Assembly Constraints

The Bill-of-Material product structure is an invaluable tool that shows how parts assemble to make a final finished product. JobTime5 assures that parts are not scheduled until feeder work orders are finished.  This is another way that JobTime5 creates schedules that can be actually followed on the shop floor. The in-house assembly of internally fabricated items depends on logically scheduling the supporting make components.  This feature provides timely scheduling of internal make items, to assure the smooth assembly of higher items.

Most ERP systems recognize Bill-of-Material structures, which reflect assembly work.  Classic ERP assumes that all assemblies do reflect the assembly constraints.  But when it comes to detailed shop scheduling, many systems, including ERP, might not guarantee that shop orders in an assembly will always be scheduled so that higher level jobs are not scheduled to start until all feeder work orders will be finished.  In many cases, it is not valid to schedule a top-level assembly order before all the sub-assembly shop orders are finished, unless sub-jobs are carefully scheduled to correctly overlap the assembly job.  If you are find that you need to re-schedule constantly, one reason might be that your ERP (or other scheduling tool) does not recognize logical assembly constraints. A typical result is that constantly reappearing net requirements reflect component shortages, and you have to constantly re-plan and re-schedule to accomplish a balanced materials and shop-floor schedule. With JobTime5  you will no longer be compelled to shrug off assembly constraints in of realistic assembly shop operations and repeatedly scramble every morning to decide what to make that day.  JobTime’s Explicit Assembly Constraint feature can save hundreds of hours of needless manual rescheduling. Your scheduling system should recognize not only capacity constraints and buy-item constraints, but also assembly constraints, consistent with your own Bills of Material (BOM’s).  It is essential for shops to recognize this constraint if they have a high percent of assemble to order (ATO) work.   In addition to assembly jobs, JobTime5 can also handle “batch jobs”, which typically require “one into many” links between large batches and multiple smaller dependent orders which will made from the large batch. 

ERP systems normally contain material planning capability to allocate material from inventory. These material allocations are called “peggings”.  ERP sees and plans both open purchase orders and shop work orders.   JobTime5 can expand the power of ERP by tying the timing of material issues and receipts to the finite-scheduled start and finish times of associated operations.  This synthesis perfectly synchronizes finite capacity with finite materials.  As each work order is finished in the schedule, its output becomes a material receipt, thereby increasing inventory, and that new material is then usable by subsequent work orders.  JobTime5 can either use the ERP pegging file or else JobTime5 can simulate peggings, tracking inventory rising and falling dynamically as it schedules, issuing materials across the planning horizon as each work order is launched in the schedule.  Net Requirements can be summarized and rapidly adjusted in JobTime, and then be confirmed by rapid re-scheduling.  JobTime can also focus on simulating the consumption of selectively designated parts or part-families.  Consumption of “commodity items” with short lead times can be set up as ‘unconstrained’ but JobTime will still project an accurate and realistic profile of daily consumption, for a potentially large number of commodity items, as well as the key major items having critically longer lead-times. This functionality augments the benefits of ERP by providing an optimized set of planned/adjusted orders which have been verified as being both capacity and materials-feasible.  By registering future consumption more precisely, the increased accuracy in the visibility of inventories, and hence safety stocks, can help lead the company closer to "right-sized" inventory levels.   


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