New cylinders for old

In January, just four years on from the birth of an idea to cut the time of gravure cylinder production, TecnoPlas began a full scale operation to produce plastics cylinders from existing steel bases, which are successfully coppered, chromed and engraved on conventional equipment. Now the TecnoGrav company (part of Image Management Technologies Group) is already supplying some major UK converters with the engraved cylinders. And Hypertec Print Services, the joint venture company it set up with its plastics supplier Hyperplast, is talking to engravers in other countries with a view to licensing the TecnoBase patented technology.

Technical director at TecnoGrav Lister Cumming recalled: "The original idea was to take the cost out of gravure. It was under pressure on price from flexo. We needed a step change in the industry. Cylinder stock of many different sizes was hanging around for years and taking up valuable space at printers. In a nutshell, we needed to find a system that would speed up time of delivery; we needed to reduce cost to the printer by not having to buy new steel bases and we needed to find a system that would allow cylinders to be re-used."

Following a look at some existing plastics systems and work with a base maker, in 2002 TecnoGrav agreed a joint development with Hyperplast. By the autumn they borrowed some plastics processing equipment and bought some time at a plastics company to conduct some beta trials and prove the technology.

The patents for the material and the processing technology have been applied for jointly with Hyperplast in the EU, USA, Canada, Japan, China, Australia, India, South Africa and Mexico. Much of the process is confidential, but basically the engineering polyurethane (non foam) produced in equipment built specially to a TecnoPlas specification is rotationally coated through the Rotocoat dispenser onto the old engraved steel base. Once the required diameter has been built up, the cylinder is left to cure for one hour before being put on a conventional lathe where it is quickly cut to size and polished. Unlike steel, the plastics material can be removed with one cut of a standard diamond tool.

"As the coating involves an exothermic reaction," explained TecnoPlas director Peter Williams, "it tends to shrink to the base on curing, making it extremely stable and strong." Unlike other plastics materials used by other companies there are no skins or different layers of material; it is consistent from surface to steel base.

The final essential component of the patents is the coating used to make the plastics surface conductive and therefore allow the copper to be accepted in the conventional plating process tank. "As opposed to 10 to 14 days for delivery of a new steel base to the required size, within three hours this cylinder can be in the tank," added Lister Cumming.

"When developing the material and the process, it was crucial that, once we reached coppering, production had to be identical to that of the conventional gravure cylinder process," stressed Peter Williams. To have to change this costly plating and engraving equipment would have defeated the object.

Following the press trials made during the beta tests, the development won the Gravure Association of America's 2003 Supplier Innovation Award. TecnoGrav daughter company TecnoPlas was created and a £250,000 investment was made in the new equipment and infrastructure.

"In the first four months of this year we have gone from a few converters including Danapak and Alcan trialling the cylinders to 19 actually using them. To date we have produced some 500 cylin- ders, all using small to mid sized existing bases," said Peter Williams. Current capacity on a one shift basis is 60 cylinders a week.

"Suddenly gravure can attack flexo. Engraved cylinders can be delivered in just five days," enthused Lister Cumming. "To the printer, TecnoBase cylinders bring huge savings. By using their existing bases we can save them one third to a half of a new steel base. And if they send them back a second time there is a huge saving. It is tangible. The printer can actually write down their projected annual saving based on how many cylinders they use. In time, with good stock management, a converter could cull its stock of cylinders. This way warehouse and inventory costs would be considerably down as well."

And the future? "In the UK we will keep the process closed to ourselves and plan to grow manufacturing," said Lister Cumming. On the licence front the joint venture company Hypertec has already received strong interest in the USA. "This time next year I believe two or three licensees will be in place," he predicted.

How far is the company from the "Holy Grail" of directly engraved plastics? "Yes, we are looking to engrave direct and yes we are developing materials," said Peter Williams. "I see it as a three-year process." However, even if the plastics are engraved directly and the cell quality of existing materials improved, he still believes the cylinder will then have to be chromed to prevent wear. And to be viable any process must be able to use existing equipment.