Grease Relubrication Improvements at a Duracell Plant

The Duracell plant in Cleveland, Tenn., manufactures alkaline batteries that are distributed globally. The facility receives raw materials for the manufacturing process, which flow through several steps to produce a high-quality battery. Each manufacturing process utilizes common industrial equipment such as pneumatics, hydraulics, rotating equipment and conveyors.

Lubrication Initiatives

Several lubrication improvement initiatives have been administered at the Cleveland plant. These include: development of a lubrication database, lubrication training for crafts personnel, standardization of grease guns/color-coding system, lubricant consolidation to one vendor, development of detailed documentation (proper amounts, frequency, type, method) within the work order task, and the use of ultrasonic technology to accurately determine proper grease amount.

Two areas were identified for improvement by the maintenance department, environmental contamination and grease cross- contamination.

Environmental contamination of greased bearings was a problem. An aggressive plant atmosphere is typical for this industry, including airborne contaminants such as MnO₂, graphite and cardboard dust. These contaminants collect on the grease fittings at various lube points and require careful cleaning to prevent these contaminants from being pumped into the bearing.

Often, the amount of care required to sufficiently clean the fitting is not provided, resulting in obvious hard particle contamination and premature bearing failure.

Cross-contamination of greases was also a common problem. This was a consequence of individual mechanics being free to use whichever grease they preferred when conducting a routine PM, including relubrication tasks. The lack of control was amplified by the presence of multiple incompatible greases incorporated into the process. Grease incompatibility creates many issues, including clotting, base oil separation, thermal breakdown, thinning, thickening and formation of hard deposits, all of which can accelerate bearing failure.

Solution

One approach to correcting these issues was to standardize the grease guns and then color-code the guns for each line. The bearings and lube points were evaluated for the correct grease and each grease was assigned a color. A grease gun standard was selected and a separate gun was purchased for each grease that was to be used on a production line, and each gun was marked with tape to designate the grease by color (Figure 1).

Figure 1. Color-coded Grease Guns

The next tactic was to install color-coded grease-fitting covers at each fitting according to the required grease type for that lube point. The covers were intended to prevent contamination and to minimize confusion for the mechanic (Figures 2 and 3).

Figure 2. Color-coded Grease Fitting Covers

Figure 3

A list of lubes and the color-coding scheme was installed at the production line and the work order task was modified to include the number of strokes, lubricant type, and relubrication frequency to further minimize confusion.

The lube procedure change was simple and yet has been highly effective.

Summary of Benefits

• Cost savings of more than $35,000 due to lubricant consolidation (capable of purchasing bulk product by standardizing lubricants)

• Nine proactive rebuild jobs vs. 33 reactive

• Reduced replacement costs

• Minimized unscheduled downtime

• Lower maintenance costs

• Enhanced awareness in craftspeople revealed more opportunities for improvement in lubrication and overall equipment maintenance