SMT Assembly Quoting: Placement Points, Setup and Tiers

Almost every placement point price in electronics assembly is quoted the same way on the surface and built differently underneath. Two factories can quote within a few per cent of each other per point and return totals that differ by a wide margin, because the point price is only the middle of the bill and the ends of it — the one-off setup and the way the material is handled — are where the divergence lives.

Understanding how the number is assembled makes the quotation comparable and removes most of the arguments that follow a purchase order.

How the Point Count Is Priced

A point is one placed component. The count is taken from the placement file and the bill of materials, and the price per point falls as the quantity rises, because the machine time per point is largely fixed while the setup is spread over more boards. A short run therefore carries the highest unit point cost, and the same assembly ordered in a larger batch carries a lower one without anything about the work having changed.

The count is not identical to the bill of materials, and it is worth confirming the basis. Components that are placed twice, parts that are not populated on this variant, and the difference between the number of line items and the number of placements all move the total. A quotation that states the assumed point count can be checked; one that does not can only be accepted or rejected.

The One-Off Costs Around the Point Price

The engineering fee covers the work that happens before the line runs: importing the data, building and verifying the programme, defining the feeder setup and carrying out the first article. It is charged once per product rather than once per board, and it is the reason a repeat order is cheaper than the first one.

The stencil is the second one-off item. It is a physical tool that belongs to the product, it can be reused for later orders, and its cost depends on the panel size and the aperture requirements. Where a product is expected to run repeatedly, keeping the stencil with the assembly partner removes that cost from every subsequent order.

A setup or line start charge appears in some quotations and not in others. It covers the changeover and the machine time that the order occupies regardless of its size, and on a very small batch it can be a significant part of the total. What matters is that the three items are listed separately, so that a comparison between two suppliers compares the same things.

What Changes the Number Afterwards

Component complexity is the first variable. A board of passives and standard packages runs at the point price; the same number of points in fine pitch packages, ball grid arrays or connectors with a long pin row consumes more inspection and more machine time and is quoted differently. The capability question comes first in that case — whether the parts can be placed reliably at all — and the price follows it.

Material handling is the second. In consigned work the customer ships the parts and the assembly quotation covers the process only. In turnkey assembly the material is procured, inspected, stored and issued by the factory, and the component cost, the risk of substitution and the lead time of the supply chain are absorbed into the service. Neither model is cheaper in principle; the one that is cheaper depends on where the customer’s own purchasing strength lies.

Testing and programming are the third. Electrical test, firmware loading, functional verification, conformal coating and final assembly are separate operations with their own time, and an order that includes them should show them as separate lines rather than folded into the point price.

Lead Time Tiers and Where the Date Comes From

A lead time tier is a promise about the queue, and the queue starts when the material is complete rather than when the order is placed. In consigned work that is the day the parts arrive and are verified against the bill of materials. In turnkey work it is the day the last line item is in stock, which for a long lead device can be the dominant term in the whole schedule.

With material in hand, a conventional assembly run takes a few days and an expedited tier can compress it substantially; what the expedite buys is priority against other work, not the removal of a process step. Where a date is critical, the useful discussion is about which stage is holding it — material, programme, stencil or line capacity — because only some of those respond to priority.

Four Checks When Choosing a Factory

The line capability and the smallest package the equipment can place come first, because a factory that cannot place the parts reliably cannot quote them meaningfully. The inspection equipment comes second: solder paste inspection, optical inspection and X-ray for the joints that optics cannot reach are what make the process measurable rather than hopeful.

The ability to work in both consigned and turnkey modes comes third, since a customer whose purchasing situation changes should not have to change supplier with it. The clarity of the delivery commitment comes fourth — a factory that states a tier, states its cost and confirms it in writing is easier to plan a launch around than one that agrees to whatever is asked.

The assembly itself runs through SMT assembly, the material side through component procurement, the all-in model through turnkey assembly, the verification through PCBA testing and the inspection criteria through quality management.

Where a Small Order Loses and Where It Gains

A prototype batch of a few boards is the most expensive way to buy assembly, and there is no quotation practice that changes it. The programmes, the stencil, the feeder setup and the first article are the same whether one panel or fifty is built, so the fixed cost lands on a very small quantity. The practical response is to plan the prototype and the first production batch as one programme where the schedule allows, so that the setup is paid for once and amortised over both.

What a small order does gain is the freedom to change the design. Where a prototype run is expected to be followed by a revision, the money spent on setup is partly a payment for the knowledge that the revision is worth making, and treating the two orders as unrelated purchases is what makes the total look unreasonable.

Comparing Two Quotations Line by Line

The comparison is only meaningful if the two documents describe the same scope. The point count and its basis, the quantity, the assembly mode, the inspection stages, whether programming and testing are included, and the delivery tier all have to match before the totals can be placed side by side. A quotation that omits paste inspection and a quotation that includes it are not competing on price; they are describing different products.

Where the difference survives that alignment, it usually traces to material. One supplier may have assumed a substitute part that the other priced as the specified device, or one may have included the loss allowance and the other left it to be discovered at the end of the run. Asking which parts were assumed and how the loss is treated closes the last gap between two quotations that appear to be for the same work.

FAQ

Why is the per point price lower on a larger order? Because the setup is divided across more boards; the machine time per point does not change, so the unit cost falls as quantity rises.

Which is cheaper, consigned or turnkey? Consigned work avoids purchase margin but requires the customer to manage supply; turnkey absorbs the sourcing and the risk. The cheaper option depends on the customer’s own purchasing strength.

When does the quoted lead time start? When the material is complete and verified, not when the order is placed, which is why a long lead component can dominate the schedule.