Lotus Evora - Manufacturing Process

[Mark H]

Lotus Evora - Manufacturing Process

by John Vigar, (Continuous Improvement Manager for Lotus Cars)

The Evora assembly process is the most advanced ever undertaken by Lotus

and is probably also one of the most sophisticated for low volume niche car

production in the world.

The manufacturing process for Evora actually started life alongside its initial

design programme back in late 2006. We had to ensure that the car could be

manufactured and assembled to a high specification, to budget and on time.

Manufacturing feasibility has been extremely important to us right from the

start.

Even before Evora’s final design and engineering had been completed, we

knew exactly how to build it and how its dedicated assembly lines would look.

We also needed to get all our suppliers fully on board ready to work with us to

ensure that we met the aggressive delivery target for ‘start of production.’

The heart of the Lotus Evora is its special extruded aluminium chassis. This is

manufactured at our new Lotus Lightweight Structures facility, which is based

in Worcester, UK.

The following represents the sequence of how we build the car within our

General Assembly and Final operations at Lotus:

The Evora starts to take shape as it is processed through the General

Assembly part of the Lotus Production System. Superlatively painted body

panels (using specially developed environmentally friendly water based paints)

leave the Paint Shop and are decanted and distributed to their respective

‘point of fit’ workstations within the production lines. The first part of the

assembly production system for Evora (the Factory 5 chassis line) focuses its

efforts to assemble Evora’s unique modular structure. It is here that Evora

presents Lotus with a new way of building cars.

Whereas current Lotus cars have their rear sub-frame and front-end structures

gradually built up in situ (on the chassis to form a single unit); the Evora is very

different. The whole of the chassis structure is made up in three modules i.e.

the front-end structure, the main ‘centre body’ section and the rear end

section. Each of these sections are pre-assembled separately and as the

main ‘centre body’ section progresses along the Factory 5 production line, the

other two modules are added as complete sub-assemblies. This takes place at

strategic locations, which allow the sections to be ‘married up‘ to form the

overall support structure of the car. The roof is also assembled and bonded.

This modular approach provides greater flexibility and efficiency. It makes

access far easier to assemble (or replace) parts, and it better facilitate

engineering updates and new model year changes. Evora’s modular structure

also offers several advantages in improving ergonomics for the production

team member.

However, that is not to say that assembling Evora isn’t complex. There are

over 30 possible option combinations for the rear engine module alone and at

least another 24 combinations for the car’s front-end. These represent a range

of customer options e.g. left-hand or right-hand drive steering, painted or nonpainted

callipers, brake discs, different oil cooler options – and this is before

we get to talk about Evora’s high-quality interior. This means that each module

can be specified to meet the customer’s exact requirements.

Also, within Factory 5, the car’s doors, windscreen, bulkhead, roof and body

sides are assembled. All the body panels are imported from France. The

tools that produce these parts are made with chromed steel surfaces. This

ensures that the quality and desired finish of the panels is extremely high.

On leaving Factory 5, the car is then transferred, somewhat counter-intuitively,

to Factory 4 (the numbering of each of Lotus’s factory reflects the way the site

has developed over the decades - rather than its sequence in the process

today). Here, the first few stages are laid out as a carousel line, which is

equipped to dispense various fluids (as oils, coolants and brake fluid) into the

car. Evora then progresses through the main trim assembly production line.

A large number of Evora trim components are manufactured on site at Hethel.

We have invested in state-of-the-art cutting facilities, which allows exacting

standards to be replicated and meet our sophisticated CAD interior trim

designs. All leather for the Evora is cut and trimmed using this technology

which also allows for the most cost-effective arrangement of pattern shapes to

be cut whilst simultaneously, minimising ‘off-cut’ waste from each leather hide.

The trim assembly line, like the chassis line, utilises a ‘lean racking’ which has

been introduced to house our line-side “Kanban” parts delivery system. This

tubular framed system makes efficient use of line-side space, which also

presents materials in an optimum and ergonomically friendly state. Team

leaders and members have also used its simple construction to create ‘tailormade’

sub-assembly benches, parts trolleys and visual control stands. This

flexible system allows for an effective and efficient organisation of the

workplace to support the people who assemble the car.

Lotus has also developed its own ‘Visual Process Control’ systems for the

Evora line. These help to ensure that the car is built to the highest quality

standards and also track Quality, Costs and Delivery (QCD) performance

measures. Visual Process Control is an important feature of the Lotus

production system. It helps supervisors and team leaders to focus their efforts

on producing Right First Time quality within each work stage.

Evora becomes instantly recognisable once its front and rear ‘Clam-shells’ are

fitted. These are assembled in Factory 4 where all interior parts are also

installed (including special Recaro seats). Either cast or forged alloy wheels

(optional) are assembled towards the end of that line to conclude this phase of

the production process. The car then receives a standardised Quality

Inspection Process (QIP) audit before it is routed to the next factory (Factory

8) for ‘cosmetic’ processing and verification.

Factory 8 houses a rolling road test but before the car can be ‘passed to sales’

an independent team of quality inspectors inspects it very thoroughly. Every

aspect of the car is checked, which will confirm that it totally meets the

expected quality standards.

There has been considerable pressure on us to make sure that we have all the

relevant parts to cater for all the different global markets. Fortunately, by

having a dedicated assembly line for Evora, we have been able to uphold the

mantra for ensuring ‘right part, right place, right time’ delivery.

At 27 months, the Evora introduction programme has been a challenge. The

timing plan has been very aggressive for an all new vehicle of such high

quality. However, being fast-to-market required a tight programme. Despite

very short lead times we have done it and its creation is a credit to our

designers, engineers and the whole manufacturing team.

Lotus Evora: 205 g/km CO2

32.5 mpg (8.7 litres / 100 km) - Combined Cycle

22.8 mpg (12.4 litres / 100 km) - Urban Cycle

43.5 mpg (6.5 litres / 100 km) - Extra Urban Cycle

 

 

Related images are here:

 

http://www.midlandslotus.co.uk/forum/index...=sc&cat=178

 

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