Factory assessment and audit of Indian manufacturers for international buyers: what to check, when, and with what

TCR Engineering, a Navi Mumbai inspection and testing company founded in 1973, carries out factory assessments and stage inspections of Indian manufacturers for international buyers, anywhere in India. The work runs in four stages, from vendor assessment before the order to final inspection before shipment, under TCR's documented third-party inspection system. Laboratory tests are performed under NABL certificate NABLT0726MH18640.

• Who it is for: a buyer outside India who is about to place, or has placed, an order with an Indian manufacturer and cannot be at the works for every stage.
• The four stages: vendor assessment (factory audit) before the order; incoming material inspection before machining; in-process inspection before assembly; final inspection before packing and shipment.
• Report conclusions: Recommended, Recommended with Conditions or Not Recommended for the assessment; PASS, FAIL or PASS SUBJECT TO CORRECTIVE ACTION for the final inspection.
• Report clock: an audit report within 2 working days of the visit, a flash report within 4 working hours, and a non-conformance report the same day.
• Coverage: supplier works across India, under TCR's third-party inspection manual TCR/TPI/M-01.
• Accreditation position: the Mahape laboratory is NABL accredited under certificate NABLT0726MH18640 for tests in its own laboratories. TCR Engineering is not accredited as an inspection body under ISO/IEC 17020, and its works measurements are reported as works measurements.

The question a buyer is really asking

A buyer in Hamburg, Houston or Johannesburg who has found a capable-looking manufacturer in India has three worries, in this order. Is the company real and able to make this part? Will it make my part the way my drawing says? Will what arrives in my port be what I paid for? A brochure, a video call and a sample sent by courier answer none of them, because none of them shows the buyer the measuring room, the material store or the machine that will actually cut the order.

Third-party inspection answers them with an independent person at the works at the moments that matter, reporting what was seen, measured and witnessed against the buyer's own documents. The value is not the visit. It is choosing the right moments, and measuring in a way that will stand up if the result is disputed.

Four stages, and what each one checks

Each stage is triggered by the manufacturer's written notification, with the date confirmed by the buyer, so that an inspector does not reach the works to find the job not ready. Three working days' notice is enough to plan travel for most locations in India.

The factory assessment ends in one of three words, and the buyer should insist on one of them. A report that lists observations and stops short of a conclusion leaves the decision exactly where it was. "Recommended with Conditions" is the most useful outcome in practice: it names what the manufacturer must put right, a calibration overdue, a material certificate chain that breaks at the stockist, before the buyer commits.

The stage most buyers get wrong

Asked when to inspect during production, most buyers pick a date halfway through. For precision mechanical equipment the right moment is fixed by the process, not the calendar: after the critical parts are finish-machined, heat-treated and ground, and before they are assembled.

That is the last point at which every tight-tolerance feature, every hardness value and the runout of each individual component can be measured directly, and the last point at which an error can be corrected by regrinding or replacing one part. Once the unit is assembled, those features are either hidden or can only be measured through the assembly, and a fault found then costs a strip-down instead of a single part.

Proving a micron tolerance at someone else's works

Precision orders often carry features toleranced at ±0.005 mm, a band only 10 micrometres wide. No hand-held instrument carried to a factory can prove conformity to that band on its own. Temperature alone can use it up: steel grows by roughly 12 micrometres per metre for every degree Celsius, so a 200 mm part measured at 24 °C instead of 20 °C reads close to 10 micrometres large. ISO 1:2022, the standard on the reference temperature for geometrical product specification, fixes that reference at 20 °C.

The method that holds up has four parts:

1. The manufacturer's own coordinate measuring machine or precision comparator, in its temperature-controlled room, with the room and part temperature recorded against every measurement and the part soaked to temperature first.
2. TCR's inspector witnesses the measurement and checks the machine on the day against a calibrated gauge block brought by TCR, traceable to national standards, before and after the series.
3. A stated decision rule. Conformity is decided to ISO 14253-1:2017, the GPS standard on decision rules for verifying conformity or nonconformity with specifications, so a result that sits within the measurement uncertainty of a limit is reported as exactly that, and the decision on it stays with the buyer.
4. TCR's own portable instruments for the checks that do not need a measuring room: a portable hardness tester and a surface roughness tester travel with the inspector.

The assessment in stage 1 therefore tells the buyer something more valuable than "the factory looks good": whether the manufacturer's measuring room and its machine are fit to prove the tolerances on this drawing. If they are not, no amount of later inspection will make the parts conform.

Shailendra Singh heads non-destructive testing and third-party inspection at TCR Engineering and coordinates the firm's inspection assignments across India.

Tests that add assurance beyond the visit

An inspector at the works sees the surface. For critical parts, four additions turn an inspection into evidence:

• Positive material identification of the steel at stage 2, so the grade is checked on the metal and not only on the certificate. The laboratory side of this sits in chemical analysis.
• Magnetic particle testing of heat-treated and ground parts at stage 3, followed by demagnetisation, to find grinding cracks that are invisible to the eye and open in service. TCR runs it as part of conventional NDT.
• A heat-treatment witness coupon from the same batch as the parts, sealed by TCR's inspector and hardness-tested in TCR's NABL-accredited laboratory, so that hardness is proven without indenting a finished cutting edge. See mechanical testing.
• A first-article check of one tight-tolerance feature before the full run, where the assessment shows the manufacturer has not made parts to this tolerance before.

Where an order calls for sampling rather than checking every piece, TCR samples to ISO 2859-1, the attribute sampling scheme indexed by acceptance quality limit, at the plan the buyer specifies.

What the report promises, and what it does not

TCR Engineering acts as an independent third party with no commercial interest in the manufacturer. Its reports record what the inspector verified, measured and witnessed, at the place and time stated, against the buyer's approved documents. A satisfactory report is independent evidence that the items inspected met the drawing and the inspection plan at that stage.

It is not a transfer of the manufacturer's obligations. Responsibility for design, workmanship, warranty and conformity stays with the manufacturer under the purchase contract, and the report is not a certificate of conformity for items that were not inspected. Measurements taken at the works are reported as works measurements, not as accredited test results; results from samples tested in TCR's own laboratory carry the NABL position of each test.

A buyer comparing inspection agencies should read that boundary carefully in every proposal. An agency that promises more than it measured is selling a sentence, not assurance.

What a buyer should send before the first visit

1. Approved drawings, with the features that carry the tightest tolerances identified.
2. The bill of materials, material specifications, and heat-treatment and hardness requirements.
3. The approved inspection and test plan, with acceptance values for dimensions, runout, alignment and any functional test.
4. Functional or trial-run details, including test material, who supplies it, and what counts as acceptable.
5. Export packing requirements.
6. The purchase order, or its technical part, so the inspection is against the revision actually agreed.
7. A short letter from the buyer to the manufacturer naming TCR as the inspection agency, so access and the notification procedure are settled before the first visit.

With those in hand, the vendor assessment can usually be fixed within days of confirmation, subject to the manufacturer's agreement to the date. For buyers sourcing castings, forgings, pipes and valves, the same discipline applies to source inspection, and the post on third-party inspection services in India sets out the wider service line.

This article was written and edited by the TCR Newsroom, the editorial desk of the TCR group, covering materials testing, inspection and asset integrity work across TCR’s laboratories in India and Saudi Arabia and its alliances in Qatar, Japan and beyond.