How to Order PCBA from Kilandu

Ordering Turnkey PCBA: What Happens and When

Ordering assembled boards from an overseas factory goes wrong most often in the first week, before production starts. Files arrive incomplete, the BOM contains a part that went end of life two years ago, and the quotation that comes back is based on a different scope than the one the buyer had in mind. The process below is designed to surface those issues before a purchase order rather than after. Typical turnkey lead time is 2 to 5 weeks from a complete file set.

Step 1: Send the files

A quotation needs the Gerber files including drill data and board outline, a BOM with manufacturer part numbers, descriptions and quantities, the assembly drawing showing component orientation, polarity and any keep-out or masking areas, and the quantity you expect to build. If the design has a controlled-impedance requirement or a customer-specified stack-up, include it. If the board is to be conformally coated, the assembly drawing should show the areas that must stay clear. The quotation requirements page lists the file set in full and explains why each item changes the price.

Step 2: DFM review

Our engineering team reviews the design against our process before quoting. This covers panel utilisation, footprint and solderability, placement feasibility for fine-pitch and high-mass components, component availability and lifecycle risk, and any stack-up or impedance issue that would affect yield. Findings come back with the quotation rather than emerging at the line. The DFM review page explains what the check covers and what each class of finding usually changes.

Step 3: Quotation

The quotation is broken into its parts rather than given as one figure: component cost against the BOM, bare board fabrication, assembly, test, and any tooling or stencil amortisation. 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.

Step 4: Material plan and order confirmation

Once the quotation is accepted, the material plan is fixed. Long-lead and single-source parts are identified first and ordered ahead of the rest, buffer stock is agreed where a part is critical, and any part at risk of obsolescence is raised with a proposed alternative. The production date is built backwards from this plan. Where you supply material yourself instead, the same plan is built around your delivery dates rather than ours; component sourcing covers both routes.

Step 5 to 7: Fabrication, assembly and test

Bare boards are fabricated, components are placed on high-speed SMT lines, through-hole and mixed-technology parts run on automatic DIP lines, and the assembly moves to functional test. The equipment list is on the factory capabilities page. Solder paste volume is verified by 3D SPI before placement, AOI runs after reflow, and X-ray is used where joints are hidden. Fabrication capability is set out on the PCB fabrication page and the placement and soldering process on the SMT assembly page. What each inspection step can and cannot catch is covered under PCBA testing.

Step 8: Inspection, packing and shipment

Finished assemblies are inspected to the acceptance class agreed at quotation, packed for the shipping method agreed, and shipped with the documentation pack. Lot-level traceability is retained so a question raised later can be traced back to the production conditions that produced the board. How that record is held is described on the quality assurance page.

How long each step takes

Lead time is quoted as a range because it is driven by the material plan rather than by machine availability. The table below is what the steps typically consume on a turnkey build, and what moves each one.

Step	Typical time	What moves it
File review and DFM	1 to 2 working days	Incomplete file set, BOM without part numbers, missing stack-up data
Quotation	1 to 2 working days after DFM	Obsolete or single-source parts needing researched alternatives
Material plan and procurement	2 to 5 working days	Allocation, minimum order multiples, imported lead times
PCB fabrication	5 to 10 working days	Layer count, copper weight, surface finish, impedance control
Assembly	3 to 7 working days	Component count, fine pitch, mixed technology, quantity
Test and release	1 to 3 working days	Test coverage, fixture availability, documentation pack

What happens when the file set is incomplete

We list what is missing and what it affects rather than filling the gap with an assumption. Three cases come up repeatedly. A BOM that carries descriptions instead of manufacturer part numbers can still be quoted, but it is quoted as an estimate until the parts are matched, because one description frequently maps to several parts at very different prices. An assembly drawing without polarity marking is workable on a single-sided board and not on a mixed-technology one. And where a customer-specified stack-up is absent, the board can be fabricated to our standard build, but the impedance and thermal behaviour then follow our stack-up rather than the one the design was simulated against. Where design data genuinely does not exist, a sample or photograph from a previous build helps us understand the assembly, but it does not replace the drawing for a new build.

Prototype first, or straight to production

Prototype and volume builds run on the same lines and the same process here, so the result of a prototype is representative of what a volume build will be. That is the reason to run one where the design is new, where the assembly carries fine-pitch or high-mass components, or where a previous supplier produced yield problems worth understanding before committing to volume. Where a design is already in volume production elsewhere and is stable, a first article from production tooling is usually enough. There is no fixed minimum order quantity, and the turnkey PCBA page sets out what a build includes end to end.

Changes after the order is placed

A change to the BOM or the design after material is ordered has a cost that depends entirely on how far the order has progressed. Before material is released, a change is normally free apart from the re-quotation. After long-lead parts are ordered, those parts are either carried into the customer's account or used on the next build. After fabrication, a new bare board is required. After assembly, assemblies are reworked where the assembly allows it and scrapped where it does not. The rule we work to is to state in writing which of those situations applies, and at what cost, before doing the work rather than after.

Commercial terms

Quotations are issued in USD by default, with the currency, the trade term, the lead time and the minimum order quantity stated on the quotation itself rather than agreed verbally later. Payment terms are set at the start of a programme. A deposit against material is normal on a first order because components are purchased against it, with the balance against the shipping documents; on a running programme the terms are reviewed rather than carried forward automatically. Where a customer needs the quotation structured for an internal approval process, additional breakdown lines can be provided on request.

Common mistakes that delay a first order

• A BOM without manufacturer part numbers. This turns a quotation into an estimate and adds a matching round before it can be firmed up.
• Leaving the acceptance class unstated. Class 2 and Class 3 differ in inspection criteria and in the records retained, so the class has to be fixed at quotation.
• Not mentioning conformal coating. Coating changes the masking plan, and masking is derived from the assembly drawing.
• Assuming a surface finish. The finish decides the storage window, the solderability and the fabrication cost.
• Missing an impedance or stack-up requirement. The fabrication house cannot infer a controlled-impedance target from the Gerber alone.
• Comparing a headline figure rather than a structure. A lower total that omits test or assumes a cheaper finish is not a lower cost.

Where to send the files

Send the file set to alden@kilandu.com. Files are held for the project only, under access control, and are not disclosed to third parties. If you are comparing suppliers, the quotation requirements page explains how the quotation is broken down so the comparison can be made line by line, and the Shenzhen factory page describes the site the boards are built on.