Equipment: The cutting edge

One of the most notable changes in the converting industry in recent years has been the shift to shorter print runs. You might expect this trend to play into the hands of manual and semi-automatic die-cutting machines, as they are suited to short run-lengths. Instead it has fuelled greater innovation in the area of high speed, fully automated die-cutters – enabling packaging producers to make these shorter runs more economic.

Maximising productivity, by increasing line speeds and preventing line stoppages, is one way in which designers of die-cutters are responding to the trend towards shorter runs. According to packaging equipment manufacturer Bobst, misfeeds caused by variations in the stack of sheets coming from the printer cause the majority of stops when running at speed.

Bobst was the first to market, in 2000, with a dynamic register system to overcome this problem and has since applied the technology across its folding carton and corrugated die-cutters. As opposed to traditional lays, which just register the sheet edges, dynamic systems like our Power Register II take hold of the sheet and use cameras to identify the actual position of the print. The system then moves the sheet into the perfect location before handing it over to the gripper bars, explains Stuart Taylor, UK and Ireland product manager for Bobst SP die-cutter products.

Quality is critical
The company claims that on the Mastercut 106, Power Register delivers perfect register at the machine’s maximum speed of 12,000 sheets per hour (sph). High running speeds are key to improving productivity across shorter runs, but only if they can be achieved without a detrimental effect on cutting quality. It’s quality sheets on the floor that’s critical, not necessarily the running speed of the machine, affirms Paul Thompson, press manufacturer Heidelberg’s UK product manager for packaging and label finishing systems.

He says this is something Heidelberg’s Dymatrix machines  achieve through the combination of its Dyset registration feature and positive registration of the sheet in all machine sections. The moving upper platen cutting method of the Dymatrix range also reduces nicks in the sheet, he adds. The cutting pressure is even and smooth and the transfer of the sheet is gentle.

The challenge of balancing the need for speed and quality has been compounded by many brand owners switching to lighter-weight boards and papers in a bid to become more environmentally friendly.

Stock problems
According to Bobst, the main issues arise where brands are changing from solid board to litho-laminated microflute, as register becomes more difficult to maintain. Generally, there is a small mismatch between the edge of the litho sheet and the edge of the carrier and this ‘skirt’ can fold in when it hits a conventional lay, affecting the register, explains Taylor.

Die-cutters with dynamic register systems are ideal for coping with this because they register to the print not to the sheet edge.

Spanish manufacturer TMZ-Talleres Morato says one of the problems its machines used to encounter when cutting lightweight board at high speed was that when the gripper bars stopped, the sheet didn’t always remain flat. To overcome this issue, besides redesigning several parts involved in the movement of the gripper train, the company has developed a new feeding system to attain high register accuracy.

Other manufacturers have adapted die-cutters to better cope with lighter-weight materials, too. While Kama claims that marrying the conflicting requirements of speed and quality is not an issue for its die-cutters, owing to their design, as the gripper bar transports the sheet on its long side, it has made changes which make lightweight materials easier to run. These include the addition of a feeder with suction belt as well as new adjustable side and front lays and making improvements to the delivery unit.

Masterwork Graphics has developed a new ‘speedy’ feeder with pneumatic side lays and vacuum belts to improve feeding quality. It has installed sheet smoothing units in the platen area to compensate for thinner running materials.

However, when it comes to running speeds, the company seems reluctant to be drawn into a contest with its competitors. Speed and accuracy have always been an issue with die-cutting, and with the advent of new high-speed printers, the bottleneck will remain the maximum speed that can be achieved by the die-cutter, says European sales manager Ken Farnsworth. This appears to be 12,000sph, but only one manufacturer seems to be developing their technology to that limit.

For us, the emphasis is on manufacturing more versatile machines. For example, our new Duopress is capable of foiling/embossing and die-cut/stripping in one pass, while our Webfoil 920 is a three-headed foiling/embossing machine with inline die-cutting, converting printed products from a roll as opposed to being sheetfed. With either machine, we are putting the equivalent of 10,000 sheets on the floor. It aims to provide added value through offering two processes in one pass with the need for only one operator, which can cut costs.

Heidelberg, too, believes there’s more to productivity improvements than faster running speeds. With decreasing run lengths, makeready speed can be more important than actual running speed, says Thompson.

Quick switch
At last year’s Drupa, the German extravaganza of printing technology, Heidelberg demonstrated a complete job changeover in less than 10 minutes on its new Dymatrix 106CSB. The machine was changed over from a 16-up straightline carton to a six-up corner box with embossing in under eight minutes by one operator. Thompson says this was made possible by features such as automated micro adjustment of the cutting plate, hydraulic chase and quick lock tooling.

Hawkes, a UK supplier of cutting systems, has also made headway in reducing changeover times. It claims that, thanks to the fact the machines are easy to set up and no makeready is required on tooling, job changes can now be carried out in seconds, reducing downtime by up to 45%. Hawkes adds that many systems are supplied with hard cutting belts, which can be changed in less than 10 minutes – giving more flexibility when handling difficult materials.

Madern, a manufacturer of rotary – as opposed to flatbed – die-cutters, has been focusing on making changeovers easier and cheaper to accommodate shorter runs. Packaging producers typically opt for inline rotary die-cutters when they want to produce standardised packs, for example, cigarette cartons, in large volumes and at high speeds. The downside of rotary inline is the high cost of the converting dies.

Madern says that due to the trend towards shorter runs, it is focusing on developing lower cost rotary dies. We now offer a wide range of die solutions, from very economical, flexible wraparound plate dies, solid or sleeve dies, all the way up to the fully segmented dies for very long production runs, says the company’s global sales director Jos Van Oekel.

Of course, hand-operated die-cutters still have their place, as Heidelberg’s Thompson points out. There are a great many cylinders still running efficiently on a day-to-day basis. While this technology is old now, for very short run lengths and composite work they can be a good addition to a fully automated die-cutter. However, in the carton industry automation is key and has been for many years, he adds.

It’s clear that in the drive to increase productivity, packaging printers are increasingly turning to automated die-cutters. Not yet clear is whether faster inline cutters or more flexible offline cutters will emerge as the technology of choice for packaging printers, or whether, as is the case at present, this will continue to be determined by the application in hand.

EQUIPMENT ROUND-UP
Smurfit Kappa Corrugated has developed embossing tool technology aimed at increasing the impact of corrugated packs such as pizza boxes. The tool allows logos, numbers, letters and shapes to be embossed on to corrugated board.

EskoArtwork has joined forces with Manroland, Bobst and Dr Lauterbach & Partner to develop a JDF-based system to control production of cartonboard packs from order to delivery.

Xerox has made its foray into packaging with the launch of the Stora Enso Gallop integrated digital printing and die-cutting line, powered by Xerox. The integrated system comprises a Xerox iGen3 digital printing press and a Kama die-cutter.

TMZ-Talleres Moratos has launched a new automatic die-cutting machine to handle bigger sheets. The RW-205 €CO-VISTA handles 5,000 130×205 cm sheets per hour and is equipped with a stripping unit.

Drupa 2008 was the launchpad for the world’s first B3 die-cutter from Kama. The 6,000sph ProCut 53 can cope with stocks up to 800gsm and can cut, crease, perforate, kiss-cut, cold emboss and produce Braille.

Bobst previewed four ‘families’ of folding carton converting machines at Drupa. The Mastercut, Expertcut, Visioncut and Novacut are said to feature improved ergonomics and a new control system.

Gallus used Drupa to launch its ICS 670 mid-web carton printing and converting machine. The ICS 670 enables packaging printers to go from roll to die-cut pack in just one pass, in the space of 30 metres and using a variety
of processes.

Heidelberg introduced the Dymatrix 106CSB Pro. The machine is said to reduce set-up time by up to 15 minutes on repeat work and even more on a new job if connected with Prinect.

Hawkes Technical has announced that from now on, it will be handling European sales for Delta Industries, a US manufacturer of rotary and flatbed cutting systems.

Popular Articles