Slitter glossary

Slitter glossary

Underwind / underwound

The term ‘underwind’ refers to the position on the roll where the web meets the roll and winds onto it – the roll winds from underneath.

Overwind / overwound

The term ‘overwind’ refers to the position on the roll where the web meets the roll and winds onto it – the roll winds from the top of the roll.
Differential shaft

Differential shafts

Differential chucks (also known as ‘slip chucks, or ball chucks’) are fitted to the rewind shafts of slitter rewinders to eliminate tension variances that can develop due to (sometimes very minor) material thickness variations across the parent roll.  Differences in the overall material thickness of rolls being slit can result in each slit roll being different diameters and […]

Air shafts

Winding machine shafts that use air-bladders to secure rolls both axially and radially during winding.


See air shafts


When talking about shaftless roll handing we are usually referring to the unwind/ master roll part of a winding machine.  When rolls or cores are held in place without shafts the system might be referred to as ‘shaftless’.  The parent/ master roll will be held in place by two chucks, one each side of the […]

Splice table

A splice table, with web clamps or vacuum systems, is a device mounted on a winding machine to assist the operator to join to neatly join two webs.

Web guiding

Web guiding is used on winding machines to correct unevenly wound rolls.  A sensor reads either the edge or a printed line and using an extremely fast actuator motor moves the parent/ master roll from side to side to correct the web position laterally. Universal web guiding systems…


The shaft onto which the parent/ master roll is loaded.


The shaft onto which a roll is wound onto.


See web guiding


A touchscreen is used in control systems to facilitate fast and very user friendly controls.

Touch screen

See Touchscreen

Idle rollers

Rollers on a winding machine that are not driven by the machine, and are therefore ‘idle’ and are  free to be driven by the web.

Lay-on arms

Arm-mounted rollers that apply precise amounts of pressure in order to eliminate air from fast-wound webs, ensuring perfectly wound finished rolls.  Lay-on arms are often used when running filmic substrates at speed.


Term used to describe film materials.


Term used to describe materials being fed through a machine as a web.

Layon arms

See Lay-on arms

Shear knives

Circular knives that rotate together as a male and female pair acting much like a pair of scissors, generally used for heavier gauge films and papers.


The bottom part of a shear knife pair.

Razor blades

Razors used for cutting, normally held in place by a razor comb or razor blade holders.  Useful for slitting some thin filmic substrates.

Offloading tree

Utilised to offload slit rolls from the rewind shafts.  The offloading tree can also provide support for the rewind shafts on cantilevered machines.


Low density polyethyline (LDPE) is a petroleum based film used for a variety of packaging including the rings that hold together multipacks of canned beverages and as a coating on some board based food and drinks containers. Find out more –


Bi-Oriented (or biaxely) PolyPropylene (BOPP) film is packaging film used in the food and drink industry.  BOPP is also used to carry security features on anti-counterfeiting and cigarette carton packaging.


Polyethylene terephthalate (PET) is a polymer resin widely used in food and drink packaging. The name is confusing because this product does not contain polyethylene. Find out more –


A slitting/ winding machine with a single rewind shaft.


A slitting/ winding machine with two rewind shafts, allowing rolls to be alternately wound on each shaft.

Duplex turret

A slitting rewinding machine with a total of four shafts.  Two sets of shafts are used for winding while the remaining two sets are used for offloading.

Separate unwind

Term used to describe when the unwind part of a winder is not built into the same sideframes as the rewinding part of the machine.  A separate unwind is sometimes utilized when additional processing machine (like laser perforation) is placed in the web path.

Integrated unwind

Meaning the unwind mechanism is mounted as a part of the cutting / rewind part of the winder.  Using an integrated unwind minimises the machine footprint and reduced the risk of material contamination found with machines with separate unwinds. Although the cost of an integral machine is higher due to the greater rigidity required, it […]

Peel-off roller

When unwinding some low-tack and adhesive rolls the material being unwound can remain stuck to the parent roll longer than is helpful to the overall process, this can lead to a running web either gaining too much tension or temporarily losing tension.  This problem is solved by including a peel-off roller near the unwind / […]

Trim winders

Motorised winders used for the removal of excess material.

Crush cut knives

Crush cutting is a method of cutting that uses circular knives held by knife holders.

Core size ID

Core size ‘ID’ refers to the internal diameter of cores.

Minimum slit width

The minimum slit width on a slitter specification refers to the smallest width of finish roll that is required.

Finish roll diameter

The finish roll diameter is a measurement of the diameter of the roll on the rewind of a slitter.

Unwind roll width

The unwind width measurement refers to the width of your master / jumbo roll.

Jumbo roll width

See unwind roll width…

Master roll width

See unwind roll width…

Unwind roll diameter

The unwind roll diameter is a measurement of the diameter of your master / jumbo roll.

Jumbo roll diameter

See unwind roll diameter…

Master roll diameter

See unwind roll diameter…

Spreader roller

Roller used to spread the web material.  A spreader roller can also be used to prevent interleaving of finish / rewind rolls on a simplex slitter.

Core alignment

When empty cores are placed on the rewind shaft of a slitter they need to be aligned to ensure that the rolls are wound correctly.  Lasers are accurate because they show the machine operator exactly where to place the core using a line projected by the laser unit, the position of the line itself is […]


Interleaving is the term used to describe the problems caused when the edge profiles of two rolls on an rewind shaft become intertwined.  Interleaving is to be avoided!  Interleaving is sometimes referred to as ‘interweaving’.  Interleaving is a problem particularly related to simplex slitters.

Static elimination

Some materials and winding methods can generate huge amounts of static electricity that can be dangerous to operators and damaging to materials.  There are several designs of static elimination systems. and on slitters they are often installed after the unwind and before the two rewind shafts.

Mink roller

Spreader roller with static elimination properties.


The term ‘web’ is a generic term used to describe material as it passes through a slitter / winding machine.


Generic term referring to a machine that is used to cut (slit) rolls of material while they are being re-wound.

Bowed roller

A bowed roller is typically situated before the slitting section and is used to remove wrinkles from the web material.

Reversible running

Reversible running enables salvage / doctor rewinders to run in two directions, allowing print direction to be corrected without the need to unload and re-load the roll.

Driven unwind

A driven unwind describes a system whereby the shaft (or shaftless system) of a Slitter Rewinder that houses the master / jumbo roll is driven by a motor. A driven unwind is often used when a material is tension sensitive, when an unwinding roll is driven it minimises inertia of the parent. See also Braked […]

Braked unwind

A braked unwind describes a system whereby the shaft (or shaftless system) of a Slitter Rewinder that houses the master / jumbo roll is controlled using a brake. A braked unwind is the standard unwind type used on most slitter and salvage winders. See also Driven Unwind…

Bull nose peel off

Peel off bar in a slitter, winder or lamination system designed to assist with the stripping of the paper carrier, usually as a part of a lamination process.

Closed loop tension control

The use of load cells on a slitter / winding machine to measure the actual tension of materials being wound, so the control system can make very accurate adjustments to ensure precise tension is maintained throughout the winding / slitting process. Closed loop tension control is particularly useful when winding tension sensitive materials / substrates.

Remote diagnostics

The controls on slitters are designed to be very simple to operate yet the system has extensive diagnostics should they be required.  We also provide a port on the system for secure Internet access to allow our engineers to monitor the performance of the machine remotely. To utilise the remote diagnostic system, we require the […]

FLT handling

FLT handling is a term used to denote ‘Fork Lift Truck’ handing of materials, usually rolls.  In many circumstances the use of a fork lift truck to load rolls of material onto the unwind of a slitter / winder is undesirable due to the potential damage to the materials and the winding machine. FLT Handling […]

Tendency driven rollers

Idle roll on a driven shaft, thereby using the stiction of the bearings to drive the roll.  Tendency driven rollers can be used to reduce the energy required from the web to drive the idle roll from rest. Sometimes used on slitters and salvage winders to reduce the chance of path rollers damaging materials as […]

Shafted unwind

On a machine with a shafted unwind the master / parent roll is supported by a shaft running through the core of the roll.
Constant geometry layon rollers

Constant geometry layon rollers

Constant geometry layon rollers are mounted on linear (horizontal rather than pivoting) support arms. These do not vary their force as of the geometry change unlike conventional pivoting systems.

Slit tension zone

Some of the slitters in our machine range (the Universal X6 for example) feature an additional operator controllable tension zone. The tension through the slitting knives can be set independently of the unwind and rewind tensions, ensuring the optimum tension through the slitting knives.