING THE ‘RISK’ IN ‘RISKY BUSINESS’
Another term that causes confusion in a manufacturing environment is risk. Before starting a discussion about risk, it is essential that everyone has the same, accurate understanding of what risk means.

Let’s start with the ISO 9001 definition, which states that risk is “the effect of uncertainty.” That clears it up, right?  Not quite. This doesn’t specify the amount of uncertainty in question, and in many cases the percentage of risk is unknown. This simply states that where we have uncertainty, we have risk.  How much risk is tolerable is up to each organization to determine. 

Various tools, tests and inspections exist to define and assess risk through measurement and analysis, helping organizations plan and implement appropriate actions to mitigate or eliminate the risk. For example, the automotive industry uses various tools, processes and systems, such as APQP (Advanced Product Quality Planning), FMEA (Failure Mode Effects Analysis) and PPAP (Production Part Acceptance Process), to address risk in the product design and production process. This ensures that they can deliver a conforming product on time and satisfy the customer. Understanding it in this way, risk must be a part of initial planning and assessment to account for any uncertainty in the product or process.

REWORK AND REPAIR AND REGRADE, OH MY!
Several other terms that often lead to misunderstandings are rework, repair and regrade, which are typical actions taken as a result of rejects in production. So, let’s start with reject. If you have a product/part that fails to meet the drawing requirements (i.e., blueprint, specification, etc.) either physically or functionally, then you have a reject, or nonconformance. Now a decision must be made for how to handle the reject: rework, repair or regrade? Maybe even scrap it! 

Going further, to rework something is to return it to complete conformance with the drawing requirements both physically and functionally. To repair something is to return it to intended functionality, but some aspect of the product is not in conformance with the print. 

Let’s say my wife and I manufacture printed circuit board (PCB) assemblies for computers. My wife, the inspector, finds a board with a missing resistor. She brings it back to me, the technician, to show me the issue.  “I can rework that,” I say casually. She asks how.

“Elementary, my dear. Just add the resistor to the PCB and solder it in, following the normal process. It will be in complete conformance with the drawing and just as good as new!”  I say robustly. 

“Very well, Sherlock, get to work!” she smiles and goes back to inspecting.

A while later, the inspector-wife finds a PCB with an open (cut) trace and the board not functioning. She brings it back to me. “I can repair that!” I say nonchalantly.

“How? With a resistor?” she quips.

“Not quite. I’ll just add a jumper wire across the open trace and solder it in. It won’t meet the print requirements physically, but it will function normally as intended,” I explain.

“Hmmm…” she considers, “Sounds risky. We may need to get customer authorization for that since it is nonconforming, even if it is functional.”

“That’s correct! Or we could regrade it for use in a different application,” I add. 

“What do you think these are, eggs?”  she laughs, returning to her inspection station.

This brings us to regrade. Like eggs, many products can be regraded. In manufacturing, this is where a product may have different functions or uses based on its characteristics. For example, in the aerospace industry, many electronic components used in defense or space must undergo extensive and strenuous testing to qualify for certain applications. Those that fail to meet the requirements, however, may still be useful in other commercial contexts and can be regraded for those applications.     

It is important to define, clarify and understand the terms used by your organization in planning, controlling, measuring and analyzing products and processes. In order to contribute effectively to processes and comprehend critical aspects of operations, all team members must come to terms with these terms. And, if you’re married like me, you must come to terms with your spouse!


MEET OUR EXPERT

Dale Wicker, Quality Program Manager
Dale Wicker is one of the Program Managers in the Quality Group of the Michigan Manufacturing Technology Center.  Dale Wicker manages and delivers training and implementation assistance to organizations in the field of Quality Improvements. Some of these projects involve assistance with implementing a Quality Management System such as ISO 9001 (generic commonly used Quality System), ISO/TS 16949 (the automotive version Quality System), and AS 9100 (the aerospace/defense version) Quality System.  

Since 1991, the Michigan Manufacturing Technology Center has assisted Michigan’s small and medium-sized businesses to successfully compete and grow. Through personalized services designed to meet the needs of clients, we develop more effective business leaders, drive product and process innovation, promote company-wide operational excellence and foster creative strategies for business growth and greater profitability. Find us at www.the-center.org.