Don’t Procrastinate…Innovate: Maintaining to the Weakest Link, Part 1 — Weakness as a Desired State

Remember the television game show Weakest Link? Its authoritarian host Anne Robinson specialized in shaming failing contestants with the words, “You are the weakest link, goodbye!” Unlike the TV show, which is designed to provoke disharmony among team members and negatively exploit the knowledge gaps of its contestants, the asset-management world cannot afford to be so dismissive. It can however, take an innovative approach toward improvement by recognizing, exposing, understanding and exploiting weak links in a positive manner.

When weakness is desired

Innovation springs to the forefront when we are open and able to reframe our viewpoint. For example, by not accepting such adages as “we have always done it this way,” and scrutinizing a perceived problem that might otherwise have been ignored is an opportunity to be seized upon! When looking to increase a maintenance organization’s effectiveness, it’s important to identify and address weak links in the organization’s culture and team dynamics, as well as in the maintenance system and approach to performing asset management.

Most readers will naturally consider “weak” an undesirable state. With synonyms such as fragile, frail, brittle and others, it’s easy for a maintainer to have a negative view of the term. Yet in the world of machine design, weak links can be desirable, purposely exploited and made an integral part of a machine’s design to 1) protect the more valuable or precise aspects of the machine design; 2) make the machine design more universal and adaptable for the end-user; and 3) reduce costs.

Rarely will a maintenance organization have had input into the design of the machines in their charge. Instead, most have to develop a maintenance approach based on the often inadequate and subjectively worded maintenance manual (if one exists) and the sum experience of the planner or maintainer writing the machine maintenance plan. In this first part of our examination of weak links, we will look at the various aspects of machine design and learn how to recognize and take advantage of those that are built-in.

Using weak links to achieve reliability

Reliability of any machine is primarily achieved by performing the simplest of maintenance observations and tasks based on its weakest links. Often thought of as “nuisance” or “pain” points, weak links are instantly identifiable as the parts on the machine that always need to be replaced or adjusted or opened and closed. Identifying and focusing your proactive maintenance approach on these items is a fast and effective way to assure asset reliability with minimum cost, maximum uptime/throughput and minimum energy use.

Weak links primarily present themselves in two formats: consumables and adjustables.

Consumables are the machine items designed to wear out over time and be replaced with like-for-like items. Consumables are relatively inexpensive sacrificial products designed to provide machine functions and protect vital machine systems or machine components that come in direct contact with the raw material or finished product. Typical examples can include:

• Machine function—Friction linings for clutch and brake systems; hydraulic fluid for transmission, motion or braking systems; belting/sheaves or chain/sprockets for power transmission.
• Machine Systems—Bearing and gearbox lubricants; filter and breather devices; fluid seals; electrical fuses and anti surge devices; shear pins; covers and caps
• Direct-contact components—Wear bars and liners; belting or slat for product conveyance; guide cams and rails; contamination shields and deflectors.

Adjustables are the items on a machine designed to be set up, adjusted or calibrated to compensate for delivery, speed, wear, misalignment, balance and out-of-true conditions due to site or machine conditions.

Pinpointing weak links

Identifying the consumable and adjustable items on a machine can be as simple as opening the Operations and Maintenance (O&M) manual to its specifications page where all its recommended oils and greases, replacement belt, sheaves, chains and sprockets, filters, fuses, tire sizes, etc. are usually listed. These specification pages are also where the adjustment specifications for calibrated products are listed, along with the acceptable wear limits for friction materials wear liners, and other items.

Keeping in mind that the machine has been designed to operate perfectly with these strategic sacrificial weak links in place until the device or fluid becomes exhausted or worn to its critical replacement point—after which the machine will continue to run a short while before failing—it makes sense to design a failure-prevention program specifically around the condition of the weak-link devices.

To aid in this type of program, simple Go/No-Go measuring devices or gauges can be used. These can be included as part of a condition checklist PM program designed to monitor the state of every weak-link device and report to planning and scheduling when an exception or No-Go state has been found requiring replacement of the weak-link device.

This type of condition-based program is easy and inexpensive to implement. The key to its success is based on training the maintenance crew how to measure condition correctly, and execute the program with consistency and diligence.

Training maintenance crews on these aspects includes instilling in them the discipline to respond quickly once a No-Go state has been found. Since one weak-link failure can accelerate other weak-link failures and can lead to major downtime repair, accurate checks and quick response times will pay huge dividends in machine life-cycle performance.

Capturing the benefits

To help ensure that you reap the dividends from machine performance that the approach will generate, the second part of this two-part column (coming in July) will investigate the undesired weak link, and how people behave in various situations that can seriously impact a machine’s capability to perform either in a good or bad way. Meanwhile, remember that understanding and exploiting a machine’s weakest links is simply a matter of reframing how we look at piece of equipment by stating, “You are the weakest link, hello!” Good luck!