>>Hello All,
>>I have a Jobs.Dbf (one row per job) with a one-to-many relationship into JobParts.Dbf
>>
>>The production process is semi-automated with machines that can receive/take parts simultaneously from several sources (feeds), for example: conveyor belts, mini gantries, collection bins, etc.
>>
>>Operators are spending too much time managing the manual part of the process: supplying parts to the various feeds. Each time a change of part is required the whole process has to stop. Ideally I would like to queue the jobs so that transitions in the Part Feeds are minimized.
>>
>>Any ideas appreciated
>>Pete.


>Machine setup times are reduced by streaming jobs together that have a high degree of "matching"; ie. schedule jobs based on the parts they require, and how those part requirements are similar to other jobs. Jobs that have similar parts requirements require less setup between jobs.
>
>You have to look at the average number of jobs in the queue, the number of production lines, the different product configurations, etc., before you can design an appropriate algorithm.


Gerry, thanks for responding. The "high degree of matching" is what I am aiming for. The best analogy of what is happening, that most people here can probably relate to, is the production facilities of say Dell Computers. Multiple orders are received more or less continuously, where each order has small variations - size and type of disk drive, amount of RAM, type of mother board and CPU, etc.

In my case the scale is considerably smaller - the number of jobs in the queue is typically between 150 and 200, only two production lines, during a typical day there might be 24'ish product configurations.

At the moment the work day is split into two production runs:
- the morning run, to process orders received during the previous afternoon, and
- the afternoon run, to process orders received that morning.

I guess I need something like (in pseudo code):

Select Jobs.ID, JobParts.PartID ;
	From Jobs Join JobParts On Jobs.ID = JobParts.JobID ;
	Into Cursor JobSchedule ;
	Where Jobs.Completed = {} ;
	Order By "high degree of matching"

Yep - that high degree of matching is the killer!
Pete.