Establishing who you are actually buying from
Every meaningful audit question depends on this one, and it is the question most rarely asked directly. The word “supplier” covers at least four very different entities in magnet supply.
| Entity | Can provide | Cannot provide | How to identify |
|---|---|---|---|
| Manufacturer (mill) | Process control, root cause analysis, capability data, tooling, requalification | Usually not: small quantities, domestic stock, credit terms, fast response across time zones | Owns furnaces; can describe its own sintering and plating lines in detail |
| Technical distributor | Domestic stock, engineering support, mill selection, duty-paid pricing, corrective action management | Not direct process control — it flows through the mill relationship | Holds inventory, employs engineers, names its mills, has its own quality system |
| Trading company | Price, and access to capacity | Engineering judgement, reliable traceability, meaningful corrective action | No stock, no technical staff, no named mill, margins that seem impossible |
| Catalogue reseller | Fast small-quantity fulfilment | Lot traceability, per-lot certification, custom capability | Sells by web catalogue; grade stated without certification |
The specific failure this prevents
A quality event occurs. You raise a corrective action request. If your supplier is a trading company, the request travels to a mill it does not control, arrives translated and incomplete, and returns three weeks later as a paragraph asserting the parts were fine. Nothing about your process improves and the same failure recurs. Corrective action capability is the single most important thing you are buying and the hardest to assess from a quotation.
Which standard the application actually requires
Requiring a certification the application does not need narrows your supply base and adds cost to every part for the life of the program. Requiring one it does need and discovering the gap late is worse.
| Your application | Minimum | Preferred | Why |
|---|---|---|---|
| General industrial | ISO 9001 | ISO 9001 | Documented process control and corrective action is the whole requirement |
| Automotive, Tier 2 or below | ISO 9001 | IATF 16949 | PPAP and control plan discipline flows down even where certification is not mandated |
| Automotive, direct to OEM | IATF 16949 | IATF 16949 | Contractual requirement in almost all cases |
| Aerospace | AS9100 | AS9100 + AS9102 FAI capability | Configuration management and counterfeit prevention are the differentiators |
| Medical device component | ISO 9001 | ISO 13485 | Depends on device class and whether the magnet is patient-contacting |
| Consumer product | ISO 9001 | ISO 9001 + substance testing | Compliance risk is chemical, not dimensional |
Detail on what each standard contains, and on the difference between a system certificate and a product document, is in certificates and compliance documents explained. Two cautions worth repeating here:
- Read the scope statement and the site address. A certificate covering “distribution and warehousing” does not cover manufacturing, and a manufacturer certified at one plant may build your parts at another. Confirm the certified site is the site making your part.
- Verify the certificate is live. Most accreditation bodies publish searchable registers. Expired and withdrawn certificates circulate as PDFs for years.
Flowing a standard down does not transfer the obligation
Requiring IATF 16949 of your magnet supplier does not discharge your own obligation to control the part. The standard makes a supplier more likely to catch problems; it does not make your receiving plan unnecessary. Certification and verification are complementary — see incoming inspection and acceptance planning.
The magnet-specific audit checklist
A generic supplier audit template will pass a mill that cannot control the things that matter for magnets. These are the process control points specific to sintered permanent magnet manufacturing.
Incoming material and traceability
- Alloy lot identity is maintained from receipt through to finished part. Ask to trace a finished lot backwards to its alloy lot on the spot, using their records rather than a prepared example.
- Incoming alloy composition is verified, not merely accepted on the supplier’s certificate.
- Heavy rare earth content is documented — the composition data that determines both grade conformity and export licensing status.
Pressing, sintering and ageing
- Alignment field strength during pressing is monitored and recorded. This sets the degree of grain orientation and therefore the achievable Br. It is a genuine process variable that weak operations do not control.
- Furnace profiles are recorded per cycle with charts retained and traceable to lots. Ask to see last month’s, not a demonstration.
- Furnace calibration and thermocouple verification on a defined schedule.
- Lot segregation through the furnace — how do they prevent commingling between customers and grades in a shared cycle?
Machining
- Diamond wheel condition and dressing schedule, and how dimensional drift from wheel wear is detected between setups.
- In-process dimensional checks with recorded frequency, not end-of-run inspection only.
- Chip and crack control against a defined workmanship standard with retained boundary samples.
- Swarf handling. Neodymium fines are pyrophoric; how this is managed tells you a great deal about the operation’s general discipline.
Coating
- Bath chemistry monitoring frequency and records — plating quality is bath chemistry, and this is where corner-cutting is most common and least visible.
- Thickness verification per layer by XRF, with sampling frequency defined, not total thickness only.
- Adhesion and corrosion qualification testing with retained reports, and the trigger for requalification after a process change.
- Edge coverage control. Edges are where coatings thin and corrosion initiates.
Magnetizing and measurement
- Magnetizer field verification schedule. A capacitor-discharge magnetizer whose output has drifted produces parts that look perfect and measure low.
- Saturation verification method — how do they demonstrate that parts are fully saturated rather than merely magnetized?
- Fixture control for multipole and radial patterns, including identification, storage and periodic verification.
- Measurement laboratory: hysteresisgraph, helmholtz coil and fluxmeter present and calibrated, with traceable calibration certificates and a gauge R&R on the flux measurement system.
- Temperature control in the measurement area. Remanence drifts roughly −0.12%/°C, so an uncontrolled measurement room is a source of unexplained variation.
The three requests that reveal the most
- “Trace this finished lot back to its alloy lot.” Live, on their system. Speed and confidence tell you whether traceability is real or reconstructed on demand.
- “Show me a nonconformance from the last six months and its corrective action.” A supplier with no recorded nonconformances is not a perfect supplier; it is a supplier that does not record them.
- “Show me the calibration certificate for the fluxmeter.” If magnetic measurement equipment is uncalibrated, every magnetic number you have ever received from them is unsupported.
Red flags
| Observation | What it usually indicates | Severity |
|---|---|---|
| Cannot or will not name the manufacturing facility | Re-selling without supply chain control | High |
| Certificates show values identical to the published datasheet | Datasheet reproduced as a certificate; no per-lot measurement | High |
| No lot number linking certificate to packaging | Traceability does not exist in practice | High |
| Price materially below the market including duty | Grade substitution, origin misdeclaration, or both | High |
| No magnetic measurement equipment on site | Cannot verify its own product | High |
| Quality manual is generic and unmarked by use | Certification obtained for the certificate | Medium |
| Furnace charts not retained or not traceable to lots | Process control is not evidenced | Medium |
| Zero recorded nonconformances | Problems are handled informally and never analysed | Medium |
| Reluctance to discuss which grades carry Dy or Tb | Composition not tracked; licensing exposure unknown | Medium |
| Certificate scope excludes the process making your part | Certification is real but irrelevant to you | Medium |
| Cannot describe its own change notification process | Silent process changes will reach you | Medium |
Price below the market is a finding, not a win
Magnet cost is dominated by rare earth content, and no supplier has privileged access to cheaper neodymium. A quote materially below others for the same specification is explained by something: a lower grade than stated, a thinner coating than specified, an origin declaration that will not survive scrutiny, or parts that are not fully saturated. All four are invisible at receiving unless you are testing for them, and all four surface later at your cost. If a price is inexplicable, the correct response is to ask for the explanation.
Conducting the audit proportionately
Not every part warrants an on-site visit to a mill on another continent. Match the depth of assessment to what failure would cost.
| Method | Effort | Establishes | Appropriate for |
|---|---|---|---|
| Document review | Hours | Certification validity and scope, sample certificates, financial standing | Catalogue and low-risk purchases |
| Self-assessment questionnaire | 1–2 weeks | Declared capability; a baseline to verify later | New suppliers of non-critical parts |
| Remote audit | Half a day | Live records, live traceability exercise, facility walkthrough by video | Most industrial programs — the practical default |
| On-site audit | 1–2 days plus travel | Actual practice, housekeeping, operator competence, the things a camera does not show | Qualified programs, high volume, safety-relevant parts |
| Second-party audit via your distributor | Low for you | Mill assessment performed by a party with leverage and language capability | Buyers without the resource to audit an overseas mill directly |
The underused option
A technical distributor that already audits its mills, holds domestic stock and carries the corrective action relationship gives you most of the benefit of a mill audit without the travel, the language barrier or the leverage problem — a mill that ships a container a week to a distributor will respond to that distributor faster than to a customer buying a pallet a quarter. Ask your distributor for its own mill audit records; a supplier that performs them will share them.
Managing the approved supplier list
- Approve to a scope, not in general — by material, process, grade range and part family. A mill excellent at sintered blocks may have no radial magnetizing capability at all.
- Re-assess on a defined cycle, typically annually for critical suppliers, with the cycle shortened by performance rather than lengthened by familiarity.
- Trigger re-assessment on change — new site, ownership change, process change, or a significant nonconformance.
- Track performance objectively: on-time delivery, lot acceptance rate, corrective action response time, documentation completeness. Perception drifts; data does not.
- Keep the second source warm. An approved supplier that has not shipped in two years is an entry on a list, not a supply option — the mechanics are in the second-source playbook.