You have ordered a granite surface plate, the delivery arrives, and with it comes an inspection report. What should that report contain, what do the numbers mean, and how do you judge whether the document is enough for your quality system? Instead of repeating that granite is stable and precise, this article walks through an actual (anonymized) report field by field, so purchasing and quality teams can check deliveries against their own requirements.
A sample report, field by field
The sample above shows the structure of the report we ship with our plates. Each field answers a specific question:
- Part number and dimensions tie the report to your order and drawing revision - a report without a revision reference cannot be audited later.
- The standard and its version (for example GB/T 20428 or ISO 8512-2, with the grade) define which limit values apply. A "Grade 0" claim without the standard citation is not checkable.
- Date and environment (typically 20 +/- 0.5 C) matter because granite readings drift with temperature gradients; a report measured on an unconditioned shop floor is not comparable with one from a controlled lab.
- Measurement points, lines or the evaluation range show how flatness was actually assessed - a 5 x 4 grid with a least-squares plane is a common arrangement, and the sample states it explicitly.
- Results with limits and a clear PASS/FAIL statement are the core: a number without its limit and judgement basis forces the reader to guess.
- Instrument and calibration information provides the traceability link - which instrument, with a valid calibration from an accredited laboratory.
"The instrument has a calibration certificate - what else do I need?"
This is the most frequent question from buyers. The distinction: a calibration certificate proves the measuring instrument is traceable; it says nothing about your plate. For the product itself you need the product-specific inspection report (flatness and any geometric items against the agreed limits), plus the instrument's certificate referenced inside it. For periodic re-verification of plates in service, laboratories usually follow their own calibration procedure and schedule - the delivery report is the baseline that later measurements are compared against.
Documents to agree on before ordering
Before placing the order, confirm with the supplier which documents will be delivered: the inspection report and its format (our template or yours), the standard and grade applied, whether a flatness map is included or only a summary value, the calibration status of the measuring instruments, and whether third-party or customer-witnessed inspection is required. Agreeing the document list at quotation stage is what makes acceptance at your site uneventful.
You can see typical applications of our plates and tools on the granite measuring instruments page, and if you are still selecting the plate itself, our guide on how to choose a precision granite surface plate for metrology applications covers sizes, grades and support in more depth.
Being able to show a checkable report is worth more than any claim of nanometer precision - the report is the part of the delivery you can verify. When you request a quotation for a granite surface plate inspection report package, tell us which standard, which acceptance items and which report format your quality system requires, and we will confirm them in the quotation.