Needle arrays for forming ultrasonic perforations, and methods of making the same

A method of making a needle array for forming ultrasonic perforations, the method comprising:

• coupling a plurality of needles to a support plate, wherein each respective needle of the plurality of needles extends longitudinally from a respective first end to a respective tip, wherein the plurality of needles are configured to repeatedly contact a workpiece at an ultrasonic operating frequency such that each respective needle of the needle array forms a respective hole through the workpiece, wherein the support plate is configured to couple the plurality of needles together, wherein the support plate is further configured to secure a respective position of each respective needle with respect to the other needles of the plurality of needles such that the plurality of needles defines the needle array, wherein the first ends of the plurality of needles are coupled to the support plate in the coupling the plurality of needles, and wherein the plurality of needles extend away from the support plate such that the tips of the plurality of needles are spaced apart from the support plate;
• selecting a respective length of each respective needle of the plurality of needles to define a desired contact shape, contact contour, or contact plane collectively defined by the tips of the needles;
• and
• arranging each respective needle with respect to one another in a desired distribution pattern, based on their respective lengths, to form the needle array.