What a Lead Time Is Actually Made Of

A quotation says thirty days. Another says forty-five. Buyers usually read that as one supplier being faster, and it is rarely that simple: a lead time is not one number, it is six stages stacked on top of each other, and the two suppliers may be counting them from different starting points.

This article breaks the clock down, in the order the stages actually happen on our floor, and says which of them a buyer can influence and which of them nobody can.

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The assembly area in Dongguan with machines at different stages. The sign on the column marks the bay range, and a machine's position on this floor is most of what its lead time means.

The Clock Starts at the Deposit

First, the starting point. A date counted from the enquiry, a date counted from the deposit and a date counted from drawing approval are three different promises, and quotations rarely say which one they mean. Ask, because the gap between them can be two weeks on its own.

We count from deposit received and drawings approved, and we say so. Anything else quietly transfers a delay that belongs to the paperwork onto the production floor.

Materials Are Either on the Shelf or on a Truck

The long-lead items in a welding machine are few and specific: the transformer, the controller, and on a laser or robot project the source, the head or the arm. If the transformer is a standard rating it is usually in stock or a short order away. If it is a one-off rating, it is wound to order, and that single item can be half the total lead time.

This is where a buyer can do the most good. A standard kVA rating and a standard controller can remove weeks; a special voltage or a bespoke controller adds them. Asking which items in the quotation are on the shelf and which are on order is a fair question, and the answer tells you more about the date than the date does.

Machining and Sheet Metal

Frames, arms, busbars, covers. For a standard model these are batch parts and the work is mostly queue time rather than machining time: the machine waits for a slot on a mill or a laser cutter. For a special machine every bracket is a one-off, and one-off parts wait longer because they cannot be nested with anything else.

This is also the stage that absorbs design changes most expensively. A change after the frame is cut is not a change to a drawing; it is scrap plus a new queue position.

Assembly Is Where Estimates Break

On our floor a machine occupies a bay from the moment the frame lands until run-off is signed. Mechanical build, then the electrical build, then air and water, then alignment of the arms and the electrodes. Most of the labour in the machine is here, and most of the variance in a lead time is here too, because a bay can only hold one machine.

Two things push a machine out of its bay later than planned. The first is a missing part discovered at assembly, which is a purchasing failure that surfaces as a production failure. The second is a machine ahead of it in the queue that needed rework. Neither appears in a quotation, and both are why a supplier who quotes the shortest date is not necessarily the one who delivers it.

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Finished units on pallets before packing. This is the stage buyers see in photographs, and it is the shortest part of the timeline.

Run-Off Depends Partly on the Buyer

The last stage is the one where the date stops being entirely ours. Run-off means welding the customer's part, or a sample of it, and recording the result. If the sample has not arrived, or arrives as the wrong material, the machine sits finished and the date moves without anyone having done anything wrong.

Run-off is also where the weld schedule is written down in the buyer's terms for the first time: current, force, time and cap size, proved on the material that will actually be welded. That sheet ships with the machine. It is not the same thing as a parameter table from a catalogue, and it is the only version that has been demonstrated on the part.

Where the sample cannot come, we run off on a coupon of the same material and thickness and note it on the record, and the machine can ship. What we will not do is call a machine finished because it powers up. The difference between those two positions is most of what a buyer is paying for in the last week.

The stage after it is the shortest and the one most often left out of a plan: packing and documents. A standard machine goes into a crate that already exists. A machine with a non-standard footprint waits for a crate to be built around it, and a shipment without the right import paperwork waits at a port rather than on our floor. On a whiteboard this is two days at the end; in practice it is where a date that was met becomes a date that was missed, without a single machine being late.

The Three Things That Move a Date

In our experience almost every slip traces back to one of three causes, and only one of them is a production problem.

A change after the frame is cut, which re-queues the machine behind everything already on the floor.
Customer material that is late, wrong, or not sent, which stalls run-off at the final stage.
A long-lead item ordered late because the specification was still open when the order was placed.

Notice that two of the three are decisions rather than accidents. That is the useful part of the list: a date is mostly a record of how many open questions there were at the start.

How to Read a Date in a Quotation

When you compare two dates, compare the four things behind them. What is the start point? Which items are stock and which are ordered? How many machines are ahead of yours in the same bay? And what does the supplier need from you, by when, for the date to hold?

Stage	Share of the clock	What delays it	Who owns it
Order review and drawings	Days, not weeks	An open specification	Both sides
Long-lead items	Can be half the total	A non-standard rating or a bespoke controller	Supplier, decided by the buyer
Machining and sheet metal	Queue time dominates	A design change after cutting	Buyer, mostly
Assembly	Largest labour share	A missing part, or rework ahead in the queue	Supplier
Run-off	A few days	Sample late, wrong or absent	Buyer
Packing and documents	A few days	Non-standard packing, missing import details	Both sides

A supplier who can fill that table in for your order is telling you something a date alone cannot. A supplier who cannot is quoting a hope, and it may still be an honest one.

Requirements vary by destination market. Always confirm against the current edition of the applicable standard and with your certification body.

PDKJ continues to provide customized laser welding and resistance welding solutions based on different materials, workpiece structures, welding requirements, and production applications.

What A Lead Time Is Actually Made Of