Lawn King produces a couple models of push lawn mowers. A total of $60$ workers are currently employed to work on the assembly line. Hiring cost is $$800$ for each new employee, while the cost of laying off an employee is $$1200.$ The production strategy in current use is a one$-$shift$-$per$-$day level strategy at average demand. Differences between demand and production are balanced by inventory

and backorders. If a backorder occurs, the order is filled from the next available production run and safety stock is consumed if needed and replenished later. Lawn King utilizes a $$7/$unit carrying cost per month for inventory, and backorders have a cost of $$10/$unit per month. Production is estimated at $5$ mowers per worker per shift, and the assembly line operates $20$ working days $($shifts$)$ per month. Lawn

King keeps $500$ mowers as safety stock, which will be the beginning inventory for September. The regular time cost of production is $$50$ per lawn mower.

$[$Hint: production $=($# of workers$)($# of mowers each worker produces per shift$)($# of shifts per month$)]$

Each May an aggregate production plan is prepared for the upcoming fiscal year that starts in September. The aggregate plan is used for personnel planning, inventory planning, and budget preparation.

$1.$Develop an aggregate plan for fiscal $2022$ using the forecasts below

a$.$ using their level strategy

b$.$ using a chase strategy by varying the number of workers

Sept $2021-6000$

Oct$-7000$

Nov$-7000$

Dec$-8000$

Jan $2022-8000$

Feb$-8000$

March$-7000$

Apr$-6000$

May$-7000$

Jun$-7000$

Jul$-7000$

Aug$-6000$

$2.$ Calculate the economic order quantitiy. Because of the high setup cost of $$60/$order for producing push lawnmowers, production is ordered in specified quantities instead of lot$-$for$-$lot. Calculate the economic order quantity for push mowers $($assume independent of model; holding cost are given above$).$ This quantity will be used as the lot size for the MRP$.[$Hint $-$ convert holding cost given above to annual in this calculation.$]$

$3.$ Prepare an MRP$.$

Mowmaster is Lawn King's most popular model. Like all push mowers, it is made of a motor assembly $($purchased from a vendor$),$ handle assembly, and body assembly. The handle assembly is made of a handle and shifter. The body assembly consists of a blade, frame, and $4$ wheels.

a$.$ Complete the product structure tree for the Mowmaster.

b$.$ Complete a net MRP for wheels if $2000$ Mowmasters need to be shipped in week $8.$ Reminder to use $Q$ from part $2$ as the lot size for the mower.

$\backslash$table$[[$Item$,$Lead Time,Inventory,Lot size$],[$Mowmaster$,1,100,$Q$=],[$Motor assembly,$2,10,$Lot for lot$],[$Handle assembly,$1,10,$Lot for lot$],[$Body assembly,$2,300,$Lot for lot$],[$Handle$,1,0,$Lot for lot$],[$Shifter$,2,0,$Lot for lot$],[$Blade$,1,0,$Lot for lot$],[$Frame$,1,0,$Lot for lot$],[$Wheels$,2,1550,200]]$

$\backslash$table$[[$Item$,,1,2,3,4,5,6,7,8,9,10],[$Mowmaster$,$Gross Require,,,,,,,,,,$],[,$On Hand,,,,,,,,,,$],[$Level $=,$Net Require,,,,,,,,,,$],[$LT $=,$Order Receipt,,,,,,,,,,$],[,$Order Release,,,,,,,,,,$],[$Body$,$Gross Require,,,,,,,,,,$],[$assembly$,$On Hand,,,,,,,,,,$],[$Level $=,$Net Require,,,,,,,,,,$],[$LT $=,$Order Receipt,,,,,,,,,,$],[,$Order Release,,,,,,,,,,$],[$Wheels$,$Gross Require,,,,,,,,,,$],[,$On Hand,,,,,,,,,,$],[$Level $=,$Net Require,,,,,,,,,,$],[$LT $=,$Order Receipt,,,,,,,,,,$],[,$Order Release,,,,,,,,,,$]]$