A folding machine is a machine used primarily for the folding of

paper Paper is a thin sheet material produced by mechanically or chemically processing cellulose fibres derived from wood, rags, grasses or other vegetable sources in water, draining the water through fine mesh leaving the fibre evenly distrib ...

. 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 The buckle or clasp is a device used for fastening two loose ends, with one end attached to it and the other held by a catch in a secure but adjustable manner. Often taken for granted, the invention of the buckle was indispensable in securing tw ...

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 In economics, a luxury good (or upmarket good) is a good for which demand increases more than what is proportional as income rises, so that expenditures on the good become a greater proportion of overall spending. Luxury goods are in contrast t ...

machines capable of processing more complex folding jobs and unusual paper forms (in terms of

density Density (volumetric mass density or specific mass) is the substance's mass per unit of volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' can also be used. Mathematical ...

and

size Size in general is the magnitude or dimensions of a thing. More specifically, ''geometrical size'' (or ''spatial size'') can refer to linear dimensions ( length, width, height, diameter, perimeter), area, or volume. Size can also be m ...

). Organizations required to undertake mass mail-out campaigns often employ folding machines to improve efficiency. However it is very commonly used finishing process across the printing industry.

Buckle folders

Buckle folders work by feeding the paper at high speeds until it can move no further; the reaction of the paper is to buckle. High

friction Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. There are several types of friction: *Dry friction is a force that opposes the relative lateral motion of ...

rollers then grip the paper and push it through a pair of folding rollers. The paper is squeezed between the rollers in the process which results a fold. Attached rubber provides the rollers with the required grip. The front edge of the paper is then finally placed into a " pocket"—a result of the rollers pressing together with the aid of a spring.

Knife folders

A knife folder works by striking the paper with a knife between two rollers. This knife is not sharp enough to cut through the paper and simply strikes and creases the paper along the line where the fold is required. Ideally, knife folding is used with thick paper, for "cross folds" (commonly employed for maps and also known as a "French fold") or if the paper has been stitched during the folding process; stitched sheets can ruin high friction rollers.

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. The fold type in a buckle folder is set by adjusting folding plates. Most paper folders allow for a wide range of fold types. Right angle folds require the paper to rotate 90 degrees also known as an 8-page or a right angle. More folds can be accomplished by the use of a 16-page and 32-page unit. Entry-level paper folders require that the folding plates be adjusted manually, with fold settings specified on the folding plates. Higher-end paper folders will electronically adjust the folding plates for added precision and convenience. Both usually have fine tuning knobs for precise adjustments. Most paper folders push paper into the machine by use of a friction wheel; this grabs paper using friction. Friction-feed paper folders do not work well with glossy paper as the friction wheel slips on the paper's surface. Pneumatic paper folders are preferable for folding glossy paper. 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 2 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 placed onto a belt, on a table or rollers, that takes it around the end of the machine, then each sheet is individually pushed into the machine by an air-controlled suction-wheel. The sheets of paper will be separated by blowing air between them.

Folder inserters

Folder inserters are designed for mailing bills, checks and other material. Folder inserters take paper, fold it, insert it into an envelope and seal the envelope. Folder inserters are available in several designs, many equipped with multiple feed trays for several sheets of paper. Many have the ability to include inserts and return envelopes. These are mixtures of knife and buckle folders.

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

File:Letterfold.svg, Letterfold File:Concertina.svg, Concertina File:Gate-fold.svg, Gate-fold File:Crossfold.svg, Crossfold

Process videos

File:Plieuse poche.ogv, Buckle folder File:Plieuse à couteaux.ogv, Knife folder

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 Bedding, also known as bedclothes or bed linen, is the materials laid above the mattress of a bed for hygiene, warmth, protection of the mattress, and decorative effect. Bedding is the removable and washable portion of a human sleeping environm ...

. Examples of commercial clothes folders for domestic use include

FoldiMate FoldiMate was a California-based company developing a robotic laundry-folding machine founded in 2012. Their clothes folding machine was aimed to enter the market by the end of 2019. In 2021, the company folded. History Foldimate was founded by ...

and

Laundroid Laundroid was a laundry-folding machine and home robot, used to automatically wash, dry, iron, sort and fold clothes to a dedicated closet. It was dubbed to be the worlds first laundry folding robot, and was planned to go on sale in Japan first, ...

, which only work for smaller clothes, and not larger items such as bedding. Ironer-folders.jpg, Industrial clothes folders

References

{{Letterpress Print production Printing devices