Bobst DM5 continues flexo automation

Bobst showed off a brand new hybrid press, the Master DM5, at the recent Label Expo show, which includes a complete inkjet print unit, but where the main feature is actually the heavily automated flexo printing and converting.

Federico DÕAnnunzio, Bobst program manager for Hybrid Printing, with the DM5 hybrid launched at Label Expo 2019.

Federico D’Annunzio, Bobst’s program manager for Hybrid Printing says: “I don’t like the term hybrid because it means that you have one dominant technology but here I believe that the press we have made is a digital label press where all the elements are digitized, the flexo and the waste stripping, so everything is digitally automated.”

This automation comes from designing the units to take two jobs at once, as D’Annunzio explains: “Normally you have to stop the press to change the print cylinders but here you don’t. Every process has been digitised. You place a cylinder and when you need it you click a button and automatically the old job goes away and the new job comes in. The camera comes out and automatically adjusts the register and the pressure. So the operator doesn’t touch the machine. It’s digital flexo.”

Bobst has really thought this through and applies the same philosophy to all the converting stages, including cold foiling, varnishing and die cutting. D’Annunzio adds: “Even the waste stripping is completely automated. So you can change all the jobs in one second.”

As far as I can tell, all of this automated flexo is taken directly from the existing Master M5 press. So what the DM5 brings to the party is the digital unit, which comes from Bobst’s Mouvent subsidiary and is essentially the print engine from the LB702-series label presses. Thus it uses Mouvent’s printhead cluster, which combines four Fujifilm Samba printheads into a single unit complete with all the electronic cabling and ink piping. Mouvent does appear to have improved on the clusters that it showed two years ago so that its latest offerings can produce 1200 x 1200 dpi at 100mpm, which is quite outstanding, and applies both to the digital unit of the DM5 and to Mouvent’s own inkjet machines. 

It’s worth noting that the DM5 can run at the same 200mpm in flexo-only mode as the M5. Mouvent says that it could have increased the speed of the digital unit to match this by reducing the resolution but that the market demand is for higher resolution rather than faster speeds, particularly on short run jobs.

The DM5 takes media up to 340mm wide but D’Annunzio says it’s relatively easy to develop a wider version: “If we see the market needs a 510mm then we can make it.” The M5 is already available in a choice of widths including 430mm and 530mm as well as 370mm, and one of the benefits of Mouvent’s cluster system is that it’s relatively trivial to increase the width of the print bar by adding another cluster with another four Samba heads. 

Bobst’s DM5 is a hybrid press that adds an inkjet module to the M5 flexo press.

The standard M5 flexo press costs €1 million while the DM5 hybrid should be around €1.2 million, which seems like a reasonable premium to pay for the short run flexibility that the digital unit gives. D’Annunzio expects the market to split 50/50 between the M5 and DM5, saying that it doesn’t only depend on run lengths but also on how many times you use the plates, noting that digital might be cost effective on runs up to 2000, adding: “But if you reuse the same plate again then 500 to 1000 on flexo becomes more competitive.” He says that ultimately it depends on the customers and the jobs they have, adding: “If you need added value then maybe it’s better to go hybrid.”

D’Annunzio has worked for several years to improve the processes around flexo printing, automating where possible to cut down on make ready times and to ensure that flexo remains competitive against digital printing. This is the basis behind Bobst’s Revo concept and D’Annunzio has continued to refine this philosophy, earlier this year announcing two new technologies, Ink on Demand and DigiColor, which can also be fitted to the DM5 as an optional extra. 

Ink on Demand is a new inking system that replaces conventional inking reservoirs with a single rubber pipe that dispenses 30 grams of ink to the print unit. The result is that there’s no need for ink trays or chambered doctor blades and therefore it’s much quicker to wash up and change colours. 

DigiColor is a closed loop colour system that uses two variants of each colour and lets operators mix those colours quickly. D’Annunzio explains: “It means you can change substrate and it doesn’t matter if the substrate absorbs more colour or not.” I’ve already written a better explanation of both of these inking technologies here

Mouvent has developed this inkjet label press, the LB702-WB, which uses water-based inks.

Mouvent also showed off its aqueous inkjet press, the LB702-WB, which was shown two years ago as a prototype. Essentially it’s a variant of the existing UV inkjet, using the same printhead clusters but with additional drying units to cope with the water-based inks. The result is a press that’s suitable for indirect food contact though as with most aqueous inkjet inks it’s best suited to paper-based substrates. 

D’Annunzio says: “We have seen so many advantages on paper that we have focused the machine to paper because on a rough surface the UV ink tends to affect the surface roughness. But with water-based you can go deeper. It’s perfect for wine labels.” It should be said that the samples coming off the press at Label Expo were extremely good. It prints up to 340mm wide and can be configured with up to seven colours. It too can produce 1200 x 1200 dpi at 100mpm. It’s available to order now but by the middle of next year there will be a primer to allow it to print to film-based substrates as well.

I think that Mouvent and its inkjet technology warrants a much more in-depth look so I’ll leave this for now. In the meantime, you can read more about the inkjet printers at mouvent.com and about the DM5 at bobst.com.

Leave a Reply

Your email address will not be published. Required fields are marked *