Perforation Uses | Ties Per Inch | Types | Internal Folding Perforations

Perforation Uses

Perforations on continuous forms can be used on the left and right sides of the form to make a stub so that the lineholes can be easily removed after the form has been through a printer. Perforations are used as a means of keeping forms together in a continuous stream as they are fanfolded, but allow the forms to be detached from each other after they have been imprinted upon. Also, they provide a way to remove internal sections of the form itself.

Ties Per Inch (TPI)

The tie or tab is the part of the perforation where the paper does not get cut, but remains intact to "tie" the paper together. The ties alternate with cut areas to form the perforation. The tied areas of the perforation are usually narrower than the cut areas to allow for easier detachment of the sections separated by the perforation. The proper TPI to use is generally determined by the type of form and the function of the perforation on that form. The following are some of the common TPI and their uses on continuous forms:

• 4 TPI: 4 TPI is the most often used stub perforation for single and multi-part forms. It allows for easy removal of the stub and lineholes once the form has been run through the printer. 4 tie is also used as a folding perf, but should be used with caution because it tends to break easily, especially on multi-part sets. It should not be used on letterheads when a cleaner edge is desired after the perfs are detached.
• 6 TPI: 6 TPI is also used as a stub perf, but it does not detached as easily as a 4 TPI. It is sometimes used for the stubs on the first and last parts of a multi-part set of 5 or more parts. It provides more strength to the entire set so that the stubs will not loosen up before the form has been through a printer. It also is the most popular TPI for fanfolding both on single and multi-part forms. It provides strength to hold the continuous stream of forms together so that they will not fall apart when going through a printer.
• 8 and 10 TPI: The perforations in this group can be used as stub and internal perforations, but are most often used as folding perfs on one part forms of a heavier stock, such as 32 lb. ledger and 100 lb. tag. They are also used on multi-part sets to provide more strength with the fanfolded perfs.
• 12 TPI: 12 TPI is also referred to as a "statement perf". It is most often used as a perf within the form that allows the user to remove a section of the form. For example, the top or bottom section of a "statement of account" form may be removed to be sent back with a payment. A 12 TPI perforation is durable and many times it is best to fold over the perf so that it detaches easier. It can also be used as a folding perf on heavier stock.
• Letteredge or Invisible Perf: As the name implies, the letteredge perf is nearly invisible and leaves a clean, smooth edge after the perf is detached. It is most often used for all of the perforations on letterhead forms because of the clean look it leaves when detached. The most common ties per inch for letterhead perfs are 50, 66, and 72. Most forms manufacturers use one of these as the standard for all of their letteredge perfs unless a specific TPI is requested. Letteredge or invisible perfs should not be used for fanfolding on multi-part sets or on single part forms that are of a paper stock heavier than 28 lb. ledger. It is too difficult to control the cutting depth of the perf which may result in a perforation that does not detach properly.

Perforation Types

Internal Folding Perforations

In addition to folding perforations used for fanfolding, continuous forms may also have internal folding perforations. The internal perfs are not actually folded, but are necessary when the finished form is smaller than the depth at which the press or collator can actually do the fanfolding. Most presses are set up to print forms only at preset depths. On a 22" press for example, the 22" represents the circumference of the printing cylinder and only the form depths that can be divided into 22" can be printed on that press. 11", 7 1/3", 5 1/2", and 3 2/3" are the common preset depths of forms that the 22" press can produce. When fanfolding on a 22" press or collator, the common fanfolding depths are 11" and 7 1/3". A 5 1/2" form would not be folded at 5 1/2", but at 11", so each 11" sheet would contain two 5 1/2" forms. The perforation separating the two 5 1/2" forms on the 11" sheet would be known as the internal folding perf. Since folding weakens perforations, the folding perf needs to be of more ties per inch than the internal folding perf so that both perforations will burst or detach using equal force on both. For example, you may find that on a single part form of 20# bond, an 8 tie perf will be used for the folding perforation and a 6 tie will be used for the internal folding perforation. The 8 tie is a stronger perf than the 6 tie, but it will weaken slightly when folded so that it will be comparable to the 6 tie unfolded perf.

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