In this study, the type of pre-notching used on the specimens was of the through-thickness crack type, from the middle point of one side to a point just passing the centre of the specimen. The pre-notching was done in two steps. First, the notch
tip was obtained by drilling using a 0.3 mm diameter bit. After that, the rest of the notch was obtained using a precision coping saw blade. Water was used for cooling in both of these steps. It is also possible to achieve the pre-notching by means of wire electrical discharge machining (WEDM), laser-induced micromachining (LIM) or high pressure water jet cutting. The unfortunate thing about the first two methods is the white layer of melted material on the notch tip. The third method presents the problem of the large diameter of the water jet compared to the size of the specimen. For these reasons, all of these methods were discarded as a means of obtaining the pre-notching.