Bespoke Monitoring For Self-Adhesive Label Work

The production of self-adhesive labels at Field Boxmore Wrexham (UK) was presenting specific inspection problems on the web for print quality and for die-cut registration.

However, Field Boxmore Wrexham operations director, Bruce Reynolds, could not find a suitable system on the market, according to Visi-tech Systems.

Producing self-adhesive labels on a new Edale Alpha UV Flexo machine, Field Boxmore wanted to install a video web inspection system on to the press but the problem was that the matrix is stripped off very soon after die cutting and there was no space in which to place a camera to view the print and die cut together.

If the camera was placed after the separation of the matrix and substrate, then the print and cut can be viewed but the register marks would have been stripped off with the matrix.

If the camera was placed before the die cut, then the print to cut register cannot be viewed.

Visi-Tech Systems said that it is not an uncommon problem and similar situations apply to most narrow web machines.

Most printers simply accept the compromise but Field Boxmore Wrexham wanted an acceptable solution to the issue, added the company.

Visi-tech came up with a custom system consisting of two cameras.

The main camera was mounted just after the last printing unit, enabling complete viewing of the print, whilst a second camera was placed to view the stripped matrix before it was rewound.

That in itself posed a challenge, since the Edale Alpa press is one of the most compact machines on the market and there was very little space in which to place the second camera.

As a result, Visi-tech developed a miniature web viewing camera measuring 120mm x 100mm x 70mm.

Alex Lyne, Visit-tech's product manager, commented: "It was certainly a challenge to make such a small camera and we were very pleased with the results.

As far as I know this is the smallest strobe integrated web inspection camera in the country, possibly the smallest in the world.

In addition to the development on the camera, we have also made some changes to our control software to allow the main camera to constantly scan over the web, whilst the secondary camera remains fixed on the register mark.

With both cameras viewed simultaneously on a single split screen monitor, it really is a very neat system." Bruce Reynolds explained: "I am very pleased with the way in which Visi-tech addressed the problem.

When it became apparent that there was no off-the-shelf product available to us, Visi-tech was quick to run tests with its cameras and provide us with an alternative proposal.

The resulting custom installation is really quite clever and does the job just fine.".

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