Oil-Dri Corporation is a 64-year old company that manufactures absorptive and adsorptive materials at facilities in North America and England. Georgia (U.S.) has two processing plants for the crushing, screening, conveying and packaging of clay products.
Maintenance professionals at the Georgia Oil-Dri facility developed a proactive maintenance plan to improve equipment reliability and reduce cost of production. A central feature in the plan was the implementation of a regimented lubrication practice. Several aspects of the planned improvements are discussed in this case study.
Before
Prior to the planned changes, the company employed 2.5 lubrication technicians: one for the Georgia North plant, one for the Georgia South plant and a laborer from the cleanup crew working four hours per day on lubrication tasks. There were no established lube routes and no lubrication guidelines recommending which products should be used for certain applications. Greasing was random and sporadic.
The layout of plant processes was sketched, starting with primary and secondary crushing circuits followed by conveying/elevator circuits and associated rotating equipment.
Several changes were required for the lubrication plan improvements, including the following:
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Review relubrication frequencies
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Review relubrication volumes
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Create an orderly plan for relubrication of machines
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Review statistics of existing automatic and single-point application equipment
Machine lubrication volume and frequency requirements were determined by evaluating operating conditions, including component size, load, rotation of shaft (RPM) and environmental conditions.
Single-point and multipoint lubrication systems were reviewed for proper operation, with some being found defective. Additionally, shaft alignment was reviewed and found to need improvement. Prior to improvements, a string or straight edge was used to align equipment.
Cleaning Bearing Exterior Reduced Bearing
Temperatures by 15 to 35°F.
After
Multiple greases are no longer used on bearings and couplings at the Georgia plants.
Some bearings were covered with grease, resulting in insulation of the bearing and overheating. The bearings were cleaned of excess material. In some cases, temperature drops were significant. One bearing application dropped from 82ºF to 47ºF following cleaning. Changes of 15 to 35 degrees were common.
By gathering and recording all the necessary information such as shaft diameter and speed data (RPM), lubrication amounts and frequencies were reduced, improving the lubrication application.
Proper lube frequency and proper lube amounts required less time and materials. This allowed the lube technician to take on additional duties including developing an automatic lube strategy and inspections to enhance the relubrication practice.
The lubrication inspection route enabled the technician to observe and feel the equipment during actual operation. Dry components were discovered on daily rounds, and this initiated an inspection route system for the maintenance mechanical and electrical areas.
Lubricant handling improvements were implemented, including checking the cleanliness of lubricants and securing a clean storage area for grease and oils.
Following the definition and execution of the new practices, equipment operators were introduced into the process. Increased ownership is evident by the immediate feedback from the results of the proactive efforts.
Presently
Contaminant monitoring and a solid lubrication process control are reducing both reactive breakdown maintenance and its costs.
Bearings operate at cooler temperatures and achieve a longer life. For example, bearing temperature before the improvements was typically 90ºF to 100ºF. A typical bearing temperature is now 70ºF to 75ºF.
A dual-purpose office and grease lubricant storage area was developed at Georgia North storage facility. The office space will provide the lubricant technician with a desk, file cabinet and a bulletin board where lube charts can be posted for process control (SPC) tracking.
Facts
The facts of this case study are clear. These structured lube routes now require only one lubrication technician vs. the previous staffing of 2.5 technicians, saving $35,000 per year. This is a significant direct cost savings and the machines are better lubricated than was previously possible.
