Aluminum Folding Carton Production
Folding carton manufacture is a highly developed process and laminated aluminum foil paperboards respond well to all of the carton-making operations.
Cutting-creasing, is the key process in the production of folding cartons. A carton layout, in which web or sheet width and multiple carton blank arrangement are determined. Sometimes, the individual carton-blank repeats can be placed as to almost eliminate board waste, as shown in here. Where the shape of the carton permits, the blanks can be nested or interlocked, as in here. The layout and a detailed drawing of the carton blank are sent to the die maker for producing the die.
The die itself is a complex arrangement of tempered hard steel Rules some of which are sharpened to cut through the foil board web, while others are rounded to crease the web without cutting it.
Cuts and creases produced by this arrangement of rules determine the shape of the carton: its flaps, its tucks, and its other features. If the cartons are to be run "12-up" (12 carton blanks produced at one stroke), 12 of these dies are nested together in the most efficient way. The rules are held in place by plywood or metal blocks called furniture, and are securely locked in a form called a chase (both of these terms are carried over from letterpress printing). Cutting rules are flanked by strips of resilient material, such as rubber or cork, to force the sheet away from the die after it has been cut and the pressure released. Once the job is made ready the foil-board sheets or web is fed through the cutter-creaser, where it is scored (cut and creased) by steel rules.
As the cut and creased web moves out of the cutter-creaser, the waste board surrounding the blanks (the dark areas in here) remains attached to the blanks in several places called nicks. These small uncut areas are the result of intentional nicks in the edges of the cutting knives. The web moves from cutter-creaser in the stripper, where these nicks are torn away and trim removed.
Stripping is the last operation for many carton styles; they are ready for delivery to the packager. However, other styles require gluing, either along a glue lap, or in the corners. Most foil cartons for cosmetics, foods, bottled goods, and many other products are one of the glued types.
The folding cartons requiring gluing are stacked in the hopper of a carton gluing machine, printed side down. They are stream fed from the hopper, through the glue-applicator rolls, and through the folder, which folds the carton along the two working score lines and applies pressure to seal the glued seams. This pass through the folder also makes partial folds along the other score lines to facilitate setup of the flat cartons when they are later run on the carton-filling and closing lines. This partial score-line folding is called pre-breaking or pre-folding.
Supplementary operations, when specified, are for the most part performed on the press sheet, (foil/board stock), prior to die cutting the cartons. These may include printing, embossing, and special coating, although most carton stocks are now coated in web-form before or after printing, depending upon location and type or purpose of coating. All but random or overall printed designs are made to register with carton design.
Aluminum foil laminated boards is produced with various gauges or bare or coated foil on one or both sides of any of a wide range of fiberboards to meet many combinations of end use requirements. Various types and styles of folding cartons are illustrated in here.