Shrink Wrapper

Shrink Wrapper

A shrink wrapper creates bundled packages by wrapping containers in shrink film and heat-sealing them in an oven. This end-of-line machine produces the familiar multipacks of bottles or cans found in retail stores, facilitating transport and shelf stocking.

The machine operates in two phases:

1. Wrapping — enclosing containers in shrink film (printed or neutral)
2. Shrinking — heating in an oven to make the plastic adhere tightly to contents

How Shrink Wrappers Work

The shrink wrapping process follows a systematic sequence:

1. Product division — finished bottles travel to a divider creating two or more rows
2. Infeed — containers enter the shrink wrapper in organized formation
3. Film wrapping — shrink film encloses the product group
4. Heat shrinking — bundle passes through oven (shrink tunnel) where heat makes film conform to containers
5. Cooling — fans cool the film after shrinking
6. Discharge — completed bundle proceeds to handle application or palletization

Types of Shrink Wrappers

Sealing Bar Shrink Wrappers

Sealing bar machines position film perpendicular to package flow. When the package crosses the film, the sealing bar activates and the package stops momentarily for sealing. A cutting blade separates the wrapped package from film for subsequent packs.

Characteristics:

• Production speed: maximum 25 bundles/minute
• Package stops during sealing operation
• Suitable for lower-volume production

Film Launcher Shrink Wrappers

Film launcher machines wrap film around packages using bars dragged by chains while products run continuously along the conveyor without stopping. Film wraps with 5-8 cm overlap beneath the package, self-adhering as it passes through the shrink tunnel.

Characteristics:

• Production speed: up to 200 packs/minute per lane
• Available in one, two, or three-lane configurations
• No sealing bar required — continuous operation
• Highest throughput for industrial applications

Shrink Wrapper Comparison

Configuration Options

Shrink wrappers vary according to several parameters:

• Production speed — measured in strokes or bundles per minute
• Infeed orientation — inline or at 90° from upstream machine
• Tray insert function — capability to include cardboard tray support within bundle
• Lane configuration — single, dual, or triple lane systems
• Separation gates — pneumatic or electric operation for product grouping

Tray Insert Applications

The tray insert function places a cardboard support (tray or flat pad) inside the bundle, providing structural support for containers such as:

• Mayonnaise jars
• Vinegar bottles
• Other products requiring additional stability

Shrink Film Technology

Film Type

Most shrink wrappers use LDPE film (Low-Density Polyethylene), available as single or coextruded material. Film is unwound alternately from two reels positioned under the conveyor belt with motorized unwinder.

Film specifications:

• Neutral or printed — customizable with company logos
• Printable up to 10 colors using flexographic systems
• Perfect product adaptation ensuring stable packaging
• Automatic reel joining available on some models

Reel Changeover

When one reel approaches depletion, the system slows and alerts the operator to cut the film and seal it with the second reel. Some machines perform automatic junction between coils.

Shrink Tunnel (Oven)

The shrink tunnel applies heat to make film conform to products:

• Electrical resistances heat the air
• Hot air circulation shrinks the film around contents
• Cooling fans set the film after heat-shrinking

Antistatic Systems

Continuous operation requires antistatic bars to neutralize electrostatic charges generated by high-speed film processing. Without proper static control, issues include:

• Processing interruptions
• Electric shocks to operators
• Reduced product quality

Ionizing bars mounted in charge-formation areas neutralize static electricity electrochemically by ionizing surrounding air.

Applications

Shrink wrappers package products requiring grouped transport for retail distribution:

• Water bottles — classic 6 or 12-pack configurations
• Beverage cans
• Food containers
• Any bulk products for shelf restocking

After shrink wrapping, bundles may receive handle application (via separate handle applicator machine) before palletization.

Leading Shrink Wrapper Manufacturers

Established brands in the shrink wrapper market include:

• Zambelli
• Dimac
• Krones
• OCME
• SMI Group

Used shrink wrappers from these manufacturers offer proven reliability with available spare parts and service support.