15 07 19

Pagina 1

1 EXERCISE 1 - AS/RS single deep selective racks, one machine per aisle - Storage capacity required = 120000 pallet locations - Throughput capacity required = 90 PL/h - Bay dimensions: length = 2,8 m * depth = 1,4 m * height = 1,6 m - There are 3 pallet locations per bay - I/O at the second level - Rack length max = 100 m - Rack height max = 21 m - Horizontal speed = 2,2 m/s - Vertical speed = 0,9 m/s - Fixed positioning time = 6 sec - Fixed time for the fork cycle = 10 sec - Acceleration + deceleration = 9 sec - 70% of the cycle is dual command cycles - FEM 9851 is applicable QUESTION 1: size AS/RS system (24/30) Assume in the third aisle there are three empty pallet location: A(right, column 34, level 6), B(left, 28, 8) and C(right, 18, 4). A PL located in (right, 38, 12) has to be retrieved in that aisle. Another PL has to be stored and a dual command cycle can be performed QUESTION 2: choose the best location (A, B, C) in which to store the pallet load (6/30) 2 EXERCISE 2 - Low level picker-to-parts system 20 working aisles - Racks are 14 m long and 1,6 m high - Pickers use traversal routing and batch picking policies - Lines per order = 8 - Pieces per line = 2 - Orders per batch = 5 - Average reduction of order lines compared to the sum of the lines belonging to the different order composing the batch (due to the adoption of the batch picking policy) = 30% - Set-up time for a pick tour = 50 sec - Fix retrieval time per line = 5 sec - Retrieval time per piece = 4 sec - Average speed of the truck = 1,2 m/s - Each location has the same probability to be visited - Furthest couple of aisles is the 10 th QUESTION 1: assess the average picking time per tour (24/30) Now, change storage policy, adapt a class-based storage (with traversal routing policy, batch picking…