Wraparound Case Packer

Overview

A wraparound case packer builds a corrugated case directly around a group of products, rather than loading product into a pre-made box. Loose product arrives on a conveyor, the machine collates it into a fixed count and pattern, draws a single flat corrugated blank from a magazine beneath the group, and folds that blank up and around the product. Hot-melt glue is applied to the flaps as they fold, and a compression section holds the case square until the adhesive sets. The result is a tight five- or six-panel case that uses less board than a regular slotted carton because the blank is cut to the exact group dimensions.

This style of packing is common for bottles, cans, jars, pouches and trays in food, beverage and household lines. It runs from about 15 cases per minute for large heavy groups up to 50 or more for small lightweight arrays. The machine sits downstream of a filler, labeller or shrink bundler and upstream of a palletiser.

Collation and grouping

Product enters on the Infeed Conveyor and passes through a Lane Divider that splits the single stream into the number of lanes the case pattern requires. A Metering Belt, driven by a Servo Motor, sets the pitch between products and opens a controlled gap so that exactly the right count accumulates. Photoelectric units, the Product Sensor, track each item and signal when a group is complete. A servo-driven Group Pusher then drives the finished group sideways onto the waiting blank. The pusher rides on a Linear Guide Rail for repeatable travel, and the lane width is set by the Rail Adjuster during changeover.

Blank magazine and feed

Flat corrugated blanks sit face down in the inclined Blank Hopper, constrained by adjustable Hopper Rail guides and held under light pressure by a Coil Spring pack. A friction Blank Gate lets only the bottom blank leave the stack. The Suction Feeder carries a row of Suction Cup bellows on a Feeder Arm; a Vacuum Pump supplies the vacuum that peels one blank free. The blank lands on the Blank Conveyor, a vacuum-belt section that positions it square beneath the wrapping zone. A Blank Sensor confirms each blank arrives and warns the operator when the stack runs low.

Wrapping and folding

The Wrapping & Folding Station is the core of the machine. As the group is pushed onto the blank, fixed Folding Rail profiles lift the two side panels of the blank up against the sides of the product group, while the Forming Mandrel supports the case base. A Plough Folder then folds the leading and trailing flaps over the top of the group; its Plough Plate is a polished plate timed to the main shaft by a Folder Cam. The case ends are closed by a pair of Tucker Arm units, each a pneumatic Air Cylinder driving a Tucker Blade that folds the end flaps inward. A Side Compression Rail keeps the panels vertical while glue is applied and starts to set.

Hot-melt glue system

Adhesive is supplied by the Hot-Melt Glue System. EVA pellets melt in the Glue Melter, a heated Glue Tank using two Heating Element cartridges to hold the pool at 150–180 °C. A Glue Pump, built around a Helical Gear Pair in a Gearbox Housing, meters molten adhesive through an insulated Heated Hose to the guns, with a Pressure Sensor monitoring delivery pressure. Each Applicator Gun fires beads through a Gun Nozzle when its Gun Solenoid opens, timed to the moving flap so the glue lands only where the panels overlap. A Glue Controller regulates temperature on the melter, hoses and nozzles and times the guns to line speed.

Compression and discharge

A freshly glued case is not yet rigid, so it passes into the Compression & Discharge Conveyor section. The Compression Section runs a driven Top Press Belt and side belts that squeeze the case while the hot-melt cools, held in tension by Coil Spring packs and driven through a Drive Belt pair. By the end of the compression run the bond has set and the case holds its shape. The case then transfers to the Discharge Belt, driven by the geared Discharge Motor, which carries it to a palletiser or accumulation table.

Drive, control and safety

The mechanical stations are timed by the Main Drive, whose variable-frequency Main Motor turns a Main Shaft feeding the station pulleys, while the metering belt and group pusher run on independent servo axes for fast recipe changes. The Control System uses a PLC Module for the sequence and a HMI Panel for recipe selection and diagnostics, with a Power Supply feeding the 24 V logic. Air for the tuckers, gate and vacuum generator comes from the Pneumatic System through an Air Preparation Unit and a solenoid Pneumatic Manifold. The Safety Relay runs the emergency stop circuit, interlocked Safety Guarding encloses the folding and gluing area, and a Light Curtain protects the open product infeed.

Variants and use

Wraparound packers are chosen where board cost and pack tightness matter, since the blank is sized to the group and uses less material than a regular slotted container. Tray-style variants fold only the base and sides to produce an open shelf-ready tray, while full wraparound builds a closed case. Changeover between case sizes takes 10–20 minutes and covers lane width, blank hopper size, folder timing and glue pattern. High-volume beverage and canned-goods lines favour this format because the same machine can switch between many pack counts by recipe.