Film Bundling Machine

Overview

A film bundling machine collects loose products into a set count and wraps them in shrink film to form a single retail or transport bundle. It sits at the end of a filling or labelling line and replaces the cardboard tray or wrap-around case with a thin film bundle, which uses less material and weighs less. Typical work is grouping PET bottles into a 6-pack, gathering cans into a 4x6 block, or banding a stack of cartons. Output runs from 20 bundles per minute for large packs up to 60 for small counts of light products. The machine has three working sections in line: a Collation Infeed that forms the group, a Wrap Station that drapes and seals the film, and a Shrink Heat Tunnel that shrinks the film tight. A Cooling Conveyor sets the finished bundle and carries it out.

Collation and grouping

Products arrive single file on the Infeed Conveyor from the upstream line. The Lane Divider splits the stream into the number of lanes the bundle pattern needs, holding products in formation with stainless Guide Rail walls. Each lane runs through a Grouping Gate, a pneumatic stop that counts products with a Product Sensor and releases the exact count for one bundle. When the matrix is complete, the Pusher Bar transfers the whole group sideways into the film. The pusher runs on a Servo Motor and a Linear Guide Rail pair so its stroke and speed match the product weight, which keeps light items from tipping and heavy items from skidding.

Film unwind and feed

Film comes off a reel held in the Film Reel Cradle, which carries reels up to 600 mm in diameter on a Reel Mandrel. A Film Brake holds back the reel so it does not overrun when feed stops. The web passes over the Dancer Assembly, a spring-loaded arm whose Dancer Potentiometer reports arm angle to the control system. The PLC reads that angle and trims the Feed Roller speed to keep tension steady through the start-stop cycle, since slack film wraps unevenly and tight film tears at the seal. The driven Feed Roller meters a measured film length for each bundle, set in the recipe by product height and bundle length.

Wrapping and sealing

At the Wrap Station the metered film hangs as a Film Curtain across the product path. As the pusher drives the group through the curtain, the film drapes over the top and front. The Folding Arms then sweep film under the trailing edge so the product is enclosed on four sides with the two film edges overlapping below. The Sealing Bar closes onto the Anvil Bar and a hot Seal Blade both cuts the web from the reel and welds the trailing and leading edges into one continuous tube. The bar carries a Heating Element and a PTFE Tape cover so molten film does not stick to it, and a Pressure Sensor checks that seal force is in range before the cycle continues. A weak seal here shows up as an open bundle after shrinking, so seal temperature and dwell are logged per bundle.

Shrinking in the heat tunnel

The wrapped, loosely sealed bundle enters the Shrink Heat Tunnel on the Tunnel Conveyor, a stainless Mesh Belt that tolerates the heat. Inside, the Heater Bank of finned Heating Element units raises air to between 140 and 220 C, and two Recirculation Fan units drive that air across the bundle through adjustable Air Baffle louvres. The film softens and contracts around the product, pulling tight at the corners and forming the bundle. The Tunnel Housing is a double-skin stainless box with an Insulation Pack of mineral wool to keep the outer skin safe to touch and to hold heat in. Each zone has a Tunnel Temperature Sensor feeding a Temperature Controller, so the entry zone can run hotter to start the shrink and the exit zone cooler to avoid burning thin film. Dwell time, set by the conveyor speed of 6 to 20 m/min, decides how complete the shrink is.

Cooling and discharge

Hot film stays soft for a few seconds after the tunnel, so the bundle passes onto the Cooling Conveyor. A Cooling Fan blows ambient air over the bundle to set the film while the Cooling Belt carries it to the next line stage. Cooling locks in the tight wrap and stops bundles sticking to each other when they collect at the discharge. From here bundles go to a palletiser, a case packer, or straight to a stretch wrapper for the pallet.

Drive, control and services

The infeed, film feed and wrap timing run off the Main Drive, a variable-frequency Main Motor turning a Main Shaft that phases the stations through belts and pulleys. The tunnel conveyor and cooling belt have their own gearmotors so their speed is independent of cycle rate. The Control System holds a PLC Module for sequencing and a HMI Panel where operators pick a recipe, view counts and faults, and set tunnel temperatures. Recipes store film length, group count, seal time and tunnel set points, so a changeover between bundle formats is a screen selection plus a few rail adjustments. The Pneumatic System supplies clean air through the Air Preparation Unit to the gates, pusher and seal cylinder. The Safety Relay and interlocked Safety Guarding, including a Light Curtain at the infeed and guards across the tunnel mouths, stop the machine if an operator reaches into a moving or hot zone.

Materials and variants

Frames are powder-coated mild steel with stainless guards and product-contact rails for washdown areas. Film is usually LDPE or co-extruded PE between 35 and 80 micron; thinner film cuts cost but needs tighter tunnel control. Electric tunnels are standard; gas-fired tunnels exist for very high throughput where running cost matters more than installation simplicity. Smaller machines combine the wrap station and tunnel on one frame for counts up to 30 bundles per minute, while high-speed lines split them so the tunnel can be longer for a fuller shrink. Some configurations add a flat pad or tray under the product before wrapping for heavy bundles, which the collation section places ahead of the pusher stroke.