In high speed flat bed plotting systems, the movement of the marking head is controlled by a computer to plot various patterns. The plotting head includes four pen holders wherein the pen pressure can be adjusted to the desired value. The computer selects orientation, acceleration, speed, pen assignment and scale factor.
These plotters have been used to cut orthogonal line patterns in strippable films. In cutting patterns in strippable films, the four pen holders are replaced with four flat chisel point cutters, set to cut in various directions. The particular blade used is selected by the computer in accordance with the direction of the cut. When the cutters were substituted for the pens, it was found necessary to operate the plotter in the speed range of between 5 and 10 inches per second.
If these flat cutters are used to cut in any direction except that for which it is set, the cutter will drag and tear the plastic film.
Point scribes have been used for some time in engraving and marking instruments. These point scribes were tried in hand operated X-Y plotters but were found to be very erratic and tended to drag and tear the film. In the past when making patterns on a strippable film, the high speed X-Y plotter has been used only for making straight line cuts. Any curvilinear designs had to be cut by tedious hand cutting techniques.
Diamond point cutters were tried by applicant in high speed flat bed plotters at normal cutting speeds, point pressures and accelerations, but were found to tear, drag and gouge out material. Ruby, sapphire and tungsten points scribes were also tried but it was found that they wear down too fast.