Corporate Buyers Guide

The heat shrink tunnel is wide and high on the inside. The sleeve shrink tunnel is narrow and tall. Both tunnel designs may use electric hot air, electric radiant heat or steam to heat the film or sleeve around the product. The best heating method is determined by the type of film and the cost/availability of the energy. If steam is used in the manufacturing process, diverting it to the shrink tunnel may be a very efficient move.

The location of the heat source in relation to the product is critical for heat sensitive product. For heat sensitive product the time in the tunnel is important. Very strong heat in a fast and short tunnel may be the answer.

The width of the belt and the material that it is made of is important for certain products. The belt width determines the maximum width of the product. This along with the tunnel height gives the size limits of the process. The tunnel length and belt speed determine the time available for the film to shrink.

PVC and polyolefin are the common film materials used and are thickness wise in the 60 to 100 gage range.

The automatic L sealer wraps product that has a certain maximum width which was established when the machine was purchased. Further, the product has a maximum height. This is a common limitation with shrink wrap machines. One rule says that the height should be no more that half the width of the product. The length of the product is flexible. The maximum length is usually determined by the size of the L sealing bar, but this can be modified in the field.

What makes this sealer automatic?  It is the continuous folding and feed of the plastic film, the insertion of the product plus a pulling roller mechanism under the product to move it into the sealing position. From there on to a shrink tunnel oven or to a holding table. A timing mechanism coordinates the movement of the sealing arm with all the other motion.

The sealing arm can have either hot wire or hot knife sealing edges. The hot wire sealer gets hot only during the sealing action while the hot knife is hot all the time.