Make Maintenance More Efficient with Equipment Bills of Materials

Scott Hoff, Life Cycle Engineering

Most computerized maintenance management systems (CMMS) have the ability to create bills of materials (BOMs) for equipment or assets. These would include the components needed for a piece of equipment. All types of asset-intensive industries, from oil drilling and automotive manufacturing to food and pharmaceutical manufacturing, can benefit from equipment or asset BOMs.

Perhaps, like me, you’ve experienced life without BOMs. To find parts, you either had to use cheat sheets or refer to drawings from the machine builder in order to find a manufacturer’s part number. I can recall being called out of bed in the middle of the night when a piece of equipment was down and the spare part could not be located because the manufacturer’s part number could not be found. You had to look in drawings, schematics and catalogs to find a part number.

In the early days, not everyone had access to the documentation, especially the nightshift. Everyone had their own lists, which varied from person to person. I’m not sure these personal lists were ever updated, but we all lived by them. There was always a go-to guy when you couldn’t find a part. "Go see Johnny. I’m sure he has the correct part number."

How can good equipment BOMs increase the efficiency of your maintenance program? They can help the maintenance planner plan a task or job faster. Planners do not have to spend time looking in drawings, manuals or catalogs to find part numbers that could be right at their fingertips. BOMs can be created for certain preventive maintenance tasks, shutdowns or redundant tasks. Of course, it takes time to create good equipment BOMs. There is also some responsibility for maintaining them. If BOMs are not maintained correctly, this creates confusion and wastes time for all end users.

Equipment BOMs can also help reduce downtime. Do you have craftsmen working on backshifts, weekends or nights? Having equipment BOMs will reduce equipment downtime because the right parts can be identified and procured quickly, even in the middle of the night.

Using a good BOM system can help manage system sub-components. Do you have sub-components with replacement parts that are hard to identify? For example, you may have a conveyor that uses lifts, curves, different length belts or widths, gearboxes with motors, or a hoist that is made of several components. These sub-component items can be broken out into their own BOMs and be part of a sub-BOM for a conveyor system.

I have created BOMs for a process like injection molding. Although there were more than 20 different mold types, it was easy to set up a BOM for each type. The technician could check the storeroom’s balances, see what was out for repair and what was coming in, as well as the minimum and maximum balances.   

In addition, equipment BOMs help manage your spare-parts inventory. When a piece of equipment or asset is decommissioned and removed from the shop floor, the associated spare parts can sit in the storeroom for years, taking up valuable space. With equipment BOMs, the task of identifying which spare parts belonged to the decommissioned piece of equipment is a simple task. All that’s required is a little cross-checking to ensure the parts are not used on some other equipment along with removing the items from the CMMS and the storeroom. This helps reduce the total dollar amount of your spare-parts inventory.

All types of industries can benefit from using equipment BOMs. While time and effort will be required to create and maintain them, you no longer will be wasting time looking for part numbers in drawings, catalogs and schematics. Once BOMs have been set up correctly and everyone knows how to access them, you will have a lot fewer headaches and less equipment downtime. 

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About the Author


Scott Hoff is an asset management services technician with Life Cycle Engineering. He has more than 33 years of experience in roles including maintenance mechanic, engineer...