Transcript Intelligent Management of Container Terminals Chuqian Zhang

Outline
 small
item storage and retrieval system
 picking
 case
operations
study
 1 
Small Item
Storage and Retrieval Systems
 2 
Picker-to-Stock Systems: Storage
 bin
shelving
 modular storage
 gravity flow rack
 space saving system
 3 
Bin Shelving
 oldest
method
 advantages
 simple
 low
initial cost
 variable bin content over time
 4 
Bin Shelving
 disadvantages
 under
utilization of space inside bins
 limited vertical space of columns of bins
 ill positioned picking height
 more space
 expensive
 difficult
for personnel supervision
 security problem
 5 
Modular Storage Drawer/Cabinets
a cabinet holds drawers with modular storage
compartments
 especially suitable for sets of components (put in
compartments of the same drawer)
 save space
 more human factors in storage and retrieval

 6 
Gravity Flow Rack
 SKUs
fairly similar in shapes and size
 inclined rack, high at end
 loaded at back and unloaded in front
 back-end goods pulled to front by
gravitational force
 FIFO
 usually for fast moving goods
 7 
Space Saving Systems
 mezzanines
 high
floor height
 use mezzanines for secondary storage
 mobile
storage unit
 8 
Picker-to-Stock Systems: Retrieval
 cart
picking
 tote picking
 man-up system
 robotic item picking
 9 
Cart Picking

equipped with different peripherals
paperwork station
 marking equipment
 ladder
 bar-code accessories: scanner, reader, data terminal
 automatic location directions
 light guiding system
 RF links
 compartments for sorting batch orders

 10 
Tote Picking
 picked
items to totes
 totes on conveyors for pickers to carry or
push them around
 compartments on totes for multiple orders
 11 
Man-up Systems
 man
aboard an AS/RS system for picking
 full usage of height (e.g., 40 ft) in storage
 generally pick multiple orders
 important for slotting of storage area and
sequencing of picks
 12 
Robotic Item Picking
 13 
Stock-to-Picker Systems
 carousel
 horizontal
 vertical
 miniload
 14 
Horizontal Carousel
 limited
height
 a picker on multiple carousel
 15 
Vertical Carousel
 shorter
 better
 better
pick time than horizontal carousel
picking position
item protection
 16 
Miniload Automated Storage and
Retrieval System
 low
floor space requirement
 manual or automatic storage and retrieval
direction
 greater maintenance requirements
 17 
Automated Item
Dispensing Machines
 automated
vending machine with
conveyor or pneumatic system to send
selected items to the collection point
 18 
Summary Characteristics of Alternative Broken
Case Picking Systems
Bin
Shelving
Flow Racks
Storage
Drawers
Gross Cost
Net Cost
Floor Space
Reqt.
Human
Factors
Maintenance
Item
Security
Flexibility
Pick Rate
 19 
Horiz.
Carousel
Vertical
Carousel
Miniload
AS/RS
Auto. Disp.
Summary Characteristics of Alternative Broken
Case Picking Systems
Bin
Shelving
Flow Racks
Storage
Drawers
Gross Cost
Net Cost
Floor Space
Reqt.
Human
Factors
Maintenance
Item
Security
Flexibility
Pick Rate
 20 
Horiz.
Carousel
Vertical
Carousel
Miniload
AS/RS
Auto. Disp.
Chapter 8
Picking Operations
 21 
Picking Operations

expensive: order picking (50%); shipping (15%);
receiving (15%); storage (20%)

nature of items setting constraints on batching or
zoning of orders
items
Qty
volume and
weight of
items in lines
lines
of
items
 22 
Typical Distribution of an Order
Picker’s Working Time
55%
60%
50%
40%
30%
20%
15%
10%
20%
10%
0%
Traveling
Searching
Extracting
 23 
Other
Schemes of Picking Orders
documentation, reaching,
searching, extracting,
counting, restocking
do not change (much) with
schemes of picking orders
sequencing orders; un-grouping, grouping
and regrouping lines
traveling distance
and sorting effort
change with schemes of
picking orders
What is the best mode to pick in a given situation?
 24 
Schemes of Picking
Picking Schemes
Freeform Picking
Single
Order Picking
Zone Picking
Batch Picking
Progressive
Assembly
Downstream
Sortation
Split Single
Order Picking
Manual
Sortation
Complete Single
Order Picking
Automated
Sortation
 25 
Single-Order Picking
 good
for
 order
integrity
 “large” orders or emergency orders
 long
traveling distance for a few items
 high distance traveled per line
 26 
Batch Picking
 picking
multiple orders in a trip to reduce
distance traveled per line
 need to sort item
 several
compartments (in a pick cart) to differentiate
lines of different orders
 group items and quantities during picking and
sort later
 27 
Zone Picking


a dedicated, non-overlapping zone to each picker
pros






reduced travel distance
familiarization of locations and products
minimal congestion
clear accountability
minimal socialization
cons


extra effort in order assembly
workload imbalance
 28 
Methods to Assemble Orders

zone
1
progressive order
assemble

zone
2
downstream
sortation
zone
1
zone
2
 29 
zone
3
sorting
zone
3
Improvement of Picking Operations
 issue
pack optimization
 pick from storage
 pick task simplification
 order batching
 slotting optimization
 pick sequencing
 30 
Issue Pack Optimization
 reduce
counting, inventory checking, and
packaging effort
 encourage
customers to order in full pallets,
or full cases
 create half-pallet or quarter-pallet units and
encourage customers to order in such units
 31 
Pick from Storage
 streamline
picking by having primary
picking area (other than secondary back-end storage)
 smaller
in size
 better equipment
 10 to 20 times quicker
 Is
it possible to achieve the same
throughput by picking directly from
storage?
 32 
Pick from Storage
 possible
if
 highly
sophisticated logistics information
system
 random
storage, intelligent slotting, activity
balancing, dynamic wave planning
 high
degree of mechanization
 disciplined workforce
 33 
Pick Task Simplification
work element
Method
Requirements
bring pick location to picker; batch
picking; zone picking
automate information flow
stock to picker systems; classifying and sorting
orders
computer-aided order picking: automatic
identification, light, RFID, headset
reaching
items at waist level
vertical carousels, person-abroad AS/RS;
miniload AS/RS
searching
stock to picker; direct picker to
location; highlight location
stock to picker systems; person-abroad AS/RS;
pick-to-light systems
extracting
automated dispensing
automatic item pickers, robotic order pickers
counting
weight counting; standard size
scale on picking
restocking
automated restocking
real time WMS
socializing
dedicated pick zone
traveling
documenting
idling/waiting
dynamic zone sizing; advanced job on
hand
 34 
real time WMS
Trade off for Traveling

reduce traveling by batch picking, zone picking,
and wave picking

batch picking (i.e., grouping orders in picking)

zone picking (i.e., ungrouping lines (items) of orders in
picking and regrouping lines into orders)

wave picking (i.e., all zones picking the same set of
orders at the same time and regrouping items into
orders)
 35 
Case Study
Dallari, F., G. Marchet, and M. Melacini
(2009) Design of Order Picking System,
International Journal of Advanced
Manufacturing Technology, 42, 1-12
 36 
order
haracteristics
Design of
an Order Picking System
order picking
system:
equipment,
layout, human
resources, etc.
strategic level
considerations
 37 
Factors to Consider

order characteristics


individual orders: frequency, number of lines,
quantity requested, shape and weight of items, etc.
aggregate effect

average number of orders per day, total number of
SKU
 38 
Grouping of Items

different ways, e.g., by size, frequency, nature,
etc.
 case
 by
study
size
 average
# of lines  15 lines
 possibly
sub-division in group
 39 
Observations from Empirical Studies
 40 
Empirical Study

picking methods observed from 68 warehouses
in Italy

from trade journals, interviews of MHE suppliers, and
interviews of warehouse management

small- to medium-sized companies, of revenue
greater than 10 Euro
5
picking methods
 refinements,
e.g., batch vs single order picking,
setting of primary picking area
 41 
Empirical Study: 5 Picking Methods
 42 
Five Picking Methods Adopted
by 68 Warehouses in Italy
 43 
Results from Statistical Analysis

SKUs  1,000: picker-to-parts

SKUs > 1,000 & small # of lines per day: partsto-picker


large # of SKUs: hard to use picker-to-parts

large # of order lines: hard to use parts-to-picker
large # of order lines per day and large number
of items: pick-and-sort and pick-to-box
 44 
Further Segmentation by Size

small orders (i.e., order volume  0.5 m3) and large
orders (i.e., order volume > 0.5 m3)

pick-to-box: only for small orders

picker-to-parts: for both small and large orders


regardless of effect of # of order lines picked per day and the #
of items managed when applied to large orders
parts-to-picker: both small and large orders
 45 
Further Segmentation by Size:
Small Orders
 46 
Further Segmentation by Size:
Large Orders
 47 
For the Specific Case Study
 48 
Characteristics of Groups

on average an order  15 lines
 49 
Results

a pick-to-box system


group 1 items (9,000 items; 7,450 order lines/day)
picker-to-parts systems

group 2 items (1,500 items; 2,500 order lines/day)

group 3 items (300 items; 50 order lines/day)
 50 
Equipment and OPS
for Group 1 Items

different storage methods and identification technologies

storage methods

gravity flow racks for high throughput items (500 items; more than 1
m3 per week)

shelves for the rest



primary plus secondary storage for some shelved items
identification technologies

pick-to-light for 10% of items accounting for 70% of order lines

radio frequency terminals for the rest
a 4,000 m2 picking area, operated by 12 pickers
 51 
Equipment and OPS
for Groups 2 & 3 Items

homogeneous items with each outflow  1 m3 per week

a pallet storage location for each item



matching the unit loads received in the warehouse
picker-to-parts, first level as the forward area and upper
levels as the reserve area

group 2 items: batch picking policy

group 3 items: single-order picking policy
a 6,000 m2 picking area, employing 5 pickers
 52 
Results
 53 
Results
 54 