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Outline. Questions? Did you hear or notice anything since last class that has something to do with this class? Exam Results Go over exam New homework Manufacturing Planning and Control. Exam Results. Exam Results. MT1 Comparison. Outline. Why plan? Horizons Why is it called a system?
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Outline • Questions? • Did you hear or notice anything since last class that has something to do with this class? • Exam Results • Go over exam • New homework • Manufacturing Planning and Control
Outline Why plan? Horizons Why is it called a system? Activities Classifications A bit of history
Three horizons Long term 1 to more years Medium – 1 year Short weeks to 3 months
Classifications Flow Repetitive JIT MRP Project
Types of Operations MTS ATO MTO (ETO)
Capacity Capacity planning is the process of reconciling the difference between the capacity available for the process and the capacity required to properly manage a load to satisfy the timing of the output for the specific customer whose orders represent the load “The fundamentals of production planning and control”, Stephen N. Chapman, Pearson Prentice Hall, 2006, ISBN 0-13-017615-X
Capacity – Rough cut These methods that are the easiest to calculate and take the least amount of data are also the methods that are the "roughest" - meaning the least specific and detailed. Overall Factors. This method is the "roughest" of the rough-cut methods. Take the number of the items being produced on the master schedule and multiply them by the standard hours used to produce the item. The capacity required per work center is then calculated by taking a historical percentage of each work center’s usage.
Capacity – Rough cut – overall factor Overall Factors (also see Excel spreadsheet)
Capacity – Another method • Calculate hours required per work center per product in the period in which the product is to be delivered. Add all products • Product A • WC 1 0.25 hours • WC 2 0.1 hours • WC 3 0.3 hours • Units required 100 • WC 1 25 hours • WC 2 10 hours • WC 3 30 hours
Capacity Requirements Planning (CRP) – most detailed • The routing file. Containing information about the route the work is to take through the facility work centers, including the operations that are to be performed. • The work center file. Generally contains information on the various elements of lead time associated with the type of equipment in the center. These time elements can include: • Move time - the time it usually takes to move material from one work center to another. • Wait time - the time material has to wait to be moved after it has had an operation completed. • Queue time - the time material has to wait in front of an operation before it can be processed by that operation. In many operations queue time tends to be the largest element of total lead time.
Capacity Requirements Planning (CRP) – most detailed Production lead time is generally defined to be the total of move time, wait time, queue time, setup time, and run time for the given lot size of the material produced. The "downside" of using detailed CRP is that while most of the rough-cut methods can be set up on a spreadsheet using only standard information with the master schedule, CRP requires MRP to be run. In fact, most modern systems include a detailed CRP module that is linked directly into the MRP run. CRP tends to be too complex and requires too much data from other files to be run on a "stand-alone" spreadsheet application.
Example Bill of Material X – 1 A and 1 B Y – 1 A and 2 C
Example we will assume, for convenience sake, that each operation in the routing takes 1 week to accomplish. That implies that for the products due at the end of week 5 (and therefore assembled during week 5), the components to assemble those products must have been built in week 4.
