BOHEMIA, NY—FTA printer members manage doctor blade inventory and changeovers in different ways, but most—61 percent of those participating in a brief non-scientific survey, conducted in the form of a FLEXO Magazine Snap Poll this April and May—change their blades weekly.
Thirteen percent opt for switching a blade out after every job, another 13 percent every month and a matching 13 percent six months after initial installation.
The vast majority—74 percent—of those same printers utilize enclosed chamber systems. Thirteen percent elect to use a reverse angle doctor blade and 13 percent choose a two-roll system.
[infogram id=”june-2023-snap-poll-1-1h7g6k03mz7vo2o” prefix=”0h0″]
All see excessive doctor blade pressure as a potential pitfall. The greatest impact point—doctor blade wear—was cited by 89 percent of respondents. Next in succession garnering a matching 56 percent of votes—anilox roll wear and excessive ink film transfer. Chatter drew concern from 44 percent of the sample audience. Excessive plate wear captured 11 percent of the vote.
Responses came from invitations to participate that were contained in April and May editions of FTA’s MemberConnect e-newsletter. In developing the snap survey as a recurring feature, plans were formulated to approach a select printer member, considered to have an expert perspective on the topic and have the individual comment on findings as well as in-plant, first-hand experience.
“When talking about blade changes, I find that tracking them using the metric of time to be misleading in most cases. Measuring by footage, or impressions, can yield more consistent and predictable results. For example: I could have a set of blades that only ran 30,000 feet in a deck that hasn’t been used most of the week; meanwhile a set of blades in another deck could have accumulated 1 million feet and the blade change was only a couple days prior,” Dye offered.
He explained, “Metering and more so the anilox are often referred to as the heart of the press, so it is important that the metering system matches the design of the press and the way it meters caters to the application.
[infogram id=”june-2023-snap-poll-2-1h7j4dv87oyw94n” prefix=”t9S”]
“No longer is flexography only printing simple poly bags. Line counts are only getting higher, which require the necessary control that a doctor blade on an anilox can offer. I can’t compete by using fountain rollers at 2,000 fpm on 200 lpi, but at the same time, I don’t need a high-end doctor blade application for an inline flexo unit when fountain rollers are more than sufficient,” Dye stated.
He also cautioned, “It’s crucial that all do their part to ensure that the press gives predictable and reliable results.” That entails:
- Using the correct components (blades, seals and inks)
- Monitoring the conditions of the press
- Regularly examining the condition of the tooling
- Generating metrics that can reliably predict when the blade is considered worn, so that it can be replaced before it becomes an issue
“Without proper metrics and procedures, you will be left to make adjustments to prevent failure, causing unnecessary problems,” Dye advised. “A good metric to start at would be 0.008-in. standard tip blades, quality steel, 1 million-ft. target for the white; and 1.5 million feet for spots and process work.”
You must be logged in to post a comment.