FILM-STRIPPING PROCESS
The invention concerns a chemical process and a device for evenly detaching layers of resist from the surface of galvanized boards in the form of easily filtered particles. The process is best applied in the horizontal plants used in the continuous production of circuit boards. According to the prior art, processes involving spraying and squirting are being used for stripping resist. One of the many disadvantages of this is the short service life of the bath because, as the resist has been dissolved, it cannot be completely filtered out of the used solution. According to this invention, the resist is detached from the surface of the circuit board using only a moderate flow of liquid agent. The first stage of the process involves flooding the surface of the circuit board with large quantities of liquid agent from elongate nozzles in order to cause swelling. During the second stage, nozzles - involving both pressure and suction units - are used to detach the excess film. The circuit boards are subsequently rinsed using large quantities of fluid. Multiple-cascade rinsing means that there is no waste water to be disposed of and the service life of the detaching agent is extended. The resist detached from the surface is taken by the shortest route to a solid matter filter and separated from the solvent before it can be dissolved. Almost all of the film is filtered out virtually dry.