|
|
|
News Services Consulting Customer Support Scheduling Technology Research Professional Place
|
It is often the case that some operations defined on a routing require processes for which the shop has no machine resource on which to perform them. Thus the shop must send the parts to some other shop. This shop may be another shop in the same company, or it may be another company altogether. If an outside production (OP) supplier performs a relatively large number of operations, it is the usual practice to set him up as an infinite capacity machine. On the other hand if the OP vendor is only used occasionally, it is usually better to create a single "catch-all" infinite capacity machine for all such vendors. It is the common practice of many OP suppliers to commit to a certain amount of time in which they will turn around the OP operation on your parts once they receive them. An OP operation is defined in PROSPAC by setting the setup and run time standards to zero, and the FTBO (Flow Time Between Operations) time to the committed turn-around time quoted by the OP supplier. An OP resource is always set up as an infinite capacity machine because, from your point of view, his capacity is unlimited. You could not care less about his capacity, since your only concern is that he return your parts per the agreed upon FTBO time. The scheduling "engine", because it is a finite capacity mechanism, will not create a load for an OP resource due to the zero setup and run times. Yet it uses the FTBO time to calculate a schedule interval for your OP operation whose start time is approximately equal to the completion schedule of the prior operation, and whose completion schedule is approximately equal to the start schedule plus the FTBO time. In this way a Machine Load List can be published for OP resources just as easily as those for the machines on your own shop floor. These are used by production control to both advise the OP supplier when parts will be arriving, as well as to insure that the OP operation is completed and returned in time to start the following operation in the routing as scheduled.
|
|
Send mail to webmaster@heuristima.com
with questions or comments about this web site.
|
