Case Study: The Lear Seating Plant
Questions:
1. What are the major changes required for Lear Seating to apply a JIT
replenishment model for Chrysler? Think about the following
areas:
 Product Design
 Process flow
 Production Scheduling
 Communication with customer
 Inbound receiving
 Sequencing and loading
 Transportation scheduling
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2. What are the risks associated with direct shipping? What
contingency elements are required to overcome these risks?
3. Can direct shipping be achieved without collaboration with
customers and/or suppliers? What does it take to make this
happen?
4. An important consideration that allowed Lear to succeed was
proximity to its customers and suppliers. Should suppliers to Lear
consider co-locating closer to its automotive customers and
suppliers as well? Why or why not?
5. What does it really take to become a lean manufacturer with direct
shipping capabilities?
Overview
Lear ships JIT to Warren, Michigan Chrysler truck division – located 38 miles
from the plant. This is a UAW plant – but relationships with management have
always been very good. This was evident as we walked through the plant – Bob,
one of the general managers at the plant, has been working in the automotive
industry for 37 years, previously at GM and now at Lear. He has an outstanding
relationship with the workers, keeps track of all happenings that occur, and
knows every associate on a first-name basis.
New Product Development
Lear has a very close relationship with Chrysler. Lear Romulus 1 is the feeder
plant exclusively for Chrysler, producing seats for the Dodge Ram, Dodge
Dakota, Dakota Extended Quad Cab, and Dakota AN 84. Lear sales
representatives and engineers are in daily contact with Chrysler people – and
many of them reside full-time in Chrysler plants. For example, design for
manufacture is a critical element in seat design, which has major implications for
ergonomics and efficiency (and cost) at this plant. As such, many design
engineers from Lear reside permanently at the Auburn Hills design center. This
is where they go to work every day! They are there to ensure that
manufacturability elements are well understood by Chrysler designers – and
work to engage Chrysler in value analysis and value engineering suggestions
that can take cost out of the seats and make them easier to manufacture.
One section of the plant is devoted exclusively to prototype development –
building future seat models for the Ram and Dakota models. Worker input is
used as feedback to Chrysler regarding how easy a seat cover is to work with,
and this is used to input suggestions regarding which seats are selected. This
area is also used to prototype the process to assemble seats – using actual
tooling. A miniaturized seat assembly process is put together – essentially a
prototype plant that will be used to produce the product on a broad scale. This is
also used as a big input into the upfront design process.
A big concern with seating has to do with the torque controls for bolts used to
assemble seats. This is a big safety item that is of concern to the federal
government automotive safety agencies. As such, all torque settings are
controlled by using an automated torque gun that not only automates the
process, but collects real-time electronic data that is fed into an SPC system.
This data is stored in real-time to a database, that allows complete traceability of
the actual torque applied to every seat produced in the plant. Because every
seat is barcoded with the VIN for the truck it is going into, this allows complete
traceability of failures in Failure Mode and Effects Analysis studies that may be
required down the road.
Strategic Initiatives
A number of strategic initiatives are current priorities in the plant.
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Ergonomics - A number of lockout assembly fixtures are also used for all
foam and frames. These ergonomic tools prevent injuries stemming from
muscle fatigue and repetition within the plant. Plant-wide job rotation is
also used – workers are cross-functionally trained, and move to different
parts of the assembly line on a periodic basis.
Six Sigma was implemented two years ago – and has become a way of
life within the plant. It is now engrained as a way of thinking – with a focus
on internal workers using it as well. Even the hourly union representatives
are routinely part of six sigma improvement teams – with results
documented throughout the plant.
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Supplier partnership programs are important. The foam supplier –
Woodbridge – is co-located across the street. With the exception of the
cut and sew operation in Saltillo, Mexico– 68% of Lear’s Romulus 1
suppliers are within a 300 mile radius of the plant. Although this was not
by design – it is a critical element that improves the response time for the
facility.
The plant was built originally to supply the General Motors H-car (Caprice
/ Oldsmobile), but switched over to a Chrysler supply plant in ’93-94.
Although GM decided to transfer their H-car production to Arlington, Texas
during this period, the Chrysler contract was won at almost the same time
– and the plant was idled for only one week during which time it was
completely transitioned over to the Chrysler product! This was a very
hectic time, to say the least.
Plant Operations
Plant operations are fairly stable:
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254 hourly workers – 39 salaried – running 2 ten hour shifts. Recently,
Chrysler indicated that the Dodge Ram volume will be increasing by
30% this year – which will be accommodated by running an additional
shift on Saturdays. A third shift is not yet required.
57 suppliers to the plant – 68% are located within 300 miles. This is a
big selling point for additional business to Chrysler – as this can
significantly avoid disruption.
Plant ships 10-15 trucks worth of outbound materials to Chrysler per
shift – with 7 trucks rotating on this schedule. Vinyl supplier to the
plant is Sandusky – fabric supplier is Guildford.
Lear receives 12 weeks advance build requirements from Chrysler –
with a 10 day frozen schedule of firm requirements. However, this 10
day frozen schedule can vary by sequence – and the plant receives
862 ship schedules direct from the Chrysler assembly line daily.
The plant has 13 receiving docks – with trailers full of completed seat
covers from Saltillo, Mexico arriving every day, and trucks leaving for
the Chrysler plant located 38 miles away. Inventory turns about every
two days – for annual turns of approximately 140. The plant can
product about 1200 assembled seat units (front and back) per day –
the Chrysler usage is on average 1100, providing a little extra capacity.
However, the assembly line’s start and stop times are completely
aligned with Chrysler’s plant times – “When they run weekends, we run
weekends – if they start early, we start early”.
There are 408 components in the seat – the plant generally has a two
day supply of trim covers, and 1 days’ worth of other components.
However, the plant has less than 1 shifts’ worth of foam on-hand, as it
receives foam from the feeder plant directly across the street.
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Inventory turns are at 145 – with about 2-4 hours of finished goods
inventory on-hand.
Fabric arrives in trailer loads from Saltillo, while frame assemblies and
other components are drop shipped and located in racks (see Figure
2). Material flows to one of two assembly lines – front seats or back
seats. In the first part of the operation, the frame is assembled into the
foam, the fabric/vinyl stretched over the foam/frame, and the different
seat elements (seat, back, attachments, etc) assembled in the
electronic torque area. Various custom fixtures and tooling make this
part of the operation ergonomically safe.
Next, the seat components are inspected for defects – and placed into
a repair/rework area if required. Product that is perfect proceeds to a
baking/steaming operation – then is married, assembled, and
palletized, and packaged for shipment. The pallet proceeds to an
overhead area for sequencing.
Production Scheduling, Sequencing, and Delivery
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The plant receives an electronic broadcast of vehicles coming
through the Chrysler plant in Warren – which specifies the leather
options, vinyl options, fabric options, style, etc. With 852 shipments
arriving, this amounts to one vehicle identification number (V.I.N.)
every 53 seconds. There is a 5 hour delivery window from the time
the scheduled order is received, during which time the plant must
build, sequence, and deliver the seats to the feeder location on the
Chrysler assembly line (see Figure 1). There is no finished goods
warehouse – they ship direct from the plant to the Chrysler
assembly line, with all of the seats sequenced in the right order
every time.
Travel time from Lear’s dock to the Warren Truck assembly is on
average 1 hour and 15 minutes – faster if the truck driver goes
quickly through the 38 miles! However, traffic and accidents in the
Detroit Metropolitan area are frequent – and there is always the
danger that an accident or traffic snarl will hold up a delivery.
A contingency measure is to have a total of 7 trailers in rotation –
with 54 seats loaded in sequence on the truck. Sequencing is done
on the second story automated sequencing material handling
equipment. Seats come off the line, and are transported to the
second floor in a lift. The sequencing is done using a “last in – first
out” logic. Seats are sequenced in reverse order - from number 54
at the back of the trailer, with number 1 at the front – so that when
they are delivered to Chrsyler, the first seat coming off the trailer is
number 1.
As seats come off the line, a barcode on each palletized seat
identifies where it is in the V.I.N. sequence provided by Chrysler –
and an automated material handling system positions each
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completed palletized seat assembly (front and back seats on the
same pallet for Quad trucks) onto a set of rollers that are exactly
the size of a trailerload. When a full trailerload is complete, they
are all moved automatically down to the first floor and loaded onto
one of two trailers waiting on the dock. Thus, if one seat must be
taken off the assembly area for a quality discrepancy or re-work at
one of the poka-yoke inspection areas, it is quickly repaired (or
another produced if the problem cannot immediately be fixed in
time), and sent up to the sequencing operation without disrupting
the scheduled trailer shipment. With the Quad front and back seats
on a single pallet, the back seat must be manually attached to the
front seat with a fixture. All pallets are plastic and recycled from the
Chrysler plant.
The plant has not been late for a shipment to the Chrysler plant in
over three years. This can be a very tricky situation. In most
situations, the truck drivers can radio ahead to one another to
monitor traffic conditions to take alternative routes to Warren.
However, it is a constant juggling act. For example, two weeks ago
a truck full of seats was stuck in traffic on I-94 due to a major
accident. As a contingency measure, the plant went into an
emergency mode and began duplicating the seat sequence that
was on the truck. They were over half-way through this process
when traffic began moving again – and the truck arrived at the
Chrysler plant with 20 minutes of supply before shutting down the
plant. However, the plant manager ascertained that “shutting down
Chrysler is “not allowed”.
The production rate is 68 trucks per hour, or approximately 1200
per day (1160 in a ten hour shift).
Fabric and Vinyl Input Requirements
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There are a variety of truck models, as well as various styles for each
model, that must be sequenced.
Dakota – 1 trim style X 2 colors
Dakota Extended Cap – 1 trim style X 2 colors
Dakota AN84 – 2 trim styles X 2 colors
Ram – 6 trim styles X 3 colors
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This is a total of 26 different SKU’s that must be sequenced on the plant.
By comparison, this is actually a relatively simple plant to run. Some other
Lear plants that support GM run multiple models, and within each vehicle
there are multiple types of different seats with different styles and colors.
In general, GM tends to have a proliferation of different styles compared to
Chrysler. This represents a big opportunity for simplification. A major
issue that is coming to the forefront of OTD with GM, as well as with
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Chrysler, is to create opportunities for simplification and “design in”
through greater collaboration in the product development process.
Fabric styles are an important consideration in the design process. In
general, Lear prefers fabric that stretches in both directions, not just one
direction. In the latter case, the product tends to “knuckle” in the seams.
As such, the circular knits are the preferred fabric. After the final
assembly, the seats must go through a steaming and baking process.
The steaming causes the fabric to stretch tight, then lay flat, removing
seams. The baking process does the same thing for the vinyl/leather.
Both processes are optimized to a temperature that does not negatively
affect the properties of the fabric or vinyl/leather.
Another important issue is the napped fabrics. Naps are sensitive to
touch, and sit-up when handled. This is often perceived by customers as
a defect, as the darker colors in particular appear to be a different color
when the nap is sitting up. Customers often think this is a “stain” and
complain to the dealers.
Because of these issues, Lear is increasinglyu trying to “design in” the
fabric during the design process. This is very difficult to do – the people in
the design studio at Chrysler are very particular about having suppliers
influence their design decisions – but “at least we are now talking to them
about the handling properties of the fabric and vinyul”. However, the plant
manager also noted that the Chrysler design staff “try to pit us against one
another (other suppliers)”.
A major property of automotive fabric is the wear factor. Thus, quality of
fabric is an extremely important element. In general, the plant wants to
work with fabric that is easy to pattern and work with – understanding that
plushed fabric is generally required for the higher end vehicles. Sewing
properties are also important – another consideration often overlooked by
design people.
Supply Chain Design
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Fabric is produced by Guildford, vinyl by Sandusky (Ohio) – with then
shipped to a laminator. Travel time for vinyl is 3 days to Southwest
Laminators, located in El Paso, Texas.
From there, it is shipped same day to Saltillo in Mexico, where the
fabric is cut and sewn. Another 3 days of shipping time and it arrives
at Romulus. The fabric arrives in packets of ten similar seat covers,
tied together in a bundle. Each truck contains 1 ½ days of supply for
the plant. Each truck contains enough seats to cover the requirement
projected through the Chrysler frozen schedule – which requires a bit
of scheduling on the part of downstream suppliers.
Vehicle Scheduling – Dodge Trucks
Broadcast V.I.N
To Lear Romulus 1
Point of use
Seat Assembly
Truck comes
off assembly line
PAINTSHOP
1.5 hours
5 hours
Build and
Sequence
3.75 hours
Ship to Warren
1.25 hours
Inbound - Holding
Back Seat Assembly
Loading
Prototype
Shop
Sequencing
Staging
Re-work
Final Assembly
& Back Seat Steaming
& Ovens
Marriage
Front Seat and Trim Assembly
Outbound - Trailers