Consumables
Sandvik strip for doctor blades helps increase printing productivity
Monday 09. June 2008 - Sandvik Materials Technology has used its steel melting and strip producing expertise to optimize the material properties for doctor blades for gravure and flexographic printing and is helping doctor blade manufacturers increase productivity in the printing industry.
Sandvik has a key advantage in that its totally integrated production, from steel melting to the finished strip steel product, is combined with extensive in-house
R & D, resulting in a range of stainless and carbon strip that has been designed and developed to give optimum performance and long life for doctor blades.
Control and balancing of the steels metallurgy results in strip steel with consistent properties. Specially developed hardening and slitting processes mean an almost stress free material and process control in manufacturing ensures a high degree of straightness, flatness, high strength and wear resistance. Excellent surface finish contributes to both corrosion resistance and fatigue strength.
Strip is also delivered with very smooth, burr free edges. Edge shaving techniques have been developed over many years and can be adapted to meet customer specifications. Doctor blade producers grind their own lamella edges or use Sandviks rounded edges for flexographic presses. There are two carbon steel material grades – Sandvik Sanprint RP and Sanprint EP.
For more corrosive environments, such as arises with the increased use of water based inks, there are two stainless steel grades – Sandvik Sanprint RPS and Sandvik Sanprint XPS. Stainless grades resist oxidation and emit less contaminants into the ink system.
For more wear intensive environments or for long series printing, Sandvik recommends that printing companies should test doctor blades made from Sandvik Sanprint EP and Sandvik Sanprint XPS and gain the higher productivity benefits from avoiding the unplanned stops due to worn blades that give rise to printing defects. Also, further increases in productivity can be obtained by using the high performance Sandvik Sanprint EP and Sandvik Sanprint XPS grades for the base colors when running CMYK. This avoids blade changes during four color runs and restricts changes to house colors between shorter print runs. For water based inks and CMYK set up, Sandvik Sanprint XPS is recommended to avoid corrosion issues. The choice of material grade depends mainly on customer emphasis and requirements for levels of wear and corrosion resistance.
If printing companies purchase blades with different characteristics from doctor blade manufacturers, they can tailor the blade set up to optimize blade economy and ensure blade productivity though choosing the right steel grade for particular printing circumstances. For less wear intense environments and/or house colors Sandvik Sanprint RP and Sandvik Sanprint RPS (water based inks) are recommended, but for longer runs and/or more wear intense environments Sandvik Sanprint EP and Sandvik Sanprint XPS (water based inks) should be chosen.