Crossing the Steel Divide

The dividing line in doctor blades is between steel and synthetic. Top-quality steel blades use high carbon steel, do the best possible job of metering ink from anilox rolls and are very durable. Synthetic blades have long been seen as an alternate solution for certain print applications, providing adequate performance while delivering safer conditions for anilox rolls and operators alike.

Some converters have chosen synthetic blades as a better match for their needs but have still sought the better metering ability of steel. Now, with Esterlam’s innovative line of laminated synthetic blades, superior metering synthetic blades are available directly from Provident.

“This is a shift for us,” says Andy Gillis, General Manager of Provident Group. “We’ve resisted synthetic blades because we never found any that could meet our customers’ standards in terms of performance. Esterlam’s blades are significantly different. They are engineered better, last longer, and provide the ink control customers want.”

Lamination versus molding or extruding

Most ‘plastic’ blades are extruded, in which a semi-liquid material is pushed through a die of the desired shape and dimensions. Others are molded, a process in which a liquid material is cast into a specific shape. The materials used in these processes can be formulated to provide some levels of hardness, durability and dimensional stability. Doctor blades made in these ways typically work well for a limited time period because synthetic materials are softer than steel resulting in faster wear and more frequent changes than steel blades. This can be acceptable for certain applications, but frequent replacement has its own costs: the need to buy and inventory additional consumable products, press down time during changeover, and in some cases a decline in print quality.

The alternative is Esterlam synthetic blades, which are manufactured from biaxially oriented polyesters. The polyester is heated, stretched and rapidly cooled under tremendous pressure to create a harder material with great chemical and thermal resistant properties. Combine this with a unique laminated construction and precision engineered profiling and you have excellent metering characteristics, that cause less wear on anilox rolls than a steel blade, and have durability that can approach that of some steel blades. They are lighter than steel, easier and safer to handle, and can still match color requirements within minutes of start up because laminated blades are harder than extruded or molded blades and provide a cleaner wipe.

Provident’s distribution agreement with Esterlam, the inventor and sole supplier of laminated doctor blades, enables Provident to provide a full range of the best quality steel and synthetic doctor blades on the market. “Customers who have any bladed printing, coating, laminating or corrugated applications, and most label markets are all advocates for synthetic blades,” says Mr. Gillis. “With Esterlam, we can offer customers synthetic blades that meet their needs.”

The laminated difference

Think of the strength and flexibility of plywood compared to non-laminated lumber. The difference lies in the way thin layers of wood are combined, and the same is true when several thin layers of polyester are combined to create a doctor blade. In the case of Esterlam’s E-Series blades for example, the proprietary material components have been bi-axially oriented, aligning molecules to create a strong, highly stable structure that allows blades to remain stable at a wide range of operating temperatures. The process also gives the blades springiness, much like that of steel, that non-laminated synthetic blades typically lack. This helps them maintain the desired pressure across the length of the blade and provides a “memory” for dimensional stability under prolonged use, an important attribute for printers of corrugated materials who may keep a blade in place for up to a month.

Mr. Gillis says demand for flexographic printing on corrugated material is expanding rapidly and that Esterlam’s blades positions Provident to serve that market with both steel and synthetic blades. “The laminated blades are far superior to traditional synthetic blades,” he notes. “Just as with our long-life steel doctor blades and end-seals, the difference for printers and converters is the value they receive from products delivering high ROI. Esterlam’s laminated blades can run longer while maintaining print quality, making them a more efficient and more economical consumable.”

See for yourself

Provident will be showcasing Esterlam’s blades in Booth 939 at Labelexpo, where you will be able to talk with technical experts and see the difference lamination makes in doctor blade technology, and maybe help you cross the steel divide for some applications.