Sample preparation saw

A saw having a system for determining the size of a cutting blade used in the saw, the cutting blade being a sacrificial cutting blade, the cutting blade moving from a non-contact, home position to a sample contact position, comprising:

• a through beam photoelectric emitter and receiver pair, the emitter and receiver positioned on opposite sides of the cutting blade, the emitter and receiver pair positioned such that a largest cutting blade is moved above the beam regardless of a horizontal position of the cutting blade, the emitter and receiver pair generating signals indicating the absence of the cutting blade between the emitter and receiver pair;
• a controller, the controller receiving the signals from the emitter and receiver pair;
• and
• a blade axis position sensor for sensing a vertical position of a rotational axis of the cutting blade and for generating a blade position signal to the controller,
• wherein the sensor senses the vertical position of the rotational axis of the cutting blade when the cutting blade is moved above the beam, and wherein the controller calculates the blade size based upon the emitter and receiver pair signal and the blade position signal.

A method for detecting the size of a cutting blade in a saw in which the cutting blade is a sacrificial cutting blade and in which the cutting blade moves from a non-contact, home position to a sample contact position, the saw having a through beam photoelectric emitter and receiver pair, the emitter and receiver positioned on opposite sides of the cutting blade and generating a beam therebetween, the emitter and receiver pair generating a signal indicating the absence of the cutting blade between the emitter and receiver pair, the saw further including a sensor for sensing a vertical position of a rotational axis of the cutting blade, and a controller, the method comprising the steps of:

• positioning the blade in a low position such that the beam is blocked;
• moving the blade out of a path between the beam and monitoring the photoelectric sensor signal;
• generating a signal that the blade is out of the path of the beam;
• sensing the vertical position of the rotational axis of the cutting blade and upon sensing a predetermined criteria, recording the vertical position of the cutting blade;
• generating a signal indicting the vertical position of the cutting blade;
• and
• calculating the size of the cutting blade based upon receipt of the signal that the blade is out of the path of the beam and the signal indicating the vertical position of the cutting blade.