GB725110A - Etching machine - Google Patents

Abstract

725,110. Etching apparatus. DOW CHEMICAL CO. Sept. 10, 1953 [Nov. 26, 1952], No. 25110/53. Class 100 (2). An etching machine for etching printing plates and the like comprises a tank 1 containing a liquid etching composition 2, a series of paddle blades 40 having horizontal parallel axes lying in a plane above the upper surface of the etching liquid in the tank and adapted on being revolved to splash the etching liquid about the'tank, upstanding baffles 43 between the paddle blades adapted to guide the splashed etching liquid in a generally vertical direction, a removable cover 12 adapted to form a closure for the top of the tank so as to prevent escape of etching liquid on being splashed in the tank, a work-holder plate 16 above the baffles below the underside of the cover 12, and a motor 79 on the top of the cover adapted to impart to the work-holder simultaneously a translatory and rotational motion in a horizontal plane. The tank 1 is supported on a framework 3 on legs 4 and has a sloping bottom 5 and outlet pipe 7 so that the etching liquid may be circulated withdrawn from the tank and recirculated by pipes 57 and 53, the latter being provided with holes 55. An upstanding baffle 10 runs along one side of the tank 1 and below the baffle are heat-exchanger pipes 50 for keeping the etching liquid at the required temperature. A ledge 11 is provided around the edge of the tank on which rests the cover 12. The cover 12 may be raised by means of a handle and is provided with rollers 19 which run on the ledge 11. The table is supported in the raised position by arms 17, supported on columns 22 and provided with a counterweight 23. The work 60 to be etched is clamped on the work-holder plate 16 by clamps 61 and 63, the latter being adjustable to accommodate different sizes of work pieces. The workholder plate 16 is mounted for rotation in a plane parallel to the cover on the lower end of a shaft 66 which extends through a slotted opening 67 in the cover 12. The other end of the shaft 66 is journalled in bearings 68 mounted on a carriage plate 69 in turn mounted on bearings 70 adapted to slide on ways 71 on the top of the cover. The shaft 66 carries a pinion 72 adapted to engage teeth 73 at either end of a rack 74, reciprocatory movement of the shaft 66 and plate 16 being effected by the motor 79 driving, through suitable gearing a rod 75. Owing to the space 81 between the teeth 73 on the rack 74 a period of idle rotation of the work 60 is obtained, thus giving different partsof the work a random motion with respect to the etching fluid. The paddles 40 are driven by a motor 49.