Quality assurance
Seven checkpoints. Zero folklore.
Quality systems fail in the gaps between documents. Ours is built as a chain of measured hand-offs — each step records a number, and the last number is published where you can read it.
Raw glass verification
Each incoming tubing lot is sampled for coefficient of expansion (dilatometry) and hydrolytic resistance (ISO 719 grain test). Lots outside borosilicate 3.3 limits are rejected before they touch the shop floor — about 2 % are.
Control limit
COE 3.3 ±0.1 ×10⁻⁶/K · HGB1
Dimensional gauging
Wall thickness, concentricity and outer diameter checked against pattern drawings with digital gauges at forming stations. Ground joints are lapped, then gauged against master cones and sockets.
Control limit
Joint gauge fit ≤ 0.05 mm
Annealing verification
Every lehr run is temperature-logged through the 570 °C curve. Samples from each batch pass between crossed polarisers, where residual stress appears as birefringent colour — visible proof the batch will not crack in your autoclave.
Control limit
Residual stress < 10 nm/cm path
Thermal shock sampling
Statistical samples cycle from 200 °C into 27 °C water. A single failure quarantines the production lot for 100 % re-inspection.
Control limit
ΔT 173 °C survival, AQL 0.65
Gravimetric calibration
Volumetric instruments are calibrated with distilled water on 5-figure balances in our NABL-accredited ISO/IEC 17025 laboratory at a controlled 27.0 ±0.5 °C, with air buoyancy correction applied.
Control limit
TUR ≥ 3:1 against class tolerance
Scale & marking durability
Enamel and stain graduations endure a 121 °C autoclave cycle series and an acid dip before a pattern is approved. Laser-scribed serials are permanent by construction.
Control limit
500-cycle legibility test
Serialisation & release
Class A instruments receive a laser-etched serial; the measured value, uncertainty, operator and balance ID are written to the public verification registry at the moment of QC release. Then — and only then — the instrument ships.
Control limit
100 % of Class A serialised