Slitting & Rewinding

Multiline removable optics for easy open perforation with double or triple lines

with double or triple lines. When creating a stand- up pouch or a piece of solid packaging, ensuring the easy open perforation at the front of the packaging matches that at the back is a very important consideration. If the process, and therefore the application, is not precise the line at the front won’t be level with the line at the back. Currently, the growing trend in order to solve this problem is to split the line between front and back into two or three, to increase the likelihood of matching the two sides. Due to space and investment limitations, most


converters do not consider installing 12 different laser heads to create these additional lines. This is why the most realistic, efficient and profitable solution is to split the original laser head from one line into multiple lines. There are different ways of doing this, but Comexi’s preferred style is to use multiline removable optics to split the laser. This system means that customers only need to acquire a special optic to divide the laser for jobs that require it. The customer can then insert and remove this special optic from the laser as necessary, keeping the equipment functioning as normal. This manual operation is also quick, taking only five minutes. The standard configuration of Comexi’s slitting line has four laser heads of 100W. Therefore, four

urrently, one of the most frequent questions from slitters and rewinders is how to create an easy open perforation

tracks with double lines or four tracks with triple lines can easily be created to work simultaneously, when using a multiline removable optic. Laser heads minimum separation must be 170mm (6.7 in), so the maximum number of heads also depends on space. Sometimes, some lasers (half of them) can be placed in one bridge and the others (the other half ) on the following bridge and this can solve many spacial-difficulties. An alternative way to divide the laser beam is

with mirrors (what it is usually called a beam splitter). This is a completely different solution as it is a fixed solution. Once this system has been chosen the laser will always be divided. However, this solution has a clear benefit: It saves space, which means, when compared to the removable optic solution, more tracks requiring multiple lines can be used. Imagine a job that requires 16 tracks, each

forming a double line, this can’t be achieved with just four laser heads and multiline optic lenses. In this case, the best solution becomes a combination of the two methods. Dividing each laser head into two with beam splitters creates eight tracks. Following this, multiline optic lenses can then be added on every split beam creating the desired 16 tracks. It is recommended to install 300W laser heads, instead of the regular 100W, in cases such as these, so each split beam always has a maximum power of 150W.

However, with two laser beams it is suggested

to not divide lasers with mirrors because of the problems that arise when working with cross direction such as calibration and loss of power. Dividing the original laser into multiple beams could affect day-to-day performance. There is no price difference, nor significant

savings between multiline optics and beam splitters, although multiline optic lenses can offer greater flexibility.

Alliance grown with new CI8 offset press

Comexi’s CI8 technology following the government’s latest economic transformation and policy upgrade in China. Recently, the Chinese government has been encouraging enterprises to invest in protecting the environment, focusing on saving energy and reducing consumption, decreasing CO2 emissions, improving production eficiency and promoting Industry 4.0 technologies and equipment. Since 2015, the Chinese government has also imposed strict controls on VOC emissions. The introduction of a Comexi CI8 at Caihua’s site will positively promote the transformation in China’s flexible packaging industry. Caihua is


recognised as one of the leading technological companies in the

16 September 2017

aihua, specialist manufacturer of laminated flexible packaging materials, has invested in

production and lamination of all types of materials for the flexible packaging industry. Its products are widely used in the pharmaceutical, agriculture, electronics and food fields. Three years ago, Caihua acquired three other

Comexi machines that have helped it to boost efficiency and effectiveness. With this new installation, Comexi strengthens its presence and expansion in the Asian continent where the

group has installed hundreds of machines in the last 10 years. Comexi’s CI8 offset press provides maximum

flexibility in the production process, allowing very short time-to-market due to its agile prepress system. It is characterised by its use of lithographic plates, with an approximate saving of 95 per cent compared to photopolymers or engraved cylinders used in traditional flexography or gravure technologies. Comexi’s offset technology is capable of

generating significant savings due to its quick creation of plates. Moreover, this press replaces solvent inks for EB curing technology, which allows the use of solventless inks. This press prints in eight colours with a band

width of 900mm (35.4 inches) to 1.100mm (43.3 inches) and a maximum speed of 300m/min (984.2ft/min). Its high print quality and quick- change capability, paired with cheap plate production, are the main elements that characterise this press. In recent years, the demand for this printing technology has doubled and it is continuously growing, especially in Asian countries.


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