Specification builder · Tier A
Digital caliper and micrometer set with pin, bore and gauge-block references for dimensional testing of medical devices
A calibrated set of hand measuring tools - digital calipers, outside and tube micrometers, pin and bore gauges and a gauge block set - for measuring the dimensions of needles, cannulas, syringes, tubing and moulded parts. It is bought by drug and device testing laboratories, local disposable-device manufacturers, universities and procurement agencies checking supplies. Accuracy depends as much on the accredited calibration certificates and the reference gauges as on the tools themselves.
What this equipment will do
- Products and parts: needles and needle tubing, IV cannulas and catheters, syringe barrels and plungers, tubing and moulded plastic parts.
- Outside, inside, step and depth dimensions to 0.01 mm with digital calipers, for parts up to 150 mm (ISO 13385-1).
- Outside diameter and thickness to 0.001 mm with micrometers, 0 to 50 mm - for example needle tubing, cannula and catheter diameters (ISO 3611; needle tubing limits in ISO 9626).
- Wall thickness of catheters, tubing and cannula hubs with a ball or pin anvil micrometer.
- Inside diameter (bore) of needles, cannulas and small tubing from 0.30 to 1.50 mm, go/no-go with pin gauges (ISO 9626), and larger bores such as syringe barrels.
- In-house checks of the calipers and micrometers against the lab's own gauge blocks between external calibrations (ISO 3650).
- Direct reading of bores from 6 to 20 mm to 0.001 mm with a three-point bore gauge. (with the optional module)
- Wall thickness of narrow-bore tubing with a bore down to 2.5 mm, using a tube micrometer with pin anvil. (with the optional module)
- Outside diameters to 0.0001 mm with a high-accuracy micrometer, for reference work. (with the optional module)
- Grooves, narrow slots and small recesses with a point or blade micrometer. (with the optional module)
- Comparison of parts against gauge blocks with a digital indicator on a comparator stand. (with the optional module)
- Batch statistics (mean, range, SD, Cp/Cpk) and control charts of the readings. (with the optional module)
Not covered: Needle bores below about 0.3 mm, needle points, bevels and other very small features need the optical measuring microscope (non-contact).; Thickness of glove films, packaging films and foils at a defined presser-foot force needs the digital thickness gauge.; Outline profiles, angles and radii of small moulded parts need the profile projector or optical measuring microscope.; Fit and leakage of luer connectors need the luer connector test system (ISO 80369-20).
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Standards this specification draws on
- ISO 13385-1:2019 Defines the design and metrological characteristics of calipers, including how maximum permissible errors are stated and tested.
- ISO 3611:2023 Defines the design and metrological characteristics of micrometers for external measurements, including error of indication and face flatness/parallelism.
- ISO 3650:1998 Defines gauge block tolerance grades (K, 0, 1, 2) and requirements for the reference set.
- ISO/IEC 17025:2017 Competence standard for the laboratory issuing calibration certificates and for the testing lab using the tools.
- ISO 14978:2018 General concepts and requirements for GPS measuring equipment, including how makers must state metrological characteristics.
- ISO 14253-1:2017 Decision rules for proving conformity or non-conformity with a specification, taking measurement uncertainty into account.
- ISO 1:2022 Sets 20 deg C as the reference temperature for dimensional measurement.
- ISO 9626:2016 Specifies outside diameter and inside diameter limits of stainless steel needle tubing that the set is used to verify.
- IEC 61326-1:2020 EMC requirements for electronic measurement equipment; the relevant electrical conformity route for battery-powered digital tools (IEC 61010-1 basic safety does not apply to these low-voltage hand tools).
- IEC 60529 Defines IP codes (IP54, IP65, IP67) for protection of the tools against dust and liquids.
Common mistakes in tenders for this equipment
- Specifying only display resolution (0.01 mm or 0.001 mm) instead of maximum permissible error; resolution says nothing about accuracy, and cheap tools with good resolution can be wrong by several digits.
- Accepting copies of well-known tool brands bought from local markets; demand serial numbers confirmed by the manufacturer and check the tools against gauge blocks at acceptance.
- Accepting 'traceable' calibration certificates from non-accredited sources, or certificates checking only one point, with no measurement uncertainty or accreditation mark.
- Forgetting setting standards, optical flats, gauge block accessories and setting rings, so the 25-50 mm micrometer and bore gauges cannot be zeroed or checked in-house.
- Using calipers for needle diameters or thin walls; their error of +/-0.02 mm is larger than many needle tubing tolerances, so a micrometer, pin gauges or an optical microscope is needed.
- Copying one maker's exact ranges, IP code, encoder type, battery life and wireless system into the specification, which locks the tender to that maker.
- No budget for annual recalibration, so tools and gauge blocks fall out of calibration after the first year and results become indefensible.
- Ordering pin gauge sets that do not cover the needle and cannula bores actually tested, or expecting pins to measure fine-gauge needle bores below about 0.3 mm.