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.
Week #9. Users of fat-top technology experience fewer press stops required to clean plates and therefore enjoy more press uptime. How?
Most understand that flat-top technology is a forgiving plate that offers great ink laydown and SID. But for those who have already dialed in their process and inks are laying down without graininess (a.k.a pinholing) and mottle (a.k.a. orange peel) is the difference that great within overall print quality – assuming you're plates are also running clean?- The flat-top dot structure lends itself to accept ink precisely on the dot face versus the face/shoulder radius of a conventionally sharpened digital dot. Keeping the ink on the plate face and off the plate shoulders is critical to prevent fill-in within screens that results in dirty print on the press. Dirty print means rejected product, press stoppage/downtime; in short, lost revenue!
- Note, this doesn’t even include the likelihood of damaging delicate screens on the plate as the press operator attempts to remove the ink build-up from unwanted areas of the plate shoulders and relief area.
- As a press runs a job for several thousand feet or impressions, some operators experience photopolymer plate swell, which then requires them to adjust their impression setting accordingly so they do not see dot gain or halos around printed images. Remember, flat-top plate technology is arguably most known for its impression latitude. In other words, if one press operator over impresses the plate then another would have achieved a perfect impression, the difference between the two products is often minimal. Therefore in the unfortunate event that the plate does swell, this slight difference in increased plate caliper is often non-distinguishable on the printed product.
- Keep in mind it is always wise to do a swell test to determine the best photopolymer product is being used with your ink system.
Check us out next week, our final installment, when we address "What are cynics saying about flat-top technology?
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.