The Fundamentals of
Flow Manufacturing
A White paper prepared in cooperation with
This paper is the
result of a collaborative effort between the Business Process Consulting Group
(BPCG) and J.D. Edwards.
The J.D. Edwards’
team would like to thank Bob Shepka, Dennis Hobbs, Gerard Leone,
BPCG gives a
special thanks to the folks at J.D. Edwards for their assistance and
contributions, especially Dave Parrish, Jean Marie Thompson, Mark Kazlauskas, Mike Hennessey, and Randy Sell.
Table of Contents
What is "flow" manufacturing? *
Where did the concept of "flow" come from? *
Why do companies use "Flow"? *
What industries use flow manufacturing today? *
How do I recognize "Flow" when I see it? *
What are the system requirements to support "flow"? *
Flow manufacturing
& flow processing methodologies have gained a great deal of popularity over
the last decade. During the last 5 years as flow practitioners began reporting
significant benefits, more and more companies have started to research in
earnest how flow processing could positively impact their business. Some of the
benefits realized by companies who have adopted "flow" techniques
include:
·
Inventory
reduction
·
Quality
improvements
·
Improved
response time to customer requirements
·
Reduction of the
working capital needed to run a business
·
Increased
productivity
·
Floor space and
capital asset utilization improvement
All of these
companies have one thing in common: the desire to achieve a competitive
advantage to increase their market share. They all know their customers expect
high quality products, delivered on time, configured to specification. They
realize more and more of their customers are no longer brand loyal and will
seek out the supplier who can best meet their requirements.
Pro-active
companies are not discouraged by this challenge. Rather, they see the ability
to meet or exceed their customers’ expectations as a significant
differentiation from their competitors. A growing number of companies are
looking at flow processing as the method to help them achieve this competitive
advantage.
Flow production is
not a new concept. Although the "flow" solution is surprisingly
simple, many interpretations exist as to what flow processing is. This is
particularly true when used for manufacturing applications. The
"flow" type of manufacturing has been labeled in many ways. These are
just a few:
·
Assembly line
manufacturing
·
Continuous flow
manufacturing (CFM)
·
Repetitive
manufacturing
·
Just-in-Time
(JIT)
·
Lean
manufacturing
·
Agile
manufacturing
·
·
Kanban
manufacturing
·
Cellular (or
cell) manufacturing
·
Demand Flow
Manufacturing
"Flow"
manufacturing contains elements from all these activities and programs.
Unfortunately, just the label "flow" manufacturing can be as
misleading and inconsistent as any of the labels listed above.
Any manufacturing
method must be consistent and repeatable. The "flow" manufacturing
techniques presented in this paper are consistent, repeatable, and have been
implemented worldwide for the production of many different kinds of products.
This paper is an
explanation of fundamental flow manufacturing and administrative processing
techniques. It was created to help develop a clear understanding of flow
concepts and to define flow terminology.
"Flow" in
manufacturing is a technique that causes product to be produced one unit at a
time, at a formulated rate, without wait time, queue time, or other delays. Thought of as a pipeline, a product progresses through its
manufacturing processes without stopping, hence the term "flow".
The sum of the work
time required to progress through the flow manufacturing processes is almost
always shorter than the time required to route products through a factory in
batches. Significant reduction in manufacturing lead-time drives the benefits
associated with flow processing. It is from this ability to produce a product closer
to its actual work content time that the benefits of flow processing are
realized.
The goal of the
flow manufacturer is to establish and design a manufacturing line capable of
producing multiple products, one at a time, using only the amount of time required
to actually build the product. Wait time, queue time, and other delays are
eliminated in flow manufacturing.
The rate at which
work progresses through the factory is called a "flow rate" or
"Takt". The "flow" of a product is achieved by causing all
of its work tasks to be grouped and balanced to a formulated Takt time. A
single unit of work (a Takt time’s worth) is performed by a person and/or a
machine. The partially completed unit is then passed to the next resource down
the line where another "Takt" worth of work tasks are performed. The
unit of work progresses in a flow through all the manufacturing processes until
all of the required work has been completed.
Work tasks are grouped together to a
formulated Takt time.
This establishes the flow rate of a
product.
Often, flow
manufacturers may choose to change the output of the line to closer match the
mix and volume of customer requirements. With a flow line designed to produce
products using a formulated Takt time, the flow manufacturer has the ability to
regulate the "rate" of the line. This rate is identified every day
based on that day’s customer requirements. The rate of production
is adjusted by changing the number of labor resources on the line. This causes
Takt times to be missed or gained. The number of Takt times missed or gained is
matched to the number of units required that day. The ability to change output
rate every day, driven by changes in customer order requirements, is a powerful
tool for managing both work in process and finished goods inventories.
It is extremely difficult to match
workloads across manufacturing departments.
Overcoming
Capacity Imbalances
Grouping similar
types of work and machines together create traditional departments and work
centers. This grouping of work and machines assists with organizational control
and facilitates the collection of performance, routing, and inventory reporting
data. In most cases, the similar work and machines are then geographically
located in one area of the facility. In most cases, this grouping of work or
machines provides little consideration for the equal distribution of capacity.
This unequal distribution of capacity can create imbalances between
manufacturing processes. These imbalances are often manifested in pools of
excess inventory.
"Flow
lines" overcome this imbalance problem. Flow lines are progressive
assembly lines established with a facility layout allowing standard work tasks
to be accomplished in a sequential and progressive manner. Where possible, all
the processes necessary to produce a product are physically linked together.
The physical arrangement of the resources is important as it allows work tasks
to be distributed, accumulated, and balanced evenly throughout the entire
manufacturing cycle.
Balancing to Takt
and physically linking manufacturing processes together so the completed output
of one process can be directly consumed by another dramatically reduces
inventories and cycle times. Because manufacturing processes are simply divided
into equal elements of work, grouping of similar labor and machines into a
department no longer seem necessary. Only the resources necessary to produce
the requirements are located on the line.
Without imbalanced
departments, pools of work in process cannot accumulate. Also, the balancing
and linking of all processes allow products to be produced in the work content
time only. The normal wait and queue times for products that are routed in
batches through the different manufacturing departments is eliminated.
Physically linking manufacturing
processes together so the completed output of one process can be directly
consumed into the next dramatically reduces inventories and cycle times.
Product Families
Based on Common Processes and Materials
Many manufacturers
produce products by families. These families define which products will be run
on which production line. This family designation often dictates the dedication
of manufacturing resources to specific products and production lines. In most
cases, these families have not been defined by manufacturing. Family
definitions are usually reserved for the Sales, Marketing, or Financial groups
with little regard given to the actual manufacturing requirements of the
product.
Flow manufacturers
also produce products using a family definition. However, family member
selections for multi-product flow lines are based first on the commonality of
their processing paths or "Process Flow Definition". Further
selections are based on similar work element times and the commonality of work
steps and materials used. Flow production lines are optimally designed to
produce a "family" of similar products which all share common
manufacturing processes and materials. By grouping products in this manner, all
family members can advance through their required resources one unit at a time.
Producing multiple
products on the same line has many benefits for the flow manufacturer. A
multi-product line has the ability to produce many products in the same shop
floor footprint. This is important to the flow manufacturer to alleviate the
costs of bricks and mortar expansion. It is common that different products have
different sales cycles. If product lines are dedicated to fewer product types,
alternating sales cycles can lead to the "hire/fire" of employees in
an attempt to match production capacity to customer requirements. The more
products run on a single line, the less the impact of alternating demand.
Producing multiple products on the
same line reduces the impact of demand fluctuations
Production and
Material Signaling
There are two
primary resources needed to produce any product: labor and material. Flow
manufacturers balance and link their manufacturing processes together, staffing
those resources to customer requirements to produce products. Material required
to build product is placed into the flow lines utilizing a technique called
Kanban. The Kanban system utilizes a series of signals to indicate when parts
are needed for production.
The Kanban
methodology is a material presentation method designed to simplify material
handling and inventory management. Instead of purchased materials being placed
in "kits" and issued to production based on a production schedule,
materials are instead associated with a Kanban or "signal".
Backflushing simplifies inventory transactions
Kanban systems require fewer inventory transactions and reduce the amount of
system maintenance activities normally required to keep up with the real time
environment of the shop floor. Materials from suppliers are transacted into
stores or directly into an in-process location. Material is then relieved from
"in-process" using a "Backflush" transaction. The Backflush
transaction reduces the available on-hand inventory in the
"in-process" location by deducting the purchased material content of
a product’s Bill of Material.
The Backflush
transaction occurs after all work to build the product is finished and all
required purchased materials are consumed into the end item. Simplifying the
material input and output transactions cause the on-hand inventory to be highly
accurate. Many flow manufactures have eliminated cycle counting and physical
inventorying unless mandated by regulations.
A Kanban system
that places materials directly on the flow line where it is consumed into the
product offers several advantages to the flow manufacturer. All material that
resides on the line is available for use on any product. Materials are
available for consumption into any product that requires their use. Because
components are not assigned to a specific shop order and are already on the
line, any product demanded by the customer can be manufactured immediately, in
its work element time. In a Kanban system, parts do not need to be
"de-allocated’ from one shop order and re-allocated to another.
The capability for
all material in the manufacturing inventory pool to be available for any
requirement gives the flow manufacturer a great deal of flexibility in rapidly
meeting customer needs. Kanban systems provide the flexibility to insure a
rapid response time to the customer.
By using
"supermarket" stocking locations, material shortages are virtually
eliminated from the shop floor. As opposed to an item on a shortage report
hidden away on a desk, the Kanban signal is a card, bin, basket, pallet, cart,
or other designated physical signal that is difficult to ignore. When a Kanban
container is empty, there is no inventory accuracy debate.
Kanban signaling dramatically improves customer response and inventory accuracy
In a Kanban system,
a relationship that identifies where materials are used and where they are
refilled must be established. These relationships are known as "Kanban
Points, Kanban Links, and Kanban Chains. When Kanban material has been consumed
by the building of product, a Kanban signal is created. The empty Kanban
"signals" the need to refill or replace the materials used. This
signal can be a card or the empty container itself.
A refilling point
for material used on the production line will be located within a short
distance from the line. The designated pull paths identify the "used
at" and "refilled from" locations of Kanban material for the
material handler performing the actual replenishment. Empty Kanbans are
refilled from a designated "supermarket" location. In turn, supermarket Kanbans are then refilled either from stores or
the supplier directly. If suppliers are qualified, materials can be delivered
directly to the supermarket location.
A goal of any
Kanban system is to keep inventory moving through the manufacturing process at
a rapid pace. This velocity is intended to improve the turn rate usage of the
inventory investment and to reduce the working capital requirements of the
business. The key to this rapid turning of inventory is the frequency of
replenishment of the Kanbans. Empty Kanbans must be refilled using a
predetermined "Delivery Frequency".
The Delivery
Frequency is established for each pull path for each part or component. The
amount of inventory investment is in proportion to how often material is
replenished. The longer the replenishment times the greater the inventory
investment. Conversely, more frequent replenishment means smaller inventory.
More frequent replenishment also means more material handling time. While
tempting to think only of reduced inventories, Kanban systems must establish
the optimum strategy to balance between inventory investment and material
handling costs.
Scheduling
production in a "flow" factory is also significantly simplified once
the factory layout and Kanban signaling drive the flow of work through the
factory.
Production planning
on a flow line occurs at the finished goods level. Subassemblies are produced
on feeder processes. There is no need to schedule subassembly production as the
output from these feeder processes is consumed directly by downstream
processes.
Another type of
Kanban is used to signal the next unit of production on the flow line. An
"in-process Kanban" is used to signal the next unit in sequence.
Kanban signaling
generates the communication to the shop floor when to begin work on a specific
product. Products are planned into the flow line one unit at a time in a
specific sequence to insure a balanced "flow" of work through the
factory.
Because products are manufactured one piece at a time, they can be sequenced to
move down the flow line in the same order as customer requirements is received.
The planner has only to determine the order of manufacture. The person in the
first workstation in the flow line, upon receiving an empty In-Process Kanban
as a signal, simply begins production of the next unit in the same order the
planner has chosen.
Configure-to-Order
custom products may require a sales order configuration document be sequenced
with the product. This Configuration Traveler flows along with the product as
it advances through manufacturing. Lead-time through the factory is so
significantly reduced that shop floor tracking and expediting can be
eliminated.
Manufacturing
Lead-time is generally measured by determining the critical path through the
multi-level Bill of Material for a product. Manufacturing
"response-time" in a "flow" factory is measured by
determining the critical time line through the process relationships required
to build the product.
The length of
lead-time through a factory has a direct and predictable impact on the amount
of in-process inventory that will exist.
What is "flow processing" within a
business’s administrative processes?
The same dynamics
of flow manufacturing seen on the shop floor can be seen in the administrative
processes in the back office. The concepts of linking and balancing processes
together will yield the same results. Even though office processes are not
normally thought of as a product, the type of processes used to accomplish tasks
is the same.
In offices, the
same department methodologies exist. These departments are isolated and located
remotely throughout the business. All work performed in these processes use the
same logic as the batch manufacturer. Work usually proceeds in "batches".
Most of the processing time is the move time between departments and time spent
waiting to be processed. The actual work content time to do the work is the
smallest component of lead-time. Administrative batch processing generally
results in the same levels of inventory as manufacturing batch processing. The
only difference between manufacturing and administration inventory is that the
administrative work in process inventory resides in in-boxes on someone’s desk
or as electronic files instead of on pallets or in containers on the
manufacturing floor.
It is conceivable
that the time required to complete administrative "paperwork" is
often greater than the time necessary to manufacture the product. Could the
time required to process an administrative procedure be shortened if it is
processed in its actual work content time instead of the time to actually do
the work in addition to the time spent routing the work through all the various
departments?
"Flow" in
administrative processes is a work method that causes administrative tasks to
be performed in a successive and progressing manner without wait time, queue
time, or other delays. Administrative Flow processes are established in office
areas that perform "repeatable" tasks that can be linked and balanced
together in a sequential manner.
Where did the concept of
"flow" come from?
Flow Manufacturing
is not a new or radical concept for the new millennium, but it certainly is
more sophisticated and better equipped than it was in the past.
When the industrial
revolution began in the 1860’s, manufacturing was first challenged with the
question of how to manage a machine and it’s enormous
product output. Output that far out paced that of a person focused to the same
task. These initial machines were focused toward the industries that revolved
around the weaving of cloth. Any products requiring the shaping or cutting of
metals were still extremely labor intensive and a major issue of management
within these industries was the productivity of the workers.
Around 1885 these
management issues were addressed when Frederick Winslow Taylor began publishing
his work. What
A boost for his
methods was given when Henry Ford began building large manufacturing facilities
for his new motor cars. His first successful production model was the Model N,
but his fame truly grew with the first full production year of the Model T in
1909. Ford proposed to build a car that would be affordable for every American.
Key issues for this to be successful were productivity, cost, and availability
of product. The issue of productivity was addressed by having the car pulled
through the plant at a constant speed where groups of parts were accumulated
for the workers to assemble. In this production line Ford had some workers
doing one or two small tasks while others did more. Ford had proposed that ‘A
man must not be hurried in his work’ so the timing of the individual tasks was
critical.
Productivity was
further increased when Ford introduced the moving assembly line for chassis
assembly. Production time improved from 12 hours and 8 minutes to 1 hour and 33
minutes. Not only was productivity improved but the goals of cost reduction and
increased availability were also achieved. The flow of the product and further
productivity gains were made when Henry Ford announced that the Model T was now
available in "Any color so long as it is black." A remarkable
achievement during the production of the Model T was the fact that even as the
production volume increased, the selling price was consistently reduced,
beginning at $850 in 1909 and reduced to $260 in the final full production year
of 1926.
Driven by customer
demand, the challenge in manufacturing during the 1920’s became product
variety. Many manufacturing facilities struggled to gear up for production of
new product models. It was not unheard of for factories to be down for up to 6
months to establish new tooling. Up until this time, manufacturers focused
primarily on labor productivity to achieve a competitive advantage. Innovations
in technology became the new productivity tools that allowed many manufacturers
to remain competitive. This period marked the advent of technological changes
in machine tool cutting points, synthetic abrasives, and multiple rotary
cutting points particularly in lathes and milling machines.
Manufacturing
through the 1930’s and 1940’s was still driven by large quantity production
runs, although runs similar to the 17 years of the Model T were no longer
possible. Consumers were more and more the drivers of change in a product life
cycle. As the 1950’s began, demand for specialized products started to take
hold. Not only were products more specialized, but they also had limited life
cycles. Batch manufacturing methods had arrived!
In batch
manufacturing, quantities were often based upon what would make the machine
productive and not necessarily what the market required. This subtle change in
focus pitted manufacturing departments against marketing departments throughout
industry. Batch manufacturing had allowed machines to become productive when
large quantities of a product were built, but batch processes had created
problems for manufacturing when trying to build a mix of products. Solutions to
this dilemma were found in the discipline of Group Technology around the mid-1950’s. Group Technology proposed that manufacturing
focus on the similarity of material shape, size, or method of manufacture. The
focus on materials gave limited advantages, so the discipline was expanded to
include machines and operations. This evolved into what we know as cellular
manufacturing, where a group of machines and people have autonomous authority
over all administration, planning, and operations to produce products.
Many companies in
the
Through the 1960’s
and into the 1970’s, these two schools of manufacturing continued down separate
paths. One, looking for better ways to manage batch
production, the other finding ways to allow one-piece-flow of a mix of
products. Into the 1980’s many product markets within the
Flow Processing
today is a proven technique that allows work to be performed without
bottlenecks or delays. By linking and balancing work steps to enable products
to flow one at a time, manufacturers are achieving significant results.
Although the products may vary in volume, in type, and in mix, the techniques
remain the same: definition of the processing flow of a product, standard work
definition at a detail level, and designing the production flow line. When the
line has been designed for product flow, a set of tools that balance the work
to a calculated flow rate or "Takt" are employed. As the design and
balance of the line is completed, the flow of material and calculation of
material quantities, using Kanban techniques, are executed. Using these basic
tools, a flow processing line can be created and implemented.
Manufacturers on a
global basis have had to address productivity increases, operating cost
reductions, quality improvements, and shortened customer lead-times. Many
companies have chosen the tools of flow processing as a solution to these
issues.
Inherent in the
methods of flow processing is a series of behaviors that can influence
improvements in all the aforementioned areas.
Productivity
Improvement
The quantity of
units produced by a team of people in a given period of time is generally
accepted as the measurement of a factory's productivity. The tools of flow
processing include continuous process improvement strategies (known as Kaizen
programs in
Operating Cost
Reduction
A flow factory's
operating costs are reduced as a result of the following factors:
·
Total Quality
Management (TQM) activities that improve process quality,
reduce scrap, rework, and warranty costs.
·
Inventory
reduction as a direct result of shortened manufacturing lead-time.
·
Improved
resource and floor space utilization through the elimination of waste and
unnecessary inventory
Shortened
Customer lead-time
The marketplace is
expecting a significantly shorter order fulfillment lead-time than it did a
decade ago. A factory that arranges its resources in a flow relationship
creates, by default, a significantly shorter manufacturing lead-time. The
shorter the manufacturing lead-time, the quicker the response to a customer
order without having to carry finished goods or work in process inventory.
Operational
Benefits
Production planning
in a flow line is simplified. Planning occurs at the shippable product level.
Subassembly production planning is virtually eliminated. Multi-level Bills of
Material can be dramatically compressed or flattened. Varying the flow line’s
staffing level controls the flow rate. The flow manufacturer tends to drive
production planning to a make-to-order schedule. Actual customer orders drive
the labor resources required in the production process each day.
Cost accounting
methods can be simplified with flow processing. Because the lead-time through a
flow facility is consistent, repeatable, and not volume sensitive, Activity
Based Costing can easily be implemented. Labor costs can become elements of the
overhead that is applied proportionally to each product. A variable overhead
cost may also be created to account for extraordinary conversion costs driven
by the use of special machines or resources.
The reporting in
flow processing is simple and direct.
·
Actual backflush
units versus planned completions
·
Kanban material
usage variance
·
Resource
utilization reporting
·
Supplier
delivery frequency actual versus planned
What industries use flow
manufacturing today?
|
Aerospace & Defense products |
Injection molding and die casting |
|
Automotive Assembly |
Insulation materials |
|
Automotive parts and accessories |
Machine tools |
|
Castings and forgings |
Machining job shops |
|
Ceramics |
Material handling equipment |
|
Clothing and shoes |
Metal fabrications |
|
Computers and peripherals |
Medical equipment |
|
Digital Imaging equipment |
Photocopiers |
|
Electric motors and controls |
Paper products |
|
Electronic / Circuit Card assembly |
Pharmaceuticals |
|
Fabrication job shops |
Plastic resin |
|
Glass products |
Plumbing Products |
|
HVAC products and accessories |
Printing |
|
Household appliances |
Subcontracted assembly |
How do I recognize "Flow" when I see it?
Following are some
background and guidelines on how to identify a manufacturer that is using Flow
Manufacturing techniques.
When walking into a
factory for the first time, you are likely to find one of three basic types of
manufacturing methodologies used to make products:
·
Process Manufacturing
·
Discrete Batch
Manufacturing
·
Flow
Manufacturing
Following is a
description of some basic distinctive features of the three methodologies with
special emphasis on Flow Manufacturing.
Process
Manufacturing
This type of
manufacturing tends to be the most highly automated. Upon arrival to a process
factory, one of the first things observed is the size and apparent complexity
of the machinery in use. The second distinctive aspect is that a limited number
of people operate the factory. Factory layout is usually determined by the
order of the processing steps required to make the products. Commonly only one
type of product is being manufactured in a process at any given point in time.
In process
factories, products are nearly always produced in units of measure that are not
"Each". Typical units of measure in a process factory relate to:
·
Weight (Oz, Kg,
Tons)
·
Linear
measurements (Feet, Yards, Meters)
·
Surface
measurements (Square Feet, Square Yard, Square Meter)
·
Volume
measurements (Gallons, Quarts, Cubic Meters)
In process
factories, it is plausible however, that the shipping unit of measure may be
expressed in "Each".
Due to the nature
of their conversion methods, process manufacturers already "flow" their
products. What differentiates a process manufacturer from a Flow manufacturer
is that production quantities are processed in batches or lots. These
production lots are usually established following some sort of algorithm that
focuses on resource utilization. Sometimes, however, they are the result of
someone’s educated guess.
Process
manufacturers could obtain significant benefits from the tools of flow
processing. Inventory management both at the in-process level and finished
goods level would be a point of focus. Two key aspects that a process
manufacturer could benefit from are resource balancing and Kanban management.
Resource
Balancing
In spite of the
natural flow of production within any single process, it is likely that two or
more adjacent processes will not be balanced. These imbalances have the
potential of generating large amounts of semi-processed product. The balancing
of resources to a Takt time will tie resource utilization to customer
requirements. The use of in-process Kanbans will control the flow of product
between processes, thus keeping inventories of semi-finished product at
formulated levels.
Kanban
Material Kanban
techniques could be used within the process to manage and control the transfer
of semi-finished product from a supplying process to a consuming process in the
factory. These replenishment techniques can also be applied for controlling
supplied materials consumed at the required processes. Another common
application is as a tool to signal the replenishment of finished goods
inventory shipped to customers.
Discrete
manufacturing
Discrete manufacturing
is one of the most common production methodologies. Shippable end items are
usually measured as "Each". Quantities produced in manufacturing can
vary from a unit of one to large batch quantities. There are usually more
people than machines used to convert the purchased material required to make
products.
Factories typically
have their resources arranged in departments or work centers. These areas
consist of resources – (people and machines) grouped together based upon the
kind of work they perform or the machines they use. Factory layout may appear
to lack a logical relationship. The movement of materials between resources may
look disorganized, and the distances traveled by those materials may be
relatively long. The only common thread across departments is the similarity of
work or machines within a department. Because semi-finished products have to
travel across departmental boundaries, large quantities of inventory typically
build up throughout the factory.
This functional
organization or resources has its roots in the need to organize manufacturing
so as to facilitate the collection of earned hours for people and machines.
This data is later used to track efficiencies and for the absorption of
overhead dollars. The grouping of resources into departments pays little or no
attention to the need of balancing the work across resources. When observing a
typical discrete batch manufacturer, you will see that each resource works to
its "own beat". Individual resources have no regard for the supplying
process’s ability to feed or the consuming process’s ability to consume.
For material
replenishment, discrete batch manufacturers generally resort to the use of
pick-lists based of the latest MRP run. Once customer orders are entered into
the system, they will take part in the generation of net requirements. These
net requirements will call for the allocation of materials to the associated
work order, shop order, or schedule. The timing of entry of a customer order
into the system determines when the materials will be allocated to the order.
This could turn into a "battle of wits" among production schedulers
trying to get their orders first in line. This allocation methodology is almost
guaranteed to cause material imbalances resulting in shortages.
Flow
manufacturing
When you enter a
flow manufacturing facility, you will immediately notice how organized the
factory appears. You will also notice that most operators are building product,
not moving it. A deeper look into the flow factory will reveal:
Resources are
linked
In sheer contrast
with the discrete batch manufacturer, the manufacturing resources in the flow
factory are not arranged in functional departments or work centers. The Flow
factory layout follows the sequence of manufacturing processes required to make
a product family. There are signals in between resources called In-Process
Kanbans. These signals regulate the product flow as downstream workstations
pull the semi-finished unit from the In-Process Kanbans. Resources within a
production line appear to be balanced, and products move at a relatively
constant pace. In a flow factory, you can tell how a product is made by simply
looking at the production line that makes it.
Products move
In a flow factory,
products are manufactured in a progressive fashion, accumulating work as they
are moved from workstation to workstation. The most likely unit of material
transfer is one unit of product at a time. However, there are cases in which it
might make sense to transfer more than one unit of product at a time (one
customer order could be for two units). In a flow operation, accumulation of
semi-finished product in between workstations is highly unlikely. The only
valid accumulation of inventory would be for balancing a resource whose work
cannot be broken down in Takt time increments. Even in such cases, the amount
of inventory is calculated and kept constant. It is also very likely that you
will see a variety of products being built at any point in time in a
manufacturing process.
People move
The flow process does
not "chain" the person to the workstation or the machine. In order to
throttle the line up or down in response to customer requirements, people are
placed into or removed from the flow line. As the Multi-Product Flow line
operates with less than the full compliment of people each day, the people
building product will "move" from workstation to workstation to
overcome any understaffing. Highly flexible and cross-trained employees are a
key source of productivity in flow processing.
Materials move
Supplied materials
consumed by the various resources involved in making a family of products are
available at the line in material Kanbans for the operators to consume. In the
most likely scenario, the majority of parts are within
the operator’s reach or very close by. As materials are consumed, the on-hand
inventory at the line is depleted and a signal is generated for replenishment.
Once the container, gaylord, or pallet is removed
from the workstation, the operator is left with a secondary quantity of material.
This extra inventory will allow the operator to continue to work while the
Kanban is replenished. The use of Kanban in the flow factory has resulted in
the virtual elimination of material shortages on the line.
Everything has a
place
In the flow factory,
orderliness and neatness are critical parts of everyone’s working environment.
All material locations are clearly marked. Only the necessary tools, fixtures,
gauges, and other resources are present at the workstations. No noticeable
clutter or mess is accepted.
No Inspection
department
Production
employees in a flow factory frequently use a series of graphic work
instructions. These graphical renderings are color coded to emphasize quality.
Employees do not rush through their work; they take the appropriate time to
ensure that the units transferred to the next downstream workstation are of
perfect quality. Since quality is built into every product, units do not have
to be inspected, unless regulations require it.
Employee
satisfaction is high
Because of the
requirement to move with the flow of the product, operators receive extensive
amount of training in a variety of jobs. Operators also participate in Kaizen
(Continuous Process Improvement) activities resulting from their daily feedback
to production management. The supervision required is significantly decreased
because of the line design. The product flow indicates what to do and when to
do it. The operators in a flow factory are highly motivated and nearly
self-managed.
Visual queues
By simply taking a
walk through the factory floor in a flow facility, you can easily tell what is
going on. Sequencing boards at the head of each line clearly communicate the
product mix to be built that day. At the end of each line, the output rate
variation is posted along with the flow rate, indicating how the line is doing
so far for that day. The Kanban boards indicate how much material is turning
and highlight any potential shortages. At the end of the day, the In-Process
Kanbans and workstations will tell us if the line was under or over-staffed.
Furthermore, the operators performing work will provide key information on the
line’s balance.
Planning is
simple
Because the line
can build a family of products at high speeds, the planning methodology
revolves around sequencing customer orders to the line on a daily basis. Gone
are the games played with forecasts and non-firm orders. Once an order hits the
manufacturing floor, it will be completed within the product’s Flow-Based
Response Time.
What are the system requirements to
support "flow"?
Introduction
Any company that
has decided to implement "flow" manufacturing or is trying to manage
an existing flow environment will have some very specific system software
functionality needs. These requirements are driven by significant differences
between discrete production and "flow" production techniques. There
are two timelines that software functionality must follow to support flow:
initial factory design and daily production execution.
Factory Design
A flow factory is
developed from information that is unique to this type of manufacturing.
Information elements that are required to develop a "Multi-Product"
Flow line are:
·
"Process
Flow Definitions": The identification of each end item’s work flow
relationships. A Process Flow Definition is used to record the specific
sequence of the resources (labor and /or machines) that are used to produce an
end item.
·
"Process
Flow Definition Map": The listing of each end item’s Process Flow
Definition in a matrix format (PFD Map). Mapping leads to the development of
end item families.
·
"Multi-Product
family definition": The analysis and creation of families of end items
that share common or similar Process Flow Definitions. Multi-Product family
definitions are used to create the shop floor layout of workstations and
machines for the Multi-Product Flow line.
·
"Standard
Work Definitions": The documentation of the work steps required to build a
product. SWD’s are used for creating work definition
at each workstation and machine. They are also used for training employees.
·
"Standard
Work Definition time map": The recording of every SWD for each end item
intended to be built in the flow line. Time mapping is used for
"banding" Multi-Product end item’s by the amount of time that their
work takes. This is helpful for flow line resource balancing.
·
"Forecasted
Volume": An estimate of the daily production volume for each end item that
the Multi-Product Flow line should be designed to produce. The estimates are
used for determining the flow line’s Takt time.
·
"Takt":
The maximum theoretical production rate for the factory. Takt is used as part
of the basis to determine how many people and / or machines will be required in
the factory. Takt is a time / volume relationship.
·
"Throughput
Volume Adjustments": The analysis and calculation of volume adjustments to
Takt time because of the impact of scrap or rework at any point in the flow
line. Analysis is performed to insure that enough factory resources are in
place.
·
"Rework, Scrap,
and Option map": A matrix that will be used to record information for each
end item’s rework percentage by process, scrapping locations, the amount lost,
and option percentages if applicable. This information is used to determine if
adjustments to an end item’s throughput volume will be required in any of its
processes.
·
"Multi-Product
Flow line resource calculations": The determination of the number of
people and / or machines needed in the factory to support the forecasted volume
of end items.
·
"Multi-Product
Flow layout": The analysis and development of the optimal factory layout.
Factory re-layout is often needed to optimize a factory’s shortest response
time.
·
"Workstation
Definition": Work element balancing among resources – A line design
objective is to divide work steps evenly among the workstations designed into
the flow line. Work step division is based on Takt.
·
"Graphic
Work Instructions": Pictorial renderings of Total Quality Management
information. Graphic Work Instructions translate "text based"
Standard Work Definitions into easy to understand pictures that employees will
use to perform in-line quality checks.
·
Kanban: The
material supply technique based on a simple signal. Kanbans are used to provide
the required materials to the appropriate places on the shop floor. "Used
at" and "refilled from" locations are established on the factory
floor and are called "pull paths". Three types of Kanbans are
generally used: In-process, two bin, and one-time use.
·
Reports
·
Line design
resource requirements
·
From / to
throughput table by process and cell
·
Flow line design
maps
·
Workstation
Definitions
·
Materials used
at a workstation or machine
Daily production
execution requirements
Daily and ongoing
support is required after the flow line is developed.
·
"Backflush":
Inventory management transfer / move transactions. Purchased material required
to build an end item product are deducted or moved from an
"in-process" inventory account into the "Finished Goods
Inventory" account by using the product’s Bill of Material.
Daily flow line
performance reporting
·
Backflush
reporting (End-of-Line and Process)
·
Kanban shortage
reporting
·
Resource
utilization reporting
·
Daily Report of
planned production.
Ongoing Support
·
"Flow Based
Response Time": The shortest, optimal flow path through the factory
resources. Flow Based Response Time (FBRT) drives customer support and
inventory strategies. Flow Based Response Time is like a critical path
analysis, but it does not use a Bill Of Material.
·
Kanban resizing:
The recalculation of material Kanban quantities caused by a change in usage
requirements.
Periodic flow
line performance reporting
·
Actual Backflush
versus planned
·
Kanban material
usage variance
·
Resource
utilization reporting
·
Supplier
Delivery Frequency actual versus planned
·
Calculated Flow
Based Response Time (FBRT) versus actual
BPCG and J.D.
Edwards are committed to flow manufacturing. This document has presented an
explanation of fundamental flow manufacturing and administrative processing
techniques. Its intent was to help develop a clear understanding of flow
concepts and terminology.
For additional
information of J.D. Edwards flow software solutions, please contact them at:
|
J.D. Edwards World
Solutions Company World Headquarters |
J.D. Edwards UK Ltd. Serving Europe, the Middle East, and Africa Oxford Road Stokenchurch, High Wycombe Buckinghamshire HP14 3AD, UK 44 1494 682700 |
|
J.D. Edwards World Solutions
Company Serving Latin America and the Caribbean 806 Douglas Entrance, |
J.D. Edwards Pte Ltd. Serving Asia Pacific No. 1 International
Business Park The Synergy, #06-01/04 |
|
www.jdedwards.com |
|
The
materials contained herein are summary in nature, subject to change, and
intended for general information only. BPCG is a registered trademark of the
Business Process Consulting Group, a division of Software Engineering Consults,
Inc.
J.D.
Edwards is a registered trademark of J.D. Edwards & Company. The names of
all other products and services of J.D. Edwards used herein are trademarks or
registered trademarks of J.D. Edwards World Source Company. All other product
names used are trademarks or registered trademarks of their respective owners.
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Source for the Flow Processing Advantage"