ABSTRACT
Machine condition plays a significant role on plant efficiency in the field of manufacturing. For this reason, maintenance has become an integral component of manufacturing. There are various methods of maintenance but preventive maintenance is key in maintaining the condition of plant equipment in manufacturers‘ state of operation. Preventive maintenance is scheduled and is based on principles of operations planning. However, research on how operations planning affect preventive maintenance in manufacturing companies remains a challenge. The general objective of the study was to establish how operations management planning affects preventive maintenance in Grain Milling Companies in Nakuru County, Kenya. The study used four objectives which were: Manpower planning, spares parts availability, production planning and plant layout. The target population for the study were grain milling companies which included, Unga millers, United millers, Mombasa maize millers and Milling corporation. The target population comprised of 226 technical staff directly or indirectly involved in machine maintenance. A sample of 113 was selected to participate in the survey using stratified random sampling technique. Questionnaires were used as the main data collection tool among the grain milling companies. Analysis of data was done using both descriptive and inferential statistics. Frequencies, percentages, mean and standard deviations were checked. Pearson moment correlation was used to establish the relationship between the independent and dependent variables and further to test the hypotheses of the study. Multiple regression analysis was used to determine the planning components that have greater impact on implementation of preventive maintenance. The findings of the study revealed that all the planning aspects had significant effects on preventing maintenance in grain milling companies. However spare parts availability, followed by manpower planning had the greatest impact on preventive maintenance in graining milling companies. The study therefore recommended that milling companies need to relook into their manpower planning especially for the preventive maintenance departments rather than focusing only on reactive breakdown staffing. Besides, milling companies should invest heavily in enhancing their sourcing strategies for their spare part. A separate inventory should also be maintained for preventive maintenance spares in line with maintenance schedules.