Heat-shrink Tubing FITCOTUBE®, Processing Equipment

Printing of heat shrinkable tubing: Variants and methods

Our FITCOTUBE® heat shrinkable tubing is distinguished by its high resistance with consistently high surface quality. Effectively, they protect wires and cables from mechanical, thermal and chemical influences. Different versions of our heat shrinkable tubing are available including international approvals and specifications, e.g. MIL or UL approval. They are particularly suitable for the requirements of automotive, environmental, medical, aerospace as well as industrial engineering. An additional application for heat shrinkable tubing is for specific marking of wires and cables as well as wire harnesses and cable looms. Color coding is the simplest and at the same time clearest option for marking. However, if designations with specific information are further required, meticulous marking by means of printing is possible. This ensures clear identification as well as information on performance characteristics and potential approvals. Labeling of heat shrinkable tubing via printing is primarily required in railroad and aerospace engineering, but sometimes also in industrial engineering, audio and video applications, and event technology.

Possibilities of printing of heat shrinkable tubing

The following four methods can be distinguished for the printing of heat shrinkable tubing:

1. hot stamping
2. tampon printing
3. thermal transfer printing
4. laser printing

Printing of heat shrinkable tubing via hot stamping

The most basic of the above-mentioned printing processes is hot stamping. It involves first heating stamps with the desired character set. Subsequently, these are pressed onto the shrink sleeve over an ink ribbon in order to carry out the printing. Hereby, printing with alphanumeric codes is made possible. However, since changing the stamps used, followed by reheating, is extremely time-consuming and cost-intensive, the hot stamping process is only useful for printing very large quantities.

Tampon printing

Tampon printing of heat shrinkable tubing is an indirect process whereby the printing ink is transferred from the printing mold to the shrink tubing utilizing an elastic tampon, usually made of silicone rubber. During this process, the ink is transferred in varying thicknesses by pressing it pointedly against the desired areas. However, since tampon printing is limited as a printing format in the variation of sizes and only allows a low ink layer thickness, GREMCO does not conduct any printing using this technique.

Printing of heat shrinkable tubing via thermal transfer printing

The most commonly used process for printing of heat shrinkable tubing is currently thermal transfer printing. Individual pins are heated electronically in a print head to produce the desired print image. By means of a thermal transfer ribbon, the printing of the shrink tubing is completed. Due to the electronic control, thermal transfer printing is characterized by high efficiency as well as fast adjustability and is therefore excellently suited for frequently varying printing patterns. Furthermore, in addition to alphanumeric codes, barcodes and graphics are also possible. Consequently, this is our main printing process.

Laser printing

In the laser printing process, the required information is transmitted via laser to the printer in a file format. This data is then transferred to an electrically charged image drum using a laser to discharge the image drum at specific points. The still charged parts of the image drum in turn attract the color toner. Finally, the shrink sleeve is passed between the drum and the transfer unit and again pulled onto the printer paper utilizing an electrical charge. The printing now lying loosely on the paper is immediately fixed and pressed using heat and roller pressure. The described procedure is unusual regarding the printing of shrink tubing, which is not practiced by GREMCO.

Consistency and material

The print resistance is primarily dependent on the material. Especially with our preferred method of thermal transfer printing of heat shrinkable tubing, attention is required to the material combination of the shrink tubing to be printed and the material of the thermal transfer ribbon in order to ensure lasting printing. Furthermore, the respective surface condition of the tubing is important for clear printing. For these reasons, we recommend specially surface-treated shrink tubing made of polyolefin, the surfaces of which enable particularly clear printing. On request, it is nevertheless possible to try printing on other types of tubing. Due to the signal effect as well as the easy legibility GREMCO mostly uses white or yellow hoses for printing, imprinted in black color. Of course, any other color combination is also possible on request.