SLAC’s digital can printing technology
Chris McKenzie, the chief operating officer, international, and chief marketing officer, the SLAC Group, gives The Metal Packager the story behind the company’s digital can printer with inkjet technology.
First launched in 2016, its next generation of the mini can line, which lowers the traditional volume threshold for DWI and opens up low-cost opportunities for annual volumes of 50 million cans or less, is expected to hit the market in Q4 2022.
Inkjet printing on cans and other curved surfaces
For decades, inkjet printing has traditionally been used on flat or near flat surfaces. To print directly onto curved or cylindrical surfaces such as cans or aerosol containers, inkjet approach poses great challenges. However, its cost-efficiency and “direct-to-shape”/ “direct-to-object” concept has lured many can equipment manufacturers into this field.
To print well onto cylindrical can surfaces with the current available UV ink is challenging, requiring a multidisciplinary approach, which includes, but is not limited to, mechanical design, electrical, electronic, surface energy understanding, ink science, UV control, colour management, software engineering, image processing, data flow, and system control. As inkjet printing is a non-contact method, the flight and landing of ink drops onto the curved surface brings a third dimension into the engineering, making it even more complex and more hybrid but offering many benefits.
When designing an inkjet printer for cans or other curved products we need to take many points into consideration: the shape of the printed surface, the array of printheads, time of flight of ink drops, loading and unloading of cans, curing, colour arrangement and presentation, movement printing or non-movement printing, can flow, quality control, to name but a few. These challenges can only be overcome by extensive experimentation and tweaking of the technology, increasing the R&D cost and thus raising the threshold for developing such a machine.
The rise of SLAC’s first digital can printer with inkjet technology
SLAC developed its first Digital Can Printer with inkjet technology in 2016, with model SLAC SC-DP-200-6, which caught the attention of experts and engineers in this industry rapidly. Centering on SLAC’s new digital printer is the concept of SLAC’s mini can line, which lowers the traditional volume threshold for DWI and opens up low-cost opportunities for annual volumes of 50 million cans or less.
The first three digital can printers made by SLAC were purchased by top Chinese can manufacturers and put into use for producing small-batch, personalised market orders. All can making companies are inching their ways into the digital, personalised, or customised can market, which is believed to gain the upper wind with emergence of the Generation Z and MetaVerse concept. Now five mini lines are operated in China and two more lines will be built this year with many more in negotiation globally. As well as these leaps forward, as has been recently added into the public domain, we’re also honoured to be the suppliers of the mini line to the Ball Corporation Digital Centre in Brazil.
Equipped with premium industrial printheads, UV ink and UV-LED lights for curing, SLAC digital can decorator prints all digital labels directly onto the cylindrical can surfaces with no need of physical print forms. On a rotary can printing table composed of 18 mandrels, cans are fed, inkjet printed with different CMYK colours on different mandrels, cured and discharged in a full work cycle, as can be seen here. The workflow of SLAC digital printer offers distinct advantages compared with conventional printing methods: no changing of printing plates, no machine adjustments, no misprints and no spoilage.
The non-contact printing technology the SLAC machine utilises has no changeover downtime; limitless design possibilities; designs stored in digital file; label change in a click; one-can-one-picture, each can in the printing queue can have a different image printed; high flexibility, even a lot size of 1 is possible; no ink changes; no roller cleaning, scalable print quality (print resolution and grayscale printing); high productivity; fast investment payback; and less time to market.
SLAC’s first model of SC-DCP-200-6 is capable of running in excess of 200 cans per minute (600dpi*300dpi) — the lower the resolution, the higher the speed. With the highest printing resolution of 600dpi*600dpi presented by the machine, the output is around120-140 cans per minute.
SLAC scooped the gold award in the Global Can Supplier Awards for its ground-breaking digital printing technology at CanTech’s Grand Tour Trade in Istanbul in March 2019. This award honours the supplier in the industry showcasing the most promising innovations within the can making industry.
SLAC’s success in South America
In the same year, SLAC started to supply digital can printer to Ball Corporation Digital Centre in Brazil, which built its first mini line at its production facility in South America. In the face of the serious Covid-19 pandemic, SLAC offered remote training and assistance 24/7 instead of direct site visits to get the equipment commissioned. The remote help turned out to be challenging but very successful, giving customer more opportunity to gain hands-on experience and to deepen their understanding of working mechanism of the machine. Jackson Cui was the project manager responsible for the successful remote commissioning of this mini line.
In 2022, the customer praised the technology as game changer in this industry and invited all customers in South America to embrace a new era of digital printing. As a high-quality, environmentally-friendly and flexible machine that’s easy to operate, SLAC Digital Printer promises to revolutionise the future of can printing.
An excerpt from this customer’s review:
This new technology will deliver photorealistic image quality with up to 600 dpi resolution, and “an infinity’ of colours. It will enable beverage producers to order smaller printed batches, have more than one design in the same print run, as well as use can labels for marketing campaigns.
Depending on production volume, cans could be digitally printed and ready for filling in as fast as 24 hours. The service has a minimum quantity order of just 400 units with different designs, compared to the minimum 50,000 units required for lithographic printing that is economically viable.
Beverage producers will be able to design cans for special occasions which meet the needs of their main customers, such as a canned water with the brand of a large hotel chain, a canned wine from a renowned restaurant or even a beer specially developed for a famous band touring the country.
With the new technology, the can will become even more the protagonist of marketing campaigns, bringing the brand and the consumer closer. The possibilities become endless – with the can of your favorite drink becoming a ticket to concerts in the MetaVerse, or an exclusive work of art in the hands of collectors, for example.
Indeed, as industry experts have predicted, many of the new market opportunities for metal packaging are likely to be from smaller volume ranges, in average run sizes which in the past would have precluded DWI. With digital inkjet printing, small volume running is possible and printing costs are lower than conventional offset on runs lower than 30,000 beverage cans or 25,000 monobloc or DWI aerosols. In a new era of consumer interaction, the ability to personalise your cans is essential.
SLAC’s latest digital printer scheduled to hit the market in Q4
The year 2022 also witnesses the birth of a new model of SLAC Digital Printer– SC-DCP-200-G2. This model is the latest development outcome of SLAC’s continued effort in R&D of digital printing technology. As a mainstream and forward-looking can making equipment supplier in the world, SLAC fully understands its customer’s requirement in this “either innovate or die” age. The machine is updated to a new height of performances with applications of new technologies while maintaining a reasonable cost.
- In the previous model SC-DCP-200-6, printing resolution options are 600dpi x600 dpi, 600dpi x300dpi, 300 dpi x300dpi, while in SC-DCP-200-G2, the resolution choices are 1200 dpi x1200 dpi, 1200 dpi x900 dpi, 1200 dpi x600 dpi, 600 dpi x600dpi, a great leap forward offering high quality commitment as well as flexible printing scenarios for weighing different setting factors.
- A totally new printhead housing is designed in the new model SC-DCP-200-G2. With this new printhead housing or platform, the printheads are easy to locate and adjust positions, delivering easy access, more user-friendly operation and simpler size change opportunities for different can diameter and heights. The redesign increases the printing length from the previous 178mm to current 235mm, covering all beverage cans seen on the market this eliminating some of the print challenges of multiple heads on one height of can.
- Moreover, a new printhead arrangement is also adopted on the new model. In industrial inkjet printing, the state-of-the art printhead types are piezo-based printheads, both as binary and gray scale, with or without recirculation, with bulk PZT or thin film PZTMEMS, etc. In addition, industrial inkjet applications also require high and long-term printhead reliability in order to achieve productivity and high manufacturing yield. Therefore, a reasonable array of the printheads, especially the nozzles, is of paramount importance to successful printing. In our new machine type, a new creative printheads arrangement instead of butt joint arrangement is applied.
- An ink recirculation system, in which ink is recirculated rather than getting stagnated or idled during machine stop, is integrated into the system. For the UV inks used in can printing, there is a need for heating, degassing, filtration, and/or recirculation. The ink movement will help avoid sedimentation that may otherwise block nozzles. It has been proved by many researchers that printheads comprising recirculation systems help maintain ink homogeneity and fluidity and reduce greatly printhead maintenance time.
With these new updates, our SC-DCP-200-G2 is scheduled to hit the market in Q4 2022.