Assessment $2$: Total $12\mathrm{.}5\%$ Individual Assessment

Question $1(6\%)$

A warehouse consists of $5$aisles of racks $($racks on both sides of each aisle$)$ and a loading dock. Forklift trucks are used to transport loads between the loading dock and the storage compartments of the rack system in each aisle. Trucks move at an average speed of $140$ m$/$min loaded and $180$m$/$min empty.

Load handling time $($loading plus unloading$)$ per delivery totals $1$ min per storage$/$retrieval$.$ Traffic factor is $0\mathrm{.}9,$ worker efficiency is $100\%$ and reliability$/$availability is $96\%.$

The average distance between the dock and the centre of the aisles are $200,300,400,500$ & $600$ meters. Suppose the warehouse is organised into a class based storage strategy on activity level of the pallet loads in storage, so that aisles $1$ & $2$ accounted for $70\%$ of the deliveries $($Class A$)$ and aisles $3,4$ and $5$ accounted for the remaining $30\%($Class B$).$

Assume that the deliveries in Class A are evenly divided between aisles $1$ & $2$ as are those in Class B between aisles $3,4$ & $5.$

How many trucks would be required to achieve $100$ storage$/$retrieval deliveries per hour?

Question $2(6.)$

Major appliances are assembled on a production line at the rate of $55$ per hour. The products are moved along the line on work pallets $($one product per pallet$).$

At the final workstation the finished products are removed from the pallets. The pallets are then removed from the line and delivered back to the front of the line for reuse. AGVs are used to transport the pallets to the front of the line; a distance of $600$ ft$.$ the return trip distance to the end of the line is also $600$ ft$.$

The pallets form queues at the end of each line so that neither the production line nor AGV is starved for pallets. Each AGV carries four pallets and travels at a speed of $150$ ft$/$min$.$

Time required to load each pallet onto an AGV is $15$ sec$.$ time to release a loaded AGV and move an empty AGV into position for loading at the end of the line is $12$ sec$.$

The same times apply for pallet handling and release positioning at the unload station at the front of the line. Assume the traffic factor is $1$ since the route is a simple loop.

How many vehicles are needed to operate the AGV system?