Apparatus and method for rotary die X, Y, and theta registration

A method of correcting registration error of a rotary die apparatus, the method comprising the steps of:

• actuating a rotary die comprising a rotary die cylinder and an anvil cylinder, wherein the actuating includes rotating the rotary die cylinder, having pattern protrusions extending from an outer wall, in an opposite rotational direction of the anvil cylinder continuously at a predetermined rotational speed;
• feeding a strip of material through the rotary die between the rotary die cylinder and the anvil cylinder, wherein the strip of material is cut, embossed, or stamped with a pattern when fed through the rotary die;
• sensing, with a sensor, fiducials on the strip of material as the strip of material is fed through the rotary die;
• receiving, with a control system, information from the sensor regarding the fiducials;
• calculating, with the control system, a registration error based on a difference between an actual location or orientation of the fiducials and a desired location or orientation of the fiducials, wherein the registration error may include error amounts along an X-axis, along a Y-axis, and about a theta axis, wherein the X-axis is along a direction of feed of the strip of material, wherein the Y-axis is transverse of the direction of feed of the strip of material, and the theta axis is an axis of rotation perpendicular to the X-axis and the Y-axis;
• outputting control signals from the control system to one or more actuators, wherein the or more actuators are operably connected to the rotary die and drivable to translate the rotary die along an X-axis, translate the rotary die along a Y-axis, and rotate the rotary die about a theta axis, and wherein the control signals command the one or more actuators to adjust the rotary die relative to the strip of material in accordance with the registration error calculated at least one of:
• along the X-axis, along the Y-axis, and about the theta axis while the rotary die continues to rotate.

A rotary die apparatus comprising:

• a rotary die comprising a rotary die cylinder and an anvil cylinder each defining a longitudinal axis, wherein the rotary die cylinder has an outer wall and pattern protrusions extending from the outer wall and configured to cut, emboss, or stamp a pattern onto a strip of material being fed between the rotary die cylinder and the anvil cylinder while the rotary die cylinder rotates about its longitudinal axis in an opposite direction than the anvil cylinder, wherein the pattern protrusions are circumferentially spaced apart from each other about the rotary die cylinder by a pattern gap;
• a motor operably connected to at least one of the rotary die cylinder and the anvil cylinder to rotate the at least one of the rotary die cylinder and the anvil cylinder;
• a camera configured to capture and output image data of one or more fiducials on the strip of material;
• one or more actuators operably connected to the rotary die and drivable to translate the rotary die along an X-axis, translate the rotary die along a Y-axis, and rotate the rotary die about a theta axis, wherein the X-axis is along a material feed direction of the rotary die apparatus, wherein the Y-axis is transverse of the material feed direction, and the theta axis is an axis of rotation perpendicular to the X-axis and the Y-axis;
• and
• a control system operably connected to the camera and to the one or more actuators, the control system being configured to receive image data from the camera, calculate a registration error based on a difference between an actual location or orientation of the fiducials and a desired location or orientation of the fiducials, and output control signals to the one or more actuators to adjust the rotary die relative to the strip of material in accordance with the registration error calculated at least one of:
• along the X-axis, along the Y-axis, and about the theta axis while the rotary die cylinder continues to rotate about its longitudinal axis, wherein the control system commands the one or more actuators to adjust the rotary die only when the pattern gap of the rotary die cylinder is facing the anvil cylinder.