This chapter lists 11 basic guidelines that should be followed for shop control to work properly and provide good results.
1. Use MRP to generate the master schedule
The purpose of shop control is to execute the master schedule. Do not use manual planning to create the master schedule. Only MRP is capable of incorporating interdependent demand and properly coordinating supply dates with dependent demand dates.
2. Do not release jobs without allocated material
Do not release jobs to production without allocated material. Material availability provides the means by which jobs are started in proper order of assembly and rescheduled to reflect actual release dates. Releasing without allocated material disables the self-adjusting nature of the master schedule and distorts material allocation for other jobs.
3. Assign job sequences in priority order
Jobs are automatically prioritized in the Work Center Schedule screen based on remaining sequence days relative to required dates. To optimize shop workflow and meet sales order required dates, it is essential that job sequences be assigned to workers in the suggested priority order whenever possible.
4. Issue material in real time
In order to insure accurate on hand quantities for MRP generation, job issues, order picking, and stock counts, and to give users confidence that inventory numbers have meaningful value, it is essential that material be issued to jobs in real time through the Work Center Schedule screen prior to starting associated job sequences.
5. Update labor as job sequences are finished
Shop control depends on timely labor updating so that work center queues reflect current conditions for worker assignments. It is therefore essential that job labor be updated through the Work Center Schedule screen as job sequences are finished. We strongly recommend that you use Standard Hours completions from most scenarios.
6. Process subcontract POs in real time
Shop control depends on timely updating of all job sequence processes. It is therefore essential that POs for subcontract job sequences are generated in real time as needed through the Job Subcontracting screen and are received in real time through the PO Receipts screen.
7. Always receive finished items at a reasonable cost
To insure the integrity of inventory costing, which affects job costing and cost of goods sold, it is vitally important that finished items be received to inventory at a reasonable unit cost in the Job Receipts screen. A “reasonable” cost means one that is not significantly distorted by an obvious costing error such as an extra zero in job hours entry. When the actual job cost is dramatically different than the estimated job cost and there is no time to investigate the cause, always enter a reasonable unit cost instead of accepting an obviously erroneous cost.
8. Require 100% participation among shop personnel
Shop control is a system that is totally dependent on “just in time” process updating to have any meaningful use. Like any complex system, it is only as good as its weakest link. Therefore, shop control requires 100% participation among all workers and supervisors in entering their own material issues, labor hours, subcontract POs, job receipts, and job releases on a just in time basis with no tolerance for delay. Total participation will dramatically improve your efficiency and shop throughput.
9. Do not change SO required dates - use the Expected Ship date as your customer communication date
After a sales order line Required date is initially established, leave it fixed, even when it is dependent on a supply job that is trending late. The fixed date preserves greater priority for the supply job and maintains high priority for the sales order within the Shipment Planner in the Order Picking screen. The Sales > Late Supply screen will help your office staff manage the SO line Expected Ship date for items that are running behind schedule.
10. Never reopen closed jobs for cost correction
Never reopen a job to correct job costs by reversing and redoing transactions. Job cost discrepancies have already been posted to variance accounts and it is not possible to retroactively change receipt costs and apply those changes to subsequent issue and picking transactions.
11. Do not change WC capacities to reflect daily deployments
In order for capacity metrics to have comparison value over time, it is vitally important that work center capacity settings – Total Hours / Day, Job Hours / Day, Buffer Days -- stay fixed and only get updated when capacity significantly changes, such as when you add or subtract a shift, machine, or workstation. These settings represent a potential or typical capacity and are not to be used to reflect actual hours being deployed or the existing queue days on any given day.
