Sourcing glass diffraction gratings from China

UK duty on unmounted glass diffraction gratings

Heading 9001 covers unmounted optical elements, excluding glass elements that are not optically worked. For an unmounted, optically worked glass diffraction grating, the relevant residual line is 9001 90 00 90. The supplied tariff facts contain only this relevant commodity line, so the table shows it without adding unrelated products.

Read from the UK Trade Tariff on 30 September 2026, the duty for goods from China under this line is 0%. The supplied record lists no anti-dumping or countervailing duty, suspension or attached import control for this line. Import VAT is separate from customs duty; see import duty and VAT.

Confirm the commodity code using the substrate, optical processing, drawings and mounting condition. Describe a loose grating separately from a complete optical instrument. For the wider family of unmounted optical elements, see the unmounted optical prisms guide.

Specify the grooves and optical test conditions

Specify transmission or reflection operation, ruled or holographic construction, glass substrate, dimensions, thickness, clear aperture and groove direction. State groove density, working wavelength range, diffraction order, blaze wavelength where applicable, coating and acceptable surface defects. Include drawings showing the usable area and any orientation mark outside it.

Agree how diffraction efficiency will be measured, including wavelength, incidence angle, polarisation and diffraction order. Request batch results against these conditions and approve a sample in the intended optical arrangement. Specify individual packing that prevents contact with the grating surface.

If the gratings are supplied as consumer products in the UK, the importer is responsible for consumer safety and applicable labelling requirements. Establish the intended buyer and use before preparing sales information.

Worked duty example

Illustrative example, not a quote: Illustrative laboratory replenishment batch of unmounted glass diffraction gratings under 9001 90 00 90, invoiced at £2,000 free on board, with £800 of freight and insurance to the UK. The customs value is £2,800. Duty at 0% is £0. Import VAT at 20% is charged on the customs value plus duty, £2,800, so it is £560. With no duty, the only import tax is the VAT, which a VAT-registered importer can usually reclaim. The import duty and VAT guide explains each step.

Inspection checklist

Identity: check substrate, grating type, groove direction and batch labels against the order.

Geometry: measure dimensions and thickness, and check the clear aperture and edge condition against the drawing.

Optical performance: test groove density and diffraction efficiency under the agreed conditions; check unwanted scattered light in the intended arrangement.

Surface and packing: inspect for scratches, contamination, coating damage and chips without touching the active surface. Check that each grating remains secure in its protective pack. Agree these checks in the inspection brief.

What goes wrong

A grating can match the ordered dimensions yet give poor throughput because its efficiency was quoted at a different wavelength, angle or polarisation. Confusing transmission and reflection types, or reversing groove orientation, can also make the part unsuitable. Tie acceptance to the agreed optical test conditions.

Fingerprints, cleaning residue and scratched grooves can increase scattered light. Loose packing can chip edges or rub the active surface. Agree handling and cleaning instructions with the supplier, inspect arrival condition before cleaning, and retain photographs and batch results when investigating a fault.

Cambridge China Bridge sources these products for UK businesses, checking the factory and the documents before shipment. See factory verification. For components and parts, see sourcing for manufacturers.