GB1293576A - Edm method and apparatus for finishing rolls - Google Patents

Abstract

1293576 Making rolls; grinding; rolling; electro-erosion INGERSOLL MILLING MACHINE CO 5 Dec 1969 [5 Dec 1968] 59546/69 Headings B3A B3D B3M and B3V A roll for rolling sheet is given a matte surface by an electro-erosion method. In one embodiment, Fig. 7, two rolls 52, which may be crowned, are mounted for rotation between headstocks 53 and tailstocks 54. One roll 52 may be rough ground by a rotary, grinding wheel mounted on a carriage 55 movable along a guide 56 whilst the other roll 52 is electro eroded by an electrode 58 positioned beneath the roll to remove the crests between the depressions produced by the grinding operation. After electro-eroding, the roll may be polished by a fine grinding operation. In another embodiment (Fig. 6, not shown), the machine is adapted to accommodate only one roll. In a further embodiment, the roll 60, Fig. 9, is electro-eroded by an electrode comprising segments 63 fixed to a beam 64 vertically movable by an hydraulic cylinder 67. Each segment 63 is connected to a separate pulser 80 and has beveled ends (Fig. 10, not shown) so as to overlie but be insulated from its adjacent segments. Two rows of segmented electrodes may be used (Fig. 11, not shown). A liquid dielectric is enclosed in a trough 74a. If the electrode is of graphite, it is initially conformed to the desired roll contour by forcing it into contact with the rotating roll 60 so that the maximum radius areas between the depressions of the roll determine the electrode contour. When a copper electrode is used it is initially worn in by electroerosion between the electrode and roll 60 with the polarity being reversed for the wearing-in process.