CapacityPlanning (RCCP) Type of capacity planning using someload profiles (sometimes called“representative routings) defined forthe product families, focused on keyor critical work centers, lines,departments, cells, suppliers, andsupport areas (engineering,distribution, shipping).
Importance of RCCPMRP system assumes that needed capacity alwaysis available.RCCP helps to identify the key resources and totest the feasibility of the supply plan, productionplan and master schedule before doing anydetailed capacity/material planning. It also helps to initiate action for making mid- tolong-term capacity adjustments.
What is RCCP and how does it work? Rough Cut Capacity Planning (RCCP) is a rough checkto evaluate all the key resources, to test the validity ofMPS, to determine the feasibility of fulfilling theapproved Production Plan that was developed in theSales & Operations Planning process. Once the master scheduler determines that a realistic plan exists, the production plan is then load into MRP to drive the allocation for all the lower-level materials. The production plan now translates into discrete part numbers, quantities and due dates.
Overstated MPSIt is a problem commonlyencountered in operating MRPsystems .An overstated master productionschedule is one that orders moreproduction to be released thanproduction can complete.
Causes of Overstated MPSIt causes raw materials and WIPinventories to increase.It also causes a build-up of job queueson the shop floor. Since jobs have to wait to be processed,actual lead time increase.As lead times increase, forecastaccuracy over the lead-time diminishes.
Few reasons of why RCCPtechniques are not used insome companies are: Data requirements are quite high - firm demand, forecasts, past data, lead times, utilization, products and process knowledge. They dont have a stable MPS. They dont have the right skill, it is very time-consuming, or they are doing it the wrong ways.
Standard Time It refers to Setup time and Run time (processing time) which impact the workload on a resource because it actually tie up that resource.
Lead-Time Offset It is the time between the need for the resource and the date that the product has been promised. Lead-Time Offset is necessary if a product has longer lead times.
When using process routings sheet and BOM to create the Resource Profile, it is better to use this formulaRequired Resource Time = (Run Time x BOM qty) + (Setup Time x number of Setups required) + margin % of total non- standard times
Several types of capacitiesbeing used: Demonstrated Capacity - This is the proven or historical capacity of a key resource or work center. Demonstrated capacity could potentially change if resources are added or if operations are altered. In such case, adjustments to planned capacity must be considered before making evaluation of the production plan.
Planned Capacity - This is demonstrated capacity plus or minusanticipated changes or adjustments to theproduct-flow process.Maximum Capacity - This is the maximum load a resource canhandle under any reasonable set ofcircumstances. This can be achieved throughseveral means: use of available overtime, addingshifts, staff additions, offload volume to outsidevendors, pay extra for supply priorities, payingpremium freights to expedite materials delivery,etc).
Determining CapacityAvailable or Planned CapacityAdjustment Factors:Utilization. Utilization is a number between 0and 1 which is equal to 1 minus the proportion oftime typically lost due to machine breakdown,labor shortage, parts failure, or materialunavailability.Efficiency. Efficiency is defined as the average ofstandard hours of actual production (after minusthe unavoidable lost time - setup time, changeshift, rest time).
If a time standard is exactly right,efficiency is 1. If the time actually required toperform the work is less than thestandard, efficiency is more than 1. If the time actually required toperform the work is more than thestandard time, efficiency is lessthan 1.
Capacity available is determinedby multiplying time available xutilization x efficiency Capacity Available = Time Available x Utilization x Efficiency
The Resource ProfileTechnique This technique is designed to convert the master production schedule from units of end items to be produced into the amount of time required on the key resources. Resource Profile approach considers lead-time offsets. Resource Profile technique is the most detailed rough-cut approach, but is not as detailed as Capacity Requirements Planning. Resource Profile technique uses detailed data on the time standards for each product at the key resources.
Time Standard It is the time it should take an average worker working at a normal pace to produce one unit of an item. The time standard for any part has built into it an allowance for rest to overcome fatigue or unavoidable delays, etc.
It would seems logical to accept that ifthe required capacity is : No more than 10% greater than theplanned capacity, the master schedule isconsidered realistic.More than 20% greater than the plannedcapacity, the master schedule is consideredunrealistic.Between 10% and 20% greater than theplanned capacity, the master schedule isquestionable.
In many of todays ERP systems, there isalso a "What-If" scenarios analysiscapability being built into the capacityplanning module, that makes it possiblefor the scheduler to juggle the numbers -shifting workers, reschedule in and -out,alternate routings, splitting lots, addequipments, off-loading to vendors,overtime, hiring temporary workers andso on.
3 Approaches to Rough- Cut Capacity Planning Capacity planning using Overall factors(CPOF) Approach – the least detailedapproach which is quickly computed but isinsensitive to shifts in product mix. Bill of Labor – a second approach whichinvolves multiplying two matrices, the bill oflabor and the master production schedule.. Resource Profile – approach which takeslead-time offsets into account.
Drum-buffer Rope It is an emerging procedure that eliminates the need for iteration found in all RCCP approaches. It is presently used by a small but growing number of corporations.
Material Requirements Planning (MRP) It uses Master Production Schedule (MPS) of end items to determine the quantity and timing of component part production. It is capacity insensitive; it implicitly assumes that sufficient capacity is available to produce components at the time they’re needed.
APICS Monograph (Berry, Voliman, and Whybark 1979) presents case histories of several companies, including details on the capacity planning process.
Production Planning & Control Capacity management techniques usuallyare separated into four categories thatrepresent the four time horizons : Manufacturing Resource Planning (MRPII) Aggregate Production Planning Rough Cut Capacity Planning (RCCP) Capacity Requirements Planning (CRP).
In any MRP system, the samesequence is to create a masterschedule, use Rough Cut CapacityPlanning to verify that the MPS isfeasible, perform the MRPexplosion, and send the PlannedOrder Release data to CapacityRequirements Planning
Role of RCCP in the overall PPC system: To develop an achievable Master Production Schedule. To plan and control priorities and capacities. Priority Planning is the process of specifying batch quantities and their start and finish dates for all Supply Orders where procurement and manufacturing are involved. Priority Control is making the right things at the right time. It is completely dependent on maintaining a balance between MPS requirements and factory Output rates, in which suppliers delivery performance is vital. Capacity planning is the task of determining how much output is needed from factory and from suppliers. Capacity control is the comparison between planned levels and actual outputs achieved, and the identification of significant variances above or below plan. Corrective action must be done quickly (adjust capacity or changing the master schedule).
Typical resources that might be planned aspat of rough-cut capacity planning:Overall plant capacityLabor hours in total or for people with unique skillsAssembly hours in a specific cell or bottleneckprocess.Testing cell capacityEngineering hours needed to configure the finalproduct to the customer’s specification.Space required in a warehouse or storage areaWaste or effluent release, etc.Shipping laborDesign time or credit release timeInspection or QC timeSupplier Capacity
Rough-Cut CapacityPlanning FunctionsShows consumption of critical resources.Enables master schedulers to: Test end-item production plans Calculate capacity to meet the master schedule Compare and modify required and planned capacity Analyze load on key resources by time period Isolate and resolve potential problems.
Rough-cut CapacityPlanning V.S. Capacity Planning CRP uses time-phased material planinformation, while RCCP uses aggregate data. MRP takes into account capacity stored asinventory. Shop floor systems take into account W.I.P. –only consider whats needed to complete therequirement. CRP considers service and spare partsrequirements also.
EXAMPLE problem:Lets assume a lamps manufacturer I callit Johors Lamps. Johors Lamps runs 3shifts, 120 hours per week from Mondayto Friday; Planned Production Lost Timeper shift (change shift & rest time) is 35minutes, and company allows amaximum overtime of 10% of per shifteither during weekdays or through Sat.& Sunday.