How to FISH

By Howard Cooper

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Do you feel that every equipment maintenance article you read is pushing you to spend more money on overhead and more time pampering machines instead of running them? If so, here's your lucky break. Go FISHing. Functional interface stress hardening (FISH) is a methodology developed that is proven normally to eliminate:

  • 50% of mechanical downtime
  • 80% of hydraulic systems downtime and expense
  • 92% of electronics, microprocessor and computer equipment downtime in most manufacturing facilities.

Equipment life and availability go up, while drastically cutting maintenance pampering and overhead expense. If your machines take unscheduled breaks and unannounced days off (malfunctions and downtime), that's not lean. That's losing.

Are lean machines required for lean success? Absolutely? Usually? No? Is it the people and the process that count? The correct answer depends on your product and the type of machines, computers, process controls, machine tools and telecom equipment required to order, process, pack, ship and invoice for your product or service. Ask yourself these two questions:

  • Which computers, machine tools, motion controls or other equipment would affect my lean operation or my ability to deliver if they were taken out of service today for the next week?
  • How much work would my operation deliver or process today if the power went out, leaving me without machines?

Most facilities have automated during the past 20 years to 30 years to a point that leaves them completely dependant on machines. You often hear about employee appreciation, employee training, employee development and building a productive employee environment but, we often overlook that our computers and automated machine tools have become our most valuable employees.

We pay far more per hour for these semi-intelligent mechanical employees than for any human (the boss included). So, what are we doing to provide these digital marvels with a productive work environment? The answer lies within your FISHing expertise.


FISH is based on a fact of nature — things most frequently wear out, malfunction or fail at an interface.

Think about it:

  • Tree limbs break off at the joint where they interface to the tree.
  • Sidewalks usually crack and crumble along the edges.
  • Doctors replace more knee and hip joints than bones because the body wears at the joint, an interface.
  • Car suspension parts, machine gears and the like wear out at the point or surface of interface.
  • Desks and chairs get worn or damaged where you interfaced with them.

If you can find ways to protect the joint or interface from the root-cause stress, wear or damage can be eliminated or greatly reduced.

FISHing in the factory

These days, the design community is giving a lot of attention to design for Six Sigma, design for reliability, robust engineering and reliability engineering. Normally, the focus is on making individual components or modules (circuit boards, gears, crank-shafts, etc.) more reliable or robust. Failure mode effects analysis and highly accelerated life testing help discover ways to make the module more robust.

Designers spend much time and money calculating the reliability (failure rate) of individual modules as well as the reliability and failure rate of the entire system. Many times, they are greatly disappointed when the final system is built and fielded because real-world reliability just doesn’t stack up to their predictions. That’s the price one pays for ignoring this fact of nature. Designers plug all their nice modules together, into a system, and discover that, in the real world, equipment often fails because of physical or environmental interface stress.

In the plant, focusing on functional interfaces for opportunities to stress harden will bring returns in reduced amounts of malfunctions, scrap, equipment failures, unscheduled downtime and related production losses. Stress hardening equipment and components to protect them from root-cause stress can result in increased equipment uptime, accuracy, repeatability, yield, availability and productive profits, as well as reduced maintenance frustration and overhead.

How to FISH

Discover the root-cause stresses and find ways to harden against them. By way of example, consider a hot July afternoon spent trying to revive a CNC lathe that has been shut down after high scrap rate characterized by extremely rough rather than smooth ID cuts. It might take a couple of hours of unscheduled downtime before you identify, replace and re-tune a bad board. As soon as you open the axis drive panel, you realize what had caused the problem — it’s too hot in the cabinet.

So, you replace the board. The machine is fixed and the operator begins using it again, but with the cabinet door opened and a shop personnel fan blowing in it to keep the drives cooler, as operators often do in summer months. Now, you’ve got both a safety hazard and shorter machine life because of the dirt blowing into the electronics. But, hey, it works.

Rather than carrying on with this way of reviving machines, go FISHing. You pull an ”elecronic cabinet cooler” catalog from your shelf and find the right model to add to that CNC lathe axis drive cabinet. But, wait. Heat is only one stressor that causes equipment malfunction, scrap, and sometimes failure. Other circuit card root-cause stressors include: Heat, vibration, dirt, oxidation or corrosion, voltage transients and current surges. For hydraulic systems, the list includes: Heat, dirt, water, acids and varnish.

Harden or protect against all these and what would happen to failure rate? What would happen to uptime? Do you see or fee a paradigm shift? This should convert a maintenance engineer from a fire fighter to being a “Smokey the Bear,” a fire prevention bear, a reliability engineer.

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