Welcome to our first blog post in the Cold Foil Best Practice Blog Series!
K Laser is dedicated to your success so we have decided to launch a new series based off the best practices when using cold foil.
As more printers seek to diversify their product portfolio and expand their business, cold foil embellishments have become the economic and eclectic solution for many. However, there are multiple factors that determine the success or failure of your cold foil printing and lamination. The K Laser Cold Foil Business Unit is a global manufacturer of the largest selection of metallic and holographic cold foil substrates, as well as quality adhesives. In our cold foil best practice blog series, we discuss our insight and best practice for producing captivating cold foil embellished products using the flexographic printing process.
To begin, proper press set up is a must. Arranging the press properly is the first step to achieving consistent cold foil lay down and adhesion. In the first blog of our wet lamination cold foil series, we share our knowledge of proper press set up to help printers configure their equipment to be the most efficient and waste-free as possible.
Equipment & Press Setup
Due to its ease of operation, wet lamination gained market acceptance quickly and is now the most commonly used cold foil printing process. As printers invest in new cold foil equipment and retrofits, it is important to consider press configuration and proper set up. Here’s a rundown on the equipment you need to properly perform cold foil printing:
- Foil unwind and rewind
- Nip assembly with a hard (90 shore) durometer rubber
- Stripping roll
- UV Dryer (preferably 600 watts)
- Print station (flexographic, letterpress, or offset)
Now that you have the necessary equipment, let’s talk about press set up.
- Locate a nip station (entry nip) immediately after the print station that will be printing the adhesive. Either a manual or air-actuated nip is acceptable as the wet lamination nip station doesn’t require a high degree of pressure.
- Re-web the press so that the substrate enters the nip station immediately after the impression cylinder. The printed side of the substrate must not make contact with any idler rollers between the impression cylinder and the nip station. Otherwise, the printed image will be smeared.
- Locate the UV dryer as close as possible to the entry nip and before the hot air dryers. You want to prevent the hot air dryers from delaminating the foil from the substrate.
- Install the stripping roll after the UV Dryer. If you try to use the bottom roller to strip the foil from under the substrate, the foil will bunch up right before the idler roller and will eventually ride up into the UV dryer. Instead, install the stripping roll between the UV dryer and the bottom idler roller.
- Locate the laminating arm and the waste windup as close to the print station as possible for ease of operation.
Nip it good!
The most important part of the foil lamination process is to maintain perfect lamination of the coil foil onto the substrate. The cold foil must be nipped onto the substrate without any creases and must stay completely flat until it is stripped from the stripping roll. In addition, the foil must travel the same speed as the substrate. Creases, air pockets, or foil lift may occur if the foil is not flat and in speed with the running substrate; this will result in poor foil transfer quality.
We recommend using a 90 durometer (or higher) nip roll to laminate the foil onto the substrate. Install this nip roll between the print station and the UV Dryer - the foil must be laminated onto the substrate before the UV dryer. A bare idler roller can be used as an anvil under the nip roll, but ensure it is completely clean and free of any marks or scratches. P.S. When using a nip roll, be sure to get the highest durometer possible; a low durometer nip roll will cause pinholes. Here’s some guidelines to follow to ensure a seamless nip:
- The foil must enter the entry nip at 45 degrees (or higher) to prevent creasing.
- Do not feed the foil directly from the roll because this will crease the foil. Any small amount of crease will cause the foil to lift at the point of cure.
- The foil must come in contact with the substrate at the nip point to prevent air entrapment.
- The nip roll and bottom rollers must be clean. Any contamination or marks will transfer to the folded image.
- Make sure the idler roller under the UV dryer is level.
Set up for success
Achieving intricate cold foil embellishments on your client’s packaging starts from the ground up. Investing the time from the beginning to set up the press in proper order and alignment will help you achieve the intricate cold foil embellishments that your client's request. The K Laser Cold Foil Business Unit (CFBU) is here to help you navigate the complexities of cold foil printing like a pro. With the largest variety of cold foil colors and holographic substrates, K Laser takes pride in delivering quality cold foil products, on time and on budget. Contact us today to learn more about our KOLDfoil ONE products, adhesives, and print services and choose the CFBU to be your cold foil partner for the long run (and short runs too).
PART 2 Cold Foil Wet Lamination Blog Series - “Print Job Prep for Wet Lamination Cold Foil Printing
Now that we’ve set up the press and the proper nip points, it’s time to choose the proper anilox, foil, adhesive and prepare the press for print. We cover this in part 2 of our cold foil printing best practice blog series – “Print Job Prep for Successful Cold Foil Printing”
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