After the Shanghai lockdown: qualifying a second source for strapping consumables

When a city of Shanghai’s size locks down, the effects reach packing lines thousands of kilometres away. Strap rolls, seals, clips, buckles and tool spares travel in the same containers as everything else. In April and May 2022 many of those containers sat still.

For many packing teams the first response was to raise stock levels. That helps, but it leaves the underlying exposure in place: one approved supplier on one route. This article looks at the step that is easy to postpone and hard to rush, qualifying a second source for strapping consumables, using what was publicly reported about the disruption up to May 2022.

What happened at Shanghai in April and May 2022

On 8 April 2022, Bloomberg reporting republished by Fortune described a port that was still functioning but struggling to move boxes out. Lockdown rules and virus testing were keeping truck drivers away from the docks, so imports were clearing slowly. Storage yards for refrigerated and dangerous-goods containers were reported as critically full, and the backlog was expected to lengthen ship queues and push freight rates up.

On 13 May, The Maritime Executive reported that the city’s phased reopening was expected to finish nearly eight weeks after the lockdown began. Shanghai’s container volume had fallen by about a quarter in April, to just over 3 million TEU. Project44 data showed containers waiting up to 15 days at the port at the peak, easing to about 10 days as restrictions loosened. Windward counted 412 ships waiting outside Chinese ports in late April, and S&P Global estimated 384 vessels waiting at Shanghai by 25 April. Maersk said some Shanghai depots had been closed from 28 March.

The lesson is not specific to one port. A long sea route has several points where a delay can start: the factory gate, inland trucking, the terminal, the vessel and the destination. Buffer stock absorbs a delay once it has happened. A qualified second source, ideally on a different route, makes the buffer less likely to run dry.

Why “equivalent” consumables are rarely interchangeable

Strapping items are not interchangeable in the way office supplies are. A sheet clip has a nominal strap width, a sheet thickness and a profile that must suit the crimping tool. A steel seal must match the steel strap and the sealer. A wire buckle has a width, a wire diameter and a finish. PET strap has a width, thickness and grade that the tool and clip were set up for.

So a second source has to be qualified at part level. A supplier that can offer “19 mm seals” has not yet offered a replacement for the seal your sealer was set up to close.

What to compare before approving a second source

Item	Compare with the approved part	Gap often found too late
Sheet clips	Nominal width, sheet thickness, profile, finish and the crimp made by your tool	The clip closes, but the joint behaves differently
Steel seals	Nominal width, profile, sheet thickness, finish and sealer type	The profile suits a different sealer
Wire buckles	Nominal width, wire diameter, finish and buckle form	Same width, different wire diameter
PET or woven strap	Width, thickness, grade, surface, roll length and core	The roll fits the dispenser but not the tool setting
Packing and labels	Pieces per carton, rolls per pallet, label content and batch reference	Receiving cannot tell the two sources apart

Datasheet dimensions are a starting point. The decisive evidence is a trial with the actual strap, closure and tool, judged against acceptance requirements agreed before the trial.

Run the approval while stock is still available

The worst time to try a new seal or clip is when the line has run out. An untested alternative may fit the strap loosely, crimp differently in the tool or arrive in a different finish. Under pressure, those differences tend to be accepted without being recorded.

1. Start with the parts that stop a line. Usually that means the closure and strap for the highest-volume packing pattern, then tool spares.
2. Ask for samples with documents. Request the part description, dimensions, finish and packing information that would apply to production supply.
3. Trial at the station. Use production strap, the normal tool and the usual operators, and record the tool settings.
4. Decide against agreed criteria. Set acceptance before seeing results, then record exactly which part was approved.
5. Place a small first order. A first delivery tests packing, labelling and documents as well as the parts.

Our sample approval guide explains how to keep that record usable for reorders. Once two sources supply the same nominal part, keep their stock separately labelled so that a later complaint can be traced to the right supply. The distributor identification guide shows how to keep similar variants distinct in a stock system.

How much buffer to hold meanwhile

Qualification takes weeks, so the buffer has to cover that period too. Size it per part from actual consumption: joints and straps per load, loads per week and, for strap, metres per load converted into rolls at the agreed roll length. Multiply weekly usage by the replenishment time you decide to plan for. The reported waits at Shanghai give a sense of scale in May 2022, but your own route and delivery history are the better guide.

Plan where the extra stock will live. Keep PET strap indoors, out of direct sun and in its original packaging, unless the strap supplier’s storage guidance says otherwise. Metal components should stay in labelled cartons in dry storage. Rotate stock first in, first out, so that the buffer does not age at the back of the rack.

Freight options and stepping down

Ask the forwarder which alternatives exist for the route: other ports of loading, split shipments or consolidating consumables with a larger order. Each option has a cost and its own risks.

Emergency stock levels tie up cash and floor space. Set a review date when you raise the buffer, and decide in advance what evidence will justify reducing it: several consecutive deliveries arriving within the planned replenishment time, for example, or a second source that has completed its first order cleanly.

To discuss a second source for a specific part, share the part details, the tool in use and the delivery point through the enquiry page. The PET strap, sheet metal clips and steel strapping seals pages list the nominal sizes to quote. Lead time, availability and any sample arrangement are confirmed in the quotation.