1. Chapter 8 Small Item Picking Systems

2. 《 Main Knowledge 》
1. bin shelving systems
2. modular Storage Drawers/Cabinets
3. mezzanine
4. horizontal carousels
5. vertical carousels
6. automated item picking

3. Small Item Picking Systems
The major types of broken case picking systems are
picker-to-stock （PTS）system
拣选员移动式拣选系统
stock-to-picker （STP） system
存货移动式拣选系统
automated item picking
自动拣选系统

4. Small Item Picking Systems
In picker-to-stock systems, the order picker walks or rides to the picking location.
In stock-to-picker systems, the stock is mechanically transported to a stationary order picker.
In automated item picking, items are automatically dispensed into shipping cartons or tote pans.

5. The two subsystems that
1. Picker-to-Stock Systems 拣选员移动式拣选系统
The two subsystems that
must be selected are
the storage system that houses the stock 货物存放系统
the item retrieval system 取货系统

6. The three most popular picker-to-stock storage systems are
1. Picker-to-Stock Systems 拣选员移动式拣选系统
The three most popular picker-to-stock storage systems are
bin shelving
箱式货架
modular storage drawers
标准储存抽屉
gravity flow rack
重力式货架/自流式货架

7. Bin Shelving Systems
Bin (or metal) shelving systems are the oldest and still the most popular equipment alternative for small parts order picking.

8. 1.1.1 Bin Shelving Systems Advantages Disadvantages Inexpensive
require very little if any maintenance
Inflated labor requirement
Supervisory problems
Item security/protection problems
Disadvantages

9. 1.1.1 Bin Shelving Systems Disadvantages
Space is frequently underutilized in bin shelving systems.
Reasons are
◇ the full inside dimensions of a shelving unit are rarely usable.
◇ The height of bin shelving units may be limited by the reaching height of a human being.
consequences are
◇ First, low space utilization means that a large amount of floor space is required to store the products.
◇ Second, the greater the floor space, the greater the area that must be traveled by the order pickers, and thus the greater the labor requirement and costs.

10. 1.1.2 Modular storage drawers / cabinets
Advantages
1. the large number of items that can be stored and presented to the order picker in a small area.
2. excellent storage density
3. because the drawers are pulled out into the aisle for picking, space does not have to be provided above each SKU to provide room for the order picker’s hand and forearm.
4. improved picking accuracy
5. protection for the items from the environment.
Suitable for:
When the value of space is at a true premium
When facing the possibility of building additions
Cost of space and the need for item security and protection are very high

11. 1.1.3 Gravity Flow Rack Gravity flow rack is typically used for :
SKUs with high broken case cube movements
that are stored in fairly uniform sized and shaped cartons.

12. 1.1.3 Gravity Flow Rack Advantages
The back-to-front movement insures first-in-first-out （FIFO） turnover of the material.
good space utilization.
very low maintenance requirements
Walking and therefore labor requirements can be reduced with an efficient layout.
Advantages

13. 1 1.1.4 Space Saving Systems Mezzanines
The advantages of using a mezzanine is that nearly twice as much material can be stored in the original square footage.
The major design issues for a mezzanine are the selection of the proper grade of mezzanine for the loading that will be experienced, the design of the material handling system to service the upper levels of the mezzanine, and the utilization of the available clear height.

14. 1 1.1.4 Space Saving Systems Mezzanines
The key to maintaining high-order picking productivity when a mezzanine is in use is to slot the products so that most of the picking activity takes place at the floor level.The SKUs with the highest picking density should be assigned to the floor level and the SKUs with the lowest picking density should be assigned to the upper level.

15. Mobile Storage Systems
Space Saving Systems 2
Mobile Storage Systems

16. Mobile Storage Systems
Space Saving Systems 2
Mobile Storage Systems
space savings
Advantage
Disadvantage
the increased time required to access the items.
used for
very slow-moving items and when space is very scarce and/or expensive.

17. 1.2 Picker-to-stock retrieval methods
拣选员移动式取货方法
Cart Picking
手推车拣选
Tote （or Carton） Picking
拣货箱拣选
Man-up Systems
载人系统
Robotic Item Picking
机器人拣选

18. 1 1.2 Picker-to-stock retrieval methods
Cart Picking
手推车拣选
Batch picking carts are designed to enable an order picker to pick multiple orders on a picking tour, thus dramatically improving productivity as opposed to strict single-order picking for small order.
Cart picking rates range from 70 to lines per person hour.

19. Tote (or Carton) Picking
1.2 Picker-to-stock retrieval methods
Conveyors are used
Order pickers may walk one or more totes through a single picking zone, partially completing several orders at a time, or an order picker may walk one or more totes through all picking zones, thus completing one or more orders on each pass through the picking zones. 2
Tote (or Carton) Picking
拣货箱拣选
Tote picking rates range from 150 to 300 lines per person hour.

20. 3 1.2 Picker-to-stock retrieval methods Order picker truck;
Man-up Systems
载人系统
Order picker truck;
man-aboard AS/RS
载人自动存取系统
A man-aboard AS/RS offers significant floor space savings over the systems described so far.
Advantage
Man-aboard automated storage and retrieval systems are far and away the most expensive picker-to-stock equipment alternative.
Disadvantage

21. 3 4 1.2 Picker-to-stock retrieval methods
Typical picking rates in man-aboard operations range between 40 and 250 lines per person-hour. 3
Man-up Systems
载人系统
Man-aboard systems are typically appropriate for slow-moving items where space is fairly expensive. 4
Robotic Item Picking
机器人拣选

22. The two most popular stock-to-picker storage systems are
2. STOCK-TO-PICKER SYSTEMS
The two most popular stock-to-picker storage systems are
Carousels
旋转式存储传送系统
Manila Automated Storage and Retrieval Systems
轻负载自动存取系统

23. 2. STOCK-TO-PICKER SYSTEMS
The major advantage of stock-to-picker systems over picker-to-stock systems
The elimination of the travel time for the order picker
supervision

24. 2.1 Carousels 1 Horizontal carousels
水平旋转式存储传送系统 1
Horizontal carousels vary in length from feet to 100 feet, and in height from 6 feet to feet. The length and height of the units are dictated by the pick rate requirements and building restrictions.

25. 2.1 Carousels 1 Horizontal carousels 水平旋转式存储传送系统 Drawback
The throughput capacity is limited by the rotation speed of the motor drive.
The initial investment of $40,000 to $70,000 per carousel unit.
Drawback
Items with a high cube movement should not be housed in carousels.
Suitable for

26. 2.1 Carousels 2 Vertical Carousels 垂直旋转式存储传送系统
Vertical carousels range in height from 8 feet to 35 feet. Heights are dictated by throughput requirements and building restrictions.

27. 2.1 Carousels 2 Vertical Carousels 垂直旋转式存储传送系统
Advantages
1. Order pick times for vertical carousels are theoretically less than those for horizontal carousels
2. promotes more accurate picking
3. excellent item protection and security.
The cost of a typical vertical carousel is around $100,000> Horizontal carousels

28. 2.2 Miniload Automated Storage and Retrieval Systems
Miniloads vary in height from 8 to 50 feet, and in length from 40 to 200 feet. As in the case with carousels, the height and length of the system are dictated by the throughput requirements. 2 1 2 1

29. 2.2 Miniload Automated Storage and Retrieval Systems
As the most sophisticated of the system alternatives described thus far, is should come as no surprise that the miniload carries the highest price tag of any of the order picking system alternatives. Another result of its sophistication is the significant engineering and design time that accompanies each system.Greater sophistication leads to greater maintenance requirements.

30. Typical picking accuracy is 99.97 percent.
3. Automated Item Dispensing Machines
Typical picking rates are in the range of 1,500 to 2,000 picks per person-hour.
Typical picking accuracy is percent.

31. 4. Broken case picking systems comparison and selection
Summary Characteristics of Alternative Broken Case Picking Systems
System Attribute
Unit of Measure
Bin Shelving
Gravity Flow Racks
Storage Drawers
Horizontal Carousel
Vertical
Carousel
Miniload AS/RS
Automatic Dispersing
Gross system cost
Initial cost/ purchased Ft3
$5-15
$3-5
$25-30
$20-35
$40-70
$30-40
$ per dispenset
Net system cost
Initial cost/ available Ft3
#10-30
$9-15
%31-38
$65-100
$38-50
Floorspace requirements
Ft3 of inventory houses per Ft2 of floorspace
1-1.2
Human factors
Ease of retrieval
Average
Good
Excellent
Maintenance requirements
Low
Medium
High
Item security
Flexibility
Ease to reconfigure
Pick rate
Order lines per person-hour
C:25-125 T:
M:25-250 W:
50-250
50-300
25-125
T=Tote picking C=Cart picking M=Man-aboard ASRS W=Wave picking