thumb|right|A folding machinethumb|Buckle folding machine
A folding machine is a machine used primarily for the folding of paper. Folding is the sharp-edged bending of paper webs or sheets under pressure at a prepared or unprepared bending point along a straight line according to specified dimensions and folding layouts. Paper can be folded with either a buckle or a knife; thus, there are generally three types of folding machines: buckle folders, knife folders or a combination of these two types. Whilst buckle folding is the more popular of the two methods, knife folding is sometimes preferable. Folding machine models vary in sophistication, with high-end machines capable of processing more complex folding jobs and unusual paper forms (in terms of density and size). Organizations required to undertake mass mail-out campaigns often employ folding machines to improve efficiency. or if the paper has been stitched during the folding process; stitched sheets can ruin high friction rollers.
Plow folders
A plow folding machine works with a metal strip or a couple of brushes. The paper is forced to fold because of the shape of the strip or how the brushes are placed; after the paper is folded a wheel presses the folded edge for a better fold.
Paper folders
Folding machines exclusively used for folding paper are commonly referred to as paper folders. These machines are typically used for creating letter folds (C Folds) and accordion folds (Z Folds). Other commonly used folds include a half fold, fold-out, double parallel fold, gate (brochure) fold, and right angle fold. Due to rarity they've made their way in to collector archives for obsolete office equipment. Along side fax machines and paper drills, they are known for being inefficient in the modern workplace.
Pneumatic folding machines
Pneumatic paper folders push paper into the machine using a vacuum. These folders are often referred to as air-powered paper folders. This method makes it possible to fold most types of paper. Most pneumatic paper folders include a built-in compressor. These folders can have as many as sixteen folding plates or several knife folds depending on the imposition, these are adjusted manually or electronically, depending on the machine.
Feeding systems
There are two types of feeding systems used by folders: pile and continuous. The first is flat pile, in which the paper is placed on a feeding table and each sheet is then transported into the machine by friction or an air-controlled suction-wheel. A variation of this is palletized feeding, in which an entire pallet full of paper may be placed on the feeding table. The second type is called "continuous"; this involves the sheets being skillfully "rolled-out" onto a belt, on a table or rollers. An electric eye controls the belt speed, propelling the paper into the machine, then each sheet is individually pulled into the machine by an air-controlled suction-wheel. The sheets of paper will be separated by blowing air between them.
Folder sealers
Paper folder sealers are used to fold special pressure-sensitive paper. As the paper is folded, pressure rollers roll along the edge of the paper, bursting open tiny glue pockets that seal the letter shut. Pressure sealed documents are typically opened by tearing off a perforated side or tearing open the sealed portion of the letter. Documents that have been folded and sealed do not require an envelope for mailing and are often used for mailing bills, invoices and other mailed documents.
Typical folding schemes
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File:Letterfold.svg|Letterfold
File:Concertina.svg|Concertina
File:Gate-fold.svg|Gate-fold
File:Crossfold.svg|Crossfold
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Process videos
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File:Plieuse poche.ogv|Buckle folder
File:Plieuse à couteaux.ogv|Knife folder
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Other types of folding machines
Clothes folder
A clothes folder is a device or a machine for folding garments. Clothes folders range from hand operated boards with hinges to automatic folding machines of various sizes. There are several industrial variants of clothes folding machines, with some being highly specialized for certain types of clothes, or very large to accommodate large textiles such as bedding. Some modern industrial folding and filling machines are fully automated, improving speed, efficiency, and accuracy in production lines. Examples of commercial clothes folders for domestic use include FoldiMate and Laundroid, which only work for smaller clothes, and not larger items such as bedding.
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Ironer-folders.jpg|Industrial clothes folders
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See also
- Book folding
- Printing