|January 24, 2002
Spray-on Protection for Vehicles in Transit: Audi the First Manufacturer Worldwide to Use Spray-on Film
Audi is now using a process that did not previously exist in this form in the automotive industry: at a pilot facility within the paintshop in Ingolstadt, all Audi A3 and Audi TT bodies are being sprayed with a new kind of liquid film to prevent damage to the paintwork - transport protection from the spray gun, as it were. This innovative process, for which a patent application has been filed, has been developed internally by Audi.
The project manager of this patent concept is Dr. Sigrid Saulich who is responsible for preservation techniques in the Paintshop Planning department at AUDI AG. The project was launched in April 1999 together with a team made up of the Plant Planning, Process Technology, Quality Assurance and Production areas with the objective of developing an alternative to conventional preservation methods using wax coating and adhesive film.
Both wax and adhesive film have disadvantages. The use of adhesive film to protect vehicles during transit is extremely time-consuming, labour-, cost- and space-intensive. If adhesive film were used for all vehicles produced at the Ingolstadt plant, around 120 employees working in three shifts would be needed to apply it - a tedious matter considering that each piece of film has to be attached by hand.
"In the case of vehicle preservation using wax, on the other hand, the environmental aspect is decisive. This process involves a great deal of waste water and solvent, both during wax application and wax removal," explains project manager Saulich. Due to environmental legislation in the USA and Canada, all Audi vehicles shipped to these markets have to wear a "protective suit" of adhesive film.
Although, at three euros per body, wax is exceptionally inexpensive to apply, wax removal by contrast costs around 20 to 30 euros (depending on service provider). Preservation using the new spray-on film currently costs around 25 euros (approximately 35 euros per body using adhesive film). According to Dr. Sigrid Saulich: "The concept unites all the advantages of wax preservation with those of adhesive foil, at the same time avoiding all their disadvantages."
The investment volume for an application line is around five million euros. Audi has set up a pilot facility at its Ingolstadt paintshop. It takes eight application robots four and a half minutes to coat one body with spray-on film, an aqueous polyester-polyurethane dispersion.
The robots work precisely, spraying one strip after another, each around ten centimetres wide, on to the body paintwork. The roof, bonnet and boot lid are completely covered with the liquid plastic; only the exposed surfaces of the sides, nose and tail are covered. In this way each vehicle is packed in just under 1.7 kilograms of film. Once it has been applied, a large proportion of the water is removed from the protective coating in two and a half minutes with the aid of dehumidified air at 20 to 25 degrees Celsius. The material then continues to dry on the way to the cavity sealing area. The ten-minute cavity sealing process in the dryer (80 degrees) and further air-drying of the bodies on their way through assembly completes the drying process.
The spray-on film is applied at the end of the painting process. It therefore not only serves as preservation during vehicle transit, it also protects the paintwork while the vehicles are being assembled. Once the car arrives at the Audi dealer, the protective coating can simply be pulled off on the premises - like adhesive tape off a dispenser. Since dealers previously had to have the wax coating removed at special centres, the cost of this and the logistics involved are now a thing of the past. The protective coating does not have to be removed until just before the car is handed over to the customer. If a vehicle remains at the dealer for some time, the spray-on film can stay on the paintwork, providing effective protection for up to six months. Recycling of the removed film is carried out by service providers commissioned by Audi authorised dealers.
The necessary experience for volume production is being acquired at the pilot facility. Audi is planning to use spray-on film to preserve other model series in future.