Split In Routing / Difference Between Alternative And Parallel Seq

The term "Splitting" in SAP means having more than one person or maching working on an operation in a production order.
SAP assumes that only one person/machine will be working on a job at a time. If it takes one hour to make one, and the order is for 10, the system will schedule the job at that work center to take 10 hours. However, if in the operation in the routing, you select "Required Splitting", then you put in "number of splits" as 2, then the system will assume you are having two people/machines work on the job at the same time, hence it will only schedule the job to take 5 hours, not 10. If you put in splitts as 4, then the system will assume 2.5 hours to get the job done.
Also, sometimes it might be ridiculous to split the job. For instance, if that previous example order was only for 2 piedes. Having two machines working on it would be dumb, because you would have to do two setups. So the system gives you a Minimum processing time, so if it's less than, say, 5 hours, do not split it.