Warehouse Management System

WAREHOUSING MANAGEMENT SYSTEM (WMS)

WMS • WMS is group of computer programs designed to

help a distributor perform WH operations more quickly and consistently with fewer errors employing wireless technology (RF or wireless network based).

• WMS ranges in complexity from very basic tools to assist WH employees in performing daily operations to highly sophisticated systems that replace workers.

• Two Key Elements;– Use of Portable Computer Terminals (connected to

host computer and could be RF or a Palm Pilot like device operating over a wireless network) to record work performed in real time.

– Bar Codes are used to reduce amount of information to be entered directly into terminal. Each terminal contains a scanner, to scan labels that contain a bar coded representation of bin, item & lot numbers, quantities, and more whenever possible to eliminate keystrokes.

WMS CAN PROVIDE AN ORGANIZATION WITH TANGIBLE BENEFITS

• Improving WH operations and increasing efficiencies without adding headcount.

• Directed put-away and directed order picking

• WH capacity management• RF capability for data capture• Load planning• Cross docking• Picking optimization• ABC stratification• Interleaving of work

COMMON CAPABILITIES OF A WMS Receiving Inventory• Objective is to record the receipt of goods accurately.• Operator records the receipt of goods against a pur/ Tfr

order, customer return authorization, or a kitting or production work order in the simplest form of receiving

• Advanced capabilities include receiving against packing list or advanced ship notice and receiving by container.

Locating Inventory (Referred to as Putaway)• Process of moving received inventory from the dock,

kitting, or production department to a storage bin• User Directed Putaway (simplest form of

putaway): where the operator determines where to place inventory and uses portable terminal to record movement

• System Directed Putaway (advanced form of putaway): WMS determines bin in which the inventory is to be stored and directs operator to place inventory in assigned bin.

•

COMMON CAPABILITIES OF A WMS (contd)

Inventory allocation• Process of determining the bin from which inventory is

to be picked to satisfy a demand• Operator performs inventory allocation by choosing

bin from which to pick inventory from a list of available bins shown on a pick list

• WMS performs inventory allocation when an order is released for picking

Picking inventory to satisfy sales, transfer, kitting, or production/rework orders

• Basically operator uses a printed pick list and records the results on the portable terminal.

• There are quite a variety of picking methods including pick by order, wave picking, pick and pass, and batch picking .


Replenishment• Process of refilling forward pick bins (sometimes called

dedicated or primary bins) for an item from reserve inventory.

Shipping confirmation• This function is often left in the enterprise software at

the most basic level • Can be performed within the WMS or performed by

special shipping software that operates along with the WMS or a combination of both.


Cycle counting and physical inventory• In the most basic form the operator counts inventory

and records the results using the portable terminal.• More advanced systems determine the number of

counts that need to be performed each day, determine which items to count each day, assign items to count to a queue, and guide the operator around the warehouse in an efficient manner to perform the counts

WH operations • such as relocating inventory and recording inventory

gains and losses (adjustments) – an operator generally performs these activities as required and records the results using a portable terminal

ADVANTAGES OF WMS

A WMS helps improve customer service and resource utilization by eliminating errors. The result of eliminating errors can be measured by;

– Inventory accuracy – greater than 99% at the item and bin level.

– Zero returns due to warehouse errors– Checking operations are eliminated– Improved order shipment completion– Shortened order lead time and improved on-

time delivery performance

TANGIBLE COSTSCATEGORY REASONS

Inventory reduction of up to 10% (one-time savings)

Inventory visibility and accuracy

Reduced inventory carrying costs up to 35% (industry average)

Lower inventory levels; higher space utilization

Reduced investment based on cost of money @ 8%

Reduced inventory

Premium shipping costs Reduced shipping errors

Personnel handling paper - potential headcount reduction or resource redeployment

WMS automates the management of order and priorities, eliminating paper

Personnel handling order picking – potential headcount reduction or resource redeployment

RF based picking productivity increases efficiencies

Personnel handling shipping paperwork and confirmation - potential headcount reduction or resource redeployment

Eliminate preparation work for shipping documents and ERP ship confirmations

Eliminate physical inventory Cycle counting will replace physicalinventory requirement

IS WMS REALLY NEEDED?

• Is the benefit great enough to justify the initial and ongoing costs associated with WMS: big, complex, data intensive, and applications?

• The Claims:– WMS will reduce inventory!– WMS will reduce labor costs!– WMS will increase storage capacity!– WMS will increase customer service!– WMS will increase inventory accuracy!

IS WMS REALLY NEEDED: REALITY• Expectations of inventory reduction and increased

storage capacity are less likely: increased accuracy and efficiencies in receiving process may reduce level of safety stock required, impact of this reduction will be negligible in comparison to overall inventory levels.

• Lot sizing, lead times, and demand variability control inventory levels: WMS not likely to have a significant impact on any of these factors.

• WMS certainly provides tools for more organized storage resulting in increased storage capacity, it shall be relative to just how sloppy pre -WMS processes were.

• Determining factors to implement a WMS is associated with the need to do something to service your customers that your current system does not support (or does not support well) such as FIFO, cross-docking, automated pick replenishment, wave picking, lot tracking, yard management, automated data collection, MHE etc

ABC INVENTORY CONTROL


• ABC analysis or Pareto's law is a principle widely used for decision making and control in many areas of management. • ABC analysis is the process of

dividing items in to three classes according to their rupee value;

ABC INVENTORY CONTROL•

• Policies;

ITEMS Cont Records Order of Importance

AHighest Priority

Very tight

Accurate •Only 20% of the items but account for 80 % of rupee value•Very important & high value for an organization, thus frequent value analysis is required.

BPriority when Low or Out of

Stock

Less tight

Good records

•Account for 30% of the items but 15% of rupee value• Less important, than ‘A’ items and are intergroup items.

C Lowest Priority

Simplest possible

Minimal records

•50% of the items fall in this representing a mere 5 % of the rupee value.• Items are marginally important.


Managing Inventories by ABC:• ABC analysis classifies items on basis of their relative importance.

Classification may be on the basis of;– Monetary value, – Availability of resources, – Variations in lead-time, – Part criticality to the running of a facility, – arts unique to that product, and others.

Cycle inventory can be managed through ABC; • “A” value items have to be counted more frequently ie, once in a

week to do accurate monitoring of these items which has more impact on the inventory value.

• “B” value items can be counted once in a month being of moderate value having less impact on inventory value.

• “C” items counted once in 3/6 months because they are least consumed value items and has very less impact on inventory value.

ABC INVENTORY CONTROL (contd)

Obsolescence budgeting• “A” items have the most impact on the

budget, if it is determined to be obsolete and scrapped from inventory.

Reorganization of the storeroom • “A” parts should continually be moved to the

lower or easier access areas. • ‘B” items are to be moved to middle areas,

and • “C” items placed in all other areas of stores.

PRINCIPLES AND PERFORMANCE MEASURES OF

MATERIAL HANDLING SYSTEMS (MHS)

PRINCIPLES AND PERFORMANCE MEASURES OF MATERIAL HANDLING SYSTEMS

• A performance measure may be defined as a metric for quantifying efficiency and/ or effectiveness.

• Effectiveness of a MHS describes to what extent the system performs the required handling tasks.

• Efficiency describes how economically (in terms of resource utilization) these tasks are performed.

• Thus, it is possible for an effective system to be inefficient; it is also possible for an efficient system to be ineffective.

DESIGN & OPERATION OF MHS• MHS in any manufacturing setting plays an important part in

the performance of the entire manufacturing system. • Research in the design of MHS has primarily studied

system performance as a function of: – Guide path design or layout – Type of flow path – Number of lanes in each aisle,– Location of pick-up/delivery points, – Fleet size, – Unit load size, – Vehicle speed and – Queue capacity at each workstation.

• Research in the operation of these systems has primarily studied performance as a function of– Vehicle dispatching rules and scheduling, – Idle vehicle positioning, – Vehicle routeing, and – Zone definitions.

CHARACTERISTICS OF EFFECTIVE PERFORMANCE SYSTEMS

Performance measure selection is process of defining a set of measures that possess certain characteristics, found in any effective performance measurement system (PMS);

• Inclusiveness: PMS should measure all pertinent aspects of the MHS. In this way, good performance of one particular component of the system would not be possible without similar performance of other system components.

• Universality: PMS should allow for comparison under a wide range of operating conditions, ie if two competing MHS designs must be compared, then PMS should allow for this comparison, even if system characteristics differ significantly.

• Measurability: All data required by PMS should be readily measurable. Furthermore, the process of measuring the performance of MHS should occur with a minimum of measurement errors and at a reasonable expense.

• Consistency: PMS Should be consistent with overall goals of org. The value of performance measure should therefore provide meaningful insights into overall MHS performance wrt org objectives.

PRINCIPLES & PERFORMANCE MEASURES OF MHS:VEHICLE TRAVEL DISTANCE (VTD OR TRAVEL TIME)• VT is measured as actual path and not rectilinear/ Euclidean

distances. • Total VTD consists of loaded and empty vehicle travel. • Material flow can then be characterized as either: departmental

(within deptt) or intra-deptt (between deptts). • Material flow within deptt is usually not modelled in MHS analysis.• Measurement of VT may include loaded /empty vehicle travel, or

both. • VTD is easily calculated when the flow volumes (trips required per

unit time) and distances between stations are known.• VT time directly corresponds to vehicle distance when:

– The vehicle speed is constant or may be assumed to be constant, – The acceleration and deceleration effects are negligible, and – There are no delays due to blocking, queues or other congestion

effects.• A measure is also taken of vehicle travel using the ratio (RLE) of

empty versus loaded vehicle travel, ie RLE = TL/ TE, where;TL total loaded travel time, & TE total empty travel time.

PRINCIPLES & PERFORMANCE MEASURES OF MHS:Vehicle Travel Proportions • A vehicle may be in one of three states at any given time: viz

Travelling Loaded, Travelling Empty or Idle. • Idle time spent in parking area is used as a performance

measure. • Then, travel time percentages may be calculated as the

fraction of time that a device is travelling loaded, travelling empty, and waiting in an idle state; ie, T =TL + TE + TI, where– T total time, TI total idle time, TL/ TE total loaded/empty travel

time Vehicle Travel: Response Time• Response time as performance measure, is the time from

when pick-up request is made until vehicle (starting from an idle and empty condition) arrives at pick-up location) for a pick-up call.

• This measure differs from total empty vehicle transportation time in that it consists of only empty vehicle travel when the vehicle starts from an idle position and does not include empty vehicle travel from a drop-off station to a pick-up station.

PRINCIPLES & PERFORMANCE MEASURES OF MHS: Vehicle utilization

• Vehicle utilization may be used to determine the vehicle fleet size requirements for a system.

• Vehicle utilization may be based on: – Total vehicle mission time (including loaded and/or empty

vehicle travel), – The loaded vehicle time and – The average of the time-averaged loads carried by all

vehicles in the system. Note: when the vehicles are able to carry multiple loads, the utilization value may be larger than

one.

Number of loads completed• It is defined as the number of loads (or deliveries) completed

over a period of time by all of the material handling vehicles. • It is considered as a performance measure. • Some industry measure the time required for the material

handling system to deliver a specified set of loads.

PRINCIPLES & PERFORMANCE MEASURES OF MHS: Station Queues: Mean Load Waiting Times

• The mean load waiting time is defined as the mean time loads wait in queues for material handling transportation.

• These queues are located either at processing stations or at separate load transfer stations.

Station Queues: Mean Queue Lengths• The mean queue length is the mean number of loads

waiting for a material handling vehicle over a specific length of time.

• It is a means of examining the adequacy of the physical space provided for the queue.

• Blocking occurs when a workstation’s output queue (or buffer) is full and the Workstation can no longer place completed parts into this queue.

• Starvation occurs when a workstation’s input queue is empty.

PRINCIPLES & PERFORMANCE MEASURES OF MHS: MHS Cost

• MHS costs may be comprised of variable and fixed costs.

• Variable Costs: – Generally the operating costs of MHS. – Can include the cost of power, lubricants, and maintenance. – May also include the routeing or travel expenses, which are

proportional to the distance travelled.– may also be includ Costs associated with idle or waiting

vehicles• Fixed Costs: include such costs as the construction and

purchase of equipment and hardware. • In addition to the use of total cost as a performance

measure, cost ratio (C) is also used as a performance measure which is defined as: C= C in/ c out, Where– C in moving cost of one unit load and one unit distance within a

department, – C out moving cost of one unit load and one unit distance

between departments.

PRINCIPLES & PERFORMANCE MEASURES OF MHS: MHS Flexibility

• MHS flexibility is system’s ability to reconfigure (to handle new material flows) and the material flow capacity.

• Range and Response are defined as dimensions of flexibility.• Range :how much the system can change. • Response :how rapidly and cheaply system can change. Congestion• Prevents vehicles from travelling freely on a guide path resulting

into travel at reduced speeds/stoppage/blocking. • Congestion levels may be measured by following

quantities;– Vehicle Blocking Time: Time where vehicles are unable to move due

to other vehicles– Track Blocking Percentage: Blocking time (as a percentage) for

track segments due to vehicle interference.– Track Utilization by averaging the utilization of all track segments

and then dividing by the number of AGVs.– Vehicle Waiting Time at Intersections .

Congestion Index : It(Ic) is defined as: Ic =TA/TS; where, TA actual travel time, TS shortest travel time if there were no

congestion.

THE FUNDAMENTALS OF VARIOUS TYPES OF

MATERIAL HANDLING EQUIPMENT (MHE)

MHE is mechanical equipment used for the movement, storage, control and protection of materials, goods and

products throughout the process of manufacturing, distribution, consumption and disposal.

MATERIAL HANDLING SYSTEMS/EQUIPMENT (MHS/ MHE)• MHS defined “the set of all pieces of equipment

that make possible the physical movement within the distribution chain – including the production chain and WH– of raw material, work in progress and finished goods”.

• MH refers to the necessary tasks to be performed in order to move a load around the factory floor as well as to store and freight it. MH takes place one way or another along all the links of supply chain including production, distribution, and storage and retail functions.

• MHE eases manual handling chores and enhances operational efficiency.

• MHE can be capital intensive, and act of movement can be labour intensive.

TYPES OF MHE : TPT EQPTTransport Equipment• Used to move material from one location to another (eg

between workplaces, between a loading dock and a storage area, etc

• Major subcategories : conveyors, cranes, and industrial trucks. Difference between use of are wrt their path and area of operation.

• Conveyors: used when material is to be moved frequently between specific points over a fixed path and when there is a sufficient flow volume to justify the fixed conveyor investment.

• Cranes: used to transport loads over variable (horizontal and vertical) paths within a restricted area and when there is insufficient (or intermittent) flow volume such that the use of a conveyor cannot be justified. Cranes provide more flexibility in movement than conveyors because the loads handled can be more varied with respect to their shape and weight.

• Industrial trucks: Industrial trucks are trucks that are not licensed to travel on public roads.

TYPES OF MHE: POSITIONING EQPTPositioning equipment• Eg; lift/tilt/turn tables, hoists, balancers, manipulators,

and industrial robots.• Used to handle material at a single location. • It can be used at a workplace to feed, orient,

load/unload, or otherwise manipulate materials so that are in the correct position for subsequent handling, machining, transport, or storage.

• Use of positioning equipment vis-a–vis manual handling, can raise the productivity of each worker when the frequency of handling is high, improve product quality and limit damage to materials and equipment when the item handled is heavy or awkward to hold and damage is likely through human error or inattention, and can reduce fatigue and injuries when the environment is hazardous or inaccessible

https://en.wikipedia.org/wiki/Industrial_robots

TYPES OF MHE: UNIT LOAD FMN EQPTUnit load formation equipment• Used to restrict materials to maintain their integrity

when handled a single load during transport and storage.• If materials are self-restraining (e.g., a single part or

interlocking parts), then they can be formed into a unit load with no equipment; eg pallets, skids, tote pans, bins/baskets, cartons, bags, and crates.

• A Pallet is a platform made of wood, paper, plastic, rubber, or metal with enough clearance beneath its top surface to enable the insertion of forks for subsequent lifting purposes.

• A Slipsheet is a thick piece of paper, corrugated fiber, or plastic upon which a load is placed and has tabs that can be grabbed by special push/pull lift truck attachments. They are used in place of a pallet to reduce weight and volume, but loading/unloading is slower.

TYPES OF MHE: STORAGE EQPTStorage Equipment• Used for holding or buffering materials over a period

of time. • Design of each type of storage equipment, along with

its use in WH design, represents a trade-off between minimizing handling costs, by making material easily accessible, and maximizing the utilization of space (or cube).

• An AS/RS is an integrated computer-controlled storage system that combines storage medium, transport mechanism, and controls with various levels of automation for fast and accurate random storage of products and materials.

TYPES OF POWERED TRUCKS USED IN WH AND STOCK YARD OPERATIONS

• Powered pallet trucks;• Counterbalanced fork-lift trucks;• Reach trucks including double reach and four –

directional reach variants;• Stacker trucks;• High rack stacker trucks-very narrow aisle;• Side loaders;• Order picking trucks;• Tugs and tractors;• Straddle carriers-container handling

Non-powered Hand Trucks• Made of Al/Mg, steel, and wood, they have diverse and

specific applications. • Designed for specific MH functions. • Al or Mg trucks carry 150-250 Kgs of material, while steel or

wooden trucks can carry approx 500- 1000 kgs respectively. Non-powered HPT• Designed to carry unit loads on pallets from one location to

another in indoor settings. • Since loads can be heavy, distances are generally short. • They supplement motorized truck fleets and are extremely

efficient for transporting unit loads short distances when high lifting is not required.

• Non powered HPT cannot be used to lift >4-5000 and cannot lift a unit load to a height more than 8 inches.

• For HD applications, steel wheels are required while lighter duty applications require only nylon or PU construction.

• These trucks can range in weight from 100 to 200 Kgs.

• It is economical way for one person to move heavy pallet loads w/o the use of a FLT.

• Pallet truck includes two articulating steering wheels and two front load rollers.

• Ergonomic design requires only 40 Kgs of pulling force when fully loaded.

• Steering wheels include bearing dust covers for added life.

• Nose wheels are located on the front edge of each fork to assist in clean pallet entrance & exit.

• Reinforced triple formed steel forks provide twice the strength of standard single-formed forks.

PALLET TRUCKS

COUNTER SCALE PALLET TRUCK

• HPT with capacities 2 T (max), are most commonly used for the horizontal movement of pallets. It could be vehicle towed.

• For frequent movements and inclined movement battery –powered trucks are preferable in terms of operator effort and safety, and these can be pedestrian – or rider- controlled.

POWERED PALLET TRUCKS

COUNTER BALANCED FORK-LIFT TRUCKS• Counterbalanced FLT

carry the payload forward of the front wheels, so there is always a turning moment lending to tip forward.

• To balance this, a counter balance weight is built into the rear of the machine-hence the name. These machines capacity varies from 1000 to 45,000 kgs with a lift height of up to 6/7 M.

REACH TRUCKS• Reach trucks are designed to be

smaller and lighter than counter-balanced trucks and to operate in a smaller area.

• Its capacity varies from 1000kgs to 3,500 kgs with a max fork-lift up to about 11 M, achieved by having a mast that can move forward or back in channels in the outrigger truck legs.

• Then picking up or setting down a load, the truck is turned through 90 deg to face the load location; the mast reaches forward, places or retrieves the load, and is retracted back into the area enclosed by the wheels.

DOUBLE REACH TRUCKS

• A conventional reach truck can only reach one pallet deep into racking.

• For accessing double deep racking a double reach truck has to be used, which uses a pantograpgh mechanism to achieve the additional reach.

• Double reach can also be achieved on some lighter trucks by the use of telescopic forks.

• Double reach machines are also used for side-loading pallets on to road vehicles, working only from one side of vehicle.

FOUR-DIRECTIONAL REACH TRUCKS

• On a conventional reach truck, front wheels always face forward, and steering is from the rear wheels.

• 4D truck has an additional option of being able to turn front wheels through 90 deg and lock them in this mode.

• This effectively converts truck into a side loader and is especially useful in stores and WHs where stock range consists of long loads.

• For access to say cantilever storage, very wide aisles would be necessary if this option were not available.

MULTI-ECHELON INVENTORY SYSTEMS

ECHELON INVENTORY SYSTEMS• Echelon Inventory: All inventories between a

stage and final customer. • Echelon inventory at a retailer is just the inventory

at retailer or in the pipeline coming to retailer.• Echelon inventory at a distributor, however,

includes inventory at distributor and all retailers served by him/her.

• In a Multi-echelon setting, reorder points and order up to levels at any stage should be based on echelon inventory and not local inventory.

• Thus, a distributor should decide his safety inventory levels based on the level of safety inventory carried by all retailers supplied by him.

• The more safety inventory retailers carry the less safety inventory the distributor will need to carry.

ECHELON INVENTORY SYSTEMS (contd)• As retailers decrease the level of safety inventory they

carry, the distributor will have to increase his or her inventory to insure regular replenishment at the retailers.

• The level of safety inventory at all stages in a multi-echelon supply chain should be related.

• In a multi-echelon supply chain a decision must be made with regard to the level of safety inventory carried at different stages.

• If inventory is very expensive to hold and customers are willing to tolerate a delay, it is better to increase the amount of safety inventory carried upstream, far from the final customer, to exploit the benefits of aggregation.

• If inventory is inexpensive to hold and customers are very time sensitive, it is better to carry more safety inventory downstream, closer to the final customer.

MAJOR PITFALLS OF MANAGING INVENTORY IN A MULTI-ECHELON NETWORK

• Failure to achieve true network inventory optimization, because replenishment strategies are applied to one echelon without regard to its impact on other echelons.

• Base upper-echelon replenishment decisions on specious demand forecasts.

• Negative consequences of pitfalls;– Network carries excess inventory in form of redundant SS.– End customer service failures occur even when adequate

inventory exists in the network.– Customer-facing locations experience undesirable stock

outs, while service between echelons is more than acceptable.

– External suppliers deliver unreliable performance, because they have received unsatisfactory demand projections.

– Short-sighted internal allocation decisions are made for products with limited availability.

AUTOMATED STORAGE & RETRIEVAL SYSTEMS (AS/RS)

AS/RS : GENERAL

• It consists of a variety of computer-controlled systems for automatically placing and retrieving loads from defined storage locations.

• They are typically used in applications where;– There is a very high volume of loads being

moved into and out of storage; – Storage density is important because of space

constraints; – No value adding content is present in this

process; – Accuracy is critical because of potential

expensive damages to the load. • AS/RS can be used with standard loads as well

as nonstandard loads.

WHAT IS AS/RS ?

• AS/RS are means to high density hands free buffering of materials in distribution and manufacturing environments.

• AS/RS is a complete system designed to transport, stage/store, retrieve, and report on every item in any industrial inventory with up-to-the minute accuracy.

• These automated storage and mechanized systems eliminate human intervention in performing basic sets of operations that includes : – Removal of an item from a storage location automatically – Transferring the above item to a specific processing or

interface point – After receiving an item from a processing or interface

point, it is automatically stored at a predetermined location.

OBJECTIVES FOR INSTALLING AN AUTOMATED STORAGE SYSTEM IN A FACTORY

• Increasing the storage capacity • Increasing the stock rotation • Utilization of maximum floor space • Recovering the space for manufacturing facilities • Customer service to be improved • Control over inventories to be improved • Ensuring safety in storage function • Increasing the labour productivity in storage

function • Reducing labour cost in storage operation • Reducing pilferage and improving security

DEFINITION AS/RS• AS/RS can be defined as a storage system under

which a defined degree of automation is to be implemented to ensure precision, accuracy and speed in performing storage and retrieval operations.

• These automated storage and mechanized systems eliminate human intervention in performing basic sets of operations to include; – Removal of an item from a storage location

automatically – Transferring the above item to a specific

processing or interface point – After receiving an item from a processing or

interface point, it is automatically stored at a predetermined location.

GENERIC STRUCTURE OF AS /RS

PRINCIPLE TYPES OF AS/RS

• Unit Load AS/RS: It is the generic AS/RS– It is used to store and retrieve loads that are

palletized or stored in standard-sized containers.

– The system is computer controlled. – The S/R machines are automated and

designed to handle the unit load containers. – Usually, a mechanical clamp mechanism on

the S/R machine handles the load. – However, there are other mechanisms such as

a vacuum or a magnet-based mechanism for handling sheet metal.

– The loads are generally over 200 Kgs per unit.

PRINCIPLE TYPES OF AS/RS (contd)

• Mini Load AS/RS : – This system is designed to handle small

loads such as individual parts, tools, and supplies that are contained in bins or drawers in the storage system.

– This system is applicable where the availability of space is limited.

– Also useful where the volume is too low for a full-scale unit load system and too high for a manual system.

– A mini load AS/RS is generally smaller than a unit load AS/RS and is often enclosed for security of items stored.


• Deep-lane AS/RS : – This is a high-density unit load storage system

that is appropriate for storing large quantities of stock.

– The items are stored in multi deep storage with up to 10 items in a single rack, one load behind the next.

– Each rack is designed for flow-through, with input and output on the opposite side.

– Machine is used on the entry side of the rack for input load and loads are retrieved from other side by an S/R- type machine.

– The S/R machines are similar to unit load S/R machine except that it has specialized functions such as controlling rack-entry vehicles.


• Man-on-board AS/RS : – This system allows storage of items in less than

unit load quantities. – Human operator rides on the carriage of the S/R

machine to pick up individual items from a bin or drawer.

– The system permits individual items to be picked directly at their storage locations.

– This provides an opportunity to increase system throughput.

– The operator can select the items and place them in a module.

– It is then carried by the S/R machine to the end of the aisle or to a conveyor to reach its destination.


• Automated Item Retrieval System : – This system is designed for retrieval of individual

items or small product cartoons. – The items are stored in lanes rather than bins or

drawers. – When an item is retrieved from the front by use of

a rear-mounted pusher bar, it is delivered to the pickup station by pushing it from its lane and dropping onto a conveyor.

– The supply of items in each lane is periodically replenished and thus permitting first-in/first-out inventory rotation.

– After moving itself to the correct lane, the picking head activates

ADVANTAGES

An effective AS/RS provides benefits for SCM;• Helps companies cut expenses by minimizing the amount

of unnecessary parts and products in storage, and improving organization of the contents of a WH.

• Due to automated processes, it also allows for more storage space due to high-density storage, narrower aisles, etc.

• Reduces labor costs while lowering workforce requirements and increasing safety.

• Modelling and managing the logical representation of the physical storage facilities (e.g. racking, etc) eg, if certain products are often sold together or are more popular than others, those products can be grouped together or placed near the delivery area to speed up the process of picking, packing and shipping to customers.

ADVANTAGES (contd)

Enabling a seamless link to order processing and logistics management in order to pick, pack, and ship product out of the facility.

• Tracking where products are stocked, which suppliers they come from, and the length of time they are stored.

• By analyzing such data, companies can control inventory levels and maximize the use of WH space.

• Firms are better prepared for the demands and supplies of the market, especially during special circumstances such as a peak season on a particular month.

• Through the reports generated by an AS/RS system, firms are also able to gather important data that may be put in a model for it to be analyzed.

BAR CODING TECHNOLOGY & APPLICATIONS IN LOGISTICS INDUSTRY

BAR CODE (B/C)• A B/C does not change how a business operates,

but makes procedures faster and more accurate, providing useful Mgt Info in a timely manner.

• B/C can be employed in virtually all orgs and all professions to increase productivity, efficiency and accuracy of specific business processes.

• A B/C is a set of symbols used to represent alpha-numeric information. Basically, instead of seeing the number "1” or letter "A", one sees a series of bars, both fat and thin, used to represent that number.

• It's much quicker and much more accurate for a mechanical device to decode a series of black and white lines than it is to read human text.

VARITIES OF B/C• Linear: A linear B/C symbology consists of a single

row of dark lines and white spaces of varying but specified width and height

• 2-Dimensional: 2-Dimensional symbology can be configured into a stacked or matrix format. These are special rectangular codes which ‘stack’ information in a manner allowing for more information storage in a smaller amount of space.

• The amount of data that can be encoded: A one inch 2-D matrix, can encode thousands of characters of data, whereas a comparable linear bar code would have to be several feet long to hold the same amount of information.

COMPONENTS OF BAR CODING• B/C systems come in different sizes and shapes. • The complexity of system required is determined by the

application. • A basic scanning system comprises of four

components:

COMPONENTS OF BAR CODING (contd)• Component1:The B/C Printer to print B/C Labels.• Component2-The B/C Label to be attached to a box

or an asset for tracking. An item label can contain any combination of text, graphic or bar code information.

• Component3-Scanning Equipment for Data Collection to instantly and accurately read, capture and decipher the information contained in the B/C label. Scanners are much faster and more reliably than humans. Thus, significantly reducing rate or likelihood of error. Types:– Contact scanners required physical contact to scan.– non-contact scanners which can be several inches to feet

away. – Of these two types of scanners, there is also one other

major attribute; they are either decoded or non-decoded. Decoded scanners have built in H/W decoders that interpret the meaning of a B/C before sending the data to the computer. Undecoded scanners simply have light sources that capture the encrypted data and sends them to a decoder of some sort.

COMPONENTS OF BAR CODING (contd)• Component4 – Capturing the Data to an External

Database: The final component to establishing a simple B/C system is the database.

• To effectively use the codes created and scanned, A database is required to relay and update information.

• Many B/C can be tied to item numbers , which can then, in turn, be linked to information about the item, such as product description, price, inventory quantity, acctg etc.

• Eg, let's say there is widget A, with a corresponding bar code that has the value of 1234. When widget A is sold, the B/C is scanned.

• This, in turn, causes a chain reaction that tells database that now one less widget A in stock, that charge Rs 200 for widget A, that this information be passed onto accounting etc. All of these actions were caused by scanning the B/C representing Widget A.

ADVTS OF B/C & AUTOMATIC DATA COLLECTION

• Accuracy: By reducing the likelihood of human errors from manual entry or miscommunication from misread or mislabeled items.

• Ease-of-Use : B/C are easy-to-use provided appropriate H/W & S/W aspects are in place to maximize process of automatic data collection as compared to accounting for all the inventory by hand.

• Uniform Data Collection: Diverse compliance standards and standardized B/C symbologies ensure that B/C information is captured and relayed in a fashion that is universally understood and accepted.

ADVTS OF B/C & AUTOMATIC DATA COLLECTION (contd)

• Timely Feedback: B/C promotes timely feedback in that data is captured in real-time as it occurs enabling decisions to be made from current information.

• Improved Productivity: B/C improve many activities that streamline workflows throughout a business.

• Increased Profitability: Through increased efficiencies .

PRIMARY FUNCTIONS OF B/C TECHNOLOGY

Tracking• Anything that can be identified with numbers &/or

letters can be tracked using B/C technology. • Apart from greater accuracy, B/C help speed process of

recording where and what an item is, or what service is provided.

• To track product through out supply chain/ workflow. • B/C numbers also can be used to track a particular item

back to the manufacturer, eg , if a user discovers a defective supply item, B/C can help track the item back through materials management and purchasing to the distributor and/or OEM so the he/organisation can obtain a refund, the same thing done manually, the amount of time involved would make the process too cumbersome.

PRIMARY FUNCTIONS OF B/C TECHNOLOGY (contd)

Inventory Management• Maintaining accurate inventory: a very complex

process, requires knowing;– what is, – how much of it,– who has it, – where it is, – how much it is worth, and – when to reorder it.

• B/C helps manage these inventories wherever they are located, so that the right materials are available when and where you need them.

• Using a B/C also can help monitor usage patterns throughout supply chain.

PRIMARY FUNCTIONS OF B/C TECHNOLOGY (contd)

Validation• The validating function of B/C is an effective

method of ensuring quality. • Validation assures that an action has taken

place or that the item required is on hand. • The ability to validate an action by a B/C scan

helps reduce errors and waste, provides check on productivity, and helps construct the necessary documentation.

RADIO FREQUENCY IDENTIFICATION (RFID) TECHNOLOGY & APPLICATIONS IN LOGISTICS INDUSTRY

RFID is the wireless use of EM Fields to transfer data, for the purposes of automatically identifying and tracking tags attached to objects

THE ARCHITECTURE OF RFID

THE ARCHITECTURE OF RFID

1.A passive RFID tag, • which, when exposed to the EMW of the reader,

broadcasts its Electronic Product Code (EPC) info.• Tags are attached to all objects to be identified in an

RFID system.• A tag is typically composed of an antenna or coupling

element, and integrated circuitry. • Often tags carry no on-board power source and must

passively harvest all energy from an RF signal.• There are many types of tags that offer different

functionalities, have different power sources, or operate at different radio frequencies. Each of these variables helps determine which applications a particular tag may be appropriate for and what the costs of a tag may be.

THE ARCHITECTURE OF RFID (contd)

2. An RFID Reader;• RFID readers communicate with tags through an RF

channel to obtain identifying information. • In environments with many tags, a reader may have

to perform an anti-collision protocol to ensure that communication conflicts to not occur.

• Anti-collision protocols permit readers to rapidly communicate with many tags in serial order.

• Readers often power what are called passive tags through their RF communication channel.

• These types of tags carry no on-board power and rely solely on a reader to operate. Since

• these tags are so limited, may subsequently rely on a reader to perform computation as well.


3.Databases• RFID databases associate tag-identifying data

with arbitrary records. • These records may contain product information,

tracking logs, sales data, or expiration dates. • Independent databases may be built

throughout a supply chain by unrelated users, or may be integrated in a centralized or federated database system.

• Databases are assumed to have a secure connection to readers.

.


4.Power Sources• Tags may obtain their power in several different ways. • Power source is an essential property of a tag-potential read

range, lifetime, cost, and what kind of functionalities it may offer depends on it.

• Power source will also be important in determining how a tag may be oriented and what physical forms it may take.

• There are three main classes of tag power sources: active, semi-passive, and passive.

• Active tags;– Have their own source of power, such as a battery, and may

initiate communication to a reader or other active tags. – Active tags typically have a much longer operating range than

passive-tags. – Large asset and livestock tracking applications often use active

tags, since the items they are attached to (e.G. Railcars, shipping or cattle) are high in value and have physical space for a bulkier, rugged tag.


• RFID tag responds to reader broadcasting its EPC, a 96bit code:– 8 bits of header information.– 28bits identifying the organization that

assigned the code– 24 bits identifying the type of product.– 36 bits representing serialization information

for the product

RFID VS BARCODE

• Cost of a tag is higher than cost of a printed B/C label.

• B/C can be read only the LoS; labels must be positioned to be directly visible to B/C reader. RFID tags need to be within RFID reader’s radio reach (about 10 ft).

• B/C cannot be read inside other containers, RFID tags can be read through most materials. Thus, contents can be verified easily without the costly overhead of an “Open Box Inspection” and manual counts.

RFID VS BARCODE (contd) • B/C provide only limited amounts of

information –even two-dimensional B/C are limited in the amount of data they can carry. The Auto ID center’s definition of a product information server allows us to tie unlimited amounts of dynamic information to each tag.

• B/C identify classes of products –RFID tags identify individual products.

• Migration of supply chains from B/C to RFID will require significant investments and will not happen overnight, RFID and B/C will co exist.

BENEFITS OF RFID• RFID tag can be affixed to an object and used to track

and manage inventory, assets, people, etc, eg, it can be affixed to cars, computer equipment, books, mobile etc.

• Increased Labour Productivity: Spec in receiving area of WH as RFID eliminates manual operations allowing product’s faster move to storage/outbound dock.

• Inventory Reduction: • With RFID in WH, it provide more visibility to the

products so their location is more easily determined and it reduces likelihood of a stock-out occurring because of misplaced inventory or inaccurate inventory levels.

• Cycle service levels will also improve due to lower safety stock levels and the overall faster throughput of product at a WH.

• RFID shall reduce total system inventory by approx 5%.

BENEFITS OF RFID (contd)• Facility/Equipment productivity : – RFID allows more data to be processed faster

through a WMS which uses the acquired information to improve the operations of WH.

– eg, vehicles scanning at inbound gates of WH, improves dock utilization because the WMS can more effectively assign vehicles to unloading doors based on order priority.

OTHER BENEFITS OF RFID • Shrinkage: Product stolen by employees along with

misplaced items, shall reduce as WH will have a better understanding of product’s location and difficulty to move products out of WH.

• Forecast accuracy will also increase due to higher levels of visibility of product throughout supply chain, positively affecting overall efficiency and effectiveness of WH in areas such as: – Order cycle times;– Safety stock levels; – Fulfillment accuracy; and, – Cycle service levels.

• Despite individual tag being expensive as compared to B/C and inappropriate for the tagging of low-cost items but; tags are reusable and have very long lives, saving on manpower and other costs associated with label production and fixing.

RFID IN RETAILING SECTOR

• RFID is an automatic identification and data capture (AIDC) technology ie non-contact reading to track and monitor physical objects.

• A key benefit of RFID is automatic identification of individual objects coupled with automatic data capture.

• Automatic electronic identity contributes significantly to enhance supply chain visibility, and automation brings in data capture and has a direct bearing on operational efficiency in labor intensive Retail Logistics.

RFID IN RETAILING SECTOR (contd)

Supply Chain Visibility• Visibility into merchandise pipeline within enterprise is

extremely critical to ensure that an optimal level of inventory is maintained – not too much to lock in excess working capital, and not too less to cause stock-outs.

• Lack of visibility results in insufficient coord between material flow and information flow often causing a magnification of demand variability in each level up in the supply chain –the bullwhip effect.(BE is a distribution channel phenomenon in which forecasts yield supply chain inefficiencies. It refers to increasing swings in inventory in response to shifts in customer demand as you move further up the supply chain. BE was named for the way the amplitude of a whip increases down its length. The further from the originating signal, the greater the distortion of the wave pattern. In a similar manner, forecast accuracy decreases as move upstream along the supply chain, eg, many consumer goods have fairly consistent consumption at retail. But this signal becomes more chaotic and unpredictable as you move away from consumer purchasing behavior.

https://en.wikipedia.org/wiki/Distribution_channel

https://en.wikipedia.org/wiki/Supply_chain


Operational Efficiency• Logistics Management- a key element of cost in a retail

enterprise encompasse all activities that enable the movement of merchandise from vendor/mfr to PoS.

• About 25-30% of supply chain costs can be attributed to labor costs in the process of distributing merchandise.

• Retailers extensively use SW tools for WH, Yard & transportation management.

• Industrial automation systems like conveyors, carousels, unit sorters enable enhanced operational efficiency within the distribution center.

• Business process innovations like multi-order picking, pick-to-light, use of voice and wireless technologies have all contributed significantly to higher productivity in warehouse operations.


Potential Benefits of RFID to Retail Enterprises• With falling prices of tags and readers, RFID a viable

option for pallet and case level tagging. • Retailers stand to gain when individual items are

tagged, with significant opportunities in enterprise inventory management and retail store operations.

• While the current tag costs rule out the economic viability of item/unit level tagging in most cases, there still could be a good business case in certain specific merchandise categories and applications.

• Pallet and Case level tagging also has the potential to enhance operational efficiency for the Retailer.

• The likely return on investment from RFID tagging varies largely, and is an inverse function of the current level of process optimization.

RFID IN WAREHOUSINGReceiving• Whereas current B/C require scanning each product or

case before it’s moved into WH, RFID allows improvements in Throughput Speed of product at the receiving dock.

• RFID scanner reads the shipment within seconds as it passes through the portal readers.

• RFID eliminates need to physically check the bill of lading and/ or the packing slip.

• RFID will connect with the WMS to indicate if a product needs a cross-dock movement.

• RFID system will help manage flow of damaged goods into the WH. The damaged goods set aside can be read by RFID as received as damaged; significantly reduce labor hours spent on managing the damaged goods process.

• An RFID system also offers greater efficiencies in WH systems that rely on conveyors.

RFID IN WAREHOUSING (contd)

Storage• RFID provides benefits in put-away accuracy and

efficiency. • FLT drivers could still rely on current WMS system to

identify the locations for pallets and products. However, an RFID system can eliminate the need to scan B/C on the pallet and at the slot location in the racks, eg, if the pallet and slot location read by the RFID scanner do not match the WMS specification, the system notifies the driver that the product has been placed in the wrong location.

• Moreover, the need for additional B/C on each pallet is eliminated.

• RFID has potential to improve temporary storage at WH.• Since the RFID tags can be read from anywhere,

products and pallets do not have to be placed in specific or assigned locations.

RFID IN WAREHOUSING (contd)

Pick / Pack• RFID readers can integrate with the WMS and OMS

systems to ensure that the correct items and amounts are picked.

• RFID helps to measure productivity in WH. Through a type of RFID-enabled time-motion measurement, management could analyze the process to set benchmarks, evaluate employees and plan labor requirements.

Shipping• RFID reader can confirm that each item is placed onto

the correct outbound vehicle, which can improve the accuracy of the shipping process.

• This verification can be made as the product moves through the portal of the outbound dock door.

• These processes allow for an automatic double check of the items loaded into the trailer against the bill of lading

Education

Warehouse Management System