Point Count: How Placement Work Is Measured

Placement is usually priced by counting. The coordinate file contains a position for every device, the positions are totalled, and the total is multiplied by a rate that depends on the class of work. It is a transparent method and it has the advantage of being verifiable: a customer can open the same file and count the same positions.

What it does not do is describe the whole job. The point count measures one part of the placement work, and understanding what falls outside it is the difference between comparing prices and comparing offers.

What Counts as a Point

A point corresponds to a placement, so a small passive is one and a device with many leads is not. The common convention is to count leads rather than bodies: a fine-pitch integrated circuit contributes as many points as it has pins, which reflects the fact that the machine places the body once but forms many joints.

The convention is not uniform between suppliers, which is why the count deserves to be checked rather than accepted. A quotation that counts leads and one that counts bodies are describing different amounts of work, and the difference is large enough to explain a gap in the total.

Where the counting convention is stated, the comparison becomes straightforward. Where it is not, the question is worth asking, because it is cheap to answer and expensive to leave uncertain.

Component Class and Why Rates Differ

A rate per point is an average that hides a range. Placing a small passive with generous pads is a different operation from placing a fine-pitch package or an area-array device, and the difference lies in the paste volume, the placement accuracy, the inspection and the risk of rework.

Most quotations therefore apply several rates, or apply one rate with a note about the difficult classes. Both approaches are reasonable. What matters is that the classification is visible, because the classification is what determines the total on a board that carries a few demanding devices among many easy ones.

Conversely, a board of large, generous parts should not carry the rate of a dense one simply because the point count is similar. Where a single rate is applied to everything, the total is a compromise, and the customer cannot tell which way it has fallen.

The Minimum Charge and Where It Comes From

Every order has a floor, and the floor exists because the preparation does not scale down with the quantity. The stencil, the placement programme, the material verification and the first article are the same work on ten boards as on ten thousand, and below a certain quantity the pricing has to reflect that.

A minimum charge expressed openly is fairer than a rate that has been quietly inflated to cover the same cost. It also tells the customer something useful: below a certain quantity, the price is dominated by preparation, and the ways to reduce it are to reuse a stencil that exists, to settle the revision before the order, or to combine the requirement with another for the same product.

Where the minimum is close to the value of the order, it is worth asking what it covers and what would change it, since the answer indicates whether the supplier is pricing the preparation or simply applying a rule.

Hourly Rate and When It Is Used

Point counting works well when the work is repeated and predictable. It is less suitable at the extremes: a very large order where the machine configuration is fixed for days, or a very small and unusual one where the operation is closer to a technician’s time than to a machine’s cycle.

An hourly rate is the alternative in those cases, and it is also used for work that is not placement at all: rework, the insertion of a handful of components, the assembly of a unit into its housing, an investigation of a fault. Those are charged by the time consumed rather than by the joint count, which is reasonable provided the time is described.

The two methods can coexist on one quotation, and often should. Where the structure of the order is mixed, an itemised quote that uses the appropriate measure for each part of the work is easier to check than one that forces everything into a single unit.

What the Count Does Not Include

The count measures placements, and an order contains work that is not placement. The data review, the stencil, the programme, the material handling, the soldering process for inserted parts, the inspection, the testing and the packing are all parts of the job, and the point count says nothing about any of them.

That is why two quotations with the same rate per point can differ in total by a wide margin, and why comparing the rates alone is misleading. The rate applies to the smallest and most comparable part of the work.

There is also a boundary at which the count stops being informative. If a board is small and carries few devices, the placement time is a small fraction of the order; if it is dense, the inspection and the risk of rework grow faster than the count does.

The Count and the Material Behind It

There is one further element that a point count cannot express, and it is often the largest single component of a small order: the material.

Where the parts are purchased on the customer behalf, the placement rate applies to a fraction of the work, and the rest of the figure is component cost together with the surplus that a minimum order quantity imposes and the allowance for attrition during setup. Where the customer supplies the parts, that portion is absent, and the placement rate becomes a much larger share of the total.

Comparing two quotations therefore requires knowing which of the two situations applies. A rate per point accompanied by a material line is a complete offer; the same rate offered alone, with material to be resolved later, is not comparable until the second half exists.

It also explains why the same board can be built at apparently very different prices. Where the material was already in stock from an earlier order, the surplus is not charged again, and the difference between the two quotations is inventory rather than work.

Using the Number Properly

The point count is most useful as one line of a structured quotation rather than as the headline figure. Where the count, the classes, the one-off charges and the additional operations are listed separately, the customer can see which part of the total would change if the quantity, the revision or the schedule were different.

That structure is what allows two suppliers to be compared properly, and it is also the basis for a sensible decision about the order. The work it describes is carried out as SMT assembly and, where inserted components are present, as mixed technology assembly, with verification through PCBA testing and the controls under quality management.

FAQ

Should a point be counted per lead or per body? Per lead is the common convention for multi-lead devices, but the convention should be stated so that two quotations can be compared.

Why is there a minimum charge? Because the preparation does not shrink with the quantity, so below a certain number of units it dominates the price.

When is an hourly rate appropriate? For work that is not repeated placement: rework, manual insertion, assembly into an enclosure, or an investigation whose extent is not known in advance.