There are many factors that will allow you to consistently produce high-quality flexographic photopolymer plates. Below I’ve compiled my list of recommendations to keep your platemaking consistent.
Keep Your Plateroom Clean and Dust Free
One of my most important recommendations is to maintain a clean and dust free plateroom environment. The plateroom should be an enclosed area to facilitate proper ventilation and elimination of dust. Dust and dirt will ultimately make it to your exposure frame and result as pinholes and imperfections in your plates.
Perform Stain and Focus Tests on Your CDI
If you think about what your CDI (Cyrel Digital Imager) is doing, it is basically imaging a negative directly onto your plate material. A stain test will verify that you are using the proper imaging power levels to ablate away the imaging mask or LAMS layer on the plate material. It is important to use a transmission densitometer to verify that after ablation, the ablated or imaged area falls within the CDI manufacturers and plate material suppliers density guidelines. This image or ablated area that will become the image that you print after exposure and processing.
Focus tests are necessary to ensure that CDI is imaging as sharp and crisp as possible. If your CDI is out of focus your plate and print quality will surely suffer. It is the same concept as taking a picture; your camera lens should be in focus to deliver the sharpest image as a camera out of focus equals a blurred image. The same is true when a CDI laser ablates the image onto your plate material.
Monitor and Maintain Floor Height/Plate Relief
Monitoring and maintaining floor height/plate relief is extremely important because it is the foundation for your printed image. We all know the saying, “your house is only as stable as its foundation” and that certainly applies to maintaining the proper relief for your plate material.
Too little relief and you’ll be printing not only your image but on the floor of the material and filling in reverse type as well. Too much relief there will not be enough support to hold fine detail areas or screen dots. They can fold over or collapse under printing pressure. Floor height/plate relief can quickly and easily be checked with a micrometer.
Inspect Your Exposure Bulb Intensity
As your exposure bulbs age, there is a drop off in their output intensity. Eventually, the UVA output will no longer have the required levels to properly expose more demanding images (screening/dots) onto the plate material. The easiest and most reliable method for checking bulb output is to use a UC output measurement device such as a Kuhnast meter. Keeping a record of your bulb’s UVA output will allow you to be proactive and eliminate plate exposure issues before they occur.
Measuring and monitoring these critical components will help you consistently produce quality plates. By following the above recommendations you will be equipped to keeping your plateroom running efficiently and effectively. Mark Andy Print Products has a team of experts dedicated to helping you solve your platemaking inefficiencies while offering the latest DuPont plates, platemaking equipment, and CDI units.
About the Author
Dr. Flexo (Bill Enright, Senior Applications Engineer at Mark Andy) has been in the printing industry for over 30 years, serving in a variety of different roles from plate mounting to operations management. Bill has earned his doctorate in printing. Throughout the years, he's learned the quality of a print job is only as good as the consumables that go into it.