Abstract: A continuous drier for board-shaped piece material, especially for coated in-layers or printed circuit boards, is described which comprises a drying chamber, in which the board-shaped piece material to be dried is exposed to a guided air stream while being transported in a transport plane along a transport path from an entrance to an exit of the drying chamber by transport means acting preferably at its longitudinal edges. The drying chamber is equipped with an inlet for incoming air and with an outlet for outgoing air. Arranged above and below the transport path of the board-shaped piece material are infrared radiators the radiation of which acts directly on the coated piece material and which, in addition, form a heat source for the guided air stream. The air stream in the drying chamber is guided counter to the transport direction of the board-shaped piece material and substantially parallel to the transport plane. A coating installation comprising such a continuous drier is also described. (FIG.

Abstract: A process for producing thin photoresists on printed circuit boards wherein a metallic-layered substrate is conveyed beneath a free falling curtain of a photopolymerizable substance, said substance having a viscosity of 30-120 seconds DIN cup 4 @ 25.degree. C. and being applied at a curtain height of 5-25 cm. above the board to form a coating having a dry film thickness up to about 1.5 mil after the coated surfaces are dried, whereupon the surfaces are available for photoimaging, developing, etching and stripping operations.

Abstract: A severing organ for trimming the width of a curtain of coating material poured onto an impingement site on a substrate, in particular a printed circuit board, to be coated and being moved at a distance below the foot end of the severing organ transverse to the direction of the flow of the curtain consists of a single separating element whose upper end is designed as a knifelike sharp severing edge.