UK based converting equipment engineer Henderson Engineering won two high security contracts to design and build ‘double hit’ hard embossers to operate on pre-metallized polyester film on a narrow web – just 304mm wide.
The contracts – one in Italy and one for a European mint - were won and the machines designed in collaboration with Henderson’s regular partner company, Eskay Holographics. The identities of both customers are subject to confidentiality agreements, but the applications are in the security printing field, for items such as currencies, credit cards and passports.
The main engineering challenge with the machines was to incorporate a panel to panel embossing method, where the embossing nip cycled between two points. This was done with a series of lift-off cams that were manufactured to very tight tolerances to maintain a smooth transition between nip positions.
Both machines incorporated cantilevered unwind and rewind cores of 76mm, unwind/rewind batch diameters of 381mm, and operated at a maximum speed of 65m/min. Henderson built in a two zone tension control system, with closed loop control. A single drive and electrically heated die rollers with closed loop temperature control were also provided.
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