Machining

KÖMATEX sheets can be easily and quickly worked with the standard tools used to process wood and metal. To prevent breaking and splitting, the tools must be sharp. Generally, you should use a high cutting speed and slow, continuous forward feed, Normally, it is not necessary to cool the cutting tools, but in special cases, compressed air is sufficient. Deep notches and sharp edges can cause premature breaking of the material if too much weight is placed on the affected area.

The following machining information covers a variety of procedures. Click on the one you wish to explore.

• Finishing
• Sawing
• Drilling
• Milling
• Turning
• Cutting, punching and perforating
• Water jet cutting

For a smooth or glossy surface, KÖMATEX can be finished with buffing wheels made of felt, unbleached calico or sisal weave or felt tapes. Some enamel paints can also be used, as well as fine-grit sandpaper. To smooth uneven edges caused by sawing, drilling or milling, use a flat scraper with a grinding angle of 15°.

To cut KÖMATEX, use a high-band, jigsaw or circular saw with a cutting speed of 9,500-10,000 sq. ft./min. Depending on the thickness of the sheet, the saw blade should have a tooth pitch of 5 – 10 mm (3/16" - 3/8").

For Circular saws, we recommend using a tooth geometry alternating between flat and trapezoidal. The blade diameter (Y) and the tooth number (N) must be appropriate for the material, the machine type and the machine speed. To avoid rough edges and cracking, always fasten the material to minimize vibration. This is important on sheets that are 3 mm (1/8”) or less thick, both for single and compound sheets. We suggest a cutting apparatus identified for “plastics cutting.” We do not recommend using shears or a guillotine for cutting KÖMACEL, as they can produce an unsatisfactory edge.

When cutting with a compass saw, use only sharpened (unset) saw blades (plastic, PVC). The feed should be manual, slow and continuous.

In some cases, it might be a good idea to consult your saw blade manufacturer. Always observe the instructions provided by the machine manufacturer.

KÖMATEX sheets can be worked on twist drills used for metal (DIN 1412) with 30° grooves tilted to the axle center of the drill. The center angle can be up to 110°. The back slop angle should be no less than 12 – 16°. Speed of cutting and feeding depends on the depth of the bores: the thicker the sheet, the lower the speed. For holes with a diameter larger than 20 mm, use double cutters with guide pilots. Cut holes larger than 40 mm in diameter on circular cutters (curling drills).

Milling tools must be ground for plastics and designed to give room for a proper volume of chips. You will obtain good results working at high forward feed and moderate cutting speed with deep cuts. Router use is easy with KÖMATEX when the plotter system is equipped with a special ball-headed miller and linked with suitable computer software.

For rough turning, we recommend combining low forward feed with a high cutting rate. The point of the turning tool should be rounded at a radius of at least 0.5 mm to keep the surface free of striation. Precision turning restricts the depth of cut to a maximum of 2 mm. At a high forward feed, the cutting speed is usually lowered to prevent the material from breaking.

KÖMATEX sheets up to 3 mm (1/8”) thick can be die-cut using steel rule dies. The best results are achieved when the cutting edge is as sharp as possible and the proper dies are used. Better cutting can be achieved if the KÖMATEX is warmed slightly before cutting.

Sheets up to 3 mm (1/8”) thick can be punched and perforated with a profiling knife or bipartite tool or cutting dies. We recommend using a punching tool with facets cut on both sides. The cutting angle must be less than 70 degrees. Heating KÖMATEX will greatly improve its workability.

KÖMATEX is well suited for this procedure. Multiple sheets can be stacked to obtain faster runs. Consult your equipment manufacturer for the maximum thickness possible. The cutting speed will depend on the sheet type and thickness as well as the quality of the cutting unit. KÖMATEX allows for many complex contours when this method is used.