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Gorilla Flexo™ Articles:  Tips and Techniques

Gorilla Flexo™ Tips and Techniques

The following tips and techniques have been submitted by fellow printers and can be put to use in your shop right away. No elaborate installations or implementations, no planning or meetings required. They are the result of many years of practical, hands-on experience working in and around pressrooms on a daily basis. Some are quite simple, and may even be obvious to many of you, but they can easily be overlooked and therefore, are worth mentioning here. Others are unique and creative solutions to common problems printers face every day.

New Tips:
Are Your Screens Filling In?
Achieving Dense Black & Halftone on Same Plate!

If you’ve got a particularly useful tip or technique, please submit it here
so other printers can benefit from your experience.
Submit Your Gorilla Flexo Tip or Technique

 

Equipment Maintenance .....................................................

  • Cleaning Rollers
    Submitted By: Bruce K. Boutin

    When running photopolymer film through the press it is always best to have good quality film which has been wound evenly. This is optimal, but not always possible. Hence, whatever you have for film stock is what you run. I've found that using 2" masking tape will help to straighten the film being run by putting 1 piece on each of the outer edges of film on 2 or 3 rollers before the print cylinders lay their impressions.

    After running 30" film, then 40" film, then 24" film, and various widths I've found that even though I remove the tape from my rollers after a couple of times (or even once) there is still a sticky residue left on the rollers from the tape. Even though the rollers are cleaned regularly with my normal solvent N-Propynol, the residue from the tape will remain. In order to remedy this I use a rag saturated in acetate to clean the rollers. This will eat through the residue as well as any tape remaining to leave a clean roller.
     
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  • Sonic Cleaning of Anilox Rollers
    Submitted By: Bill Yeager

    One of the issues that I have seen regarding sonic cleaners is that it is extremely important that the roll is not left in one position for too long. This can cause damage to the anilox roll that will cause you to replace rollers prematurely. Most manufacturers of narrow web sonic cleaners offer the option of purchasing a roll motor to turn the anilox continuously, an option well worth purchasing.
     
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  • Close-Fitting Parts
    Submitted By: Frank Burgos

    Avoid abusing close-fitting parts such as plate cylinder gears, journals, bushings, etc.. If a part is difficult to remove, install, or adjust, removing a burr or applying a lubricant can make a great difference in machine performance and ease of operation.
    Don't just get a bigger hammer!
     
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  • Filing Parts
    Submitted By: Frank Burgos

    When filing burrs off of cylindrical parts, follow the curvature of the part with each stroke to avoid flat spots. With practice, very little material is removed and parts remain within tolerance longer.
    Note: Most files remove material in only one direction.
     
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  • Nip Rollers
    Submitted By: Frank Burgos

    "Open" or unload all nip rollers when leaving machines down for an extended period of time. If not, flat spots may develop on rubber nips resulting in accelerated wear, quality problems, tension problems, etc.

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Set-Up ............................................................................................

  • Running Solids with Halftone Screens
    Submitted By: Mary Orther, owner www.stickersexchange.com
     
  • One of my favorite tips has to do with running solids with halftone screens. I use two print stations. One plate is the Solid background and the second plate is the halftone. I match them up on the press and "voila", a nice solid black background and a clean halftone with no fill-ins.
     
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  • Epson Photo Printer for Negatives
    Submitted By: Mary Orther, owner www.stickersexchange.com
  • We just recently started using our Epson Photo printer for negatives. We purchase Film Transparencies at an office supply store and set the printer preferences to Luster Photo, which pours on the ink for an adequate black background. For finer and smaller type, we outsource our negatives. But this little printer has been a life saver.
     
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  • Impression Setting Sequence
    Submitted By: Dave C.
     
  • I usually set my impressions in order from last station to first station. This way, I see only the impression of the station I'm setting, without interference from the other impressions.
     
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  • Dry Registering - C.I. Press
    Submitted By: Tony Hicks
     
  • Many C.I. printers are familiar with "dry-registering", or registering plate cylinders before inking up. I mark the bull gear on the drum with a magic marker or "White-Out" (this applies to C.I. presses with one large bull gear). I then bring the mark around by "jogging" and line the mark up with a scribe line or register mark on the plate cylinder. To avoid over-shooting the plate cylinder while "jogging", I also make three or four "warning" dots ahead of the mark.
     
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  • Removing Plates from the Mounting Tape
    Submitted By: Frank Burgos
     
  • If you are having difficulty removing plates from the mounting tape, you might try the following:
     
  • For Rubber Plates- A blend of ordinary wood shellac and normal propyl alcohol brushed onto the back of the plate makes for easier removal. I've used about 25% shellac to 75% alcohol, but you'll need to find what works best with your particular situation. Mounting tape, impressions, etc. all play a part in how strong the bond between tape and plates are after a run. Wiping the shellac off of the leading and trailing plate edges, taping them down, or sealing the edges may help combat plate lifting.
     
  • For Photo Polymer Plates - Try a blend of extender and normal propyl alcohol applied to the back of the plate. Again, the ratio of extender to alcohol is arrived at by trial-and-error. Adding a little colored ink can help catch missed spots.
     
  • Review "Material Safety Data Sheets" and observe all applicable safety precautions. Be sure that these ideas are consistent with your company's materials policies before trying them.
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Print Quality ..................................................................................

    Are your Screens Filling In?
    Submitted By: Nick Coulbeck, Kingsway Printers, UK

    Having to continuously clean out your plate screens? Try this simple guide. It should give a better anilox/plate match.

    Working with a standard 150 dpi plate:

    Minimum plate dot 4% = minimum anilox 600 lpi (38 mic.)
    Minimum plate dot 3% = minimum anilox 700 lpi (33 mic.)
    Minimum plate dot 2% = minimum anilox 900 lpi (25 mic.)
    Minimum plate dot 1 % = minimum anilox 1200 lpi (18 mic.)

    This formulae stops the minimum dot falling in the anilox
    cell.


    Achieving a Dense Black & Halftone on Same Plate
    Submitted By: Nick Coulbeck, Kingsway Printers, UK

    If you are running a solid black, on the same plate as a halftone process image, and need to achieve a strong density, add the solid image area to your cyan plate. Gripped slightly back, this will underlay the black, and give the black something to sit on, giving it density.
     

    Detecting a Bubble Under a Plate
    Submitted By: Sean Houer, Finewrap Australia

    I have a great way of detecting whether or not a bubble may be emerging in a plate. When I splice over onto a new reel most new presses will lift the impressions for a given length, this is to avoid damage to the plates from the actual tape join. When I splice at the Rewinder and inspect the beginning of the new reel and the end of the original reel, I can see where the impression lifted momentarily and where the impression came back down. When the cylinder was lifting of the substrate I should be able to see any higher spots on the plate that is likely to suffer a bubble. Also it helps to listen out for the changing tone of the plate while it prints, if it starts to get really noisy chances are you have bubble trouble.
     

    “Shimming” Combination Plates
    Submitted By: Marty Vavra, Label Products Mngr., Wal-Mart

    If you are using a plate that has a combination screen and solid image areas, and you use shellac on the back of the plates for easy removal, come back with a second coat of the shellac (fine paint brush) for the solid images areas (only). This will create a shim effect in the solid images, causing the solids to begin printing first before the screen areas of the plate, when setting impression. Also, using a permanent black marker, mark the plate (backside) at the plate gap. The solvents in the marker etch into the plate backing and create an aggressive surface for the plate to stick to the sticky back, preventing plate lift and moisture from getting under the plate.
     

    Particles Sticking on Plates
    Submitted By: Chuck Cotrell

    I operate a wide-web C.I. flexo press and normally unwind large rolls whose surface comes close to the ground. My co-workers and I were constantly wiping dirt, metallic flakes, etc. off of our plates due to static picking particles off of the floor and carrying them to the plates via the web. I discovered that by unwinding the roll with the film coming off the bottom, the side of the web facing the floor contacted the drum, not the plates, and the plates remain cleaner for a much longer time. (Unwinding direction may differ on other equipment)
     

    Measuring Additives
    Submitted By: Frank Burgos

    It is best to measure when adding ingredients to inks and coatings. Doing so helps to maintain consistent quality, reduces waste, and simply helps avoid potential problems during the run.

    Think you don't need to measure? Try a little experiment just for fun. Prepare a bucket or other container by covering the opening. Now, cut an opening just large enough to pour into without being able to see into the bucket. Pour in an additive (observe all applicable safety procedures), recording how much you expect you've added. Pour the contents of the bucket into a measuring cup/container and compare the actual amount with what you "thought" you added. Try it a few times. How accurate are you? How consistent?
     

    Video Inspection
    Submitted By: Frank Burgos

    If your video inspection system lacks the sophisticated software/hardware to automatically pan vertically/horizontally across your print, try this. By entering a value for the number of gear teeth different to the repeat, I could get the image to "pan" vertically. Also, in cases where the plates are mounted more than "one up", dividing or multiplying the cylinder repeat by the right number allows viewing each impression.

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Miscellaneous Tips .......................................................................

    Clean Hands!
    Submitted By: Frank Burgos

    Most printers know the annoyance of having ink-stained fingertips and nails. I've discovered a product that works so well that I had to mention it here. It's called "Invisible Glove" and when used consistently and as directed, it is amazing at keeping your hands and nails cleaner. So far, I've found it at Western Auto, Wal-Mart and Sherwin Williams Paint stores.

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