Daetwyler Swisstec – MDC Pearlstar, a doctor blade with a fluid-repellent coating
MDC Pearlstar provides a new fluid-repellent coating (Source: Daetwyler Swisstec)
Daetwyler SwissTec, a Swiss manufacturer of precision doctor blades repositioned themselves a few years ago to meet the changes in the global market. This repositioning also included the development of new doctor blade products, such as the MDC Pearlstar provided with a fluid repellent coating.
Written by Ansgar Wessendorf
The doctor blade – Function and types
In the flexo and gravure printing processes, the doctor blade is a blade-like, smoothed steel bar which ensures that surplus inks or other transfer media is cleaned from the surface of the anilox roll or the printing cylinder so that the only media remaining is contained in the cells (“doctoring”).
In flexo printing a special variant of the chamber doctor blade is used which is made up of a combination of positive and negative blades with a flange-mounted chamber containing the relevant transfer media. This blade/chamber system is attached to the anilox roll and therefore ensures optimal filling of the cells and a continual even ink transfer.
Selection criteria for doctor blade materials
To find the most suitable doctor blade for each customer and for each application, Daetwyler Swisstec has developed a range of coated and uncoated doctor blades over the past 45 years. According to the company, probably the best-known doctor blade in the printing industry is the self-developed “Longlife” blade.
In addition, the segmented blade profiles have also been further developed to provide print-shops with the most convenient doctor blade for their individual needs.
In general, the doctor blade must fit to the respective application to ensure that the print job can be performed as efficiently as possible. In doing so, print-shops must consider many relevant factors to achieve optimal and efficient print and coating results.
New fluid-repellent coating
A crucial problem with doctor blades is the build-up of transfer mediums. This is of particular importance, as such a phenomenon may impair the function of the doctor blade later in the print run.
In order to counteract this problem, Daetwyler Swisstec has developed the new MDC Pearlstar doctor blade for flexo and gravure printing and coating applications. It offers the promising opportunity, to reduce and even completely avoid the adhesion of colours, paints or adhesives during printing and lamination.
According to the manufacturer’s specifications, this is the first doctor blade with a fluid-repellent coating which can be used to achieve outstanding results, particularly when used with cold seal mass, lacquers or other adhesive colours and other transfer mediums.
In contrast to other similar products, this new type of coating is not applied in a galvanic process and therefore offers several advantages. The reduced build-up of printing inks and other transfer media results in fewer drips and streaks in the printed image and contains very high performance parameters when used with cold sealing materials and printing inks. It eliminates or reduces ink splashes when used with UV-curable inks and lacquers and back doctoring during the flexo printing processes.
MDC Pearlstar is offered with lamella (segmented blade), multi-blade and Flexolife profiles. This doctor blade quality is available in widths from 10 mm – 60 mm (0.39” – 2.36”) and the material strength ranges from 0.15 mm to 0.25 mm (0.0059” to 0.0098”) in the standard version. Other configurations are available upon request.
Daetwyler Swisstec – Company Overview
The headquarters of Daetwyler SwissTec AG are located in Bleienbach in the canton of Bern, Switzerland. Since 1972 the company has been producing high-quality, coated and uncoated doctor blades for gravure and flexo printing, as well as for special applications such as coating and laminating. Recently, Daetwyler Swisstec has been focusing on these special applications and has been carrying out development work with its technical team, which currently consists of 40 technicians worldwide.