Sealing it up - WIP - 3M's door sealing tape

Automotive Design & Production, Dec, 2002

Sometime the distance between a new technology and its application can be long, measured in years. That's what some folks at 3M Automotive discovered, Of course, while the journey may be long, the destination can be worthwhile.

In the mid-1980s it had convinced BMW to use 3M Acrylic Foam Tape as a primary door seal (as a replacement for pins, clips and channels). The tape began to be deployed on the 5-Series. Presently, BMW is using it on the 3- and 7-Series, as well. Mercedes uses it for the A, M, and S Classes. The Jaguar X-400 has taped primary door seals. As does the Volvo S-80, Lancia Kappa, and the Land Rover L322. Among the advantages are functional (e.g., less leakage), physical (they eliminate corrosion sites and weigh less than wire carriers or channels), and economic (estimated to provide an average savings of 36% compared to the other primary door seal attachment methods--pin and channel rivet, pin and channel weld, pin and channel screw, and flange/wire carrier).

So what do many of those vehicles have in common? [up arrow]$. So 3M engineers--undoubtedly heirs to those who, in 1978, had to try to convince carmakers to use double-sided acrylic foam tapes--have been working to convince automakers that the tape-attached door seals are viable for lower-cost, high-volume vehicles. And here's where there was a twist of sorts. Volkswagen engineers were working on the luxury Phaeton. Not a lower-cost, high-volume vehicle by any means. The Phaeton engineers benchmarked the Mercedes S-Class and the BMW 7-Series, both of which, as mentioned, use the 3M tape for primary door seals. And so they selected it for the Phaeton. And because of the Phaeton's level of importance throughout the VW organization, their "blessing" of the tape has meant that it is now something that can be considered across the board. Which brought the 3M engineers to the Polo A04 world car platform (i.e., it is being built in Spain, Slovakia, Brazil, the Peoples' Republic of China, and South Africa). VW select ed Saargummi as the seal development supplier and Thyssen Nothelfer as application equipment supplier. 3M had to coordinate and assure VW of a 100% secure application method and total process capability.

VW redesigned the door to increase the planar surface available for maximum wet-out of the tape seal. The 3M engineers selected the 5402 material from its line, and a liner sub team developed a new high-density liner. 3M and Saargummi engineers redesigned the rubber seal; there's single sealing for the base Polo AO4 (one seal on the door, not sealing on both the door and body). The Thyssen Nothelfer engineers created equipment that automatically installs the seal. In Europe and Brazil the seals must be completely attached in less than one minute (there's more time in China).

So while it is a long time (comparatively speaking) sincethey started with the BMW 5-Series, arguably, the ongoing trip is worth it.

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