The photo shows the results of degating a polycarbonate cover using our Firestar f201 laser and an FH Series marking head.

One of the most common methods for creating plastic parts is injection molding. Granular plastic resin, along with any colorants or additives, is heated and injected under pressure into the mold cavity. In the case of a multi-part, cold runner mold, a feed channel and runners connect the injection orifice with each cavity gate in the mold.

After the mold cavity is cooled and opened, the molded plastic parts, still attached to the sprue (the leftover plastic in the feed channels) drops or is robotically removed from the mold. The next step in the process is to degate the parts by removing or trimming each part from the sprue. This process is performed using knifes—either manually or robotically, punch presses, pneumatic cutters, or lasers.

Because laser degating is a non-contact process, lasers eliminate the need for knife or die replacement. The most important benefit however, is the laser’s ability to be reprogrammed quickly and easily to degate a new or redesigned part. In addition, laser degating is a thermal process that tends to produce a smooth cut edge versus mechanical methods that may leave a sharp edge at the trim point.

The photo shows the results of degating a polycarbonate cover using our Firestar f201 laser and an FH Series marking head. This galvanometer-based cutting method offers the added benefit of a familiar Windows® based user interface through our WinMark Pro laser marking software. We equipped our FH head with an 80 mm focusing lens that provides a 116-micron (0.005”) spot size and a 0.8 mm (0.032”) depth of focus. At 200 watts of power, we cut the 0.93 mm (0.0365”) thick sprue at a speed of 18 inches per second (IPS) in a cycle time of 0.05 seconds per part. Similar cuts were also made using only 60 watts of power. In this case, the cutting velocity was 3.5 IPS and the cycle time per part was 0.09 seconds.