Delivery section of a web-fed press with inline cutting.
In-line die cutting and rewind section of a press.
There are two die cutting systems used in printing, in-line die cutting and off-line die cutting. In-line die cutting involves the substrate being cut and trimmed on the press. In off-line die cutting the substrate is rewound onto a role or sheets are stacked onto pallets, then transported to other equipment where the material is trimmed and cut at a separate piece of equipment within or outside the facility.
For in-line die cutting capability, a press must have one or more die cutting stations. There are two types of die cutting: rotary die and platen-type die cutting. In North America, 90% of die cutting is done using rotary dies. In Europe, the exact opposite is true. In other words 90% of die cutting in European Flexo plants is done using a platen-type die cutter.
Rotary die cutters are known for their simplicity and high speed. The basic elements are: a gear driven anvil roll, a die slot for die location, a means for positioning and applying pressure to the die, and a waste rewind assembly.
Best Management Practices & Pollution Prevention
Cyclone baler, showing waste partially separated into bales according to color and paper type. Whenever possible, bales should be completely separated.
After die cutting the product, the waste portion of the web is separated and collected as the press is run. Typically this is collected using a cyclone-baler system. The cyclone is ducted to the die cutting section of the press. The vacuum created strips the trimmed paper away to the baler where it is baled and later sent for recycling. Other trim scrap collection systems involve rewinding the trim scrap onto another roll core or routing the trim scrap from the stripping section through shoots made out of PVC into rolling totes. The scrap is then manually fed into a baler or shipped off site in totes, uncompacted.
Carefully designed printing cylinder layouts and cutting dies can help minimize the amount of scrap that must be trimmed off the product. This will minimize waste, substrate costs, and increase press efficiency by printing more product in less time by maximizing the number of copies printed with every turn of the printing cylinder.
For access to vendors who may supply alternative materials and equipment, see the PNEAC Vendor Directory.
In some state and local governments, businesses (printers) may be subject to waste minimization requirements and recycling requirements.
Health & Safety
Care must be used when handling and installing dies onto the press. Wearing gloves will help prevent cuts to hands or nicks to the die. Extreme care must also be taken when the press is running and the dies are rotating. Personnel must keep hands and loose clothing clear of the rotating die. Stop the press completely before clearing any items that are caught or stuck in the die nip.