FIELD OF THE INVENTION

The present invention relates to the field of cutting and sealing sheets of meltable material.

BACKGROUND OF THE INVENTION

Tools for simultaneously cutting and sealing sheets of meltable material, such as synthetic substrates, are desirable to prevent a cut substrate from having loose edges as depicted inFIG. 6A. For example, carbon dioxide lasers are commonly employed for both cutting and sealing a sheet of synthetic material; however, carbon dioxide lasers are relatively expensive. Thus, there is a need in the art for a reliable, effective, and relatively lower cost tool for simultaneously cutting and sealing sheets of synthetic material.

SUMMARY

One aspect of the invention comprises a tool for cutting a substrate having a thickness and comprised of a material having a melt temperature. The tool comprises a blade having a cutting tip at a distal end of the blade and at least one shoulder disposed on one side of and proximal the cutting tip. The cutting tip and the shoulder are positioned such that at least a portion of the at least one shoulder is in contact with at least one cut edge of the substrate defined by a cut line formed by penetration of the substrate thickness with the cutting tip. A heater, such as an induction coil, is configured to heat the blade shoulder to a temperature selected relative to the substrate material melt temperature to cause the portion of the shoulder in contact with the cut edge of the substrate to seal the cut edge.

In one embodiment, the blade is a rotary blade with the cutting tip spaced a first radial distance from an axis of rotation of the rotary blade, and the at least one shoulder has a periphery extending no greater than a second radial distance from the axis of rotation, wherein the second distance is less than the first distance. A motor and transmission system are configured to rotate the rotary blade. The cutting tip and shoulder(s) may be separate components mounted to a shaft. The tool may have means for rotating the tool head on an axis perpendicular to the axis of rotation of the rotary blade, such as to angle the blade so that the radius of the blade is parallel to the direction of relative blade travel.

The blade may have a pair of shoulders disposed on opposite sides of the cutting tip. The heater may comprise an induction coil that at least partially surrounds a portion of the blade. The cutting tip may be faceted, such that it includes a perimeter and a plurality of sharp cutting points disposed along the perimeter. A hold down foot having an opening sized to fit the blade and the at least one shoulder may be configured to apply downward pressure on the substrate.

A motion system may be configured to impart relative motion between the blade and the substrate, such as a gantry system, a positioning table, a linear positioning stage or slide. In one embodiment, the motion system may comprise a gantry system of a converting table or cutting table, sometimes also referred to as a finishing table, and the tool may be one of a plurality of interchangeable tools configured for use on the finishing table. The tool may have a fume disposal system, comprising a vacuum system configured to create a source of vacuum, and a conduit system connecting the vacuum source to an opening adjacent the blade.

Another aspect of the invention comprises a method for cutting a substrate comprised of a material having a melt temperature. The method comprises providing a blade comprising a cutting tip at an outer perimeter of the blade, and at least one shoulder disposed on at least one side of and proximal the cutting tip. The method comprises heating the blade, such as with an induction coil, to a predefined temperature and penetrating the substrate with the cutting tip such that a portion of the shoulder is in contact with the substrate while imparting relative motion between the blade and the substrate along a cut line to create a cut edge. The predefined temperature is selected relative to the melt temperature of the substrate to cause the portion of the shoulder in contact with the cut edge of the substrate to seal the cut edge.

The blade may be a rotary blade. The blade may have a pair of shoulders disposed on opposite sides of the cutting tip, in which case the method comprises sealing opposing cut edges of the substrate defined on either side of the cut line. The method may further comprise moving the blade relative to a stationary substrate, such as with a gantry system. The blade may be mounted on a tool head, with the method further comprising angling the tool head so that a radius or width of the blade runs parallel to a direction of relative blade travel. The blade may comprise an interchangeable tool of a finishing table, in which case the method may comprise installing the interchangeable tool on the finishing table prior to cutting and sealing the substrate, removing the interchangeable tool after cutting and sealing the substrate using the finishing table, or a combination thereof.

