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ABC Machines

Machines are essential to production environments.  But not all machines are created equal. The impact of breakdowns varies widely. Because resources are limited, it is important to have a strategy to manage machines according to how critical they are to the operation.

An ‘ABC Machines’ strategy is one way to organize machines to allocate resources.  While the exact name used to describe this strategy may vary by company, the purpose is the same. Companies assess their equipment and make contingency plans based on risk, the difficulty of repair, and a host of other factors. The category (A, B, or C) determines how detailed the contingency needs to be.

The first step in assessing machine risk is to make a system for categorizing them.  Higher risk machines are ‘A’ machines.  Low risk machines are ‘C’ machines. Do not take the term ‘machine’ literally. If you have specialized tools or lifting equipment, include them in your assessment strategy.

There are many factors that affect a breakdown’s impact on production that should be included in your review.

  1. Redundancy: Are other machines available to do the same task?
  2. Frequency of breakdowns: Machines that breakdown often have a larger impact.
  3. Repair expertise: Can the machine be repaired in-house, or do you have to bring in an outside technician?
  4. Alternatives: Can a different machine pick up the slack?
  5. Utilization: How heavy is the load on the machine?  Can it catch up later?
  6. Replacement cost: How hard is it to replace if it has a catastrophic failure?
  7. Complexity: How easy is it to break the machine?
  8. Production loss: How much lost production does machine downtime cause?  How are customers impacted?
  9. Availability of parts: Can repair parts be easily ordered?  How long will they take?
  10. Machine Age: Is the machine at an age where you should expect maintenance problems to increase?

An ABC Machine strategy entails three basic steps.

Step 1: Categorize Your Machines

Create an assessment matrix for your machines based on your specific working environment. Use the criteria listed above as the basis of your review.

The assignment of a letter to a machine should be based on a scoring system. Try to take gut feel out of the decision and base the letter assignment on real data.

ABC Categories

  • “A” Machines: Downtime results in a stoppage of production for more than a short time or a significant drop in production capacity for an extended period. Few alternatives exist for “A” machines.
  • “B” Machines: Downtime results in a momentary/short stoppage, a significant reduction in production for more than a short time, or a long-term small loss in productivity. Less productive alternatives may exist for “B” machines.
  • “C” Machines: Machines can generally be fixed or replaced easily and quickly, or there are readily available alternative methods. Downtime is generally not highly costly.

Step 2: Make Contingency Plans

The second step involves creating a contingency plan for what you will do when a machine breaks. Focus on “A” machines first, and be highly detailed in the planning. Know the phone numbers of parts sources and repair options. Have a strong TPM (total productive maintenance) plan to avoid problems. Inspect these machines extensively and often. The priority should be on prevention, but “A” machines need a highly detailed contingency and recovery plan.

Once all “A” machines are done, go through the same process with “B” and then “C” machines. Obviously, the planning will be much easier for these machines if the impact is lower. ‘A’ plans should be much more detailed.  ‘C’ plans may involve grabbing a new tool from the tool crib.

For all machines, include the following in the plan:

  • Production Recovery: What should be done to manage production? Do alternate tools need to be rented or borrowed? Do additional shifts need to run? Who needs to be notified of the problem? How should orders be prioritized if downtime will be for an extended period? In some cases, you will be able to shift production on the fly and make an alternative product. In other cases, you will lose the output because it can’t be flexed over.
  • Repair Plan: Know who can do the repair. Know who the backup is if that person is not available. Know where to get parts. Get critical parts on hand.
  • Downtime Planning: Know what the operators should do if a production line stops. Make the most of any downtime.

Step 3: Move All Machines Toward “C”

Once you have your machines prioritized, work to migrate them toward “C” machines. Obviously, put your effort on the “A” machines first. Stock up on hard-to-find parts. Teach more people how to repair the machines. Find ways to prevent breakdowns. The bottom line is that you should not settle for having machines in your operation that can shut down production. Identify the sources of risk and systematically go about eliminating them,

  • Occasionally, a machine on a mixed-model line will only stop production of one model. If that model can be pulled out of the mix, the impact might be lessened. Don’t let your team get too far behind on one model, though.
  • While the “ABC” review process itself is simple, executing it can be challenging, especially if the company has a large number of homegrown pieces of equipment, or older pieces of equipment. The impact may be unknown if support is not readily available.

The challenge with putting together an ABC Machine plan is that it is time consuming.  It entails a lot of effort that will likely never be used.  Often, it is difficult to muster the time and effort required to get an ABC machine plan in place.  Daily demands often overshadow this sort of project.  Worse, getting the plan done is only half of the problem.  Keeping the plans updated is the other half of the challenge.

Make sure that you check the progress of the plan. Also keep in mind that the ABC machine management works best when there is a strong maintenance plan in place. Use this categorization in conjunction with a total productive maintenance system.


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