Chapter 9 Storage & Warehouse Systems

1. Chapter 9 Storage & Warehouse Systems FACILITIES PLANNING & DESIGN Alberto Garcia-Diaz J. MacGregor Smith 1. Warehouse Layout Model 2. Storage Equipment 3. Automated Storage & Retrieval System

2. Dedicated & Random Storage Section 9.3 Dedicated Storage A set of storage locations assigned to a specific product Decision variable xjk = 1 or 0for assigning or not assigning product j to location k Measure of effectiveness Minimize total expected distance traveled

3. Input Data q= number of storage locations n = number of products m = number of input/output points (docks) Sj= number of storage locations required by product j Tj= number of trips in/out of storage for product j pi= percentage of travel in/out of storage to/from point i dik = distance or time required to travel from point i to location k

4. Mathematical Model

5. fk = pidik Min ( f1 xj1 + f2 xj2 + … + fq xjq ) ( fk xjk ) =

6. Solution Procedure (a) Relabel the products according to the decreasing order of their Tj / Sjvalues (b) Find the values of fk (expected distance traveled between location k and docks) (c) Assign the locations to products according to their f-values from lowest to highest

7. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Example Warehouse’s dimensions: 40 x 40 ft Storage Location: 10 x 10 ft One receivingdock at the northeast corner of the layout One shippingdock at the midpoint of the west side Two products A and B Product A: 100 pallets per week (TA=100) Product B: 80 pallets per week (TB=80) Product A requires 10 storage bays (SA=10) Product B requires 4 storage bays (SB=4) p1 = 180/360=0.5 p2 = 180/360=0.5

8. 30 30 30 30 30 30 30 30 35 35 35 35 45 45 45 45 TA=100 SA=10 TA/SA=10 TB=80 SB=4 TB/SB=20 Consider Product B first and Product A second. p1 = 0.5 1 2 3 4 B B B B 5 6 7 8 A A A A p2 = 0.5 9 10 11 12 A A A A 13 14 15 16 A A

9. RACK STORAGE CAROUSELS AS/RS (Automated Storage Retrieval Systems) STORAGE SYSTEMS

10. One of the primary methods of material storage Utilizes the vertical space in the warehouse Highly cost efficient RACK STORAGE SYSTEMS

11. Walk Through Racks Push Back Rack Very Narrow Aisle Racks Drive-in Racks Gravity Flow Racks Mobile Racks Double Deep Racks Rollout Shelf Racks Reel Racks Cantilever Racks Stacker Systems Wire Coil Racks Sheet Storage Racks RACK TYPES

12. WALK THROUGH RACKS

13. Provides easy accessibility to the adjacent aisles Pickers time is greatly reduced Allows more lighting into aisles Higher utilization of vertical space FEATURES

14. PUSH BACK RACKS

15. Pallet loads are literally pushed back into the rack When pallet is retrieved, the deeper pallet load automatically advance to the aisle High density and high accessibility Used to store large number of pallets for a long time and then remove and ship them as seasonal products Used mostly in combination with drive-in racks FEATURES

16. VERY NARROW AISLE RACKS

17. Permits aisle widths less than 5 feet Provide significant floor space reduction Used at heights of 40 feet to 50 feet Provides 100% selective storage Pallets are accessed with turret or side loader lift trucks Sometimes racks are designed with top and bottom monorails FEATURES

18. DRIVE-IN RACKS

19. Used for bulky and light weight parts Parts are mainly in cartons Fork lift is the material handling device used Parts are typically stacked one over the other in large numbers FEATURES

20. GRAVITY FLOW RACKS

21. Used for parts in cartons Parts are supported on rollers in the rack system Material transfer is done with ease Easy to move parts along the same row as less effort is required due to the presence of rollers FEATURES

22. MOBILE RACKS

23. High density storage systems 100% utilization of pallet positions Number of rows of racks mounted on mobile bases Storage carriages are driven by electric motors Used mainly in cold or ultra-cold warehouses where aisle space is at a premium Used when speed of product movement is not a major concern FEATURES

24. DOUBLE DEEP RACKS

25. It is like placing two rows of racks together Uses a deep reach lift truck for storage and retrieval Increases floor space usage to about 60% to 65% Used for high throughput operations Low initial cost High productivity Less equipment damage FEATURES

26. ROLLOUT SHELF RACKS

27. Specialized storage Mainly for delicate and costly parts Used for dies, measurement tools FEATURES

28. REEL RACKS

29. Special type of storage Mainly for cables and wires in reels FEATURES

30. CANTILEVER RACKS

31. Used to store long pipes and wood Parts are stored using the fork lifts Highly economical Can be used till heights of 22 feet FEATURES

32. STACKER SYSTEMS

33. Provided with an integral crane Easy handling of heavy items High storage and retrieval speeds Eliminates fork lift usage FEATURES

34. WIRE COIL RACKS

35. Used to store wire coils Used to house rubber hoses and hose assemblies FEATURES

36. SHEET STORAGE RACKS

37. Store material in the form of sheets Can be used to store glass Permits a height of 10 feet FEATURES

38. ADVANTAGES High pick rates Motorized, computer controlled and independent rotating aisles of shelving Parts are carried to the picker rather than the picker going to the parts like in the case of racks Mostly set up in pods of 2 or 3 Pick rates vary from 80-200 picks/person hour CAROUSELS STORAGE

39. DISADVANTAGE Adding more people cannot significantly increase pick rate Only one picker can operate at a given time Thus reduces the ability of the warehouse to respond to surges in demand CAROUSELS STORAGE

40. Horizontal Carousels Vertical Carousels Independent Rack Carousels TYPES OF CAROUSELS STORAGE

41. HORIZONTAL CAROUSEL

42. It is a series of rotating bins of adjustable shelves driven on the top or bottom by a motor Rotation takes place on an axis perpendicular to the floor at about 80 feet/minute Horizontal lengths vary from 15 feet to 100 feet Height varies from 6 feet to 25 feet Prices start from $5000 and increases with the number of bins and weight capacity FEATURES

43. VERTICAL CAROUSEL

44. It is a horizontal carousel placed on its end and enclosed in sheet metal Height ranges from 8 feet to 35 feet They include excellent item protection and security Only one shelf of items is exposed at a time All items cannot be looked at, at the same time Prices range form $10,000 onwards FEATURES

45. They are multiple one level horizontal carousel stacked on top of one another Order picker accesses several pick locations at any time Each levels operate independently and have their own power and communication link Hence they are very costly INDEPENDENT RACK CAROUSELS FEATURES

46. Improved Space Utilization 75 % of rack space can be recovered High saving in pickers time Allows quick access to goods via a system of shelves operating on a shuttle mechanism It brings the exact pick/store location to the operator Increases retrieval productivity by more than 2.5 times AUTOMATED STORAGE AND RETRIEVAL SYSTEMS (AS/RS)

47. Access area of the system is ergonomically designed to present stored items at an ideal height for picking High employee safety and improved throughput AUTOMATED STORAGE AND RETRIEVAL SYSTEMS (AS/RS)

48. AUTOMATED STORAGE AND RETRIEVAL SYSTEMS (AS/RS)

49. WAREHOUSE DESIGN STRATEGY

50. Automated Storage & Retrieval System Unit Load: W x L x H L H W