A laser beam is transmitted through a drill bit comprising diamond or other suitable light-transmitting material having sufficient hardness. The laser beam exits a tip of the drill bit, thereby heating and softening the material being drilled at and/or near the interface of the drill with the material being drilled. The process may be utilized to drill hard and brittle materials such as ceramics and semiconductors, composites and ceramic matrix composites. The process may cause high pressure phase transformation, resulting in a more ductile and plastic material near the drill point/tip. The process provides more rapid drilling, improved surface quality in drilled holes, and less tool wear.

An improved apparatus and method for laser assisted machining are provided, by utilizing a computer to develop interrelated heating and machining plans, from a variety of input data describing the material to be machined, the properties of lasers and pyrometers used for heating the material, and computer models of the machining arrangement, workpiece and final part to be produced. An iterative process continues until the machining and heating plans result in the cutting zone of the workpiece being maintained at a desired temperature with no obstruction in the line-of-sight of at least one laser and pyrometer throughout the machining process, while also maintaining the cutting tool at or below a desired maximum temperature.

A laser-transmitting machining tool is disclosed. The laser-transmitting machining tool has a plurality of faces including an entrance face, a rake face, a flank face connected to the rake face, a rake side face extending between the entrance face and the rake face, and a flank side face extending between the entrance face and the flank face. The connection of the rake face to the flank face defines a cutting edge. The rake face extends away from the rake side face to define a rake angle. The entrance face is configured to receive and refract a laser beam to the rake face, the flank face, and the cutting edge for causing the laser beam to refract into and heat the workpiece at a compression region extending proximate at least the rake face and a tensile region extending proximate the flank face.

A method involves processing multiple workpieces, each composed of a material with a machinable surface characterized by distinct compressive and tensile regions. In at least one workpiece, the compressive region exhibits greater strength than the tensile region, while in at least one other workpiece, the tensile region is stronger than the compressive region. The method includes selecting a workpiece from this group, ensuring that the chosen workpiece is made of a material different from at least one of the other workpieces. A set of opto-mechanical tools is prepared, and from this set, a tool is selected based on its rake angle, specifically choosing a tool with a midrange rake angle between approximately 136 and 165. This selected tool is used to machine the chosen workpiece.