A valid aggregate unit is a weighed average of hours required, weighted by percent sales
Fictitious machine = .32(4.2)+.21(4.9)+.17(5.1)+.14(5.2)+.10(5.4)+ .06(5.8) = 4.856 hours of labor
An aggregate forecast can be obtained in the same way.
# of fictitious machines demanded = .32*fore. for A55+.21*fore. for (K42) +…. + .06* fore. for M38
If variety of products, sales dollars is good approximation as an aggregate unit
9.
Planning Steps hierarchy Forecast of aggregate demand for t period Planning horizon Aggregate production Plan : Production and Workforce levels for each period Master Production Schedule : Production levels by item by period Material Requirements Planning : Detailed Time table for production and assembly of Components and subassemblies
7520 2000 1400 June 5520 2000 2000 May 3520 1200 1200 April 2320 900 900 March 1420 640 640 February 780 780 1280 January Net cumulative demand Net predicted demand Predicted demand
C I : cost of holding one unit of inventory one month = $ 80
K ; Number of aggregate units produced by one worker in one day
It was observed that 76 workers produced 245 disk drives in 22 days
K = 245/(76x22) = .14653
19.
Aggregate Planning: Example Strategy 1 : Chase the demand by changing work force levels Month Number of Working days Number of Units produced Per worker (Bx.14653) Forecast Net demand Min. # of Worker required (D/C) Initial Calculations Table D C B A
20.
Aggregate Planning: Example Total cost = 755(500)+145(1000)+30(80) = 524,900 Month # of Workers # of units per workers # fired # hired Cum. Product. Produc Tion (BxE) Cum. Demand. Inven tory. A B D C F E G H I Aggregate Production/capacity plan
21.
Aggregate Planning: Example Min. Number Of Workers required 411 Strategy 2: Constant work force : Keep the work force level constant throughout the planning horizon Month Cumulative net demand Cumulative # of units produced per worker Ratio (B/C) Required workforce for strategy 2
22.
Aggregate Planning: Example Total cost = (411-300)(500)+5963(80) = 532,540 Month Production Per worker Monthly Production (Bx411) Cumulative production Cumulative Net demand Inven tory Aggregate Production/capacity plan
Be the first to comment