Order Picking, “Bucket Brigades”_Part-1

Supply Chain & Logistics

Strategic Warehouse Management

Order PickingOrder Picking

1 Bus 307: Strategic Warehouse Management

Why Is Picking Important?

Order picking is the highest priority in the warehouse for productivity improvements

Receive/Put-away Picking Shipping Support0

10

20

30

40

50

60

Proportion of Time and Money Spent on Major Activities


Why Is Picking Important?

Order picking is the most labor intensive functionOrder picking has become increasingly difficult to manage• Smaller orders• More SKUs

Quality and service focus has resulted in efforts to• Reduce damage• Increase accuracy• Reduce transaction times


Order Picking Activities

Travel

Search Picking

Paperwork

62.0%

16.0%12.0%

10.0%


Issue Pack Optimization

Encouraging customers to order in full pallet or pallet increments• Enables the creation of efficient pallet, half-pallet

or quarter-pallet storage quantitiesChallenges• Requires agreement and coordination with enough

customers to impact the operation• Creates an inventory cost and picking cost tradeoff

to be considered


Pick-From-Storage

Why so many storage and picking locations?• Broken and full-case picking from a large reserve

pallet location is highly unproductive

Page 150

Order Picking

ReplenishP

utaw

ay

OrderPicking

Putaw

ay

Forward PickingReserveStorage

Packing, Sorting& Unitizing

Receiving ShippingCross-docking

Pallet Picking


Pick Task Simplification

Eliminate and Combine Order Picking Tasks When Possible

Traveling & Extracting Items• Bring pick locations to picker

Documentation• Automate information flow

» Pick-to-light» RF

Picking and Sorting• Present items at waste level• Sort into totes as picked

Sorting and Packing• Small cube items can be packed directly into shipping

containers


Order Batching

Batch orders to reduce total travel timeIncrease the number of items picked per picking tour• Reduces travel time per pick

Single line orders• Provide a natural group of order to be picked

together» Minimal downstream sortation


Order Batching

Single Order Picking• Grocery store model• Maintains order integrity

Batch Picking• Multiple orders picked at a time• Reduces travel time• Results in additional sortation

Zone Picking• A portion of an aisle, multiple aisles, or machines

assigned to an operator for picking• Enhances productivity, accuracy and

housekeeping


Order Picking – Additional Definitions

Picking – the process of finding and removing stock from its storage areaWave picking – defined amount of work for pickers for a set timeBatch picking – picking a particular item that is in many orders & sorting them later by orderSequential picking – items picked in sequence from storage areas on the same side of an aisleCross picking – items picked in sequence from storage areas on both sides of an aisle


Order Picking – Additional Definitions

Progressive Order Assembly• Contents of an order are passed from one zone to

the next until the order is assembled• Zone Skipping – if the order has no item from a

specific zone, it is passed on to the next zoneDownstream Sortation• There is no specific order designated during the

order picking process• Orders are assembled separately• Costs to accumulate and sort can run into the

millions


Cluster Picking

Batch order picking for increased productivity

• Simultaneously "order pick" a set of orders (a “cluster”) in one pass through the warehouse

• Configurable number of orders per cluster

• Interleave picks from each cluster to minimize travel path

• Picker can Skip or Cancel task within clusters

A B

C D

1

23

45

Pick Path

Push Cartwith Totesor Boxes

6

A B

C D

1

23

45

Pick Path

Push Cartwith Totesor Boxes

6


Serpentine Flow

The picker-to-part order picking method


Zone Picking

Each of five workers remain in their zones (in this case an aisle). Here, this zonepicking operation is composed of five, independent, discrete picking operations.


The “Fast-pick” Or “Forward-pick” Area

ReservesArea

Forward pickArea

Receiving

Restocking Primary picking

Reservespicking

Shipping


Trade-offs With A “Forward Pick” Area

A forward pick area increases the pick density by concentrating a large number of SKU’s within a small physical space.On the other hand, it introduces the activity of restocking.Also, in general, a forward pick area concerns the picking of smaller quantities and involves more sophisticated equipment than the picking activity taking place in the reserves area. So, its deployment requires some capital investment in equipment and (extra) space.


Picking Method Selection

Discrete Zone

Batch Zone-Batch

LOW

HIG

H

MIXED

Line

s an

d C

ube

per O

rder

Order Mix

PURE

If items in most orders from same family (pure), then can establish separate zone for each family with little zone-to-zone transfer neededDiscrete picking appropriate if single order has high number of lines and/or cube

Method

Pickers per Order

Orders per Picker

Discrete Single Single

Zone Multiple Single

Batch Single Multiple

Zone-Batch Multiple Multiple


Slotting

For Each SKU, DetermineStorage modeSpace allocationStorage location

Based on item popularity and the warehouse activity profile


Flow-Cube Distribution for Pallet Storage

Items in the bottom right-hand corner of the distribution generate the most picking activity per unit of storage space and should be assigned to the most accessible racks.Items in the top right-hand require equipment with greater cube utilization while still being accessible.


Flow-Cube Distribution for Piece Storage

Items in the bottom right-hand corner of the distribution do not have to be replenished as frequently as those in the top right-hand corner and can be stored in carousels and dispensers, which allow for very efficient picking but are difficult to replenish.


Pick Sequencing

Sequence pick location visits to reduce travel timeThe “Traveling Salesman Problem” (TSP)• Complex mathematical modeling


A serpentine pick path can result in unnecessary travel (in this case along aisles 3 and 6).


A modified path outline that sorts aisles 4–6 but not their locations.


Example of branch-and-pick


Layout on the right allows the operator more flexibility for items C,D,E


Popular items should be stored as close to the travel path as possible


Bucket Brigades

Coordinating workers who are progressively assembling product along a flow line in which there are fewer workers than stationsCarry work forward, from station to station, until someone takes over your work; then go back for moreNo unattended work-in-process is allowed in the systemWorkers carry each product as far toward completion as possibleSequenced from slowest to fastest along the direction of material flowA classic Pull System


Bucket Brigades

Insignificant Walkback Time• The total time to assemble a product is

significantly greater than the total time for the workers to handoff their work and walk back to get more work

Total Ordering Of Workers By Velocity• Each worker can be classified be the speed with

which they perform their tasksSmoothness, Predictability Of Work• The work-content of the product is spread

continuously and uniformly along the flow line


Bucket Brigade Impact


Bucket brigades at Wawa

Switching to bucket brigades allowed Wawa to use narrow aisles without congestion because there is no passing under bucket brigades. Narrow aisles also freed up space for two additional aisles.

Order Picking, “Bucket Brigades”_Part-1

Documents

Transcript of Order Picking, “Bucket Brigades”_Part-1