Strapping cartons for fulfilment and parcel-style shipping after the 2020 online surge

Online retail grew sharply in 2020. The US Census Bureau reported on 18 August 2020 that retail e-commerce sales in the second quarter reached USD 211.5 billion on a seasonally adjusted basis, up 31.8% from the first quarter and equal to 16.1% of total retail sales. In Great Britain, the Office for National Statistics reported that online sales made up 28.9% of retail sales in July 2020, down from 31.9% in June but well above the 20.0% recorded in February.

For warehouses and fulfilment operations, more of the outbound flow is likely to leave as individual cartons and multi-carton consignments rather than full pallets. Strapping has a place in that flow, but only where it solves a defined problem. This guide sets out when to strap a carton, and how to do it without creating new problems in parcel handling.

When does a carton need strapping?

Good tape on a well-chosen box handles most single parcels. Strap earns its place in a few specific situations:

Situation	What the strap does	Points to check
Heavy single carton	Reinforces the closure and resists bursting	Board grade, edge protection, strap position away from the label
Several cartons sent as one consignment	Holds the bundle together so it travels and arrives as one	Bundle stability, strapping in both directions where needed, whether the carrier accepts bundles
Cartons on a pallet for business-to-business delivery	Helps unitise the pallet alongside stretch film	Film and strap working together, strap tension against carton strength
Returns or repacked goods	Secures reused boxes with weakened flaps	Whether a new box would be the better fix

The CTU Code, the IMO/ILO/UNECE code of practice for packing cargo transport units, describes an overpack as packages stacked on a load board such as a pallet and secured by strapping, shrink-wrapping, stretch-wrapping or other suitable means. It also treats strapping as an auxiliary measure, to be combined with other securing when the unit travels in a container.

Strap and closure for cartons

Match the strap to the carton rather than borrowing whatever is loaded on the pallet line. A narrow plastic strap is often enough to hold a carton closed, while a heavy pallet strap tensioned with a pallet tool can simply crush the board.

Some carton strapping machines and battery tools join plastic strap without a separate closure. Manual hand strapping generally relies on a clip or buckle, and the clip, strap and crimping tool have to be matched as a set. Our comparison of sheet metal clips and wire buckles explains how the two closure types differ and what a buyer should compare.

If a station uses more than one strap width, keep one labelled closure type per width at the station. Mixed trays of clips are a common source of joints that look right and are not.

Tension, edges and position

In carton strapping, too much tension does as much harm as too little. The strap should hold the carton closed and the bundle together without cutting into the board. Creased edges, a carton pulled in at the middle and strap marks pressed into the board are all signs that tension is too high or that edge protection is missing. Use corner protectors where straps cross edges, particularly on heavy cartons and on board that may pick up moisture in transit. Our sharp edges guide covers contact points in more detail.

Position matters as much in a parcel network:

• Keep straps and closures clear of shipping labels and barcodes so that scanners can read them.
• Place the joint on a face away from the label, and trim the tail short so it cannot snag in sorting equipment or on neighbouring parcels.
• Run straps square to the carton edges so they cannot slide off a corner during handling.
• Check the carrier’s packaging guidance on whether strapped or bundled cartons are accepted, and how they should be presented.

Before the year-end peak

Volumes that rose in spring and summer 2020 make the year-end trading period harder to plan. A few checks in September save emergency orders in December:

• Work out consumption per carton type: strap length, number of closures and cartons per day, so reorder points reflect the higher volume.
• Keep a backup tool and the common wear parts for each tool type in use.
• Write a short station card with photographs of a correct joint for staff who join for the peak.
• Agree which closure and strap are approved for each width, so that a shortage does not lead to an unreviewed substitute.

A simple in-house trial

Before changing a carton specification, pack a few cartons exactly as you intend to ship them and handle them the way the network will: slide them down a chute, stack and unstack them, and carry them as the sorting and delivery staff would. If people are likely to grab the strap as a handle, find that out in the trial rather than from a split carton, and decide whether the pack needs a proper handhold instead. Check whether the strap stayed in position, the joint held, the label stayed readable and the board was undamaged. Record the strap, closure and tool used, so that the accepted method can be repeated on every shift.

For hand strapping with clips, browse sheet metal clips and PET strap, then share your carton size, weight, strap and tool details through the enquiry page. Strength values for any combination remain on request.