吃瓜tv / PCBA purchasing
PCB assembly quotes: compare scope first
Align BOM, supply responsibility, setup, programming and test before comparing batch totals. Turn unexplained price differences into specific review questions.
Compare the same assembled product before comparing price
PCB assembly quotes are comparable only when they describe the same board revision, BOM variant, quantity, sourcing responsibility, assembly operations and verification scope. A quotation for placement labor cannot be compared directly with a turnkey offer that includes bare boards, components and testing. The first useful question is 鈥淲hat will we receive?鈥� rather than 鈥淲hich unit price is lowest?鈥�
This page helps purchasing and engineering teams reconcile two offers. It does not generate a binding quotation or rank suppliers. For the underlying service scope, see PCB assembly services. If you only need unpopulated boards, the separate bare-board quote comparison addresses fabrication-specific requirements.
| Check | Same basis means | Stop and clarify when |
|---|---|---|
| Configuration | Same PCB, BOM, variant, firmware and quantity | One supplier priced an older file package |
| Delivered scope | Same procurement, assembly, test, packaging and records | Testing or components are excluded in only one offer |
| Commercial basis | Understood currency, NRE, excess material and delivery terms | The totals include different liabilities or destinations |
Define the deliverable before comparing money
Write down the board revision, assembly variant, requested delivered quantity, and acceptable delivery condition. Ten populated boards are different from ten tested boards, and ten tested boards are different from ten boards with serialized test reports. A quotation must say which of those products is included. Identify whether the purchase covers bare boards, components, assembly labor, programming, test development, testing, coating, packaging, and freight. A blank cell should mean unresolved scope, not a free service.
Separate the quantity being built from the quantity you need delivered. If an assembler proposes extra units for process setup or destructive qualification, ask who pays for those units and who owns any usable remainder. Do not apply an arbitrary yield multiplier to every order. A prototype build may deliberately allocate some units to destructive analysis, while a production order may have a different acceptance and replacement arrangement. Document the actual commercial treatment instead of converting assumptions into unit prices.
Freeze a common reference package for every supplier. Include the BOM revision, fabrication data revision, assembly drawing, approved alternatives, and test description. If one supplier sees a later BOM with an unavailable component removed, its quotation is not comparable with an earlier response. Send a concise clarification sheet with numbered questions and record the reply date. Procurement can then distinguish a real price change from a change in scope. This is especially useful when purchasing and engineering work in different time zones.
For mixed variants, state quantities by variant rather than only a family total. Different firmware, fitted components, or coating masks can create separate setup and handling work even when the bare board is shared. Ask which charges repeat when a variant changes and which charges are genuinely common.
Record the requested lot quantity and any alternatives as separate quantity breaks. Clarify whether the quantity is assembled boards, panels or sets of several boards. State the required test outputs and acceptance documents, not simply 鈥渢est required.鈥� The PCBA file preparation guide explains the complete data handoff; this comparison page focuses on what the resulting offers include.
Separate recurring costs from reusable setup
Classify each amount by what triggers it. Components, placement work, per-board inspection, and packaging often vary with quantity. A stencil, program preparation, fixture design, or first-article engineering may be charged once for a particular revision. That does not automatically make every setup item reusable forever. A changed land pattern can invalidate a stencil, and a firmware interface change can invalidate part of a functional test program.
Ask for ownership and retention terms for tooling. A quotation that includes a fixture but does not say whether it is retained, transferable, or maintainable leaves a future purchasing risk. Record the fixture revision, storage duration, maintenance responsibility, and conditions for requalification. Distinguish a charge for making a fixture from the time to run it on each board. Otherwise a repeat order may appear unexpectedly expensive even when no new hardware is needed.
Use two totals: initial-build cost and repeat-build cost under explicitly unchanged assumptions. Suppose the same hypothetical order contains 600 currency units of reusable setup and 900 of recurring work for 30 delivered boards. The initial cost is 1,500, or 50 per delivered board. If the setup is truly reusable and the recurring scope is unchanged, the repeat calculation is 900, or 30 per board. This is arithmetic, not a predicted repeat quotation; component availability and actual production conditions still require confirmation.
Do not divide the initial total by a speculative annual volume to hide prototype expense. Budget the first build separately, then request real quantity breaks. The next decision may be whether to simplify a fixture or reduce variants, not whether to push a supplier for an unsupported percentage discount.
Normalize three quotations with the same worksheet
Consider a fictional 20-board order with identical PCB revision and BOM. Quote A lists 1,100 for boards, components, and assembly, plus 200 for setup; functional testing is excluded. Quote B lists 1,450 including the same build, setup, and a specified functional test. Quote C lists 900 for consigned-parts assembly and setup, but the customer must supply components. The totals cannot be ranked as 900, 1,300, and 1,450 without first resolving those differences.
If the customer-input component cost for Quote C is 400 and its separately quoted test is 150, its comparable amount becomes 1,450 before any other adjustments. If Quote A's matching test costs 180, its comparable amount becomes 1,480. Quote B remains 1,450 only if its test definition genuinely matches the reference scope. The calculation shows why a comparison needs line items; it does not show that one procurement model is inherently cheapest.
Keep uncertain adjustments visible. Do not fill a missing test price with an invented market rate just to finish a spreadsheet. Mark that quotation incomplete and request clarification. If a supplier proposes a different test method, evaluate whether it detects the specified failure modes before treating the two services as equivalent. Two tests with the same duration can have very different coverage.
Keep currency, tax, shipping terms, payment fees, and validity date in separate columns. A landed-cost comparison depends on the actual destination and commercial terms, so this worksheet does not calculate customs or tax rules. Record who supplies those figures. The defensible result is a like-for-like engineering and purchasing comparison, with unresolved differences still visible to the person approving the order.
Treat component overage as an inventory decision
Component purchasing can dominate a small assembly quotation. Separate fitted demand from handling overage, minimum order quantity, packaging quantity, and reserve stock. For a component used twice on each of 25 boards, fitted demand is 50 pieces. If the assembler requests 10 additional pieces and the purchase pack contains 100, the order may leave 40 pieces after the planned 60-piece allocation. That is not automatically a loss; ownership, return, and future usability determine its value.
Request overage by component type and packaging rather than applying one blanket percentage to every BOM row. A low-cost passive on a reel and an expensive processor in a tray create different handling and financial issues. The assembler should identify special handling needs and confirm the acceptable delivery format. Do not assume loose parts, cut tape, reels, and trays are interchangeable without preparation work.
Approved substitutions also affect comparability. A resistor with the same nominal resistance may differ in tolerance, power rating, voltage rating, temperature behavior, or packaging. A replacement IC may require firmware or qualification changes. Record exactly who approves substitutions and whether approval is required before purchase. A quotation based on unapproved alternatives is an option, not the baseline.
Include unused-component disposition in the order. Returned material should retain identification, traceability information where available, and appropriate packaging. If retained for future production, record the storage arrangement and inventory reconciliation. The best cost reduction may be a cleaner BOM and a realistic purchasing plan rather than removing inspection from the scope. When comparing turnkey and consigned supply, include your own purchasing labor and coordination risk as a separate management consideration, not as an invented supplier charge.
The component responsibility worksheet provides a way to record those owners. Do not infer a responsibility from the word turnkey alone. An agreed scope can include exceptions, such as a customer-supplied processor, provided the boundaries are explicit and every offer uses the same arrangement.
Compare test and inspection by the evidence delivered
An inspection line item needs more detail than a method name. Ask what is inspected, at what stage, against which approved criteria, and what record is retained. AOI is useful for visible assembly conditions but does not demonstrate that firmware executes correctly. X-ray can reveal certain hidden joint features but does not replace a functional test. A continuity check and a powered interface test answer different questions.
Separate test development from test execution. A functional test may require software, fixtures, loads, calibration, and a reference unit before any production board can be evaluated. State who supplies the firmware, expected limits, connector pinout, and safe operating sequence. If these inputs are not ready, obtain a conditional quotation with the missing engineering work identified. Do not describe an undefined test as included merely because a supplier uses the word tested.
Ask how failures are handled. Does the price include diagnosis, authorized rework, retest, and a record of the original defect? Are customer-design faults treated differently from assembly defects? Who decides whether a questionable unit can be accepted? A clear escalation path avoids discovering commercial disagreements when the schedule is already under pressure.
For prototype builds, request only the evidence needed for your next engineering decision. Blanket requests for every possible test can consume the budget without answering the actual uncertainty. Conversely, omitting access or programming work may prevent meaningful bring-up. Package-specific assembly recommendations are available through TI's SMT documentation; use the relevant component guide when defining special package requirements rather than treating a generic quote checklist as a process specification.
send files and unresolved requirements for review.
Compare two quote scopes
Mark each row aligned only when both quotations match the same common requirement, including the same agreed exclusion. Add the common scope reference and unresolved exceptions. Different quantities, currencies, revisions or unconfirmed scope rows withhold the numerical comparison. The worksheet does not read uploaded offers or verify what suppliers agreed.
PCBA quote scope comparison
The optional worksheet needs JavaScript. Use the readable checklist above or contact 吃瓜tv directly.
Enter complete batch totals, including one-time charges once. The tool reports average amounts and a difference only after you mark the comparison basis aligned. Even then, 鈥渁ligned鈥� is your record, not independent validation. The smaller total is not automatically the best value; supply continuity, evidence quality and unresolved technical risk still require review.
Read the schedule and delivery conditions
Separate requested delivery from confirmed lead time and identify the start condition. An assembly schedule may depend on released files, material availability, customer approvals and test readiness. Compare the same milestone: ex-factory dispatch and arrival at your receiving site are not the same date.
Record quote validity and any components subject to repricing. Identify freight, insurance, duties and taxes as included, excluded or unresolved according to the actual offer. Do not turn an estimated freight allowance into a confirmed landed cost. Where trade terms are used, preserve the named place and the agreed rule rather than copying an abbreviation without its context.
Discuss engineering changes before award. Ask how unused material, work in progress, new tooling and revised testing are treated if the design changes. Repeat pricing may depend on reusing an approved fixture or existing setup. Confirm that those assets remain suitable for the new revision before assuming a recurring-only price.
Send a clarification-ready RFQ and approve exceptions
Prepare one brief containing the reference package identifier, quantities by variant, procurement split, acceptance work, delivery target, and open questions. Attach a comparison worksheet rather than burying critical requirements in a long email thread. Each supplier can then confirm, exclude, or qualify the same items. Keep technical exceptions beside the associated cost line so the lowest total cannot conceal a material change.
Before approval, review three questions with engineering: are the component choices authorized, does the fabrication and assembly scope match the released revision, and will the delivered evidence support the planned validation? Review three more with purchasing: what is payable now, what may change, and what happens if material or schedule assumptions change? These are different decisions and should not be collapsed into a single total.
Record the final agreed scope as an order attachment. If a late change occurs, update the revision and obtain a clear price and schedule impact before the changed build starts. A supplier response saying that a drawing is acceptable does not necessarily approve every functional assumption in a separate test spreadsheet. Use explicit cross-references and an accountable approver for exceptions.
The downloadable worksheet provides fields for these decisions; it does not calculate a quotation or send files automatically. If your package is incomplete, identify the missing BOM, test, or procurement decision and request a scoped review. A productive inquiry explains what you need built and which uncertainty you want resolved. That lets the assembly team respond with useful questions rather than an attractive but incomparable number. For the next build, retain the final worksheet so purchasing can compare the same accepted scope rather than restarting from an old headline price.
Common quote-comparison questions
Can I compare different currencies in this worksheet?
No. It intentionally withholds the price comparison. Agree a dated conversion basis outside the tool, including any fees or currency risk, and document the normalized values before using a common-currency comparison.
What if one quote excludes a test I do not need?
Confirm that the exclusion is appropriate for your product and align both offers to that same requirement. A lower price can reflect a legitimate narrower scope, but the decision should be explicit.
Is this an online quotation request?
No. It prepares a comparison brief on your device. You can contact 吃瓜tv directly with files and quantity options, with or without the worksheet. Downloaded information is not transferred to the form automatically.
Bring the open questions to 吃瓜tv
Send the project reference, available files, quantity options and the decisions you need help with. If you used the worksheet, review its assumptions and attach the downloaded brief yourself. Opening Contact does not send the worksheet or place an order.
Technical references and scope
These official references explain data, standards or handling concepts. Use the applicable controlled documents and project agreement for acceptance. Links do not certify 吃瓜tv, qualify a product or replace engineering approval.
Project worksheet and supporting references
Download the project review worksheet (CSV). Record evidence and open questions before submitting files. This download does not send information to 吃瓜tv.
Technical references: . References support the stated scope, not blanket manufacturing approval.