E-coating has until now been accomplished by lowering a car’s body-in-white into a long tank of e-coat fluid, running it through the tank for some distance, and then raising it out again, as it progresses along a conveyor line. RoDip 3 is a clever new way of subjecting a body-in-white to an e-coat bath, and it is a good example of “simplicity for its own sake.” This improved e-coating process provides a number of significantly improved critical coating and process factors, and the innovation might be said to be simplicity itself, which results in these improvements. Once you see RoDip 3 in action, the response is, yes, of course, haven’t we always done it that way?
“RoDip” is meant to convey roll and dip or rotation and dip, and this mechanical process does just that -- the car body dives into the tank head-first, and goes through a full 360° of rotation in the tank’s fluid, then exits by rolling back up to level, and onward. This is possible whether or not the car body is on a carrier, and is very simply activated by cams, levers, and guides, the conveyor itself remaining always on a level.
From an operating standpoint, RoDip 3 reduces the length of the e-coat tank, reduces its volume (the tank is deeper but much shorter), cuts electrical usage and heating, reduces the costs of chemicals and coatings, and maintenance (including personnel required). The line proceeds continuously without interruption or pause.
From a process and quality standpoint, rolling a car body through a 360° rotation in the tank means improved flooding with no trapped air bubbles or pockets, much shorter drain time (the body is on a steep angle upward as it exits the tank on its way back to level), and all of the e-coat fluid rapidly drains back into the tank. Additionally, there is no conveyor interference between the car body and the fluid coating process. For the future, it will be easy to modify the process as desired, so that a tank may be bypassed altogether, adjust quickly for body type, or use for dip or spray (aluminum vs. steel).
The RoDip 3 system was reviewed at early adopter BMW’s Munich facility.