Product Reviews

The web press market is where some of the beasts of the industry lurk. It's where products such as Goss's Sunday 5000 and Manroland's 96pp Lithoman, capable of producing 100,000 copies per hour, reside.

And with bigger presses, and therefore higher speeds, efficiency is of the utmost importance and this is just one of the reasons why inline converting is gaining in popularity.

According to Adrian Purdy, managing director at Purdy Graphic Systems, it’s better to incorporate this kind of equipment inline because, for example, a rotary trimmer, if inline, shouldn’t slow the web press down when using a normal substrate. But it gets more complicated when handling a heavier stock or more complicated cutting patterns. This could slow production down although the press will continue to run perfectly well.

If you start at 180gsm per square metre, and put UV varnish on it, then it’s big, heavy and very slippery – this will limit how quickly you run the press, says Purdy.

Speed is always the watchword regardless of whether the converting equipment should be inline or offline. One revolution of the press can produce four or five pieces on the finishing side, adds Purdy. If you’ve got a press doing 45,000 impressions an hour you might be getting 200,000 pieces out of that. And this becomes too fast for an operator to handle.

With these kind of volumes being churned out, automation becomes a big factor, both inline and offline. With trimmers there is a degree of automation in the cutting process as jobs are memorised for recall while knives can be pre-set on the rotary cutter.

The design of the blade on a trimmer should also be considered. As an alternative you could have a compound
knife which is made up of multiple segments – the advantage being that its easier to handle heavyweight materials, says Purdy.

For lighter substrates, a one-piece blade is better. It’s also less costly and can be re-sharpened, adds Purdy.

But with the web technology changing all the time, flexibility on your converter is important. As the time passes you may find that your print jobs become more complex, especially in the web offset arena. The market is unlikely to stand still so it pays to keep tabs on your converting kit.

WHAT"S NEW IN... CONVERTING FOR WEB OFFSET

• Apollo Sheeters has been acquired by MarquipWardUnited, the US manufacturer of corrugating, sheeting, and finishing equipment for the paperboard market

• At Drupa, In-Log exhibited a cross-section of its post-press products including its CT/1080 and CT/2080 rotary trimmers, capable of producing up to 120,000 copies an hour on two sides

• A QCC Variable Rotary Cutter was exhibited on the Scheffer stand at Drupa, together with a high-speed inline inserter, which has been designed specifically for producing closed end mailers. The firm says the QCC line allows printers to cost effectively finish pre-printed rolls from multiple press lines with different web and cut-off sizes