Firstly, it must be said that digital printing for the decoration of 3D objects is quite recent application and to date it is not yet comparable to a well-established technique such as pad printing. However, this does not mean that one of the two technologies is necessarily better than the other. Each has its own space in the market and will always have, we can also say that they can even coexist. In this article we will try to analyze what development these two technologies may have and what they will mean to industry in the coming years.
Pad printing is the most widely used technique for printing shaped objects.
If we think about the time passed from the late 1980s up today, it is easy to perceive how the industry has evolved and more precisely that closely related to 3D object printing. At that time, pad printing was competing with technologies such as hot stamping and screen printing and we all know how it has developed to this day.
Pad printing is an indirect printing process, where a silicone rubber pad picks up and deposits the graphics to be printed from an engraved cliché to the piece; this entails a preparatory phase, which passes from the graphic realization to the development of the cliché. Solvent-based inks are used, specifically designed to satisfy all materials on the market. UV inks are also used, but only for applications that accept certain limits, such as coverage and especially reduced resistance to testing on different types of materials, the color scale is limited.
The introduction of hermetic systems, replacing open trays, as ink containers, have led to a considerable simplification of the pad printing process, which, combined with its application possibilities, that is to print any geometrical object and on multitude of objects, have made pad printing the most used technique in the major sectors of industry.
It is definitely the most suitable for printing from one to several solid colors, halftones or process-color with optimum print definition of thin lines on shaped objects. For several decades it has been consolidated in the industrial sector, and has adapted over time to changes in the market. Originally created for single color print, it soon became clear that a second wet on wet color could be printed, up to process-color or multiple colors print. This has made pad printing appealing to lots of applicative fields where an object calls out for customization. We went from the use of simple single or two-color machines, to more complete multi-color machines, run by an operator.
Today, the most successful companies always use newer and extremely flexible machines, and have oriented their choices on modern full-electric equipment, where all movements are numerically controlled. This choice was not only for greater energy efficiency, but also for higher performances and greater application flexibility than pneumatic drive machines.
Labor in industrialized countries is a high cost center for companies, so it is essential to constantly think about innovation and how to deliver added value to customers in order to maintain a competitive advantage over competitors. The technology has allowed pad printing to carve out an ever-increasing space in production contexts where strong automation is required. Perusing and finally offering the customer automatic machines that process parts from the load to the unloading, with quality and process control systems, allow to maximize performance, reducing to zero waste. Recognized as reliable and flexible, it is the most suitable technology to satisfy the requests that a three-dimensional object requires.
These machines can better use robotic technology. The use of this type of automation is and will increasingly become the first line of defense for a technology such as pad printing, to remain strong and competitive in a market where the goal will be to better serve its customers at the lowest cost.
But the technology advances and techniques evolve: in recent years, inkjet printing has imposed itself, more commonly known as digital printing.
Digital Printing is a direct contactless printing system, and is appreciated as a simple and versatile technique, with great potential for expansion. It is appreciated for the speed of setting up the processes and has the advantage of skipping the passage of the pre-printing phase. It is enough to start from a computer file and communicate it to the printer's conversion program. At this point, all the print parameters are digitally looming and the processing starts. The machine is composed of a group of quality print heads, which have the task of placing the drops of color with the utmost precision. The print heads work at a minimum distance from the surface of the piece to obtain the best print resolution. If this quota lacks, the print quality deteriorates.
The color feed system is modular, and is mainly based on process colors with the addition of one or two color channels for white and a transparent to finish, all purely UV Led drying.
Ductile in the image change, allows you to perform small runs in a short time, with almost zero set-up. On the other side, the production capacity is not exhilarating, the cycle times are quite long on Multi Pass machines, which are better performing on Single Pass equipment. It has the limit in the choice of inks that do not have a wide range and are not suitable for all materials. Once you have configured the machine for a determined job using a certain type of ink it is not easy to replace it, as you have to empty and clean all the power channels. A time-consuming operation, which has to be kept in mind if you process objects of different materials.
Originally created to print large sizes on paper or low-thick films, it has indicated a new way finding its space and its location. Several sectors, from the ceramics, textile, paper, promotional and communication, have introduced digital printing. The benefits are many, a couple on all are the low costs of equipment and preparation of the machine, and especially the process-color printing that allows you to replicate images and decorations at high resolution, high value added. Maximum versatility of creative and innovative applications. Take advantage of new market opportunities with the ability to print small runs, accelerating production and delivery.
Over time, even 3D objects industrial customization, has manifested a growing interest and curiosity towards digital, which appears as a simpler and more affordable technique than the traditional ones in use. In fact, by comparing pad printing and digital printing, it is evident that one requires a specific technical expertise, while the other relies on a more computer and digital preparation, with the advantage of evading the pre-printing step. To understand the advantages and disadvantages of the two techniques, we first need to examine the required application. A three-dimensional object, has a shape, a dimension, and consists of an own material, depending on its use.
Why the shape? Simple, the shape is always a limit for printing in general, but not for pad printing, that has found in this condition its strength, thanks to the elasticity of the pad that adapts to the surface of the piece. Digital cannot print with quality if the surface of the piece extends beyond measure from the print head, losing the required print definition.
The size, because it directly affects productivity. In digital with MULTIPASS machines it is important to process many pieces during the printing cycle, to achieve a decent hourly production. The cycle time is long but guarantees an excellent quality of result. The alternative is the SINGLE PASS machine, which allows you to print one or more pieces at a time, and can be configured with different assemblies as needed. Increase cyclical performance, always with excellent
Pad printing works in a continuous cycle one or more pieces at a time, ensuring a competitive hourly production, whether you work with an operator or work integrated into an automated plant. This leads to lower production costs, and an economic benefit for the end customer.
, because it receives ink, which must ensure resistance according to the required specifications. Pad printing offers a series of inks designed for each material and ensures maximum reliability once tested and approved. Pantone, Ral and special colors are created, including metallic colors. Digital, works with the process-colors (Cyan, magenta, yellow and black), and separately with the white color. The resistances are not guaranteed on all materials, and the tints derive from the four-color printing process, after special color profiling, using UV Led technology that undoubtedly has the great advantage of instantly drying the printed piece that can be immediately manipulated and storable.
Digital printing, despite the limitations highlighted, is an innovative and high-quality technique with wide margins for improvement, which will allow it to impose itself in the 3D object industry.
If we compare the two techniques, it becomes essential to determine which one to adopt
. Better traditional Pad printing or better to push towards more creative solutions but with limits to evaluate such as Digital Printing? Certainly, several factors must be considered at the basis of the choice, absolutely the type of application, the production yield and the economic resource available for the investment. Last but not least is the supplier you can count on.
It can also be said that these two technologies can be used together for the benefit of customers.
In fact, even in a single system, there may be a surface of an object for which the inkjet could be better, as a given variable, but other areas where the printing works better because of the shape and type of the product.
There is no single solution that always works for each scenario, so pad printing and inkjet will always work together and neither will replace the other.
Tosh has always been at the forefront and strong of the experience and expertise gained in these forty years of activity in the printing of objects, decided to invest also in the world of digital printing. With series Jet.to, multi-pass and single-pass technology, it offers its customers with a range of machines that can meet every production need, guiding the customer in the most correct and appropriate choice.
For more detailed information and to learn more about the technical characteristics of Serie Jet.to, please consult the dedicated Web page, the brochure and contact us directly.