In general:

The traditional squeegee does not allow a standardization in screen printing processes. The effects of solvents and other ink ingredients change the squeegee material permanently. The shore hardness of polyurethane is reduced and causes the screen printing squeegee to loose flexibility, immediately influencing the current printing angle and the set squeegee pressure. This makes it impossible to keep the initial inking and the image definition constant over a print run. Thus, screen printing will remain an experiment which is difficult to reproduce.

To solve these crucial problems, the RKS company has developed a squeegee system of its own, the well-known two-component product. It consists of a hard-elastic carrier which provides a constant printing angle, a uniform squeegee pressure and uniform flexibility. The second component, a soft-elastic Vulcollan strip, exclusively uses its accurate "print edge" to provide contact in the screen. It must adapt itself to the different surfaces of the fabric and printing material in a sealing manner such that a transfer of ink can occur. For the first time, this combination ensures an absolute plane-parallel print edge. The stable carrier blade excludes wavy printing streaks which frequently occur when traditional material is used.

The RKS squeegee system is available in heights from 20 to 145 mm.
We can offer shore hardnesses from 55° - 80° for the variety of screen printing applications. Except for the 55° shore variant, all other types are available with a thickness of 6 and 8 mm. The two different material thicknesses allow a very fine grading of the hardening effect the Vulcollan strips provide.
Example: Thanks to the hard-elastic carrier, 65° shore / 6 mm has a harder effect than 65° shore / 8 mm.

We recommend for:
coarse printing material / coarse fabric / high inking    8 mm / 65° shore
accurate print applications with a high accuracy fine coating / autotype
6 mm / 75° shore

If the flexibility of the RKS carrier blade is too rigid for a special print application, we recommend the use of the HF (high-flexibility) type of our program. This version provides an RKS squeegee the carrier of which is more elastic and can be shaped. The selection of the available shore hardnesses and dimensions are offered in the same extent as for the standard RKS squeegee.

The optimum printing angle of the RKS squeegee is 18°. The vertical is referred to as 0° by us. To increase the ink application, the print angle might be changed by 2° to a maximum of 20°.

Function:

The RKS squeegee is an accurate tool and must be handled correspondingly. Compared with a traditional squeegee, it requires less contact pressure for the same printing process. Therefore, an optimum adjustment of the squeegee is crucial. Thus, adjust the squeegee parallel with the printing table or the impression cylinder, respectively. Increase the printing pressure parallel and in fine steps until a printout is obtained. This adjustment needs no correction. Even if it is replaced with an RKS squeegee of the same height, the same print result  is obtained without any changes.

Never let the squeegee run without ink since the material will become too hot by this “dry run", and the print edge will break off immediately, resulting in an unnecessary squeegee grinding and a machine standstill. These costs can be avoided by careful handling.

Also "non-stop printing" will cause damage to the service life of all polyurethanes. We recommend a change of squeegees after 5 - 6 hours when ink containing solvents is used, after 4 hours when UV ink is used. Having cleaned it thoroughly, let it exhale for at least 12 - 24 hours prior to its next application. In this way the squeegee material will always work within a constant tolerance range. In addition, there is the danger that the printing edge will break off since it has swollen by the solvent.