Hi Roza, 

In IFS the operations are scheduled only on the machine time. However, this is normally not really a problem. For an assembly operation you need to think about the work center as the assembly area. So do set machine time on the routing that corresponds to how long the operation needs to utilizes the assembly area. Labor time is set similar as the machine time, and crew size represents the number of persons required to finish the operation within that time. The assembly area work center is typically setup without cost for an assembly operation. 

I disagree.  This is completely dependent on the make up and type of business.  For many of our machines, many projects, the amount of assembly time is significant.  If this were set with no cost, it wouldn’t accurately account for the cost involved.  Only if the assembly operation is fully absorbed as overhead would I suggest that it would be set to no cost.  If however, it is recovered time as part of Cost of Goods Sold, it should definitely have a cost and the cost should match the recovery and overhead assigned to that work center.

I should clarify that the assembly work center would be setup without cost. 

The labor cost would instead be set on the labor class. 

Not always, none of our sites are set that way.  Assembly areas are treated no different than machining centers, so Setup and Run is set against the Mach values, all have cost.  Those annotated are assembly areas.  There is more than one way to do this.

If we set the machine time instead of labor time. the labor time is set up only for the cost calculation? does it mean ,in general for assembly, machine time and labor time are set with the same value?

Yes @Roza my recommendation is that for an assembly operation you set machine and labor time the same. Labor time is used for the cost and to book capacity against the labor class, and the machine time to schedule the operation, and (if required) book capacity against the work center (which represents the assembly area). 

@ShawnBerk  do you mean, that in your sites, the labor time is set to 0 for assembly area and the cost calculation is only based on maschine time and not the labor time? could you explain the reason?

@Roza  Yes, Labor Setup Time and Labor Run Factor are set to 0.  Only Mach Setup Time and Mach Run Factor are used which allows calculating leadtime for a given routing configuration, capacity resource planning, and by setting the cost and overhead on the workcenter, the cost calculation is performed utilizing the same hours.  This is the same for machine and for assembly operations.  The reason is really about simplicity, only one set of values has to be entered to gain all of the needed functionality for our purpose.

@ShawnBerk I agree with the simplicity issue which is essential. However, in this way, how to connect the labor group to this operation or work center? so far as i tried, not possible to assign personen resource to a work center.

@Roza  We don’t track the labor per employee, as such we don’t have the employees assigned to the labor classes or to the workcenters.  We use the workcenter as if the employee is a machine.  If there are 2 employees in that area or workcenter, then the efficiency for that workcenter is set to 200 which adjusts the schedule accordingly.  We also use the Utilization to indicate whether the workcenter operates the full 8 hr shift or some fraction of it.  We just do all of the planning, scheduling, and capacity measurements from the workcenter viewpoint.  We don’t report actual time for any shop orders, everything is set to a standard number of hours for the operation, all labor is backflushed.  If you are trying to measure some of these other things or track them related to employees, then it may be the setup as we have it is too simplified for your intent.

@ShawnBerk Thanks for sharing another possibility of the application!