Perforation involves making a series of small cuts in paper to enable it to be folded or removed from another part of the document. Munkfors manufactures a range of both perforating and microperforating rules for this purpose.

In a perforated paper document, the cut areas are called “cuts” and the uncut areas are called “ties”. A perforating rule is defined as the number of ties (gaps in the blade) per inch, TPI. However, it is quite common to call these ties “teeth” just like with saw blades, and thus TPI becomes interchangeable with the number of teeth per inch.

The tied areas of a perforation are usually shorter in width than the cut areas to facilitate folding or separating a document along the perforation.

Selecting the most suitable TPI depends a number of factors including:

• Paper thickness
• Paper elasticity
• Paper structure
• Paper coating
• How much a document will be handled
• How the document will be used
• Whether the perforation is used for folding or tearing

The ranges of Munkfors perforating and microperforating rules are designed to satisfy virtually all your needs in this application area.

In addition to perforation rules, Munkfors manufactures a range of cutting rules to cut paper documents to the required lengths.