US 4,555,968 A · Web fed die cutting press having automatic 3-axis die registration system

Abstract

A die cutting press for processing web material is disclosed which is operable to provide very precise alignment of a reciprocable die cutting unit with each succesive area of the web to be die cut. In operation, the web is incrementally advanced toward the work station of the press until the area next to be die cut is substantially but not exactly in the die cut position thereof. The web feed is then placed in a creep mode to advance the web until an optical sensor determines the presence of transverse alignment indicium on one side of the web. Mechanism is thereupon actuated to rotate the die unit as required to bring the die assembly into alignment with related indicium on the opposite side of the web while effecting shifting of the web longitudinally thereof in a direction of travel as necessary to maintain die registration with the first sensed web indicium. Structure then shifts the die unit laterally of the web at the work station as required to bring the die unit into precise registration with longitudinally extending indicium on one side of the web. Only then is a defined area of the web subjected to the die cut unit. A cushion of air is provided for supporting the die unit while it is being rotated, during longitudinal shifting thereof in the creep mode, and as lateral shifting is accomplished with respect to the web. Extremely accurate is thereby accomplished registration of the die unit with the plurality of indicia associated with each area of the web subjected to the die cutting operation. Sensing of the presence or absence of alignment indicia on the web is preferably carried out through the use of photooptical devices associated with light transmitting flexible glass fiber bundles that direct light to the web as well as the light reflected therefrom back to the sensor mechanism. A microprocessor receives inputs from phototransistors to control operation of the die alignment and web advancement mechanism.

A die cutting press for web material having indicia on opposite, longitudinally extending sides thereof associated with each defined area of the web to be die cut, the indicia on opposed sides of the web which are related to a particular defined web area each being provided with a segment which extends transversely of the web and at least one of the opposed, related indicia having a section disposed longitudinally of the web, said press comprising:

a base platen defining a web material work station;
means for mounting a die unit on the base platen below said power operated means in disposition for rotation about an upright axis and shifting of the die unit in a direction at least transversely of the path of travel of a web through the press;
means for effecting rotation of the die unit on said base platen;
power operated means shiftable toward and away from said platen;
web backup means carried by the power operated means cooperable with the die unit to present a web processing work station therebetween;
means for shifting the die unit transversely of an area of the web situated at said press work station;
means for feeding the web material on an incremental basis to sequentially position successive defined areas of the web at said press work station;
first sensing means movable with the die unit and having sensors positionable to sense the presence of indicia on opposite sides of web at said work station, said first sensing means being operable to determine the presence of a segment of an indicium which first presents itself to said first sensing means as the web is moved by the feeding means through a displacement to bring the next defined area of the web to said press work station;
means controlled by said first sensing means and coupled to said web feeding means and to said die unit rotating means for effecting rotation of the die unit to an extent as may be necessary and in a direction to bring the segment of the opposed indicium related to be indicium segment first sensed by said first sensing means during movement of a particular defined area of the web to the press work station, into a location where such opposed, related segment is sensed as being present by the first sensing means, while continuing operation of the web feeding means to move the web longitudinally of the length thereof as may be necessary to maintain the presence sensing relationship between the first sensing means and the segment of the indicium which was first sensed by first sensing means as said next defined area of the web is moved to the press work station;
second sensing means movable with the die unit and having sensors positionable to sense the presence and relative position to the second sensing means of the indicium section associated with a respective defined area of the web;
and
means controlled by said second sensing means and coupled to said die unit shifting means for effecting shifting of the die unit transversely of a respective defined area of the web to an extent as may be necessary to bring the section of a corresponding indicium into predetermined relative relationship to said second sensing means whereby the die unit is accurately positioned with respect to each defined area of the web moved into the press work station;
and
means for actuating the power operated means only after accurate positioning of a defined area of the web at said press work station has occurred.

11 more elements

Web fed die cutting press having automatic 3-axis die registration system

Life of this patent

Web fed die cutting press having automatic 3-axis die registration system

Life of this patent

Abstract

Claims20