Scheduling Procedure for Breakdown Maintenance

Breakdown maintenance resembles with the job production. Therefore, the scheduling of breakdown maintenance jobs is similar to those of job production with little changes. Basically the breakdown maintenance is the repair function of plant engineering. Thus when various jobs for repair are received by a plant engineering department, they are sequenced, assigned and scheduled according some predetermined rules. Again, the procedural steps differ slightly according to the system of maintenance (centralised or decentralised) followed in the organisation. However the common procedural steps are given below.

• All the repair jobs are collected at the beginning of the shift/day. If any reports of breakdowns are received during the shift they will be kept pending for the next shift/day or taken up after the present jobs are completed. However, if the breakdown is critical or the production is going to be stopped in absence of the availability of the machine or equipment, the preferential treatment is given to those machines using pre-emptive rule of sequencing.
• The repair jobs are sorted out based on the importance of the machine in the production chain. If the non-availability of the machine leads to significant losses or stoppage of the production chain, they are kept on top order.
• A probable time to repair and restore its condition will be estimated.
• The repair jobs will then be sequenced according to the priority rules. Most commonly used rule is SPT particularly when the machines are of nearly same importance in the production chain. Perhaps the reason for using this rule is that the machine that takes lesser time to restore its condition can be handed over for production at the earliest, and thus its availability is increased. This rule varies according to the production process, production system, available resources with plant engineering department like man power, spares and materials, tools and accessories, material handling equipment (such as cranes, chains, pallet trucks, lifters, fork lifts, etc.). For instance, in intermittent production system, SPT, FIFO rules are preferred while in continuous production system Pre-emptive and Non pre-emptive rules may be preferred.
• Then the availability of the manpower for doing these jobs will be noted. Based on the efficiency, the probable time that each man will be able to complete the job is written against each job.
• The assignment of the jobs will be made so as to minimise total time.
• The schedule chart will be then filled up mentioning the start timings or/and end timings and process timings.
• A report will be prepared at the end of the shift/day on the actual performance (achieved) Vs Scheduled (planned) work along with the reasons for incompletion or remarks. The left out jobs will be carried forward to the next shift/day.