Over the next few years, we'll see some major changes in the way in which vehicle makers source their doors.  The trend in both Europe and the US is toward increasing complexity of the door componentry, adding more and more electronic functions.  The main manufacturers of door modules include Brose, ArvinMeritor, Delphi and Intier.

ArvinMeritor's Door Systems group designs and makes a variety of modular door systems, plus a range of manual and power window regulators.  To date, this business has delivered well over 20 million door modules to its customers around the world and are currently producing in the region of 3.8 million door modules per annum.

In March 2005, Matthew Beecham asked Marco Foley, Communications Manager, Europe for ArvinMeritor Automotive Inc, about how the company's door module business is shaping up.

Just-auto.com: What is a door module?

Marco Foley: Today, state of the art door modules incorporate a steel or plastic carrier with relatively standard components attached on. They are ArvinMeritor's third generation of door module and represent a degree of integration largely targeted at easing the logistical and manufacturing issues involved in the supply and assembly of complex door components. However, in terms of product design integration, today's modules are still very limited. We believe that whilst the functions performed will remain largely unchanged in the future, new module improvements will push integration much further. We would expect to see single components performing multiple functions and have made significant achievements towards this integration goal with our own internal product developments.

j-a.com:  Which OEMs and models do you supply door modules?

MF: We currently supply door modules to a number of key OEMs including the Volkswagen Group and Renault Nissan.

j-a.com: Over the past few years, there have been many arguments 'for' and 'against' the use of plastic over steel carriers. Are the vehicle makers being 'won over' in favour of plastic?

MF: A plastic carrier designed to simply replace the steel carrier is only economically competitive at lower production volumes where the reduced tooling costs become a distinct advantage. However for high volume platforms, steel remains the material of choice. As with all modular strategies, the level of integration is of key importance to economic viability. This would be the case where the plastic carrier is designed to integrate some major component or perform multiple functions.

j-a.com: What is ArvinMeritor's share in Europe and the US for door modules?
MF: As the designers of the World's first door module -- on the Austin Mini in 1968 -- ArvinMeritor have long pursued a modular strategy and are committed to doing so in the future. Our estimations place us at number two in Europe and the World and with significant new business wins such as the recently announced one million door modules for Hyundai in North America, we are projecting to increase our current World market penetration in door modules by a factor of 1.5 in the next five years.

j-a.com: In terms of modularity and outsourcing, do you think doors can follow the same path and go as far as seats? i.e. is there a possibility of having complete doors manufactured and delivered just-in-time and just-in-sequence by a tier-one supplier to the OEM?

MF:  All protagonists in the door industry would agree there is still a little way to go. The key and obvious difference between the seat and complete door is that the door is an external part with huge and immediate implications for quality perception in terms of alignment, panel flushness and exterior paint colour. The OEM is therefore understandably protective of these elements of production, which are part of their core business and count as major investments.

Supply of the complete door is nevertheless the ultimate and logical evolution of the Door Module and ArvinMeritor have made significant inroads towards this goal. For a number of years ArvinMeritor has operated a 'Fraktal' production system within the Skoda's manufacturing plant in the Czech Republic, taking full responsibility for the assembly and test of painted doors in sequence before they rejoin their vehicle further along the assembly line. More recently another key European brand has entrusted ArvinMeritor to perform a similar complete door assembly process but this time in an off-site location, adding just-in-time and just-in-sequence delivery responsibility to our task.

But we have not stopped there. In the past 18 months ArvinMeritor's 'Glass Motion Module' concept has made it even easier for OEMs to achieve significant cost, weight and space savings by forming the non-visible elements of the door into a fully-tested functional module. This allows them to achieve the majority of the benefits of complete door supply without necessarily having to relinquish control over the exterior surfaces.

j-a.com: In the interim, do you see more opportunities in liftgate modules than side doors?

MF: The liftgate sits in a different plane to the side body of the car thereby reducing the effect of any possible colour variation, and the panel gaps are by necessity fully adjustable. Some manufacturers fit plastic liftgates to steel cars today without concern to the associated paint or material differences. In this regard some OEMs view it as a step towards the goal of complete door supply but whilst they share many of the same challenges, the two areas are extremely different in terms of functional, mechanical and electronic content and have a tendency towards more content like powered assisted operating.

Expert Analysis

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