CPIMDSP-Session6StudyNotes

1、-1-Session Six一Detailed Capacity Planning# Influence on Detailed Capacity Planning Explain the significance of the following in detailed capacity planning Flexibility of capacity and schedulingFlexibility of CapacityfPlan Material FirstOrder Due Date(I) Flexibility of Capacity but Not Schcd山ingThis

2、scenario applies to make-to-order production in an intermittent (job shop) environment, where thepreferred detailed capacity planning method would be CRP.* Due dates arc set based on customer orders, not flexible* Capacity needs to be flexible to accommodate time-phased load requirements imposed on

3、work centersand to ensure due date can be met.(II) Flexibility in Scheduling but Not CapacityThis scenario applies to process flow manufacturing where process flow scheduling would be the capacityplanning approach. It might also apply to high-volume repetitive production.* The manufacturing process

4、is capital intensive, so capacity is expensive and inflexible.* Due dates are set to meet internally established priorities based on forecast of customer orders and thedecisions on how much inventory to carry to meet customer demand. Whether material or capacity is planned firstRelationship between

5、capacity and priority planning-Detailed material planning is validated by detailed capacity planning. In other words, planning materialFlexibility of2first is NOT always the most logical option. Planning Material First The material plan (for example, MRP) is based on priority plan due dates. The mat

6、erial plan is validated by CRP. Planning Capacity First Capacity is the priority. Production level is based on capacity and inventory investment policies Production level is an input to sales and operations planning (S&OP) Requirements flow down to the material plan (for example, MRP) 1 Project Manu

7、facturing- This progress is highly flexible and capable of managing a broad range of product designs and designchanges- Activities on the critical path are much less flexible, and more precision is required in planning theavailability of their required resources 2 Intermittent Production一Job shop- P

8、roduction operations are designed to handle a wide range of production designs and are performed atfixed plant locations using general-purpose equipment. Detailed capacity planning, beginning with infinite loading, is the most applicable technique. ThisSpecial technique is called CRP. 3 Batch Produc

9、tion- This type of manufacturing process produces items with similar designs and may cover a wide range oforder volumes The same items are ordered repeatedly.- Production cycle times may be considerably less than the elapsed time from order receipt to ordershipment.- Detailed capacity planning in ba

10、tch manufacturing is very similar to CRP used in job shop. 4 Repetitive ManufacturingMany detail-level planning issues can be simplified in plants designed as assembly lines, which exploit the3benefits of high production, low WIE and short lead time. and arc capital intensive 4ass produciion and mas

11、s customization arc different forms within environment, depending on (he degreeto which customer requirements deviate from standard Mass production plants provide a limited range of standard product variants It is often compatible with lean/JIT techniques Fixed routine and level production schedule,

12、 which not requires a detailed capacity requirements analysisin repetitive environment. Constraining resources must be identified and the operation that takes the most time must be predicted.Mass customization plants provide a fully configurable product with limitless variety according tocustomer sp

13、ecification. but with more efficiency and cost effectiveness than a job shop. Capacity management techniques are similar to those used in project manufacturing may be employed. 5 Continuous ProductionContinuous production is a form of line production in which the material flow is constant. The proce

14、ss is, inpractice, only stopped if required by the transportation infrastnicture or when resources are not availableInflexibility of capacity and sometimes complexity in the plant as well, often make lean/JIT unsuitable inthese plants.* RemanufacturingRemanufacturing is the process of returning a pr

15、oduct to like-new conditionMRP and CRP are commonly used in planning materials and equipment usage for remanufacturing orrepair.An important planning factor in remanufacturing is the occurrence factor, sometimes called therepair factor,which determines how many times a part or component may require

16、refurbishing Define terms and concepts relating to capacity Capacity1) The capacity of a system to perform its expected function 2) The capacity of a worker, machine, workcenter, plant, or organization to produce output per time period. LoadThe amount of planned work scheduled for and actual work re

17、leased to a facility, work center, or operationfor a specific span of time Capacity planningThe process of determining the amount of capacity required to produce in the future. Capacity managementThe function of establishing, measuring, monitoring, and adjusting limits or levels of capacity in order

18、 toexecute all manufacturing schedules4* Information Used in Detailed Capacity Planning Define the data and concepts relating to work centers and load Work center一A specific production area, consisting of one or more people and/or machines with similarcapabilities that can be considered as one unit

19、for puipose of capacity requirements planning and detailedscheduling. Work cell一Dissimilar machines grouped together into a production unit to produce a family of partshaving similar routines Describe the elements of manufacturing lead time and their use in determining load Lead time一In logistics co

20、ntext, the time between recognition of the need for an order and the receipt ofgoods Manufacturing lead time一The total time required to manufacture an item, exclusive of lower levelpurchasing lead time.* Manufacturing lead time assumes that all components are available when needed. Order preparation

21、 lead time一The time needed to analyze requirements and open order status and tocreate the paperwork necessary to release a purchase order or a production order. The elements of manufacturing lead time Queue time一The amount of time a job waits at a work center before setup or work is performed on the

22、job Setup time (create load)一The time required for a specific machine, resource, work center, process, orline to convert from the production of the last good piece of item A to the first good piece of item B.* It does not include external setup time, which is the time spent on setup when machines ar

23、e still running.- Run time (create load)一The time required to process a piece or a lot at a specific operation- Wait lime一The time a job remains at a work center after an operation is complete until it is moved to thenext operation.- Move time - The time that a job spends in transit from one operati

24、on to another in the plant. Explain the use of rated and demonstrated capacity to evaluate work center capacity Utilization - is a measure of how intensively a resource is being used relative to its available time. Efficiency -is a measure of how closely the actual hours worked compared to a predete

25、rmined standard forhours worked to produce a given level of output.Efficiency = Standard hours produced / Actual hours produced Available time一arises from management decisions on the hours of availability of a work center over aspecific period of time * Ralcd capacity = Available time x Utilization

26、x Efficiency * Demonstrated capacity is usually expressed as average oulput in standard hours: the average number ofitems produced multiplied by the standard hours per item. * Detailed Capacity Planning Technique Describe the nature and significance of queues In a job-shop environment, good capacity

27、 utilization and short queue times (and thus short lead times)cannot be achieved simultaneously. For utilization to approach 100 percent, queue time needs to be high.5- Reasons for queue* A queue for a business reasons is intended as a cushion against potential disturbances in theproduction process

28、(as an inventory buffer)* A queue for economic reasons is intended to reduce production costs by saving setup time andpsychologically affecting the efficiency of the workers Explain and differentiate the roles of infinite and finite loading in capacity planningInfinite LoadingFinite LoadingInfinite

29、loading means calculating load required atwork centers by time period without regard tocapacity Assign no more work to a work center than thework center can be expected to execute in a giventime period High degree of flexibility in capacity to meet duedates;Material is planned first and then validat

30、ed byCRP;Back scheduling;Variations: Lean/JITHigh degree of flexibility in scheduling to preventoverload;Capacity is expensive and be planned first; Forwardscheduling with Gantt Chart;It is appropriate in the process industry, which hasa cont:inuous flow production. Load leveling (under infinite loa

31、ding) - Spreading out orders in time or rescheduling operations so thatthe amount of work to be done in sequential time periods tends to be distributed evenly and is achievable * Load leveling is possible when the due date of the order and/or the operation is flexible* The planner needs to know following factors: future availability of capacity, order due dates, and【iming of individual operations