Computer to screen: making the right choice
Thermal wax, inkjet and DLP are established as the main three techniques for CTS exposure, but which is best for your business?
Screen printers must constantly search for that technological edge that will give them a competitive advantage. In markets where digital imaging improves turnaround time and reduces set-up costs, commercial screen printing must maximise its efficiency.
For computer-to-screen (CTS) imaging, the technology helps users to save time in preparing screens while eliminating the need for costly film positives and the pre-press time and equipment to generate them. CTS imaging devices can also free up space in your workplace and eliminate the need for film storage. Another key benefit of CTS can be superior resolution and improved consistency and registration.
There are a number of choices when it comes to selecting the type of technology that will best suit your needs. However, establishing which is best for your business can be a little overwhelming.
The big three options in CTS are well established in the form of thermal wax, inkjet and digital light processing (DLP) UV exposure.
Counting the cost
More often than not, cost will be a deciding factor when it comes to deciding on which piece of machinery to use. CTS systems can start low. For inkjet, the Lawson Focus-CST is an economical model aimed at those producing 10 screens a day, works straight out of the box and costs around $15,000.
i-Image STE CTS system
Ascending the price scale, the i-Image CTS imaging system from M&R starts at around $35,000. The price can reach $135,000 with add-ons. The manufacturer estimates the i-Image can output around 150 screens per shift which is very useful in high volume garment decoration
Thermal wax options include Exile Technologies’ Spyder II DTS, with a redesigned control system to support Fujifilm printheads. It can produce a typical T-shirt image in under a minute.
Michael Mogge, Key Account Manager at Colour Scanner Technology (CST), says investment in a DLE engraver is higher than the other technologies – around $100,000 – but offers cost advantages and superior print quality in the long term.
The imaging costs for one screen are around four to five pence, but imaging with both ink and wax and replacement of heads will mean multiple consumable costs for the user.
“Digital light engravers have DLP UV exposure, meaning you go direct to screen with highest quality due to sharp edges and fine halftones and fast exposure times,” he says.
Expand your horizons
Andreas Ferndriger, Chief Executive of SignTronic, also notes that cost is one of the big limitations in screen printing. He instead puts forward another option in the form of CTS direct exposing, saying this offers a more effective method for screen printers.
Digital light engravers have DLP UV exposure, meaning you go direct to screen with highest quality due to sharp edges and fine half tones and fast exposure times
Ferndriger suggests direct exposing is the perfect technology to simplify screen making and to reduce the total number of processes, as no films or chemical are needed. Other benefits include shorter set-up time, better printing results and the fact that no extra handling between the different processes is required.
He explains: “CTS direct exposing is the one-step-process from the data or file direct to the exposed screen. CTS wax and inkjet are both limited solutions because they are only a masking process, which is different and offers only limited resolution, quality and automation.”
A leap of faith
Having established there are other options available in the market, how do screen printers go about deciding which one is the most suitable for their business and when is the right time to invest in this technology?
Ferndriger has no hesitation in recommending that printers make the move to his preferred CTS direct exposing methodology as soon as possible, arguing that this should now be the standard in screen printing both today and in the future.
Mogge is slightly more conservative with his advice, recommending that printers buy in good quality and ensure the machines are upgradeable for future applications.
He says: “We are producing a family of DLP machines for flat and rotary screens, as well as CO2 or YAG (Yttrium Aluminium Garnet) laser engraver and inkjets and waxjets for different applications.”
CST is producing a family of DLE machines for flat and rotary screens, as well as CO2 or YAG Laser engraver,inkjets and waxjets for different applications. Pictured: the new DLE Compact
How is the future of the CTS sector likely to pan out? In terms of new technologies, Lüscher Technologies offers more specialist options in the form of fibre-coupled UV laser diodes at 405 nm wavelength.
Urs Bachofner, Vice-President of Sales and Marketing at Lüscher, says screen printers can expect to achieve up to 5080dpi with this technology. The standard tri-optic system offers three resolutions, 635, 1270 and 2540dpi resolution, while the user will also benefit from fully automatic calibration with the technology.
Bachofner says the lifetime of these lasers is likely to be more than 20,000 exposing hours. This kit does not require any consumables such as lamps, DLP chips or inkjet heads to produce quality results, which helps the user save on additional kit costs.
“All technologies have their advantages and disadvantages,” he adds. “The question is what the customer expects or needs in terms of the quality and output speed.”
It is important to note that whilst resolutions of up to 5080 dpi are available, resolution is commensurate with speed so lower resolutions result in much faster exposure times. Therefore, it’s important to select a machine resolution that suits the type of output you are printing and the number of screens you need to expose during a shift.
Urs Bachofner, Vice-President of Sales and Marketing at Lüscher Technologies, says screen printers can expect to achieve of up to 5080dpi in print resolution when using its laser kit
In terms of how this kit lines up alongside established technologies, Bachofner suggests that newer solutions such as Lüscher’s UV laser diodes may prove a more cost-effective investment for screen printers. He remarks that with film production decreasing and prices increasing, the break-even point for CTS is reducing.
Bachofner says: “There are some substitutions available such as film by inkjet but for some applications this may be not good enough. We see other important benefits in CTS technology including the improvement of quality, especially in the technical and industrial screen-printing areas.”
Adapting to change
But what do Ferndriger and Mogge make of this technology? Mogge says CST DLE solution features the same wavelength – 405 nm and 385 nm together in an LED bundle with high power UV light – and can offer this technology depending on the type of application.
Ferndriger says laser diode technology is a different UV light source to expose screens and normally a different technology because no digital micromirror device (DMD) is used.
He says SignTronic offers two different UV light sources combined with DMDs in the form of UV-CPL high power lamps and UV-LED light source, but stresses that it is critical to offer a modular CTS concept in order to follow all customer needs.
There are no easy and fast answers because every customer uses screen printing technology differently
So where does that leave the screen printer? The message here seems to be to pay attention to the latest developments in the market and ensure that the kit you are looking at can keep up with the newest solutions. Establish what it is you want to achieve from your CTS kit and carefully examine the options available to see what is the most cost-effective solution for your business.
Ferndriger sums up the debate by saying: “There are no easy and fast answers because every customer uses screen printing technology differently. Many other parameters have a big impact to the costs and quality.
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