Warehouse Material Flow Equipment Requirements

Transcription

1 Warehouse Material Flow Equipment Requirements

2 Material Handling System Costing Module Experiential Learning Based Exercise Prepared for: College-Industry Council on Material Handling Education Material Handling Industry of America Prepared by: Russell D. Meller Department of Industrial & Systems Engineering Virginia Polytechnic Institute & State University Based on Material from: Design Plans and Ideas section of Modern Materials Handling Handling , Cahners Business Information, a division division of Reed Elsevier Gross & Associates, Rules of Thumb, 1999

3 Retail Chain Distribution E.g., Wal-Mart, K-Mart, etc. all products except clothes and tobacco batteries, CDs, brooms, screws, TP, cosmetics, etc. retail stores place order with DC each day pick in waves, zones, and sort to store WMS to control system everything is bar-coded and RF technology used

4 Zone 1 Zone 2

5 Retail Distribution Center Semi-automated facility 40 acre complex Facility: 148,000 sq. ft. (~100 yds by 100 yds) Max # of SKUs 24,000 Max Tput 98,600 units picked/shift

6 standard pallet rack High density pallet rack rider OP lift trucks

7 Pallet Jack Pallet + walk + no stack Front wheels are mounted inside the end of the forks and extend to the floor as the pallet is only lifted enough to clear the floor for subsequent travel Pallet restrictions: reversible pallets cannot be used, double-faced nonreversible pallets cannot have deckboards where the front wheels extend to the floor, and enables only two-way entry into a four-way notched-stringer pallet because the forks cannot be inserted into the notches 2(a) Manual Pallet Jack Pallet + walk + no stack + manual Manual lifting and/or travel 2(b) Powered Pallet Jack Pallet + walk + no stack + powered Powered lifting and/or travel from Prof. Kaye s website:

8 standard pallet rack High density pallet rack rider OP lift trucks

9 6(a) Sit-Down Counterbalanced Lift Truck Operator sits down ft. minimum aisle width requirement from Prof. Kaye s website:

10 standard pallet rack High density pallet rack rider OP lift trucks

11 7. Narrow-Aisle (NA) Straddle Truck Similar to stand-up CB lift truck, except outrigger arms straddle a load and are used to support the load instead of the counterbalance of the truck 7-8 ft. minimum aisle width requirement Less expensive than stand-up CB lift truck and NA reach truck Since the load is straddled during stacking, clearance between loads must be provided for the outrigger arms Arm clearance typically provided through the use of load-on-beam rack storage or single-wing pallets for load-on-floor storage from Prof. Kaye s website:

12 standard pallet rack High density pallet rack rider OP lift trucks

13 Order Picker Similar to NA straddle truck, except operator lifted with the load to allow for less-than-unit-load picking Typically has forks to allow the truck to be used for pallet stacking and to support a pallet during less-thanpallet-load picking "Belly switch" used for operator safety during picking from Prof. Kaye s website:

14 standard pallet rack High density pallet rack rider OP lift trucks

15 standard pallet rack High density pallet rack rider OP lift trucks

16 Process Flow R/C Staging Surge R/C Storage Long Term Storage Bulk Storage Replenishment Picking Areas: 1. Flow Rack 2. Carousels 3. Slow Units 4. High Value Merge Area Sortation Shipping

17 Evaluate the Material Flows Observe inbound and put-away operations Tabulate the replenishment activities Tabulate the order-picking activities

18 Process Flow R/C 45 pallets/hour pallet jacks Staging 10 pallets/hour CB lift trucks Surge R/C Storage 30 pallets/hour CB lift trucks 10 pallets/hour CB lift trucks Bulk Storage 45 pallets/hour or 540 cartons/hour rider OP truck 5 pallets/hour NA truck Long Term Storage 5 pallets/hour NA truck 40 pallets/hour CB lift trucks Replenishment 540 cartons/hour rider OP trucks Picking Areas: 1. Flow Rack 2. Carousels 3. Slow Units 4. High Vol 12,960 pc/hour Merge Area Sortation Shipping

19 Unit Conversions for Estimation 98,600 units per shift = 12,960 pc/hour = items/carton = cartons/pallet

20 Performance Standards Forklift Time Study Data: Pickup and deposit load hrs./occurrence (CB LT) hrs/occurrence (NA LT) Travel time hrs./ft./round trip Pallet jacks: 20 pallets/hr in shipping and receiving Order Pick Trucks 50 cartons/hour

21 More Standards Picking carts 40 lines per hour 2.5 pieces/line 25% of volume handled by carts

22 Estimating Capacity Required Demand and standards Variability? Paths and routes? NVA time deadheading, PM, planned idle Fractional capacity

23 Determine How many trips How far each trip How many vehicles

24 How Many How Far R/C 45 pallets/hour or 540 cartons/hour rider OP truck Replenishment 45 pallets/hour pallet jacks Staging 540 cartons/hour rider OP trucks 10 pallets/hour CB lift trucks 5 pallets/hour NA truck Surge R/C Storage 30 pallets/hour CB lift trucks Long Term Storage Picking Areas: Flow Rack Carousels Slow Units High Vol 10 pallets/hour CB lift trucks Bulk Storage 5 pallets/hour NA truck 40 pallets/hour CB lift trucks 12,960 pc/hour Merge Area Sortation Shipping Travel time estimate unloaded total distance speed Allowances pick up & put down utilization (Total time required)/(time available) = Vehicles required

25 What s Hard About This? Estimating distance traveled loaded Estimating unloaded travel Estimating effective travel speed Estimating utilization Estimating surge buffer usage

26 More On-Line Resources for the rules of thumb estimator click on Design Plans and Ideas Eskay Corp info center

27 Key Concepts Today Flow is conserved, on the average Cost standards Performance standards Appropriate parameters for standards