Take inventory of your maintenance costs

Having an accurate and well-sourced materials inventory is a pillar to a world-class manufacturing operation.

By J. Stanton McGroarty, CMfgE, CMRP, senior technical editor

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This is the third article in a three-part series on contracted MRO services. Part I of this series explained the elements that must be present for maintenance tasks to be completed successfully. Part II dealt with the timing, planning, scheduling, and communication required to put these elements into place. Part III covers some of the key inventory management issues that add complexity to the contracting processes, but also offer some interesting tools for management of maintenance cost and quality.

This series of articles began with a table of the elements that need to be present for maintenance to be performed safely, ecologically, and efficiently (Table 1). This version of the chart highlights materials and other procurement items.

Element for Success Supplier Customer
Equipment Availability Production Maintenance
Production Support Production Maintenance

Information –

  • Maintenance history
  • Equipment performance
  • Condition monitoring 
  • Equipment specifications
  • PM plans
  • Statutory requirements
  • Production, Maintenance & Reliability
  • Production, Reliability & Quality
  • Reliability & Maintenance
  • Engineering & Production
  • Reliability & Maintenance
  • Engineering


  • Maintenance & Production
  • Maintenance & Production
  • Maintenance & Production
  • Maintenance & Production
  • Maintenance & Production
  • Maintenance & Production
Parts & Supplies Procurement & Maintenance Maintenance & Production
Procedures Maintenance & Reliability Maintenance
Skills Maintenance & Procurement Maintenance
Support Equipment Maintenance & Procurement Maintenance
Safe Work Area Production & Maintenance Maintenance
Table 1. This table assumes maintenance planning and the CMMS are both parts of the maintenance department.

The maintenance elements we have discussed in parts I and II offer some flexibility when shortages occur. With the addition of some labor, a maintenance team can usually provide a patch for missing information. If the team is shorthanded, substitutions can usually be made. The organization can usually develop procedures to replace missing job instructions.

Unlike these people-based elements, the highlighted items tend to be stoppers for maintenance efforts. If a bearing, oil seal, or motor is unavailable, it usually means that work stops until a replacement is found. Sometimes a spare can be expedited in from a remote site. Sometimes a repair, usually temporary, can be made to the worn or damaged unit that has just failed, requiring a second repair when the proper replacement is acquired. Sometimes a different unit can be temporarily substituted, depriving the organization of the spare for some other critical application and perhaps degrading performance until the correct replacement arrives.

Nuts and bolts may be kept in a free-issue inventory, but bearings, seals, and other commonly stocked items must be recorded in inventory.

“Having an accurate and well-sourced materials inventory is a pillar to a world-class manufacturing operation,” says Sean J. Miller, asset care process owner at the DuPont (www.dupont.com) Cooper River Kevlar plant in Moncks Corner, South Carolina. “Without it, personnel will become consumed with parts chasing. Key roles, such as maintenance planners and engineers, will be diverted from field planning, coordination, or process improvements, instead performing clerical functions to acquire parts to sustain production. A simple $0.30 O-ring could result in hundreds of dollars of ill-spent labor and thousands of dollars of potential downtime. Although shortages may create an invigorating work climate, without an accurate inventory the team will not be capable of leaving the reactive mode in its journey to world class. In turn, the burden of inadequate MRO systems will impact the customers.” It’s also worth remembering that there is substantial cost to the previously planned and scheduled work that wasn’t performed during the emergency situation.

“A program should be based on inventory usage data so the right items in the right quantities are stocked in the right place with the right solution,” says Meeta Kratz, Sr., director, customer business issues, Grainger (www.grainger.com). “Without leveraging actual data, a manufacturer cannot realistically understand inventory usage patterns, which may result in leveraging an inappropriate solution that doesn’t effectively support cost savings goals.”

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