Case Packer

Overview

A case packer automates the final stage of primary packaging, taking empty cartons from a magazine, erecting them, loading them with product arriving from upstream equipment, and sealing them closed. This stage is labour-intensive if done by hand and rate-limiting in a packline. The machine sits downstream of weighers, form-fill-sealers, or labellers and upstream of a case erector or palletiser. Speed ranges from 10 cases per minute for heavy or fragile items up to 40+ per minute for lightweight products and simple cases.

The infeed and carton supply

Empty cartons arrive nested in a Carton Magazine, a vertical stack holding hundreds of flattened blank cases. As the Separator Head (a vacuum or mechanical picker) cycles, it extracts one carton and presents it to the Erect Station. The Magazine Gate prevents free-fall; only one carton at a time is released. The Infeed Conveyor is a timing belt or shallow incline that keeps the carton aligned as it advances to the erection tooling.

Case erection

The Erect Station is mechanically ingenious: as the carton enters, it slides over a Forming Mandrel (a tapered form, often rotating) that spreads the blank into a box shape. Side flaps fold as the carton moves. A Bottom Closer then folds and glues (or tapes) the bottom flaps shut, this is either a rotary wheel pressing flaps against glue applicators, or a sequence of cam-operated folding fingers. The erected, bottom-sealed case is then ejected by a Erect Pusher onto the product-loading conveyor.

Product loading

The case now arrives at the Product Loader, which receives product from upstream (a Multihead Weigher or individual product stream). A Case Stop positions the case under the loading zone. A Loader Arm, either pneumatic or a servo-driven robot arm, picks product via a Arm Gripper (clamping fingers or suction cups) and places it into the case. The placement pattern depends on the product geometry: single-lane products drop straight in; multi-lane loads require precise orientation. Load cells or vision systems check that product has landed; the Load Sensor confirms presence before the case advances.

Top closure and sealing

The loaded case continues to the Case Closer, which handles the most visible part of packing: sealing the top. Most commonly, this is tape sealing with a hot-melt or adhesive-backed Sealing Head that applies a carton-sealing tape (48–75 mm, typically reinforced kraft or polypropylene) across the centre seam and both sides of the case, or across three or four seams depending on the application. The Top Flap Folder folds the top flaps closed first; the Compression Plate presses down after sealing to ensure flap contact. An alternative is hot-melt glue applied to flaps before folding, which is used for higher-speed lines or when tape marks are unacceptable.

Discharge and synchronisation

The sealed case exits onto the Discharge Conveyor, which transports it downstream to a palletiser, case erector for stacking, or storage buffer. The entire packline is synchronised by a Main Drive: a variable-frequency Main Motor (typically 7.5–15 kW) drives a Main Shaft through a reducer and flexible coupling, and pulleys distribute speed to the magazine lift, infeed, erect station, loader arm, and discharge belt. Each station engages its portion of the shaft via one-way or slip clutches, so the line can run continuously. The Control System, a PLC Module running case-packing logic, orchestrates actuators and monitors sensors to sequence operations.

Control and operator interaction

The HMI Panel displays throughput, fault alarms and changeover instructions. Operators select the case and product type, then the machine auto-adjusts the forming mandrel height, loader arm trajectory, case stop position and tape applicator width. Most machines can memorise 10–20 product recipes and swap between them by touching a button. The Pneumatic System, compressor, receiver, and solenoid Pneumatic Manifold, supplies air to the separator, loader arm, case stops and tape applicator. The Safety Relay implements the emergency stop circuit; interlocked Safety Guarding around pinch points and rotating shafts prevents operator contact.

Speed and flexibility

Packing speed scales with product size and case complexity. Lightweight items in small cases can run at 30–40 cases per minute; heavy products or cases requiring precise placement might run at 10–15. Changeover between product types (SKU switch) takes 5–15 minutes for recipe change and mechanical adjustments. The economics favour high-volume, low-SKU facilities; for multi-product packaging, modular or robotic case packers are preferable.