The delivery and acceptance of granite components is the "last checkpoint" to ensure precision performance. Whether it is used for precision measurement, engineering installation or decoration scenes, only through strict acceptance can transportation losses and quality problems be avoided. The following are the core acceptance conditions that must be met:
一. Zero defects in appearance: comprehensive inspection from surface to corners Integrity determination Illuminate the surface of the component with strong light to check whether there are cracks (even 0.5mm micro-cracks require rework) and corner chipping (allowable range: ≤0.3mm and non-working surface); There must be no embedded metal chips, sand and other impurities on the surface, and there must be no bulges when touched by hand (the working surface with a roughness of Ra≤0.63μm must be "mirror-grade" smooth).
Dimension and shape accuracy
Use a laser rangefinder (accuracy ±0.01mm) to measure length, width and height, and the error must be within the tolerance agreed in the contract (such as the size deviation of 00-level components ≤±0.02mm/m);
Use a level to detect flatness, with an error of ≤0.01mm per square meter (focus on the center and four corners) to ensure compliance with the design drawing requirements.
Marking and packaging specifications
The surface of the component must be clearly marked: model, specification, batch number (such as "JG-2023-058") for easy traceability;
The packaging must be protected by three layers of moisture-proof film + foam board + solid wooden box, with anti-collision corners at the four corners of the wooden box, and the box must be marked with "fragile" and "upward".
二. Physical performance meets the standards: 3 key tests are essential
| Test items | Acceptance Criteria | Detection tools | Unqualified judgment |
| hardness | Mohs hardness ≥ 6 (can scratch glass) | Mohs hardness pen | Lower than level 6 (easy to wear, affecting service life) |
| Water absorption | ≤0.13% (24-hour immersion test) | Electronic balance + measuring cup | Exceeding the standard (easy to absorb water and deform, especially when used in a humid environment) |
| Thermal stability | "-20℃ to 60℃ cycle test without cracks | High and low temperature test chamber | Micro cracks or dimensional deviation exceeding 0.03mm after temperature changes |
三. Compliance documents: Indispensable "quality certificates"
List of required documents:
Material certificate (including stone origin and density test report, such as "Jinan Qing" density must be ≥2.97g/cm³);
Precision test report (issued by a third-party agency, including flatness, verticality and other data);
Factory certificate (with the manufacturer's seal, indicating "in compliance with GB/T 20428 standard").
All documents must be copied and archived, and the originals must be shipped with the goods to avoid quality disputes in the future.
四. Transportation protection: safety guarantee from loading to unloading
Packaging strength test
Simulated transportation bumps: The wooden box is tilted at an angle of 30° and shaken 10 times, and the internal components have no displacement and no collision sound;
Moisture-proof requirements: A humidity indicator card (≤40%) is placed in the box, and 200g of desiccant is attached (double for coastal transportation).
Transportation insurance and contingency plan
Full freight insurance (insurance ≥ 120% of the cargo value) must be purchased, and the insurance policy must state "granite component crushing insurance";
Attach a transportation route map to avoid bumpy sections (such as mountain roads and construction sections), and reserve emergency contact information (24-hour response).
五. Customer special requirements: customized project special acceptance
If the customer requires "anti-corrosion treatment", the surface acid and alkali resistance must be tested (5% hydrochloric acid immersion for 24 hours without discoloration);
For components with mounting holes, the hole diameter tolerance must be checked with a plug gauge (such as the allowable deviation of Φ10mm hole + 0.01mm/-0mm) to ensure that it matches the bolt.
VI. Acceptance report: "quality contract" signed by both parties
The report must record in detail: test data, unqualified items and processing results (such as the time for the second acceptance after rework);
The acceptance personnel and the manufacturer's representative jointly sign and confirm, clarifying the conclusion of "acceptance qualified" or "temporary non-delivery" to avoid unclear responsibilities.
Whether it is the purchaser or the manufacturer, strictly implementing the above acceptance conditions can minimize the quality risk of granite components. Especially for components used for precision measurement, any failure to meet the standards may lead to subsequent measurement errors and affect the accuracy of the entire project. A little more carefulness before delivery will reduce trouble after receiving the goods.