What We Need to Quote Your PCBA

What We Need to Quote Your PCBA

A quotation is only as good as the information behind it. Most quotations that come back higher or later than expected are not the result of a supplier padding a price, but of an assumption made to fill a gap in the file set. The list below is what we need, and alongside each item, why it changes the number.

Files

• Gerber files including drill data and the board outline. The outline and the drill file determine how the board arrays on the fabrication panel, which is one of the largest single levers on bare board cost.
• BOM with manufacturer part numbers, descriptions and quantities. A BOM priced against real part numbers is a quotation. A BOM priced against descriptions is an estimate. Where a part is obsolete or single-source, that is found here.
• Assembly drawing showing component orientation, polarity, and any keep-out or masking areas. If the board is to be conformally coated, this is the document that defines what has to stay clear.
• Pick-and-place file (centroid data: the X/Y position and rotation of each placed part). This is what the placement programme is generated from. Where it is not supplied, the positions have to be derived from the Gerber, which adds engineering time and a verification step before the first board is built.
• Quantity you expect to build, and whether that is a one-off or a repeat programme. Setup costs are shared across the quantity, so the same board quoted at 50 units and at 5,000 units has a very different unit price.
• Test specification, where in-circuit or functional test applies. The coverage agreed at quotation is what the fixture and the test programme are built against. If it arrives afterwards, the scope is priced as an assumption rather than agreed as a line.

Two documents we are not asking for. A schematic is not needed: boards are built to print from the Gerber and the BOM, and we do not design or modify the circuit, so it never enters the process. A 3D or STEP file is a mechanical input that belongs to enclosure work rather than to board assembly. Where a document is sensitive, that is understood; an NDA is signed where one is needed.

Decisions that change the price

• Layer count, copper weight and material. These determine the fabrication route and the bare board cost, and heavy copper also changes the assembly profile. The multilayer, heavy copper and high-Tg pages carry the limits we build to.
• Surface finish. The finish affects solderability, the storage window and the fabrication cost, and changing it later changes all three.
• Acceptance class. Class 2 and Class 3 differ in inspection criteria and in the documentation retained, so the class is fixed at quotation rather than chosen on the line. The criteria are set out under IPC-A-610.
• Turnkey or consigned material. If we buy the components, the quotation includes sourcing, incoming inspection and the risk that goes with availability. If you consign them, those items are yours. Component sourcing covers how each route is handled.
• Test scope. Functional test, in-circuit test, or inspection only. Where a fixture is required, its cost and amortisation have to be decided rather than assumed. PCBA testing explains what each method can and cannot detect.
• Coating, box build and packing. Each adds a process step and, in the case of coating, a masking plan derived from the assembly drawing. See conformal coating.

How the quotation is structured

We quote in parts rather than as a single figure: component cost against the BOM, bare board fabrication, assembly, test, and any tooling or stencil amortisation, with the lead time and the minimum order quantity stated. That structure is what lets you compare two quotations properly, because a lower headline figure that omits test coverage or assumes a different surface finish is not cheaper once the missing items are added back.

After the quotation

Production starts once the DFM findings are resolved and the material plan is agreed. Long-lead and single-source parts are ordered first, and any part at risk of obsolescence is raised with a proposed alternative while there is still time to change the order. Typical turnkey lead time is 2 to 5 weeks from a complete file set. The sequence is described step by step on the how to order PCBA page.

What the quotation includes, and what it does not

Being explicit about the boundary avoids a misunderstanding later. Included: procurement of the components against your BOM through authorized and franchised channels, incoming inspection and anti-counterfeit verification, bare board fabrication, SMT and through-hole assembly, the inspection steps in the standard process, the test scope agreed at quotation, and the documentation pack. Not included: PCB layout and circuit design, firmware and application software, mechanical and enclosure design, and any tooling that has not been agreed as a line on the quotation. Where a programme needs one of those, we say so at quotation rather than discovering it during the build, and we can work alongside a customer's own design partner without taking that role over.

When the BOM is incomplete or descriptive

A descriptive BOM is quotable, but it is quoted as an estimate until the parts are matched, and the customer is told that at the time. Where one description maps to several candidate parts, we list the candidates with their price difference rather than picking one silently, because the difference between an authorised part and a grey-market equivalent is frequently larger than the whole assembly margin. Three items cause most of the delay: missing manufacturer part numbers, missing quantities per board, and parts marked as an alternative in a note rather than in the part number field. Any of those can be resolved, but each adds a round of correspondence before the number can be treated as firm.

What a BOM must contain

A BOM is the document the whole build is priced from, so a missing column is not a formatting matter: it is a line that cannot be bought. These are the columns that make a BOM quotable line by line.

A BOM that arrives with these columns complete can be priced against real stock the same day, which is the difference between a quotation and an estimate. Where a BOM is descriptive rather than specific, it is still quotable, and the section above describes what happens then.

Tooling, stencils and test fixtures

Three cost items sit outside the per-board price and are worth deciding deliberately. A stencil is normally charged once and retained for the programme, so a repeat order does not pay for it again. A test fixture for in-circuit or functional test is a larger one-off, and its amortisation depends on the volume it is spread across; where the volume is small, inspection-only or a simpler functional test is often the more economical decision. Programming hardware or jigs follow the same logic. Each is stated as a separate line on the quotation so that the per-board price and the one-off costs can be assessed separately.

Price validity and component market movement

Component prices move, and on an industrial BOM the components are usually the largest single element of the total. A quotation therefore carries a stated validity period. Within that period the figure holds. Beyond it, the quotation is revalidated against current stock and pricing rather than extended automatically, because a part that was on allocation at quotation may have moved in either direction. Where a programme runs over months, the usual arrangement is a firm price for the committed quantity and a revalidation point for the balance. Long-lead and single-source parts are flagged explicitly so that a customer can see which lines of the quotation carry market exposure.

Minimum order quantity

There is no fixed minimum order quantity here. The practical floor is set by the fixed costs of a build, which are the stencil, the material plan, the setup and the inspection: below a certain quantity those costs dominate and the per-board figure rises steeply. Prototype and small-batch builds run on the same lines and the same process as volume production, so the outcome is representative of what a volume build will be. Where a customer wants to validate a design before committing, a small first build and a volume quotation issued at the same time is usually the most efficient route.

Send the file set

Gerber files, a BOM with manufacturer part numbers, the assembly drawing and the expected quantity are enough to start. Send them to alden@kilandu.com. Files are held for the project only, under access control. The DFM review is included with the quotation rather than charged as a separate engineering service, and the Shenzhen factory page describes where the boards are built.