For years, companies have been utilizing flatbed inkjet printers to decorate and label flat surfaces. Traditionally, flatbed printing applications have been onto objects such as USB drives, power banks, and notebooks. Although flatbed inkjet printers are the perfect solution for these flat parts, once the object becomes slightly curved, the printing becomes more complex. This article will outline what inkjet printing is and what the limitations are in terms of curvature of the part.
Flatbed inkjet printing works similarly to the inkjet printers found in homes and offices. But, flatbed inkjet printers can accommodate a wider range of substrates and object sizes than a standard inkjet printer. Flatbed inkjet printers can print on surfaces such as wood, stainless steel, metal, tile, glass, plastic, and more. Flatbeds feature a flat surface upon which an object is placed to be printed on. The printer takes a digitized 2D image and applies it to a 3D object by propelling tiny droplets of ink through the print heads and onto the substrate. Flatbed inkjet printing accommodates flat substrates that feed straight through the machine for printing a single side of the part. Since the parts travel into the machine on a travelling fixture and back out, manual loading and unloading of the fixture is necessary. This flatbed delivery system is typical for both large and small format pieces.
Flatbed inkjet printing is more environmentally friendly and economical than traditional solvent-based printing. The type of ink and the curing process differentiates flatbed printing from standard inkjet printers. UV curable ink is made from acrylic monomers, which instantly cure, or polymerize, when exposed to UV light. Flatbed inkjet printing operations are used in a wide variety of industries, most prominently the promotional, electronic, industrial, and drinkware sectors.
Flatbed inkjet printing offers many advantages compared to alternative methods. Switching from a traditional analog printing technology to digital printing will typically reduce manufacturing costs, simplify the supply chain, and add value to your products. Inkjet printing is optimal for high mix, low volume production. Unlike other methods, customization and personalization is practical, quick, and simple. One of the greatest benefits is the ability to produce full-color detailed images, right from the computer. Our society is becoming more and more digitized, and inkjet printers are keeping up with the times.
Inkjet printers were originally designed to print only onto flat surfaces. This is evident when examining the inkjet printheads. Printheads only jet the ink a few millimeters and decelerate quickly. Therefore, you want the printhead to be as close to the surface as possible. The throw distance can affect the print quality, especially the sharpness of images or text. In order to print directly onto the object, it should be placed directly under the printheads. Ink droplets can travel as far as 1-2mm before reaching the substrate for reproducing sharp text and 5mm or more for less detailed imagery. Although larger drops jet further, smaller drops improve graphical image quality.
Example: Printing on a ping pong ball:
Adding a third dimension adds another layer of challenges and complexities to the printing process. There are various types of shapes in the real world, but one distinct difference is the continuity in the direction of print. Objects that are considered continuous shapes include spheres, cones, and tubes. The curvature remains constant in the direction of the print, making this type of shape a little simpler to print on compared to discontinuous shapes. An example of a discontinuous shape is a tub, which requires corrections during printing when the curvature changes from flat edges to curved corners. The discontinuity across the printhead poses additional challenges. Innovations in inkjet technology have been continuously improving current capabilities, but we should still be aware of the limitations.
Some of the most popular alternatives to flatbed inkjet printing are decals, pad printing, and screen printing. All these methods allow companies to decorate curved surfaces. Decals and labels can be continuously printed on a roll, and therefore can easily cover non-flat surfaces. However, the process is usually done by hand rather the digitized, reducing throughput and increasing costs. Adhesion tends to be weaker with decals than inkjet printing, and many objects would not be able to pass the scratch test, squeeze test, or ice bucket test, respectively. Pad printing has risen in popularity due to the ability to print on almost any substrate and any shape object. The flexible silicone pad makes printing on curved objects possible. Pad printing is optimal for printing simple graphics and text in 1 or 2 colors. But multi-colored, detailed designs are not practical. Another downside is the setup time, cost, and consumables that are required. Like pad printing, screen printing requires lots of consumables as well as set-up and clean up time. Also, the process requires enough physical space to set up and wash out large screens. Orders with a high number of colors tend to be more expensive, as they are more labor intensive and time consuming to create. In addition, small order quantities and individually personalized items are impractical. Screen printing is ideal for high volume, low mix production. The operating complexity of traditional methods has influenced more and more companies to switch to digital printing.
Inkcups understands the limitations of traditional printing methods and is constantly innovating new solutions. We are focused on market expansion and production-capable systems. We have customized our larger printers, such as our X5-T, to utilize the latest printhead technology in order to print onto flat or slightly curved products up to 20 inches tall. Our Helix® rotary inkjet printer is designed to print superior quality full-color images on straight-walled and tapered cylinders. This machine is ideal for use in drinkware, barware, candle, and industrial printing industries. In addition to the numerous UV printers and inkjet inks we carry, we also perform all adhesion requirements for you. Once we have completed adhesion testing according to ASTM guidelines, we will send your samples back to you along with a comprehensive report.
Inkcups is your partner who understands your individual business needs. We are constantly innovating new solutions and are focused on your success. Our departments collaborate to create state of the art new machines that outperform other machines on the market on a price/performance basis. For more information, contact us today.