#4 | 2020
SYN] Magazin

Innovative application technology for PVC in automotive paint shops

Applying sealants with high precision, point by point, as with an inkjet printer - what sounds revolutionary has already been brought into series production by Atlas Copco. The new IDDA.Seal application process applies individual PVC drops automatically and at high frequency to the components to be sealed. This significantly saves sealing material and has numerous other advantages.

"It is a quantum leap in the automated application of sealants. The new IDDA.Seal application technology from Atlas Copco solves numerous problems that users in the automotive industry have had with certain sealing applications in the paint shop. "IDDA" stands for "Intelligent Dynamic Drop Application", the intelligent and dynamic automated application in drop shape. Specifically, this involves PVC sealings that are frequently used in automotive production for seam sealing, cosmetic sealing or underbody protection. The material is applied to welded seams or cut edges of a car body before painting. It protects against corrosion, improves vehicle acoustics and seals the interior. Until now, various application technologies have been used for this purpose, in which the material is applied in a constant flow. "Vehicle geometries and production processes are becoming increasingly complex," explains Dr. Sten Mittag, Research & Technology Manager at Atlas Copco. "With the conventional technologies we have reached certain limits” 

Sealing challenges

Until now, most automobile manufacturers have used automated application methods such as jet stream, swirl or flat stream in the production lines for cosmetic sealing and seam sealing. The nozzle must be positioned perpendicular to the component to achieve an optimal application. "The application distance between the nozzle and the car part should only be a few millimeters, which already imposes some restrictions. Not all areas can be easily reached by the robot," explains Mittag. Furthermore, it is difficult to maintain a defined height of the PVC seam, especially at high robot speeds. "With traditional application methods, material accumulations can occur, for example at the turning points. Narrow angles are also difficult to access. This can require manual rework to prevent leaks and to spread excess material. This costs time, material and therefore money," emphasizes the bonding and sealing expert.

Problem solver: Individually controllable PVC drops

Together with the car manufacturer Audi, Atlas Copco has developed the new IDDA.Seal technology especially for cosmetic sealing in the paint shop. "Our goal was to seal inaccessible areas as optimally automated as possible using robots - and thus improve sealing in particular for complex geometries," says Sten Mittag. The PVC is applied in ultra-fine drops via five nozzles that can be controlled individually. The opening and closing of the nozzles, the drop volume and the drop distance can be set individually and adapted to the desired bead geometry. This ensures considerably more flexibility. "For this purpose, we have developed a new applicator and mapped the better control options using new software," says Mittag. Classic control systems could only give the applicator the command for pneumatic opening or closing. The user does not feel the complexity of the new system. "Trained system operators can easily determine the optimum layer thickness and width of the material application in advance in the control system."

Short reaction times for precise and sharp-edged application

The robot guided IDDA.Seal applicator applies the drops in variable sizes from 1 to 1.5mm to the component with high frequency. This results in a very short reaction time of only 1ms. Even at dynamic robot speeds of 50 to 600mm/s, changes of direction are now possible without influencing the bead geometry - the application remains precise with sharp-edged contours. While conventional material application in curves often results in too little PVC on the outside and too much on the inside, IDDA.Seal ensures that the material is applied evenly also when changing direction. "Even complex bead geometries with constrictions, gaps and overlaps are realized with high quality and visual appeal," says Mittag.

The new process shows its advantages to the full, especially with complex car part geometries. The distance between applicator and component can be 5 to 80mm, in special cases even more than 100mm. By comparison, with conventional sealant application it is only 3 to 5mm. The application distance can therefore be up to 25 times greater than before. This simplifies robot programming and accessibility. In addition, the nozzles can also be positioned at an angle to the application surface in order to apply the drops at different angles, pulling or pushing. "With conventional application, we need a right angle. With IDDA.Seal, deviations from the vertical by up to 25 degrees are no problem - the geometry of the sealing remains unchanged. This means we can get by with considerably fewer robot programming points," says Mittag

Good for the environment  

And IDDA.Seal has even more advantages: The sharp-edged application makes many stencils superfluous. The high-precision application with controlled layer thickness can reduce manual rework by up to 40%. PVC material can also be saved up to 50%. "In modern vehicles, several kilograms of PVC are applied. With IDDA.Seal we apply as much as necessary, but as little as possible. By saving material we can reduce the weight of the vehicle. And every kilo of weight saved ultimately saves CO2. We also minimize the use and the amount of PVC that has to be disposed," emphasizes Sten Mittag.

Atlas Copco has filed a patent application for the new IDDA.Seal technology. The intelligent, dynamic droplet application for automated sealing has already been running since last year at development partner Audi in series production at Győr in Hungary. The next development step is already in full swing: IDDA.Seal is to be used in the future not only for cosmetic sealing but also for seam sealing at Audi.

Innovation in 60 seconds! Watch IDDA.Seal in action in our video:Request our information brochure on IDDA.Seal: IAS.marketing@atlascopco.com  

Read interview with Sebastian Blaser