I have a four-color flexographic printer, I would like to use the doctor blade system to minimize the passage of ink, what type of doctor blade should I use if my anilox rollers are not ceramic but metallic?
Oscar López – Poliempaques Ltda., Colombia
I would like to know if someone can provide me with information on the application of microscopic particles in flexographic printing in order to protect a document. Thanks.
Sara – Tags Maset, Spain
Please kindly send us addresses of suppliers of on-line inspection equipment used in flexographic printing-tape viewers, based on stroboscope. Thank you very much
I apply overlaminating polypropylene in-line using UV varnish as an adhesive, but small white dots appear between the polypropylene and the print, which gives the effect of making the colors lighter. These very small dots appear to be microscopic air droplets, but I cannot be sure they are air droplets. It happens to me using different varnishes from different vendors. I would like to know if anyone has experienced this problem and what solution has been given to it. Thank you very much in advance.
Horacio Ale – Fagra SA- Argentina
My name is Jeffrey Fragoso and I am writing to you because I have just joined
a company that makes plates for printing in Flexo and I would like to
know about their products and services because unfortunately I am
just getting to know this type of printing, and by the way it makes me very
interesting . Most of my professional experience has been in the
publishing branch but I only have experience in Offset. Greetings and I await your response soon. Thanks
Att. Jeffrey Fragoso Lozano – Montreal, Quebec, Canada.
I am doing a job with the following colors: Cyan, Magenta, Yellow, Black and Pant. 485. I can see from the Cromalin color test that at the place in the design where the five hatched colors mix, they form moire. Obviously I can get the process colors to blend properly, but I can’t add the fifth color without making it moiré. If someone can provide me with a solution on which angles to use, I will be grateful. The work will be printed with an anilox at 45>
Lic. Mariano H. Rivas. Buenos Aires, Argentina.
I would like to know more background about the Murray Davis correlation to determine the point gain and the correct way to use and interpret it. Thanking you for your response. Say goodbye,
Carlos Raineri V – Ing. Productos “Talagante”
We are about to acquire a new press and I have some questions about the anilox rollers, regarding the lines I am very clear, but I have doubts regarding the depths. Visiting Harper’s page, they say that the optimal depth is between 23% and 33% (ideal 28%) & nbsp; of the cell opening but & iquest; how the aperture is calculated & nbsp; of each anilox? with respect to its lineatura since it must be smaller opening as there are more lines by Cm and & iquest; how is the wall calculated? & nbsp; that separates each Cell. I imagine they must be different for each lineatura. The ideal cell is the one with a hexagonal shape and at 60 degrees? Note:
David Castiglione C – Caracas Venezuela
Dear Sirs: We are flexo printers and laminators; We manufacture laminated bags and we need to know a supplier of polyethylene check valves to be heat sealed, special for one inch diameter liquids. These giant bags with their adapted valve are placed in cardboard boxes and transport liquids such as wine, milk, syrups, etc. (Bag-in-Box). If you could provide contact information for manufacturers or vendors of these valves, we would be very grateful.
Ing. Rolando Sandoval – A. MULET INDUSTRIAL- Guatemala
In one of your articles we read about the results obtained using FIRST for printing, I would like to know more about what FIRST is and how to apply it in the company?
Carlos Sánchez Calderón – Printed Uyeda, Guadalajara, Jal. Mexico
The biggest advantage of printing with FIRST – (acronym that in English is: Flexographic Image Reproduction Specificatios and Tolerances), that is, specifications and tolerances in the reproduction of flexo images – is to offer a common specification for a number of variables in printing. For example, it recommends solid ink densities, dot gain values, minimum trapping sizes and values, minimum type sizes, and much more. In addition, it offers guides on how to avoid common printing problems, such as bullet banding. The specifications help the printer from a design, prepress and press point of view. If from the designer to the printer they follow the FIRST guidelines, the print will flow better and the quality will be acceptable the first time. The guides do not necessarily reflect the highest quality achievable, but rather a standard that most printers can achieve with reasonable care and cost. The FTA has published a book (in English for now) on this topic.
Michael Wiest, FTA / FFTA Technical Manager
I hear very often of the density of color. Could someone tell me what it is, how it affects an impression and how can I measure it?
Color density is the amount of color that the eye sees, that is, if a tone is more or less strong, not the quality, since it does not tell you if it is red or green, only the amount or strength of a color. The higher density you have in your inks, you will need a lower volume anilox to give the same tone. The higher the pigmentation of the ink, the higher the density with the same anilox. The density is measured with a densitometer, in the masses of a process, the densities should be more or less Y – 1.2 M – 1.3 C – 1.4 and n – 1.5. Always in an increasing sense.
In the Company we have recently had problems with the printing of polychromies (such as Photography), separation, negatives, photopolymers have been reviewed, but no progress has been made. We have a 6-ink central drum machine and even when it starts up well, after some time (10 hours), the photopolymers show wear problems and the operators incur
the “shim” to lift the rubber. What other variables should we take into account, if the rollers were checked and are fine?
Alfonso Chavarro MJ Production Riplast Ltda. Colombia
We had a problem quite similar to the one you mentioned, we could solve it by slightly changing the process in the processing of the plates, as well as the chemicals of the engraving and subsequent drying. You should also control the solvents of the inks and an excessive lynching of the plate during the process. printing process. If during printing, the points of the plate get dirty or dull, do not clean it with a tow or cloth as the points break, always do it with a brush and solvent. I hope I have been able to help you.
Where can I ask for advice, I mean any doubts or questions I have and can ask them by e-mail. What is the direction for this?
Roberto García – Painsa Mexicana, SA de CV, Mexico
For the question and answer page published in FLEXO ESPAÑOL ® , or on the Web, you can use the addresses provided by other flexgraphers or the following: firstname.lastname@example.org .
I wish someone would let me know where I can get a good book on flexographic printing. Thanks.
Sara, Spain, Maset
The FTA publishes the comprehensive textbook: Flexography, Principles and Practices, 4a. Ed. In Spanish or English, edited by experts in the field. Please send us your complete address to provide you with our Complete Guide to Publications and Services.
Terri, Marketing Department – FTA
I would like information on the elements or techniques used to know if a polyethylene film is well treated, that is, to be able to measure the dynes / cm of the film. Thanks.
It is essential to always measure the surface tension of polyethylene before printing. In the market, there are several manufacturers of pencils or markers whose ink has a set and controlled surface tension, they are specially manufactured for this purpose. It is advisable to have several markers of different voltages. For example, 30, 35, 40 dynes and check what tension we have the material before printing. This control is very easy and takes three seconds, possibly your ink supplier will be able to give you some manufacturer’s address or the formula to make the contrast liquids yourself.
I hope this forum is read by some ink manufacturer or someone who knows them thoroughly as I would like you to tell me why I have to filter them so often and I get lumps.
In our plant there is a central drum type printer with ceramic rollers which cleaning is normally done with a brush. I would like to know about other cleaning methods and if they exist in Colombia who has them.
Fernando Londoño G.
Plásticos Jaher, SA
We have the ghost problem. You are using a 600 line ceramic anilox roll with a squeegee chamber and still have the ghosting effect. It is only slightly improved if the ink drying speed is slowed but you start to have problems with highlighting or blocking. I would appreciate if you could answer me the same way.