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 5. Are all flat-top polymers created equal, or do they differ?
- While by definition, plates obtain their flat-top classification by adhering to only one plate attribute of many (1:1 imaging to plate ratio), there are several methods photopolymer manufacturers have created to eliminate oxygen inhibition that creates the sharpening or rounding of conventional digital plates. Some manufacturers rely on an additional membrane that is imaged and then laminated to the raw sheet of photopolymer. Some introduce an inert gas to the main exposure process that pushes out oxygen during exposure. Others use UV LED exposure in an effort to "outrun the oxygen". Several manufacturers have formulated the raw plate material itself to resist oxygen inhibition and result in a flat-top using existing conventional exposure equipment. Some of these methods achieve a true 1:1 image reproduction on the plate with more accuracy than others. Still, all will likely fall within the accuracy tolerance of the plate measuring device itself used to evaluate such a measurement.
- Again, the 1:1 image ratio is often the focus when testing flat-top plates. Still, other considerations include the best plate durometer for your inks and substrate as well as platemaking equipment considerations.
Check us out next week when we answer the question, “I have been told that all water-wash polymer plates are flat-top inherent; is this correct?"
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.