Formulario

Pagina 1

1 Logistics Management - Formulas 1 STORAGE SYSTEMS Storage Capacity assessment [FF = forecasting factor; i = product family, item; j = month/period] 𝑁𝑆𝑗 = ∑𝑆𝐶𝑖𝑗𝑖 #locations occupied by an item i for a period j [SC = starage capacity] - Random storage 𝑆𝐶 = 𝑚𝑎𝑥𝑗{𝑁𝑆𝑗} ∗ 𝐹𝐹 -> maximum value that I have considering the sums of all the values of each month - Dedicated storage 𝑆𝐶 = ∑(𝑚𝑎𝑥𝑗{𝑁𝑆𝑖,𝑗} ∗ 𝐹𝐹𝑖)𝑖 -> sum of the maximum values that I have for each month - Class based storage 𝑆𝐶𝑘 = ∑(𝑚𝑎𝑥𝑗{𝑁𝑆𝑘,𝑗} ∗ 𝐹𝐹𝑘)𝑘 Storage area - Bay design → draw and compute W, H, D 𝑁𝑃𝐵 = ⌊ 𝑊𝑏𝑎𝑦 𝑊𝑃𝐿 ⌋ [#pallet locations in a bay] - Module design → 𝐴𝑚𝑜𝑑𝑢𝑙𝑒 = (2𝐷 + 𝐴𝑊) ∗ 𝑊 - Number of levels → 𝑁𝐿= 𝑚𝑖𝑛{⌈ 𝑅𝐻 𝐻 ⌉ ; ⌊ 𝐵𝐻 𝐻 ⌋} [RH = rack height; BH = building height] - Area utilization rate → 𝐴𝑈𝑅𝑚𝑜𝑑𝑢𝑙𝑒 = 𝑃𝐿𝑠𝑚𝑜𝑑𝑢𝑙𝑒 𝐴𝑚𝑜𝑑𝑢𝑙𝑒 = 2∗NPB∗NL Amodule - Required area 𝐴𝑈𝑅𝑚𝑜𝑑𝑢𝑙𝑒 = 𝑆𝐶 𝐴 → 𝐴 = 𝑆𝐶 𝐴𝑈𝑅𝑚𝑜𝑑𝑢𝑙𝑒 - if the rack length is fixed (𝑈 = 𝑅𝐿) o 𝑁𝐶 = ⌊ 𝑅𝐿 𝑊⌋ o 𝑁𝐴= ⌈ 𝑆𝐶 2∗𝑁𝑃𝐵∗𝑁𝐿∗𝑁𝐶⌉ o 𝑉 = 𝑁𝐴∗ 𝑊𝑚𝑜𝑑𝑢𝑙𝑒 - If we do not know the rack length, according to the position of the I/O point → expected path 𝑃 = 2 ∗ ( 𝑈 𝑎 + 𝑉 2) → 𝑈𝑜𝑝𝑡 = 𝑎 2 ∗ 𝑉𝑜𝑝𝑡 o I/O in the middle of the storage front 𝑎 = 4 𝑃 = 2 ∗ ( 𝑈 4 + 𝑉 2) Uopt = 2 Vopt o I/O on the vertex of the storage front 𝑎 = 2 𝑃 = 2 ∗ ( 𝑈 2 + 𝑉 2) Uopt = Vopt o I/O distributed along the storage front 𝑎 = 3 𝑃 = 2 ∗ ( 𝑈 3 + 𝑉 2) Uopt = 1,5 Vopt o Number of aisles 𝑁𝐴= ⌈ 𝑈𝑜𝑝𝑡 𝐴𝑊+2𝐷⌉ o Number of bay columns 𝑁𝐶 = ⌈ 𝑆𝐶 2∗𝑁𝐴∗𝑁𝑃𝐵∗𝑁𝐿⌉ o 𝑈𝑟𝑒𝑎𝑙 = 𝑁𝐴∗ (𝐴𝑊+ 2𝐷) [𝑚] o 𝑉𝑟𝑒𝑎𝑙 = 𝑁𝐶∗ 𝑊 [𝑚] o 𝐴 = 𝑈 ∗ 𝑉 - Real storage capacity: 𝑆𝐶𝑟𝑒𝑎𝑙 = 2 ∗ 𝑁𝐴∗ 𝑁𝐶∗ 𝑁𝑃𝐵∗ 𝑁𝐿 2 NB: if we have a block stacking storage areas - 𝑁𝑃𝑙𝑎𝑛𝑒 = ⌈ 𝑆𝐶 #𝑖𝑡𝑒𝑚𝑠∗𝑃𝐿/𝑠𝑡𝑎𝑐𝑘∗#𝑙𝑎𝑛𝑒𝑠/𝑖𝑡𝑒𝑚⌉ - 𝑈 = 𝐴𝑊+ 2 ∗ [𝑁𝑃𝑙𝑎𝑛𝑒 ∗ (𝐷𝑃𝐿 + 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒𝑃𝐿) + 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒𝑃𝐿] - 𝑉 = (𝑊𝑃𝐿 + 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒𝑃𝐿) ∗ #𝑙𝑎𝑛𝑒𝑠 - 𝐴 = 𝑈 ∗ 𝑉 - 𝑉𝑇𝑆𝐶𝐶 = 𝑃𝑎𝑖𝑠𝑙𝑒 𝑠𝐻,𝑎𝑖𝑠𝑙𝑒 + 𝑃𝑙𝑎𝑛𝑒 𝑠𝐻,𝑙𝑎𝑛𝑒 + 𝑆 𝑠𝑉 o 𝑃𝑎𝑖𝑠𝑙𝑒…