How do scheduling activities differ for projects mass produc

How do scheduling activities differ for projects, mass production, and process industries? Explain the difference between infinite and finite scheduling. What information is provided by the critical ratio sequencing rule? Give examples of sequencing rules you use to prioritize work.

Solution

The two production systems that can be used in process industries are continuous and batch making. Continuous flow of material for production is required in the production where limited number of products are produced but in a high volume. In such production a continuous input and output of production happens with no certain time of start or end of production. On the contrary, the production that involves small quantities of more number of products use batch production system. In a batch production, small batches of same products are made that are followed by each other and a campaign is formed.

When the production is done with a fixed number of resources under a finite production process going through the same process it is called finite scheduling system. Infinite scheduling system is when the production process does not take the resources constraints into consideration and fixes a back date from the end date of the completion of production. Finite scheduling works on the basis of resources available and infinite scheduling works on the basis of fixed end date.

Critical ratio sequencing is the calculation of the time remaining till the due date to complete the work by the time remaining to complete the work in process. It gives the ratio between when the work has to completed as per scheduled date and how much time is actually required to complete the work. It is used to evaluate the urgency of one product to be completed over the others.

The rules of sequencing that I use to prioritize my work depends on the work and time I am provided with. Like, for example, if I have to complete 5 jobs namely A,B,C,D,E. Now to prioritize and schedule these jobs the processes that I can use are as follows:

FCFS- first come first come will schedule the jobs in sequence as they are coming up.

DDATE- the jobs are scheduled according to their due date and the ones whose due date is closest are worked on first.

SLACK- In this process the jobs are scheduled according to the least slack which is calculated by the due date- today\'s date - remaining processing time.

CR- sequencing the jobs as per smallest critical ratio.

SPT- scheduling the job as per least to most processing time.