Strapping Machine

Overview

A pallet strapping machine automatically applies plastic or steel strap around loaded pallets, tensioning and sealing the strap ends to stabilise the load during transport and storage. Strapping machines are essential for logistics operations, securing palleted cases, cartons, or bags into compact, stable units that withstand handling, vibration, and stacking.

Modern machines are fully automatic, requiring only the operator to position the pallet on the strapping platform. Strap type, tension, and sealing method can be configured via HMI for different load weights and materials.

How it works

Pallets arrive on the Infeed Conveyor, driven by the Infeed Motor. The Infeed Sensor detects pallet position and signals the Control System to begin the strapping cycle.

The pallet is positioned on the Pallet Strapping Table, and the Strap Dispenser begins to feed strap. The Strap Reel supplies plastic or steel coil strap at constant tension controlled by the Strap Brake. The strap is guided by the Strap Guide and enters the Tension Module.

The Tension Wheels, driven by the Tension Motor, compress and advance the strap around the pallet. The Load Cell measures tension in real time, feeding back to the Control System PLC to maintain the target tension (typically 200–1000 N).

Once the strap loop is complete around the pallet, the ends meet at the Sealing Head. The Seal Plates (anvil and ram) come together under pressure. For plastic strap (PP or PET), Seal Heating Elements heat the seal plates to 150–250 °C, fusing the strap ends. For steel strap, the seal plates weld the overlapped ends via resistance heating.

The Seal Motor applies the sealing pressure via pneumatics from the Air System. The Seal Sensor detects when the seal jaw returns to open position, signalling the cycle is complete.

The strapped pallet then moves onto the Discharge Conveyor, driven by the Discharge Motor, exiting the machine for further logistics handling.

All operations are orchestrated by the Control System via the Control Cabinet PLC. The HMI Panel allows operators to:

• Select strap type (plastic or steel)
• Set target tension
• Adjust seal temperature and dwell
• Monitor production counts and fault logs

The Safety Module enforces the E-Stop Button and guards the sealing area to prevent operator contact with hot seal plates or pinch points.

The Air System provides pneumatic power for the tension wheel servo, sealing press actuation, and brake solenoids. The Air Pump and Air Receiver ensure consistent 5–8 bar supply.

Strap types and applications

• Polypropylene (PP): Cost-effective, good tensile strength, suitable for light to medium loads (50–500 kg).
• Polyester (PET): Higher tensile strength and UV resistance, better for heavier loads (500–1500 kg) and outdoor storage.
• Steel: Maximum strength and reusability; used for very heavy loads (>1500 kg) and extreme environments, but more expensive and requires steel-capable sealing equipment.

Strapping machines typically handle 8–30 pallets per hour, with cycle times ranging from 120–300 seconds depending on pallet height and strap type. Some machines offer multi-face strapping (optional Table Motor rotation), applying straps vertically and horizontally for maximum stability.