Planar robot for cutting glass using hot air by crack propagation method

Glass is a typically hard and brittle material, which can be easily cut by introducing thermal stress on an artificially created crack. Although the cutting of these materials is one of the most important processes for production, it has the disadvantage that when it is carried out by saws, bits and grinders, it is accompanied by the undesirable phenomena of the generation of noise, dust and scrap. The basic principle of hot air cutting by crack propagation method is that a jet of hot air is allowed to fall on the glass plate at the point were there is an artificial crack. As the temperature increases the crack propagate along the travel of the hot air or the surface of glass plate. In the view of understanding the problem a hot air glass, ceramic, cutting planar robot is designed and the results are obtained experimentally A planar robot is designed and fabricated in the laboratory for profile cutting. A wheeled cart which is allowed to move in a guide way linearly both in X and Y direction. A variable speed D.C. motor is mounted on the cart and a permanent magnet is finely fixed on the bottom of the shaft of the D.C. motor. A template of a required profile made of wood with mild steel material surrounding its boundaries is fixed to the bottom of main frame through two stops. This template can be interchanged as the requirement of the different profile. The magnetic boundaries fixed to the D.C. motor are exactly matched with the boundaries of the template. As the motor rotates the magnetic shaft holds over this surface of the boundaries of the template and wheeled cart take free movement in X and Y direction. An extension rod attached to the robot acts as the end effector and makes use of mounting hot air jet. An electrical heater is placed over the wheeled cart and compressed air is passed through the heater on to nozzle. Initially crack is provided using diamond cutter and further cutting of the profile is performed by the hot air. Number of experiments is conducted with a planar robot and experimental results are presented in graphical form. Experiments are repeated for different glass thickness, different temperature, different nozzle diameter and different distance between nozzle and surface of glass plate on surface roughness. Strain is also measured along the crack propagation using strain gages the results are presented graphically and simulation of temperature above the crack tip is modelled using ANSYS 9.0.