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How to RFQ CNC Machined Parts Without Wasting Three Months on Basic Questions

An RFQ (Request for Quotation) is a five-minute document for the buyer and a three-week detective investigation for the shop. The asymmetry is the entire problem. This page is the bridge: what to send, what not to send, what to require from the factory, and how to fix a quote that comes back wrong.

The Real Story: Three Months of “What Material?”

An engineer in Munich designed a small aluminum bracket, modeled it in SolidWorks, and emailed the STEP file to four factories on a Tuesday. By Friday the second factory had sent a quote. By the following Wednesday two more had. The fourth one emailed back asking what material it was.

Three months and 47 emails later, the engineer had spent more time re-explaining the project than it would have taken to redraw the part in ISO. The factories that had quoted early now wanted to requote. One had used 6061-T6 instead of 7075-T6 because the drawing never said. One had assumed the surface was as-milled when it was specified Ra 0.8. One had priced the part with the holes drilled but no threads. The fourth one was still asking what material it was.

None of the four factories were wrong to ask. None of them were slow. The RFQ was incomplete, and the factories were doing what good factories do: refusing to guess. The 12-item checklist and the 7 mistakes below exist to make sure this never happens to you.

Draft note (pending Sinbo review) The case ratios, time estimates, and “X% of RFQs” numbers in this page are synthesized from public forum discussions (Practical Machinist, r/Machinists, r/engineering, Eng-Tips), standard QMS and DFM practice (AIAG, AS9100, ISO 9001), and Sinbo engineering review of typical buyer RFQ patterns. They are illustrative, not drawn from a controlled study. Sinbo engineers should replace the case ratios with real shop data before this page goes to production translation.

The RFQ Information Pyramid — What Is Must-Have, Important, and Optional

Not every RFQ needs every item, but every RFQ needs to be honest about which tier each item sits in. A 5-piece prototype and a 5,000-piece production run have very different “must-haves”.

TierWhat belongs hereIf you skip it
Must-have (Tier 1)Material designation + temper, quantity, drawing or STEP with GD&T, key tolerances, surface finish, lead time, target country for shipmentFactory will not quote, or will quote with assumptions that you have to correct later
Important (Tier 2)Critical features called out, inspection requirements (FAI, CMM, key characteristics), secondary processes (anodize, heat treat, plating), Incoterms, payment terms, RFQ response deadlineQuote will be a rough range only, with major exclusions to be negotiated later — this is where 80% of late-stage surprises come from
Optional (Tier 3)Acceptable alternates, preferred brand for material, packaging requirements, target price (if you have one), NDA, audit rights, sample policyNegotiations will start from defaults that may not match your needs; small loss of control, not a deal-breaker
Rule of thumb. A factory that quotes from a Tier-1-only RFQ is taking educated guesses. A factory that refuses to quote until you give Tier 1 and 2 is a factory that will quote accurately. A factory that quotes everything from one paragraph of text is one that will not hold you to a number when the PO lands.

What a Complete RFQ Looks Like — The 12 Items

Below is the 12-item RFQ checklist. Every item has a “why it matters” reason, so you can decide for your specific case whether to skip or include.

#ItemWhy it matters
1Part name, drawing number, revisionReference for every email that follows. Without a drawing number, every quote revision is a different document.
2Material designation — full UNS / EN / JIS code and temper“Aluminum” is not a material. 6061-T6 vs 7075-T7351 differ by 2× in cost and 3× in machinability. EN AW-6082 T6 or ASTM B211 7075-T7351 removes the ambiguity.
3Quantity (target + minimum order + annual forecast if known)1 piece, 5 pieces, 50 pieces, 500 pieces, 5,000 pieces are quoted on completely different cost stacks. Honest quantity beats inflated quantity — the factory will re-price if you lied.
4Drawing or 3D model with GD&TIf you have a drawing, send it (PDF + native CAD if you can). If you only have STEP, that’s fine — say so explicitly so the factory knows to flag tolerance ambiguity.
5Critical tolerances (the ±0.0X mm ones)Mark them on the drawing or call them out in writing. “Tight tolerances” is not a specification. If the part has 3 features at ±0.01 mm and 30 features at ±0.1 mm, the factory needs to know which is which.
6Surface finish requirements (Ra value, by feature)Ra 1.6 (as-milled) is essentially free. Ra 0.4 (ground) is 30–80% added cost. Ra 0.05 (mirror-polished) is a different process entirely.
7Secondary processes — heat treat, anodize, plating, passivation, painting, laser markingEach is a separate supplier and adds lead time. A 5-day part with 10-day anodize and 5-day shipping is 20 days, not 5.
8Inspection requirements — FAI report, CMM, key characteristics, material certEN 10204 3.1 mill cert is the baseline; AS9102 FAI is the aerospace baseline; medical has its own FAI variations.
9Quantity of parts to inspect (100%, AQL sampling, first-article only)“Inspect every part to ±0.01 mm” is an entirely different cost line from “FAI only”. The factory needs to know which.
10Lead time — standard or expedite, with target date“ASAP” is not a lead time. “Need parts in our Munich warehouse by 2026-09-15 for a trade show” is.
11Incoterms (EXW, FOB, CIF, DAP, DDP) and target countryEXW is the cheapest to quote but pushes all logistics onto you. DDP is the easiest for you but requires the factory to know your import rules. Pick one and tell the factory.
12Payment terms and RFQ response deadlineNet 30 vs Net 60 vs 50% deposit affects which factories will even respond. A 7-day response deadline is reasonable for a complete RFQ; 3 days is rude unless you offer a paid rush.
One page is enough. A complete RFQ fits on one A4 page. A 12-page RFQ with marketing collateral and an NDA is fine too, but only if the one page of technical content is at the top. Most buyers over-format and under-specify.

The 7 Most Common RFQ Mistakes (and What They Cost You)

These are the failures that turn a 5-minute email into a 3-month project. Each one is fixable in the next RFQ you send.

#MistakeWhat happensHow to fix
1Quantity inflation. Buyer says “we’ll need 10,000/year” to get a lower price, then places 50.Factory is now unprofitable on the order, cuts corners, or renegotiates. Trust is broken before parts ship.Tell the truth. A 5-piece quote is not a 5,000-piece quote, but a 5-piece quote from a factory that could do 5,000 if you grew is more useful than a discount-driven quote from one that can’t.
2Missing or unstated tolerances. Drawing has 30 dimensions, no GD&T, no default-tolerance callout.Factory picks ISO 2768 medium (m) by default; buyer expected ISO 2768 fine (f). Parts arrive 2× looser than expected.State the default tolerance class on the drawing: ISO 2768-mK or ASME Y14.5-2018 with explicit GD&T on critical features.
3Material specified by trade name only. “Stainless steel” or “aluminum”.Factory picks the cheapest grade that fits. Buyer gets 303 instead of 17-4 PH, or 6063 instead of 6061-T6.Always specify the standard + grade + temper: AISI 316L, ASTM B211 7075-T7351, EN AW-6082 T6.
4Surface finish stated as a single number for the whole part.Critical sealing surfaces and non-critical external surfaces get the same finish — either over-paying for the part or under-finishing the seal.List finish by feature or zone. Sealing face: Ra 0.4. All other external surfaces: Ra 1.6.
5“Critical inspection on all features.” Buyer checks every dimension on every part.Cost goes through the roof. Lead time doubles. Factory may refuse the order or quote inspection cost separately and unpredictably.Specify what “critical” means: 100% on which features? CMM, height gauge, or micrometer? For the rest, an AQL sampling plan or first-article-only is fine.
6Lead time given as “as soon as possible” or “urgent”.Every factory reads this differently. Some quote standard, some quote expedite, some quote “best effort” that turns into 6 weeks.Give a target date with a reason: Need by 2026-09-15 for trade show. If you need a real expedite, say so and budget for the 30–100% expedite premium.
7One drawing, multiple configurations. “Make the part 50 mm long, 75 mm long, or 100 mm long, quote all three.”Factory quotes the easiest one, ignores the rest, or quotes a generic range. None of these is a real quote.Send three RFQs, one per configuration. Or send one configuration with a clear note that the others will follow as separate POs.
The compounding cost. Each mistake on its own adds a week to the project. Two mistakes add a month. Three add a quarter. The Munich engineer’s three months was the intersection of mistakes 2, 3, 4, and 6 in the same RFQ.

Prototype vs Pilot vs Production — How Your RFQ Changes by Stage

Prototypes, pilot runs, and production runs are not the same product ordered three times. They are different products with different cost stacks, and an RFQ that confuses them will either overpay massively or fail to deliver.

StageTypical quantityWhat the buyer is testingWhat the RFQ should ask forCost expectation
Prototype1–10 piecesForm, fit, function — does the part work at all?Material cert optional, FAI optional, full inspection on critical dims only, fastest lead time, machining only — secondary ops can be added laterHighest per-piece. Often 5–10× the production unit cost. Setup and programming are amortized over very few parts.
Pilot / Pre-production10–100 piecesProcess stability, DFM validation, supply chainFAI required, material cert required, full drawing-tolerance inspection on every part, secondary ops included, lead time measured against production target2–3× the production unit cost. This is the run where you find out if your drawing is producible.
Production100–10,000+ pieces/yearCost, capacity, on-time delivery, quality consistencyStatistical process control, AQL sampling, locked process, capacity reservation, price-break by volume, frame agreement / blanket PO with releasesLowest per-piece. The unit price converges on a number driven by cycle time + material + setup amortization, not by factory effort.
Common pattern. Many buyers send one RFQ asking for “price for 5 pieces, 50 pieces, and 5,000 pieces”. A good factory will quote all three. A great factory will tell you that the 5-piece run will use completely different fixturing and inspection than the 5,000-piece run, and that the 5-piece price is essentially irrelevant to the 5,000-piece decision. Trust the factory that warns you about this.

Expedite premiums. A rushed standard order (e.g. 5-day lead time instead of 15) typically carries a 30–100% premium and a real risk of the factory deprioritizing other customers’ work to fit you in. A true expedite where the factory stops other jobs and re-sequences is 2–4× the standard price. Anything below that and the factory is either absorbing the cost, lying about the lead time, or skipping steps — none of which you want.

How to Evaluate a Machine Shop Before You Send the RFQ

Five factories will quote you. Two are worth your time. The differences are visible before you send any drawings, if you know what to ask for.

Capacity
CriterionWhat to look forWhy it mattersRed flag
CertificationsISO 9001:2015 baseline. AS9100D for aerospace. IATF 16949 for automotive. ISO 13485 for medical.The cert is a floor, not a ceiling — but the floor matters. A factory without ISO 9001 has no documented QMS.Verbal claim of certification but no cert number. No audit by an accredited body. Or certifications from unrecognized bodies.
Equipment3-axis CNC mills are commodity. 5-axis mills, multi-axis lathes, Swiss-type lathes, and EDM are differentiators.Your part may need capabilities the factory doesn’t have. A 5-axis feature on a 3-axis machine is a hand-fit operation, not a production feature.Generic equipment list with no brand or model. Equipment photos that are stock images.
How many machines, how many shifts, current utilizationA factory at 95% utilization will give you a 12-week lead time. A factory at 60% will move you in 4 weeks.Refusal to discuss capacity. Vague “we can handle it” answers.
CommunicationResponse time, English fluency, technical depth of sales staffThe salesperson is the proxy for the company. If they can’t answer a basic RFQ question, engineering can’t either.2-day response time on your first email. English that is pure translation without technical vocabulary.
Similar workCase studies or sample parts in your material, tolerance band, and industryThe fastest way to know a factory can do your part is to see them do a similar part.“We can do anything” with no examples. Or examples that look like Aliexpress-grade work.
Sample policyWillingness to make a paid sample run (1–5 parts) before committingA factory confident in its quality will happily make samples. A factory worried about cost will insist on a 50-piece minimum.Refusal to do a paid sample. Or “samples are free but you pay shipping” (which usually means the factory cuts corners on the sample).
Audit accessWillingness to host a virtual or on-site auditYou will not audit 90% of your suppliers. But a factory that refuses a video walk-through is one that has something to hide.“We are very busy, can’t host visitors this quarter.”
The cheapest quote is the most expensive. Across hundreds of CNC parts programs, the lowest-quoting factory on the first RFQ is rarely the lowest-cost supplier across the program. The first quote is a sales tool; the second quote (after revisions) is closer to reality. A factory that comes in 30% under everyone else on the first quote is either cutting corners, under-spec’ing, or planning to recover margin on the change orders.

Cross-Border RFQ: IP, Tariffs, and Logistics

Crossing a border with a custom part adds three variables to your RFQ that domestic sourcing doesn’t have: who owns your IP, what duties apply, and how the part physically moves.

TopicDomestic RFQCross-border (e.g. CN → US, US → EU, EU → CN)What your RFQ should address
IP protectionNDA usually sufficient.NDA is not enough. A non-disclosure agreement prevents the factory from telling others about your IP, but does not stop the factory from using your IP itself, or from selling to your customers behind your back.For Chinese factories specifically, use an NNN agreement (Non-Use, Non-Disclosure, Non-Circumvention) governed by Chinese law, in bilingual Chinese-English, with explicit monetary damages per breach. NNN is the standard tool for this scenario.
Tariffs & dutiesNone.Section 232 (US): 25% on steel and 10% on aluminum articles, expanded in 2020 to many derivative products. EU CBAM, UK UKCA, and other regimes apply depending on destination. Section 301 (China → US) applies to many finished goods.Ask the factory to quote DDP (Delivered Duty Paid) for a true landed cost, or at minimum CIF + estimated duties. Don’t accept EXW if you don’t know the tariff schedule for your HS code.
LogisticsTruck or parcel.Sea (cheapest, 25–40 days), air (5–10 days, 4–8× the cost), courier (DHL/FedEx, 3–7 days, most expensive). For prototypes, air is almost always the answer; for production, sea is.State your target landed date. The factory can offer a sea or air quote, but they need to know the constraint. “Cheapest” is not a logistics spec.
Material certsMill cert from the factory’s mill.EN 10204 3.1 (factory self-issued under EU-accredited ISO 9001 or PED 4.3) or 3.2 (EU Notified Body-issued) is required for EU-bound pressure equipment, often requested for aerospace regardless of destination. ASTM-compliant mill certs are typical for US-bound material.State which cert type you need. If you need 3.2, the factory must use an EU Notified Body, which adds cost and lead time.
PaymentNet 30 common.T/T (wire) is the default. 30% deposit + 70% before shipping is the most common structure. L/C (letter of credit) for large orders. PayPal for samples under $1k.Be explicit about the split and the trigger. “30/70 T/T” is incomplete; “30% deposit on PO, 70% against copy of B/L” is complete.
Section 232 caveat. The 25% steel / 10% aluminum tariff applies to articles where steel or aluminum is the “substantial material” by value or weight. A CNC machined part that is mostly steel or aluminum, even with secondary machining done overseas, is generally covered. Always confirm the current rate and applicability with a customs broker before committing — the rules have been amended multiple times since the original 2018 proclamation, with country-specific exemptions, product exclusions, and derivative-product expansions.
NNN structure (China specifically). A well-drafted NNN agreement covers: (1) Non-Use — the factory agrees not to use your IP to compete with you; (2) Non-Disclosure — the factory cannot share your IP with third parties; (3) Non-Circumvention — the factory cannot sell to your customers, suppliers, or channels. It must be governed by Chinese law and enforceable in a Chinese court. A US/EU NDA is essentially worthless in a Chinese court — the NNN closes the loop.

Resolution Workflow: When the Quote Comes Back Wrong

Even a perfect RFQ produces a quote that needs work. Here is the 5-step workflow for handling a quote that is late, too high, technically wrong, or just unclear.

  1. Diagnose the cause first. Categorize the problem: (a) lead time too long, (b) price too high, (c) technical exception taken (factory says it can’t hit a tolerance), (d) missing line items (no surface treatment, no FAI), (e) unclear / vague quote. Each category has a different fix.
  2. Ask for the underlying math, not a lower number. “Can you reduce by 20%?” produces a number, not information. “What is the cycle time you assumed, and what is the material cost per piece?” produces the input you need to evaluate the quote.
  3. Cross-check the technical exception. If the factory says “we can’t hold ±0.01 mm on the bore”, push back with the standard or the inspection method. They may be quoting to a different (looser) interpretation than you are. If both sides agree on interpretation and the factory still says no, that’s information: the factory’s process is not capable.
  4. Negotiate the things that matter, not the things that don’t. Most buyers argue about 3% on the unit price and ignore the 30% gap in lead time or the missing inspection. A 2-week shorter lead time is worth more than a 5% price drop in most cases.
  5. Document the final terms in writing before placing the PO. Verbal commitments during a quote negotiation are not enforceable. Email recap, signed PO with reference to the quote, and (for cross-border) an executed NNN. If it isn’t in the PO, it doesn’t exist.
When to walk away. A factory that is 40%+ more expensive than the median of your other quotes is either (a) not interpreting the RFQ the same way you are, (b) has a capacity or capability gap, or (c) is signaling that the work is not interesting to them. In any of the three cases, a second round of negotiation rarely closes the gap. Walk away and use one of the other three.

Prevention Checklist: 10 Self-Checks Before You Click Send

#CheckIf “no”, fix before sending
1Material is specified to standard + grade + temper, not trade name?Add the standard designation: ASTM B211 7075-T7351, EN AW-6082 T6, AISI 316L.
2Drawing has either explicit GD&T or a stated default-tolerance class (ISO 2768-mK, ISO 2768-fK)?Add the default callout in the title block.
3Critical tolerances (±0.0X mm) are flagged on the drawing or called out in text?Mark them with notes or a “critical features” callout.
4Surface finish is specified per feature, not per part?Break the callout into zones (e.g. sealing face vs body).
5Quantity is honest — not inflated?Tell the truth. Inflated quantities cost you trust and money later.
6Lead time is a date, not a feeling?“By 2026-09-15” is a lead time. “ASAP” is not.
7Inspection scope is defined — 100%, AQL, or FAI-only?Add the line: Inspection: FAI on first 5 parts, AQL 1.0 on dimensions per ISO 2859-1 normal inspection for the rest.
8Material cert type is named (EN 10204 3.1, 3.2, ASTM mill cert)?For EU pressure equipment: EN 10204 3.1 or 3.2. For others: factory’s standard mill cert is usually fine.
9Incoterms are picked (EXW, FOB, CIF, DAP, DDP)?For first-time suppliers: DDP is the cleanest. For ongoing relationships: FOB or EXW.
10Payment terms are explicit (deposit %, balance trigger)?For first orders: 30/70 T/T is the default. For ongoing: Net 30 after the relationship is established.

Standards & Sources

Quality management standards — which cert does your shop need?ISO 9001:2015 Quality management systems — requirements. The baseline QMS standard. Any serious CNC machine shop should have this; absence is a red flag.
AS9100D Aerospace quality management — built on ISO 9001 with 80+ aerospace-specific requirements (FAI per AS9102, key characteristics per AS9103, configuration management, counterfeit-part prevention). Required by Boeing, Airbus, GE, and most Tier 1 aerospace primes.
IATF 16949:2016 Automotive quality management — built on ISO 9001 with automotive-specific requirements: zero-defect philosophy, supply chain management, production part approval process (PPAP), risk management, full traceability. Required by most automotive OEMs and Tier 1s.
ISO 13485:2016 Medical devices QMS — required for any shop serving the medical device industry (FDA Quality System Regulation harmonizes with this).
First article inspection — the report that proves the first part is rightAS9102C Aerospace First Article Inspection Requirement — the FAI report format and process for aerospace. Three forms: Part Number Accountability, Product Accountability (material + special processes), Characteristic Accountability. Required by every AS9100 customer on first article, on design changes, and after a 2-year production lapse.
EN 10204:2004 Metallic products — types of inspection documents. Defines 2.1, 2.2, 3.1, and 3.2 certificate types. 3.1 is the standard mill test certificate issued by the manufacturer under ISO 9001 (or PED 4.3 for pressure equipment). 3.2 requires an EU Notified Body to co-sign and is mandatory for many EU pressure-equipment applications per the Pressure Equipment Directive 2014/68/EU.
Cross-border — IP and tariffsNNN Agreement Non-Use, Non-Disclosure, Non-Circumvention — the standard IP protection framework for sourcing from Chinese OEM manufacturers. Broader than a US/EU NDA. Governed by Chinese law, in bilingual Chinese-English, with explicit per-breach damages. Required for any meaningful IP exposure.
Section 232 (US) Trade Expansion Act of 1962 §232 — the 2018 presidential proclamation imposed 25% tariff on steel articles and 10% on aluminum articles, expanded in 2020 to many derivative products. Country-specific exemptions and a product-exclusion process exist; current applicability for any specific HS code requires customs broker confirmation.
Communication references for diagnostic patternsPractical Machinist forum, r/Machinists, r/engineering, Eng-Tips — the recurring buyer-side pain points (incomplete drawings, missing tolerances, RFQ-“tag” games between buyer and seller) that drive the 7-mistakes list above are visible across these communities. Useful for calibrating expectations, not for citing in a PO.
Frequently Asked Questions
What is the minimum information a CNC machining RFQ must include to get an accurate quote?

Five items, no fewer: (1) material to standard + grade + temper (e.g. ASTM B211 6061-T6, not “aluminum”); (2) quantity with target and minimum; (3) drawing or 3D model with GD&T or stated default-tolerance class; (4) critical tolerances and surface finish called out per feature; (5) lead time as a specific date, not “ASAP”. Without any of these, the factory will either refuse to quote or will quote with assumptions you will have to correct later. The full 12-item list in this page is what separates an “accurate quote” from a “rough range”.

Why does a machine shop ask so many basic questions after I sent them a complete RFQ?

Because the RFQ is rarely as complete as the buyer thinks. The most common reasons a factory asks 10 follow-up questions: (1) the drawing has a tolerance or feature the buyer didn’t notice; (2) the default-tolerance class isn’t stated, so the factory has to ask which one applies; (3) the material is named in trade form (“stainless”) without a standard designation; (4) the surface finish is a single number for a part that clearly has multiple functional zones; (5) the lead time is “ASAP” and the factory needs a real date to plan capacity. None of these are the factory being slow — they are the factory refusing to guess. A good factory will ask 3–5 clarifying questions and then quote in 3–7 business days.

How is an RFQ for a prototype different from a production run?

They are different products. A prototype (1–10 pieces) is about form, fit, and function — cost is secondary, lead time is the main constraint, FAI is optional, and the factory uses general-purpose fixturing. A production run (100–10,000+ pieces) is about cost, capacity, repeatability, and quality consistency — lead time is predictable, FAI is mandatory, the factory uses dedicated fixtures and tooling, and the unit price converges on a number driven by cycle time + material + setup amortization. Many buyers send one RFQ asking for “5 pieces, 50 pieces, 5,000 pieces”. A serious factory will quote all three but warn you that the 5-piece and 5,000-piece processes are completely different. A bad factory will give you one number and surprise you later.

What is a reasonable expedite or rush fee on a CNC machining order?

30–100% premium for a “comfortable rush” (compressing a 3-week standard to 1–2 weeks, using existing capacity and overtime). 2–4× the standard price for a true expedite where the factory stops other jobs and re-sequences production. Anything below 30% means the factory is either absorbing the cost (which they’ll recover on a change order) or skipping steps (which you’ll find in inspection). The honest answer on whether to expedite: if missing the date costs more than the expedite premium, pay it; if not, take the standard lead time and use the saved money to inspect the parts more carefully when they arrive.

How do I protect my IP when sourcing CNC parts from China?

A standard NDA is not enough for Chinese OEM manufacturing. An NDA prevents the factory from telling others about your IP, but doesn’t stop the factory from using your IP itself, or from selling your product to your customers. Use an NNN agreement (Non-Use, Non-Disclosure, Non-Circumvention) instead. The three clauses cover: (1) Non-Use — factory cannot use your IP to make parts for competitors; (2) Non-Disclosure — factory cannot share your IP with third parties; (3) Non-Circumvention — factory cannot sell to your customers or channels. The NNN must be in bilingual Chinese-English, governed by Chinese law, enforceable in a Chinese court, and include explicit per-breach monetary damages. A US/EU NDA has essentially no enforcement value in a Chinese court.

What is the Section 232 tariff and does it apply to my imported CNC parts?

Section 232 of the US Trade Expansion Act of 1962 was invoked in March 2018 to impose a 25% tariff on steel articles and a 10% tariff on aluminum articles imported into the United States, on national security grounds. In 2020, the scope was expanded to include many derivative steel and aluminum products. A CNC machined part that is substantially steel or aluminum by value or weight is generally covered. Country-specific exemptions exist (Canada, Mexico, Australia, Brazil, South Korea, Argentina, etc.) and a product-exclusion process is available. Because the rules have been amended multiple times and are HS-code specific, the responsible move is to ask your customs broker to confirm the current rate for your specific HS code before committing to a landed cost. For RFQ purposes, ask the factory to quote DDP (Delivered Duty Paid) to eliminate the duty uncertainty, or at minimum CIF + estimated duties.

What certifications should I look for in a CNC machine shop?

The certification floor is ISO 9001:2015 — any serious CNC machine shop should have it; absence is a red flag. Above that: AS9100D (aerospace, required by Boeing/Airbus/GE primes and most Tier 1 aerospace supply chains), IATF 16949:2016 (automotive, required by most automotive OEMs and Tier 1s), ISO 13485:2016 (medical devices, required for any FDA-related medical work). For First Article Inspection specifically, AS9102C is the standard for aerospace; many non-aerospace shops also use it as a process standard even when not required. The cert is a floor, not a ceiling — a shop can be ISO 9001 certified and still produce bad parts, and a shop can be uncertified and still produce excellent parts. Use the cert to filter, then use sample parts and a paid pilot run to verify.

How should I handle a quote that comes back 30–40% higher than I expected?

Don’t argue the number — ask for the math. A good response is: “Our target was $X per piece. Your quote is $Y. Can you share the cycle time you assumed, the material cost per piece, the setup hours, and any line items we might have missed?” Three things usually come back: (1) the factory interpreted the drawing differently than you intended — fix the spec, re-quote; (2) the factory included secondary operations (heat treat, surface finish, FAI) you didn’t explicitly exclude — confirm scope, re-quote; (3) the factory’s capacity and cost base really are higher than the market — that’s information, not a negotiation starting point. If the quote is more than 40% above the median of your other quotes after the first round, the work is probably not interesting to the factory, or there’s a capability gap — walk away and use a different supplier rather than round 2 of negotiation.

What is the difference between EXW, FOB, CIF, DAP, and DDP Incoterms?

Incoterms define who owns the shipment and the risk at each stage. EXW (Ex Works) — the factory’s responsibility ends when the part is on their loading dock; you arrange and pay for all transport, insurance, and customs. Cheapest quote, most work for you. FOB (Free On Board) — factory delivers to the port of origin and loads the ship; you own the shipment from there. CIF (Cost, Insurance, Freight) — factory pays for transport and insurance to the destination port; you own from the port of destination. DAP (Delivered At Place) — factory delivers to your named address; you handle import customs and duties. DDP (Delivered Duty Paid) — factory handles everything including import duties; you receive the part at your door with no further work. For first-time suppliers and one-off orders, DDP is the cleanest. For ongoing relationships with established logistics partners, EXW or FOB gives you more control and lower per-shipment cost.

Sources & Standards Referenced
  1. ISO 9001:2015: Quality management systems — Requirements. Baseline QMS standard; absence is a red flag for any serious CNC machine shop.
  2. AS9100D (SAE AS9100D, 2016): Aerospace Quality Management System. Built on ISO 9001 with 80+ aerospace-specific requirements; required by Boeing, Airbus, GE, and most Tier 1 aerospace primes. Backed by IAQG (International Aerospace Quality Group).
  3. AS9102C (SAE AS9102C, 2023): Aerospace First Article Inspection Requirement. Three-form FAI report format (Part Number Accountability, Product Accountability, Characteristic Accountability). Published by SAE, supported by IAQG.
  4. IATF 16949:2016: Automotive Quality Management System. Built on ISO 9001 with zero-defect philosophy, PPAP, supply chain management, full traceability. Required by most automotive OEMs and Tier 1s.
  5. ISO 13485:2016: Medical devices — Quality management systems. Required for any shop serving the medical device industry.
  6. EN 10204:2004: Metallic products — Types of inspection documents. Defines 2.1, 2.2, 3.1, 3.2 certificate types; 3.1 (factory-issued under ISO 9001) and 3.2 (EU Notified Body-issued) for pressure equipment per Pressure Equipment Directive 2014/68/EU.
  7. Section 232 of the Trade Expansion Act of 1962 (US): 25% tariff on steel articles and 10% on aluminum articles imposed March 2018 (Presidential Proclamations 9704/9705), expanded in 2020 to derivative products. Country exemptions and product exclusion process apply; current rate for any HS code must be confirmed with a customs broker.
  8. NNN Agreement (Non-Use, Non-Disclosure, Non-Circumvention): Standard IP protection framework for Chinese OEM manufacturing. Broader than NDA, governed by Chinese law, bilingual Chinese-English, with per-breach damages.
  9. Practical Machinist forum, r/Machinists, r/engineering, Eng-Tips: recurring buyer-side pain points (incomplete drawings, missing tolerances, default-tolerance ambiguity, RFQ clarifying-question loops) that inform the 7-mistakes and 12-item lists above
  10. AIAG 8D (Eight Disciplines Problem Solving): standard automotive/aerospace reject-resolution workflow, used for the resolution workflow section

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Our engineering team reviews every RFQ against the 12-item checklist before quoting. If anything is missing, we’ll flag it on the first email rather than three weeks later. Send your drawing, STEP file, or rough sketch and we’ll respond with a fixed quote inside 48 hours.

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