Flat-Top Dots
Let’s start by stating what is meant by the term flat-top dot. A flat-top dot on a photopolymer plate is one that accepts the transfer of data from an imaging device to the finished plate at a 1:1 ratio. The 1:1 imaging ratio is measured in the file, post-CDI imaging, and ultimately on the final plate.
Now, let's dive into the details of what we have identified as the most frequent questions people ask about flat-top dots. We will release one question and answer over this 10-week timeframe.
Part 3. Flat-top plates can be less susceptible to damage, wear, and can offer longer press runs. Why?
- Studies show that most plate damage and nearly all wear occurs on the press. Studies also show that a plate is far more likely to be damaged before it is worn out. Interestingly enough, both plate wear and damage does happen on press, but not necessarily when the press is moving. Stopping the press to clean plates from ink build-up (dirty print) is considered the point in time that the plate will be damaged through the attempt to clean the screens on the plate. Therefore if the press can remain up and running as a benefit from the impression latitude of the flat-top dot plates, the better we position ourselves to extend plate life.
- Ironically, plate wear can sooner be identified on the lead edge of a solid before most screen areas because screens allow more movement of the dots in the web direction. In contrast, solids take the brunt of the impact. So why do we so often identify a worn-out plate by the poor image quality within a screen?
- Wear in a solid is often considered less critical or overcome with an adjustment to impression. Wear in a screen can cause a shift in [process] color and is easily detectible, and not so easily overcome.
- Most plates sustaining damage or deemed as "worn out" are a direct result from continuous stopping and starting on the press to clean out the screens of ink build-up within the relief areas of the screen. Remember, even though you may have a designated plate relief on .022", the relief within the screens on that same plate may only measure .004" - .008" and can easily fill in.
Check us out next week when we explain why, “You can achieve better Quality Control when manufacturing and verifying the flat-top photopolymer plate. How?
If you want to learn more about this subject, please feel free to reach out to us by calling 1-800-445-4017, or by e-mail at [email protected].
All Printing Resources has formed our Technical Solutions Group (TSG) to encompass our full range of expertise in all critical areas of the flexo process. This team is made up of industry professionals dedicated to being up-to-date on new technologies along with best practices. They are armed with the latest in diagnostic tools and are experienced in problem-solving that can achieve sustainable results. The TSG has walked in your shoes, and have felt your pain.
Click here to read: Part 1, Part 2, Part 3, Part 4, Part 5, Part 6, Part 7, Part 8, Part 9, Part 10.