“Quality escape” was not a familiar term to the general public, or even to many stakeholders in the manufacturing world, until Boeing CEO Dave Calhoun used it to describe the cause of the Alaska Airlines Boeing 737-9 door plug assembly failure in January. A single improperly installed bolt slipped past inspection procedures by the supplier and the OEM. The fortune of an empty seat prevented loss of life, but subsequent grounding of all Boeing 737-9 aircraft puts the cost of this quality escape in the billions of dollars.
Whether the primary industry for your products is aerospace, automotive, energy or something else, preventing quality escapes is essential to your company’s reputation and business success, not to mention your corporate responsibility for the safety and welfare of the communities your products ultimately serve.
When it comes to manual production operations, achieving the goal of eliminating quality escapes requires a two-pronged effort:
- Shore up production procedures to prevent manufacturing flaws from occurring in the first place.
- Since flaws cannot be wiped out completely, modernize inspection methods to detect and correct flaws as early as possible in the manufacturing process.
Let’s take a look at the state of quality control programs that allows incidents like the Alaska Airlines debacle to occur. Then we’ll discuss an approach to quality control that eliminates quality escapes and contributes to your reputation and business success.
Two kinds of quality escapes: Costly and catastrophic
Quality engineers categorize quality escapes as either internal or external. An internal escape is a flaw that occurs on the shop floor but is not detected until post-production inspections. It may result in rework or scrapping of the product, which is detrimental to costs and schedules – both yours and your customer’s. External escapes remain undetected during production and assembly of products. When they involve critical structures, external escapes can and have resulted in the catastrophic failure of the end product. Aviation accidents and incidents. Major traffic events. Wind turbine collapses. In the most tragic cases, these disasters include loss of life.
As bleak as these potential outcomes may be, quality escapes nevertheless do not garner the attention one might expect. This is probably because quality escapes are relatively rare occurrences, and quality escapes that result in the kinds of costs Boeing is now facing are rarer still. Yet they pose a highly consequential risk to product safety and performance.
In response to these low-frequency, high-consequence events, best practice in many industries is to enhance manual procedures and/or add more training requirements for the operators performing these manual tasks. So far, these industries have been reluctant to adopt system solutions because investing in them is categorized as a “cost avoidance” measure for black swan events. But when the black swan event literally costs billions of dollars in grounded airplanes, recalled automobiles, failed megawatt wind turbines and the like, it may be worthwhile to set aside the “cost avoidance” label and consider more reliable solutions to the issue of quality escapes.
The problem with manual quality control
Of course, for an event to be correctly labeled a black swan, it should be unavoidable – and with manual quality control, it often is! In manual operations, “process control” typically amounts to having operators follow correct procedures from a set of paper work instructions and document task completion by initialing or stamping a paper traveler. Alternatively, operators step away from their workstation to review instructions and record their progress at a control computer.
Numerous human factors, including distraction and fatigue, compromise this process control and lead to quality escapes. No amount of training, checklists and data collection will prevent these human factors from short circuiting process controls and creating opportunities for error. What’s more, today’s intensifying schedule and cost pressures tend to proliferate error-prone activities. For example, buyoffs on each manual step may be required, but to save time your operators may prestamp or stamp behind a whole series of steps. They may also work from memory rather than consulting the work instructions.
It’s not that operators are being deliberately irresponsible or neglectful. Their job is to get the product built on time, and it’s secondary to read familiar instructions and keep records. But filling out a traveler step-by-step is supposed to serve as a quality assurance check, and stamping multiple boxes at one time defeats this purpose. Yet human nature and pressure to get the job done quickly make it impossible to eliminate such shortcuts.
Human factors also play a large role in manual inspections. The most well-trained and diligent human inspector has a limited ability to detect foreign object debris (FOD), measure material alignment or determine whether the material’s edge is correctly positioned. This is especially true when the work-in-progress (WIP) is large and potential flaws are small, as is the case in aerospace, automotive and wind turbine production.
More training, more rigorous procedures, or more checks will take quality control only so far. Quality escapes will continue to wreak havoc unless another approach to quality control is adopted.
A digital quality control solution
Certain tasks on the shop floor will probably always be performed manually. People are used in manufacturing because their agility, mobility, visual and tactile sense far outperform automated machinery and robots. People are necessary for certain processes but will always be a liability when it comes to process and quality control. The fundamental shift that will eliminate quality escapes is to leave these processes to human operators but replace people with technology to perform control functions flawlessly.
Digital quality control uses available, proven technology in two roles. First, electronic process control provides floor operators with independent control of their tasks via smart touchscreen tablets and smartphone-size devices. On these handheld devices, operators receive electronic work instructions that help them perform the right task in the right sequence at the right time, using CAD-driven laser projection for guidance directly on the WIP. The mobile devices also enable (and require) an electronic buyoff (along with space for optional comments) after each process step. ALIGN 4.0 software supports up to eight remote controls on each system control computer, multiplying the application of electronic process control on the shop floor.
Second, AI-enabled, large-field automatic in-process inspection replaces manual inspection and offers near-100% inspection accuracy in a fraction of the time manual inspection requires. From the operator’s perspective, automatic inspection happens “behind the scenes” whenever the electronic work instructions call for it. The operator is notified only when a flaw is detected. At that point, the laser projector guides the operator to the WIP location of the flaw, where early, low-cost corrective measures may be performed before the next process step.
Data generated during inspections is captured and automatically populates digital documentation. This wealth of information offers added value for your customers as well as the end users of the finished product. It also feeds as-built data into a closed-loop continuous improvement process.
Escaping quality escapes
For decades (even centuries) on shop floors across the industrial spectrum, companies have been eliminating human factors to improve production safety, quality and throughput. For example, in addition to procedural changes and training that help keep people from performing shop floor tasks that might cause eye damage, companies provide and require the use of safety glasses. Extending this same paradigm to product quality, digital quality control eliminates the human factors that have led to costly product recalls, field failures and – yes – even loss of life. Instead of dismissing a digital quality control solution as a “cost avoidance” measure, manufacturers would be well served to eliminate quality escapes by investing in this technology.