In previous newsletters, we demonstrated that high-pressure nitrogen assist gas helps to minimize or even prevent edge charring when cutting polymer composites. The most common use for nitrogen assist however is for cutting stainless steels where fine edge quality is required.

When cutting stainless with oxygen assist, the oxygen reacts exothermically with the steel, adding energy to the cut process and increasing speeds. The downside is that this reaction coats the cut edge with a blackened oxide layer. If these cut parts are slated for the welding booth, then the oxide layer must be mechanically removed to assure proper weldability. Photo 1 shows a section of 304 stainless steel that was cut with 400 watts of CO₂ power and 80 PSI of oxygen assist. Note that the cut edge is oxidized with some underside dross present.

The presence of high-pressure nitrogen adds little, if any, exothermic energy but the higher gas jet pressure does add mechanical energy, which serves to blow the molten metal through the cut kerf before it cools enough to stick and form dross on the bottom edge of the cut face. Photo 2 shows the same 304 stainless material after cutting with high-pressure nitrogen.

Virtually every trigger or pump sprayer on the market today uses a dip tube to transfer the container contents up to, and out of the nozzle. Dip tubes are manufactured by extruding molten plastic through a die, cooling the tubing, and then trimming to length using mechanical cutters or lasers. The application presented here is unique because a requirement exists to mark a ten-character code along the length of the tube during the assembly process.

We were able to cut the adhesive sheets to size using a power level of 100 watts at a speed of 75 inches per minute with no discoloration of the kraft backing paper or the high-clarity adhesive film.