Wrapping Machine

What is a Wrapping Machine

A wrapping machine is an end-of-line packaging machine that wraps plastic film around a product or a unitized load to bind it, stabilize it during handling, and shield it from dust, moisture, and tampering. In a typical factory or distribution centre, it is the last automated step before goods are loaded onto a truck or placed into storage, sitting downstream of filling, cartoning, case packing, and palletizing. Its core job is to convert a loose stack of cases into a single rigid unit that survives forklift movement, conveyor transfer, and the vibration of transport without shifting or collapsing.

The label "wrapping machine" actually covers several mechanically distinct families that should not be confused during selection. The largest by installed base is the stretch wrapper, which applies cold linear low-density polyethylene (LLDPE) film that is elongated as it is applied; the film's elastic recovery provides the clamping force. The second family is the shrink wrapping machine, which loosely encloses a product in polyolefin (POF) or polyethylene film and then passes it through a heated tunnel so the film contracts tight. A third family, the orbital or horizontal ring wrapper, spirals film around long products such as pipe and extrusions. A fourth, the stretch hood machine, stretches a tubular film open and pulls it down over an entire pallet in one fitted layer.

The modern stretch wrapper traces to the 1970s. Lantech, founded in Louisville, Kentucky, is widely credited with inventing and commercializing the stretch wrapping machine, displacing earlier and more energy-intensive shrink-hood and strapping methods for pallet unitizing. Subsequent decades added powered pre-stretch (turning one metre of film into several), programmable wrap patterns, automatic film cut-and-clamp, and integration into fully automated conveyor lines, so that today an automatic wrapper can receive, wrap, label, and discharge a pallet with no operator touching it.

The economic significance of wrapping is disproportionate to its visibility. Film and labour for wrapping are a recurring per-pallet cost incurred on every shipment for the life of the operation, while load failures in transit (collapsed pallets, damaged product, rejected deliveries) carry costs far beyond the film itself. Because of this, the engineering objective in wrapping is not simply "cover the load" but "deliver a defined, repeatable containment force at the lowest film cost and the required throughput." The chapters that follow build the framework for meeting that objective.

It also helps to place wrapping in the end-of-line sequence. Upstream, primary packaging (filling, capping, labeling, coding) prepares individual products; secondary packaging (cartoning, case packing) groups them; then palletizing stacks the cases. Wrapping is the tertiary, unitizing step that turns that stack into a shippable unit, sometimes followed by strapping for extra restraint and by a checkweigher or print-and-apply label for the finished pallet. Because the wrapper inherits whatever the palletizer produced, its rated load envelope and stability tolerance must be matched to the upstream pallet pattern, not chosen in isolation.

Selecting a wrapping machine therefore means answering three questions in order: what is being wrapped (a pallet, a retail multipack, a long extrusion, a coil), how many units per hour, and how stable or fragile the load is. Those three answers map almost deterministically onto a machine family and a configuration tier, from a low-cost semi-automatic turntable to a fully integrated rotary ring or stretch hood line.

Machine Types and Classification

Wrapping machines are classified first by mechanism (stretch, shrink, orbital, hood) and second, within the stretch family, by how the film is brought around the load. The choice between rotating the load and rotating the film is the single most consequential architectural decision, because it sets the ceiling on load weight, stability tolerance, and throughput. The table below summarizes the main types and where each fits.

Turntable stretch wrappers place the load on a rotating turntable while a film carriage on a vertical mast travels up and down, laying overlapping bands. They are the most compact and economical type and the default for stable, regular loads. Capacity is bounded by what a turntable can spin safely: standard tables handle around 1,200 kg with heavy-duty options to 2,000 kg, and centrifugal force limits how light or unstable a load can be before it shifts during rotation. They are available in semi-automatic (operator attaches and cuts film) and automatic (in-line, auto cut-and-clamp) versions.

Rotary arm wrappers keep the pallet stationary and rotate an overhead arm carrying the film carriage around it. Because the load never spins, they suit heavy, unstable, fragile, or very light loads that would topple on a turntable, and they avoid the floor-space and weight limits of spinning a heavy pallet. Rotary ring wrappers push this further: a high-speed ring orbits the film around the load and supports the highest throughput in the stretch family, reaching roughly 160 pallets per hour, which makes them the choice for fully automatic high-volume lines.

Orbital (horizontal ring) wrappers rotate a vertical ring around a horizontally fed product while a conveyor moves the product longitudinally through the ring, producing a continuous spiral wrap along the length. They are purpose-built for long, narrow items: pipe, tube, aluminium and PVC profiles, lumber, boards, doors, windows, and carpet rolls. The ring diameter is sized to the product cross-section plus clearance, and infeed and outfeed conveyors handle transfer so the wrap is continuous from end to end. Stretch hood machines and shrink wrapping machines are covered in detail in Chapter 3, as their principles differ fundamentally from spiral stretch wrapping.

A further distinction within the stretch family is the level of automation. Semi-automatic machines require an operator to attach the film tail at the start and cut it at the end of each cycle, which suits low to moderate volumes and irregular workflows. Fully automatic machines integrate into a conveyor line and perform film attach, wrap, cut, and clamp without an operator, discharging the wrapped pallet automatically; they are justified once volume is steady and high enough that operator film handling becomes the bottleneck. The same turntable, arm, or ring architecture is generally offered in both tiers, so automation level and architecture are independent choices.

Working Principles and Film Mechanics

Three physically different principles underlie the wrapping-machine families: cold elastic stretch, heat shrink, and stretched-tube hood application. Understanding them prevents the most common specification error, which is treating "stretch wrap" and "shrink wrap" as interchangeable. The table below contrasts the three mechanisms on the parameters that matter for selection.

Cold stretch wrapping works because LLDPE film is mechanically elongated as it is applied, then tries to return toward its original length. That recovery converts into an inward "containment" or "film" force that squeezes the layers of the load together. In the simplest turntable systems, stretch is created passively: the turntable pulls film off the roll faster than the roll's brake allows it to feed, so the film elongates. More capable machines add powered pre-stretch, where the film passes between two motor-driven rollers turning at different speeds (set by fixed or variable gear ratio) and is elongated to a controlled percentage before it ever reaches the load.

Pre-stretch is the dominant cost lever. Machine pre-stretch of 200 to 300 percent is routine, versus only 100 to 150 percent achievable by hand. At 250 percent pre-stretch, one metre of film off the roll becomes 3.5 metres on the load, so film consumption per pallet falls sharply while containment force rises and becomes more consistent. This is why a higher-cost machine with powered pre-stretch usually pays back through film savings alone, independent of labour. Wrap force (the carriage brake or motor torque) and wrap pattern (number of top and bottom revolutions, overlap percentage) are programmed per load to balance containment against film cost and product crush risk.

The wrap pattern itself is a key tuning variable on cold stretch machines. Extra revolutions are concentrated at the base to lock the load to the pallet (the most common failure point in transit) and at the top to stabilize the upper cases, while the middle is wrapped with a defined band overlap, typically 50 percent, as the carriage indexes up the mast. Many machines can also rope or cable the film, twisting it into a narrow high-tension band that bites into a specific level of an unstable load, and can apply a top sheet for dust and weather protection on open-top stacks. Each of these features trades a small amount of film and cycle time for a measurable gain in load security, and the right balance is set per product, not globally.

Heat shrink wrapping is a different physics. The product is first loosely enclosed in film, commonly sealed into a bag by an L-bar sealer, then conveyed through a heat tunnel. Polyolefin (POF) and polyethylene films shrink in the range of roughly 120 to 200 degrees Celsius, drawing tight to the contour of the product. The result is a fully enclosed, glossy, tamper-evident pack, which is why shrink wrapping dominates retail multipacks (beverage bottles, canned goods) and individual product enclosure rather than heavy pallet unitizing. Tunnel temperature and conveyor speed are tuned to film type and pack thickness; too much heat distorts the product, too little leaves loose film and weak seals.

Stretch hood combines elastic recovery with full top cover. The machine takes a tubular, gusseted polyethylene film, seals and cuts a length, then four grippers stretch the tube open horizontally and pull it down over the entire pallet in a single fitted layer before releasing. The film's recovery clamps the load on all four sides while the closed top resists rain and dust, making it popular for outdoor-stored goods such as building materials, chemicals, and food. Because it lays one fitted layer rather than many overlapping bands, stretch hood uses roughly 30 to 50 percent less film per pallet and runs very fast, but the tubular film and the machine are both more expensive.

Films, Media, and Standards

The film is the consumable that defines wrapping performance, and matching it to the machine is as important as the machine itself. Stretch film is specified by material, thickness, and pre-stretch capability; the wrong combination either wastes money or fails to contain the load. Film thickness is quoted in microns or in gauge, where 1 gauge equals 0.254 microns, so an 80-gauge film is roughly 20 microns. The table below maps common load weights to film thickness and machine type.

Stretch film is almost universally LLDPE, prized for its combination of stretchability, puncture resistance, and cling. Machine films can be elongated 200 to 300 percent consistently, and premium multilayer or "nano" films extend that range toward 300 to 400 percent, delivering equivalent containment at as little as 12 microns. The economic logic is counterintuitive to newcomers: a thinner premium film run at high pre-stretch on a powered machine often beats a thick cheap film run at low stretch, both on cost per pallet and on containment force. Cling additives keep the tail and overlap bonded so the wrap does not unravel.

Shrink film is selected by chemistry. POF (polyolefin) is the modern default for retail and food contact, offering clarity, gloss, and a wide shrink window; PVC is older and lower cost but releases acidic fumes when heated; PE is used for heavier industrial bundling. Low-temperature POF in the 60 to 75 gauge range is typical for L-bar machines, with shrink temperatures from roughly 120 up to 200 degrees Celsius depending on film and pack. Stretch hood uses a tubular, gusseted, highly elastic polyethylene formulated to be stretched open and recover hard.

Film failure modes are worth understanding because they often reveal a mismatch between film and machine rather than a defective load. Punctures and tears usually mean the film is too thin or under-stretched for sharp-cornered cases, calling for thicker film, corner protection, or a reduced pre-stretch ratio. A wrap that loosens in transit points to insufficient containment force, too few base revolutions, or too little overlap. Excessive film consumption with no security gain indicates the machine is under-stretching a premium film. Because each symptom maps to a specific setting, a wrapper that lets you measure and adjust pre-stretch, wrap force, and pattern is far easier to optimize than a fixed brake-only machine.

On standards, EN 415-6 (Safety of packaging machines, Part 6: Pallet wrapping machines) is the harmonized European standard covering stretch film, shrink film, hood, mobile, and film-removing machines; applying it supports presumption of conformity with the EU Machinery Directive 2006/42/EC. Sibling standards include EN 415-4 (palletizers and depalletizers) and EN 415-8 (strapping machines). For the film application practice itself, ASTM D4649 is the standard guide for the selection and use of stretch wrap films and includes Annex examples of pull-plate and wrap-in-scale methods for estimating film force, although ASTM has not certified any single containment-force tool. In North America, ANSI B155.1 governs the safety of packaging and related converting machinery.

Key Specification Parameters

A wrapping-machine datasheet can list dozens of figures, but only a handful drive the buy decision. The parameters below are the ones to compare line by line across quotes, because they jointly set whether the machine fits the load, hits the throughput, and delivers the required containment force at acceptable film cost.

Maximum load weight is the heaviest pallet the machine can handle. For turntables this is a hard mechanical limit (commonly 1,200 kg, heavy-duty to 2,000 kg) because the table bearing and drive must spin the mass; for rotary arm and ring machines the load is stationary, so weight is far less constraining. Verify the rated weight against your worst-case pallet, not the average.

Maximum load dimensions are the footprint and height the machine can wrap, for example a pallet envelope of 800 by 1,200 mm with wrap height to 2,100 mm. Wrap height is the vertical travel of the film carriage and is often a configurable option; tall and oversized pallets need an extended mast.

Turntable or ring speed sets throughput. Turntables commonly run 0 to 10 RPM, heavy-duty and high-speed models to about 20 RPM, while ring machines orbit much faster. Speed combines with wrap pattern to give pallets per hour: roughly 15 to 60 for turntables, up to about 160 for rings, and 100 to 200 for stretch hood.

Pre-stretch ratio is the percentage the film is elongated by the powered carriage (200 to 300 percent typical). This is the primary film-cost specification: higher ratios cut film per pallet and stabilize containment force. Confirm whether pre-stretch is fixed, variable by gear change, or fully programmable.

Film force and wrap pattern control containment. Wrap force is set by carriage brake or motor torque; the pattern programs top and bottom reinforcement revolutions and band overlap. Containment force is the inward holding force at the load corner and is the true measure of load security, estimated in the field by pull-plate or wrap-in-scale methods per ASTM D4649.

Additional parameters worth checking on every quote:

• Automation level: semi-automatic (operator attaches and cuts film) versus fully automatic with auto film cut, clamp, and wipe-down, and conveyor integration.
• Film carriage type: brake-only, fixed pre-stretch, or powered variable pre-stretch; powered carriages dominate any high-volume case.
• Roping or edge reinforcement: ability to twist film into a rope for high-tension banding on unstable loads.
• Top sheet and top platen: dust cover application and top hold-down for light or unstable loads.
• Power and air: electrical supply, installed power, and compressed-air demand for clamp and cut.
• Safety and compliance: guarding, light curtains, and conformity to EN 415-6 / Machinery Directive or ANSI B155.1.

Selection Decision Factors

To turn the preceding chapters into a specific machine, work through the sequence below in order. Most selection mistakes come from deciding the machine before defining the load and the throughput, so the first three steps are the most important and should be locked before any quote is requested.

1. Define the load and product: pallet versus retail pack versus long product versus coil. A long extrusion points to an orbital ring; a retail multipack points to shrink; a pallet points to stretch or hood. Record worst-case weight, footprint, height, and stability or fragility.
2. Set the throughput target: pallets or packs per hour at peak, not average. Below ~30 pallets/h a semi-auto turntable suffices; 30 to 60 favours an automatic turntable or rotary arm; above 60, move to rotary ring or stretch hood.
3. Choose the mechanism and architecture: stretch (turntable / arm / ring), shrink (L-bar + tunnel), orbital ring, or stretch hood, using Chapters 2 and 3. Stability and weight decide turntable versus arm or ring; weatherproofing and volume justify hood.
4. Specify the film and pre-stretch: match film grade and thickness (Chapter 4) to the load class, and require powered variable pre-stretch (200 to 300 percent) on any high-volume machine to control film cost.
5. Define containment force: state the required film force at the corner and the wrap pattern, and plan to verify it with a pull-plate or wrap-in-scale check per ASTM D4649 at commissioning.
6. Confirm automation and integration: semi-auto versus automatic, conveyor infeed and outfeed, auto cut-clamp-wipe, top sheet, and line control interface to the upstream palletizer.
7. Verify utilities and footprint: electrical supply, installed power, compressed-air demand, floor space, and headroom for the mast or ring.
8. Check safety and compliance: guarding, light curtains, e-stops, and conformity to EN 415-6 and Machinery Directive 2006/42/EC in Europe or ANSI B155.1 in North America.

One dimension that is easy to overlook at the quoting stage is serviceability and total cost of ownership. A wrapper typically runs 10 to 15 years, and its real lifetime cost is dominated by film (a recurring per-pallet consumable) and by downtime when a film carriage, sealer, or drive fails. Powered pre-stretch and disciplined wrap patterns cut the film bill; local spare-part inventory, field service response, and operator training cut the downtime bill. Established makers including Lantech, Wulftec, Robopac and the Aetna Group, and PT/Chronos for stretch wrappers, and BEUMER, MSK, and Aetna for stretch hood, maintain service networks that matter more over a decade than the initial price difference between competing quotes.