Methods and apparatus for forming an aperture in a composite component

A method for forming an aperture in a ceramic matrix composite (CMC) component, the aperture extending through the CMC component between a front surface and an opposing back surface at a pre-determined location and a pre-determined final dimension, the method comprising:

• selecting a tool having a tool size and a cutting surface;
• selecting an angle less than 90° at which to cut the back surface of the CMC component with the tool, wherein the CMC component has a geometry that prevents the tool from being aligned at a 90° angle to the back surface;
• cutting the back surface of the CMC component with the tool to a depth less than a thickness of the CMC component at the pre-determined location of the aperture, the cutting surface of the tool positioned at the angle, wherein the depth is constrained by a tangency of the angle of the tool to the CMC component;
• and
• cutting the front surface of the CMC component with the tool to cut the aperture through to the pre-determined final dimension,
• wherein the tool is selected to have a tool size within a range of 60% to 90% of the pre-determined final dimension of the aperture.

A method for forming an aperture in a ceramic matrix composite (CMC) component, the method comprising:

• based on a final dimension of the aperture, selecting a core drill having a cutting diameter and a cutting surface;
• selecting an angle at which to cut the CMC component with the core drill;
• cutting a back surface of the CMC component with the core drill, the cutting surface of the core drill positioned at the angle;
• and
• cutting the aperture through to its final dimension from a front surface of the CMC component with a second tool, the front surface opposite the back surface, the cutting surface of the second tool positioned normal to the front surface,
• wherein the core drill has a first diameter and the second tool has a second diameter, the second diameter different from the first diameter.