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Jack H.Integration and automation of manufacturing systems.2001.pdf
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page 570

-Available facilities

-Workforce availability

-Subcontracting potential

There are some strategies used by the Capacity Planner to Assign jobs to machines,

-Splitting of lots (batches) across identical machines

-Splitting of lots to expedite a smaller quantity

-Sequencing of lots to minimize setup times

-Alternative routings that require different resources

-Loading a facility by weight, volume, etc. (eg. heat treating)

After jobs have been assigned to machines, the capacity of the machines must be consid-

ered.

21.3 SHOP FLOOR CONTROL

No factory is perfect, and a schedule can become invalid at any time because of,

-Machine breakdown

-Sudden material shortage

-Workforce vacancy

-Tool breakage

-etc.

What to do about it,

-Wait and See

-Try to find alternative production plans/parts

-Ask engineering for replan

-Bump other jobs

-?????

21.3.1 Shop Floor Scheduling - Priority Scheduling

• Instead of scheduling before production (MRP and Capacity planning), a manufacturer may

page 571

opt to do scheduling on the fly.

Some of these methods include,

-Earliest operation due date - soonest date. This gives time until due, but ignores processing time.

-Order Slack - soonest date minus processing time. This gives the amount of time to play with.

-Shortest operation first - Do the quickest jobs first. This just clears out WIP faster.

21.3.2 Shop Floor Monitoring

It is important to know what is happening on the factory floor.

To do this we must pay attention to obvious problems like machine operation, and hidden problems such as quality, and production quantities.

Inspection covers a number of areas,

-Inspection of raw materials

-Inspection of manufactured product

-preprocess

-in-process

-post process

-Inspection of production process parameters

-tools

-fixtures

-production machinery

-Verification/calibration

-inspection fixtures

-Inspection gauges

-Inspection machinery