Guide
What does the APQP process look like for small-batch machined parts?
The APQP process is the automotive industry’s structured method for planning a new part so that the supplier, the process and the inspection are ready before production starts. It runs in five phases, from planning to feedback after launch; for a small-batch machined or cast part, the same phases still apply, but each one shrinks to a few concrete deliverables you can ask for in the RFQ.
By Saola Manufacturing engineering team · Published · Updated
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What are the five phases of APQP?
The five phases are planning and defining the program, product design and development, process design and development, product and process validation, and feedback, assessment and corrective action. Each phase ends with outputs that feed the next one.
APQP comes from the Automotive Industry Action Group. A summary by testing and consulting firm Smithers, citing the APQP 2nd edition, names the phases and their key elements: voice of the customer and a product assurance plan in phase 1; a preliminary process flow chart, design for manufacturability and a prototype build in phase 2; design verification, a characteristics matrix and a measurement system plan in phase 3; a preliminary process capability study and quality planning sign-off in phase 4; and a production control plan and lessons learned in phase 5.
The current manual is APQP 3rd edition. AIAG describes it as adding sections on sourcing, change management, program metrics, risk mitigation plans and gated management, with “updates to reflect agile product management.” It also notes “the removal of Control Plan content - now a standalone document,” published as the Control Plan 1st edition. Aerospace has its own version of the same idea in SAE AS9145, which covers APQP and production part approval together.
Why would a non-automotive buyer use APQP for machined parts?
Because the failures APQP prevents are not automotive-specific: a missed critical dimension, a process that drifts, a gauge that cannot see the tolerance, or a change nobody approved. A scaled-down APQP gives a small-batch buyer a checklist for a new supplier without the paperwork of a full automotive launch.
A typical industrial or equipment OEM buying a few hundred to a few thousand machined parts a year does not need a run-at-rate or a full set of capability studies. What it does need is the core logic: agree what matters on the drawing, see how the supplier plans to make and check it, approve the first parts against that plan, and lock the process so it does not change silently. Each phase of APQP maps onto one of those steps.
Moving a part to a new supplier, especially an overseas one, is exactly where this pays. The drawing that worked with the old supplier often relied on habits nobody wrote down: a deburr standard, a datum the inspector always used, a finish that was “the usual.” Phase 1 and phase 2 of a lite APQP are where those habits become written requirements.
What does a scaled-down APQP look like for a small-batch part?
Reduce each phase to the few outputs that change a decision: a requirements review, a manufacturability review, a process flow with a control plan, a first-article report, and a change-control agreement. Skip the elements that only pay at automotive volume.
The table below is a practical mapping, not a requirement of any standard. Use it as the backbone of the RFQ and the supplier kickoff call.
| APQP phase | Full automotive outputs (examples) | Lite version for a small-batch machined part |
|---|---|---|
| 1. Plan and define | Voice of the customer, quality goals, product assurance plan | Drawing, revision, annual volume, critical characteristics marked, finish and material notes, packaging |
| 2. Product design and development | DFMEA, design for manufacturability, prototype build | Supplier drawing review with written questions and proposed changes; prototype or sample lot if the design is new |
| 3. Process design and development | Process flow, PFMEA, characteristics matrix, MSA plan | Short process flow (operations and which plant), control plan for critical characteristics, gauge named for each |
| 4. Product and process validation | Production trial run, capability study, PPAP, sign-off | First-article inspection report in AS9102-style format, material certificate (for example an EN 10204 type 3.1), finish certificate, approval in writing |
| 5. Feedback, assessment, corrective action | Production control plan, lessons learned, reduced variation | Dimensional record per lot, change notification rule, corrective action format agreed in advance |
What should the buyer prepare in phase 1?
A clean drawing set with the critical characteristics marked, the annual volume and lot size, and every requirement that lives outside the drawing written down. Most launch problems on machined parts trace back to a requirement that was assumed, not written.
- Critical characteristics. Mark the dimensions that affect fit, function or safety. Our guide to marking critical characteristics on a drawing covers the symbols.
- Volumes. Annual quantity, lot size and how often you will order. They decide whether a fixture or a dedicated gauge is worth making.
- Specifications outside the drawing. Finish specification, cleanliness, packaging, labeling, country-of-origin marking, and any customer-specific quality manual.
- Approval package. Say up front what you need at first article. The PPAP for non-automotive parts guide explains how to scale the approval package itself, so it is not repeated here.
What should the supplier deliver in phases 2 and 3?
A written drawing review and a short process plan: which operations, in which plant, with which gauges on the critical characteristics. For small batches, a one-page process flow and a control plan limited to critical characteristics is usually enough.
The drawing review is the most valuable output of a lite APQP. It should list unclear callouts, tolerances that drive cost without obvious function, and anything the supplier cannot do in-house, such as a finish that is applied at a partner plant. Ask for it in writing, with the drawing marked up, so the answers become part of the purchase order rather than a phone call nobody remembers.
The process plan should name the operations and where each one happens, because a casting, a machining step and a finish may be in three different plants. The control plan then lists each critical characteristic, the gauge, the sample size and the reaction if it fails; the control plan guide shows a filled-in example. A full PFMEA is optional at this scale, but asking “what is most likely to go wrong on this part, and how will you catch it?” gets most of its value.
How do you validate and approve the first parts?
Approve the part on a first-article inspection report that covers every toleranced dimension, plus the material and finish certificates, and approve it in writing. Then hold the supplier to a change-notification rule so the approved process stays approved.
Check the first-article report against the drawing, line by line: every balloon present, every result inside tolerance, the instrument named for each critical dimension. A first article measured on the wrong revision, or with a caliper on a fit diameter, is a finding even if all the numbers pass. For tight dimensions, our 10:1 gauge rule guide explains how to judge whether the gauge was adequate.
Phase 5 is where small-batch buyers most often stop. Write down what counts as a change that needs your approval (material source, plant, finish supplier, process step, inspection method) and how a nonconformance is reported. That turns lessons learned from an automotive slogan into a clause in the purchase order.
How does Saola support an APQP-style launch?
A new part starts with a drawing review, and the quality page lists a first-article inspection report on new parts, a dimensional inspection record every lot, and material certification on request. Anything beyond that, such as a PFMEA, a capability study or a full PPAP, should be named in the RFQ so it is confirmed at drawing review.
Machining runs at the lead CNC plant, T.K Viet Nam Precision, on the CNC turning and CNC milling lines; finishes are managed through partner plants, and each quote states where production takes place. As the quality page says, ISO 9001 certification is in progress, not held, and there is no IATF 16949 registration, so an automotive production part that requires it is outside scope. For industrial parts where a lite APQP is the right fit, send the drawing set and the approval package you expect through the quote form.
Frequently asked
Is APQP the same as PPAP?
No. APQP is the planning process for the whole launch; PPAP is the approval package submitted near the end of it, in the validation phase. You can ask for a lite APQP without a full PPAP.
Does APQP require IATF 16949?
IATF 16949 automotive quality systems expect APQP, but the method itself can be used by any supplier. Outside automotive, it is a planning discipline, not a certification.
What is phase 0 in APQP?
Some newer descriptions add a preparation step before phase 1 for sourcing decisions, feasibility and team formation. For a small-batch part, that is the RFQ and the supplier selection itself.
How long does a lite APQP take?
It depends on the part and on how complete the drawing is. The drawing review and first article set the pace, so a clean drawing with marked critical characteristics is the fastest route.
Do I need a DFMEA from the machining supplier?
Usually not. A DFMEA belongs to whoever owns the design. The supplier’s contribution is the drawing review and, if you ask for it, a process risk review.
Sources
- Advanced Product Quality Planning, 3rd edition (APQP-3), AIAG, 2024
- Control Plan, 1st edition (CP-1), AIAG, 2024
- Understanding Advanced Product Quality Planning (APQP), Smithers, 2020
- AS9145, Requirements for Advanced Product Quality Planning and Production Part Approval Process, SAE International, 2016
- AS9102C, First Article Inspection Requirements, SAE International, 2023
- EN 10204:2004, Metallic products: Types of inspection documents, EVS, 2004