As with any niche in the manufacturing sector, there exists a whole collection of industry-specific vocabulary. To better understand rotary die cutting, it is helpful to know the basic terminology used to describe the various aspects of web converting and the rotary die cutting process.
- Rotary Press – A piece of equipment that performs any number of converting operations such as printing or die cutting, usually utilizing a separate station for each process. Rotary presses may be equipped with other specialized components to allow other operations such as laminating, sealing, laser cutting, or inspection.
- Solid rotary die – A cylindrical tool specially designed to perform a specific function or functions, such as cutting, slitting, embossing, sealing or a combination of these.
- Anvil – A smooth cylindrical roll that is used in conjunction with a rotary cutting die. The anvil provides a solid support surface against which a substrate material is cut when it passes between the die and anvil.
- Flexible die – A thin, flexible metal plate containing engraved cutting blades that is wrapped around a magnetic cylinder and then used to perform rotary die cutting.
- Magnetic cylinder – A cylindrical roll embedded with a series of magnets which hold a flexible die in place. It serves as the supporting core to a flexible die.
- Butt cut – A straight-line pressure sensitive cut perpendicular to the web material flow.
- Kiss cut – A term describing die cutting through one layer of substrate down to, but not through a subsequent layer. A common example is pressure sensitive labels where the label material is cut through, but the liner beneath remains intact.
- Lineal – Pertains to cuts or scores in the direction of web material flow. Lineal blades run around the circumference of a rotary die, and cut parallel to the web material flow.
- Metal-to-metal cutting – Die cutting completely through a material. Metal-to-metal refers to the contact (or near contact) between a die cutting blade and the anvil beneath to achieve complete cut through. Also known as crush cutting.
- Multi-Level cutting – Die cutting with variable blade heights, such that various features are cut to different depths, or down to specific layers of a multi-layer substrate. Allows for cutting to a liner and through to the anvil with a single tool.
- Perforation / Micro-perf – Die cutting that utilizes small, intermittent breaks in the cutting blade to create “ties” in the material, causing the cut material to remain in the web until physically removed by breaking the ties. Micro-perf, also known as invisible perforation, creates ties that are very small and close together, allowing the finished part to be removed cleanly from the web. Perforation blades have tie geometry that is specifically designed for the material being cut.
- Scoring – An operation where die blades press into the substrate material without cutting through it. Commonly used to create fold lines in paperboard or other packaging applications. Scoring blades are often dull to avoid cutting into the surface of the material. They are often incorporated into the cutting die.
- Sheeting – An operation that cuts across the web and completely through the material, creating sheets of material from the original roll.
- Slitting – A type of lineal cutting that cuts through the material completely, creating narrower strips of material from the original wider roll.
- Cavity – Typically describes the repeating shape on a rotary cutting die. Each cavity is identical and may repeat several times across or around the die.
- Cutting pressure – The force applied to the bearers of the die to properly engage the cutting die with the anvil surface. Pressure will vary with material properties and thickness, with some materials requiring greater force than others to achieve a clean and complete cut.
- Die Blank – A validation document typically provided by the press manufacturer containing critical dimensions and features of the die to ensure proper fit into the cutting station of the rotary press.
- Lamination – The process of combining more than one layer of material together to form a completed substrate. Examples of laminated layers include core material, liner, and adhesive layer.
- Slug – A piece of waste material resulting from the die cutting process whereby the material is cut completely through and produces an unneeded shape.
- Matrix – Describes the web material that is left over after parts are die cut and removed.
- Web – Material in roll form that has been fed through and around the various die stations, rollers, tensioners, and cutting dies/anvils. In general, the web refers to the die cut material roll while it is present in the rotary press.
- Web tension – The force used to pull material through a rotary press. It is a critical factor with significant effects on die cut consistency and quality.