3D printing’s true colours now shine through

Mimaki Engineering started out in 1975 as a manufacturer of cutting plotters. Today the company is a leading producer of digital printers. Going from 2D to 3D was a logical step, said Mark Sollman, Product Manager EMEA for Mimaki. “We were already printing with LED UV curable ink. Printing in 3D was just a matter of adding more layers,” he told Sustainable Plastics during an interview at Mimaki Europe bv in Diemen, the Netherlands.

As a manufacturer of cutter plotters and later industrial printers, Mimaki, founded in 1975 in Nagano, Japan, focussed mainly on sign graphics, industrial products and textile. Today, Mimaki offers complete solutions: 2D digital printers and cutters, 3D printers, software and ink.

As Sollman explained, “The company does textile printing, UV, flatbed, printing, solvent, large format, small format - so we have something for every customer. Although our main business is to produce digital printers,” he said.

Mimaki, however, has long been known for its willingness to move with the times, especially where technological developments are concerned. “We are an innovative company,” said Sollman. “We were the first with a textile printer, the first with a UV printer and the first to use LED technology, so to cure ink with LED light. Currently, 8% of our revenue is ploughed back into R&D.”

With the emergence of 3D printing technology, it was therefore logical for Mimaki to explore how to enter that market. Building on its extensive experience with inkjet technology, Mimaki sought to find a way to translate that into a new, proprietary 3D printing technology. It therefore announced in 2015 that it would enter the 3D printer business - and immediately began to develop its own full colour 3D printer.

As a manufacturer of digital printers, Mimaki was already producing UV machines able to print products such as signs. Over the years, the company had developed a 2D technology to print depth on substrates. “There, the ink was deposited in only one layer, but we thought that if one layer was possible, more than one layer should also work. Because the ink is cured directly, it should be possible to build this into multiple layers,” explained Sollman. “And it was.”

Proprietary technology

The company’s technology works by jetting the ink directly onto the print bed, through a nozzle, in drops measuring at the minimum 4 picolitres. This ink is actually a very fluid ABS resin. “We have to fire small drops of ink through a nozzle, so it has to be very liquid,” Sollman emphasised. The company buys the components and then compounds these into its proprietary inks, the recipes for which are secret.

To ensure the layers adhere as smoothly as possible, the system includes a small roller, that rolls each layer flat, after which this is cured with UV-LED technology. After a layer has been printed, the table is lowered by one layer print and printing continues with the next layer. The technology yields parts and objects of extraordinary quality, with not a line to be seen.

It is not a fast process, said Sollman – that’s something that still needs to be developed – but what truly sets the technology apart is this quality and the ability these printers have to print in an unrivalled range of colours. 10 million of them, according to Mimaki. “Depending on the structure or difficulty of the objects, it could take anywhere from one up to 24 or even more hours to print. In the market, our process is still quite slow. We have to be honest about that,” he said. “But printing in full colour is what gives Mimaki an edge over the competition.”

To achieve this, Mimaki has drawn on expertise gained from 2D printing and applied it to 3D: ICC Profiling calibrates the colours in question in order to make sure that the printed colours match those of the design when viewed on a monitor. Proprietary colour management software enables colour accuracy, colour adjustments and colour matching among same printer models through equalisation (by measuring colour charts), allowing the same colour output on multiple 3D printers – no matter where in the world they are located.  Some 10 million full color ICC profiles are available for printing through Mimaki’s machines.

The company has also developed a proprietary support material, which is jetted from the same nozzles as the primary resin is printed. The system’s software automatically calculates where a support should be placed and how much material to apply. Once the product is printed, the support is easily removed. “The support material is water soluble, so it can be washed away in an ultrasonic bath, leaving no trace,” said Sollman.

Mimaki currently produces a large-sized printer, a medium-sized 3D printer with a build volume of 500 by 500 by 300 mms, and recently introduced its compact model, intended as an entry-level printer that can, like the others, print an almost infinite range of colours.

And, with a street price of just €35,000, it was given a warm welcome at the Formnext exhibition in 2021. “The closest competition offers something similar for €100,000. Which makes us a very interesting option. Our first, big machine was a huge success, but it was a bit too expensive for smaller companies. So, we developed the smaller one as well,” said Sollman.

The machines all feature multiple print heads. “In the new, small machine, which has a significantly lower price and a build volume of 200 by 200 by 70mm, there are two print heads. And in each of these print heads are 4 lines. That means eight channels, making it possible to jet CMYK, white, a clear varnish and two channels for support material. The clear inks that can be jetted independently or even combined with colored ink to create translucent objects,” Sollman explained.

And, while entering a new market segment is never easy, Mimaki is satisfied with how its printers are performing in the market. The initial investment in R&D and the effort involved in launching the new products are paying off, with the development of high-quality colour printers that the market is embracing.

“Also, we already had the structure to place the machines through our business model. We sell through partners and we had that whole infrastructure set up already,” he added.

E-learning, here to stay

That infrastructure, built up over the years, consists of a network of partners with who Mimaki collaborates, all of whom receive a thorough training prior to being permitted to become a partner. “Full training is mandatory,” said Sollman. “We are quite strict in that. The reason is simple and practical. If we sell machines into Europe and the partners selling them lack an adequate knowledge of the machine, we’d have to send technicians in, which is expensive. So, instead, all partners must go through a rigorous training.”

All the training used to be done here at the office, but the pandemic has put an end to that. Today, all training occurs online via e-learning and Mimaki has a dedicated staff of three for all e-learning tasks.

“Our customers adapted very well to this situation of e-learning and online,” Sollman noted. “It's also turned out to be a far more efficient way to work, and far less expensive. An additional advantage proved to be that our partners were actually also learning more -  because they had to do it themselves instead of depending on us. Of course, we help them along. But basically, they're doing most of the work themselves.”

‘A very dynamic industry’

One highly recurrent question about additive manufacturing is when to use it. People are still trying to figure out where it's going to and what else it can do.

“That’s absolutely true,” said Sollman. “But it’s also part of what I like about this industry. People are very open – they like to share knowledge. It's a very dynamic industry. Still, the question ‘how can I make money with this?’ is one we get incredibly often. More often even than questions about the price of the machine.”

It is a good question. 3D printing, in general, requires a new way of thinking, he continued.  And new processes for product design, which is something designers are currently wrestling with, as creating a good 3D file is not easy.

“Trying to fit 3D printing into an existing way of doing things, or into a production process that works perfectly well is not the way forward. You must ask yourself: Why is this handy? How can I exploit the benefits?” he said.

“It's exactly like 15 years ago for digital printing. Eventually, everybody will catch up and will be doing it.”

He mentioned a few instances where customers had successfully fit 3D printing into their production flow, including one company in the USA that manufactured shoes. This company used the 3D printers to produce models of new shoes. “As a result, they are able to produce about three months earlier,” said Sollman. “The marketing team has a real-life 3D model and no longer needs to watch the street. So, for this company, it's not about the money or the ink, it's about producing earlier and getting ahead of the rest. That was interesting to hear.”

New developments

Another insight gained from the market was that in the 3D printing industry, the actual printing process is less of an issue than what comes before and what comes after – in short, the file preparation and finishing processes.

It led to the development of a completely new end-to-end solution that was also launched by Mimaki at the Formnext show last year. “Nobody else that we know of sells the whole solution. But we can now offer a total workflow, if you are buying a machine,” said Sollman. “The idea is to accelerate the adoption of 3D printing by making it more accessible through the use of more automation. It’s offered on a subscription basis.”

The 3D Print prep software has been developed to simplify the 3D printing process. Compatible with all Mimaki’s 3D printers, it helps users to prepare and finalise their 3D files before printing, autocorrecting file errors and optimising the 3D data used in 3D printer modelling to optimise the shape of the model.

“It detects and automatically fixes errors in among others, size, thickness, gap and hole filling, hollow shapes and material colour,” explained Sollman. “This makes it easier to configure a 3D print file, even for users with only limited experience with 3D printing technology.”

The company has also launched what it calls an ‘intelligent support materials removal unit’, designed for use with the new small-sized Mimaki 3DUJ-2207, and developed in collaboration with AM Solutions – 3D post processing technology, that will allow them to  speed up and automate their post-print workflow. ”The system is Industry 4.0 ready,” Sollman said.

Applications

So, what are customers actually using these high-quality colour 3D printers for?

According to Mark Sollman, gaming is a huge market. Gaming?

“Indeed. Frankly, most of our printers are being used to print gaming characters. It’s a huge trend. Gamers want to print their own avatars in full colour. One customer has five or six of our machines, simply to print these avatar models. Customers can order them online. This customer is currently producing up to 500 pieces a day.”

Other applications include personalised glasses, architects’ scale models and stop motion animation. Prototypes are another key application. “In prototyping, we’ve saved customers months of development time,” he pointed out.

“Also, there are a number of interesting medical applications. We can 3D print very realistic anatomical models  - 3D printed hearts, brains – for educational purposes, or for surgeons, to practise the techniques they will use on a particular patient.”

Geographically speaking, America and Europe are Mimaki’s most important markets, when it comes to 3D printers, he added. “Most of the industry that uses these full-colour 3D printing machines are based in these regions, rather than in, for example, China.”

Looking ahead

It is often said that 3D printing is inherently sustainable because it is additive rather than subtractive in nature, and promotes a lighter and stronger design. More specifically, said Sollman, are aspects such as the fact that Mimaki’s machines use LED technology, which means a low energy consumption and lower energy bills. Moreover, printing in full colour means that steps such as painting are eliminated.

“We are internationally certified with ISO 1401. Our aim is to make greener and sustainable products, with lower VOC emissions, but this will take a while. Perhaps another five years,” he said.

“Going forward, next to a more sustainable process, we will be striving for more speed. And, of course, we are hoping to greatly expand our installed base. We are working on a number of things, which I am not at liberty to disclose. Only that the next step will be a faster 3D colour printer.”