How to judge whether the quality of imported paper machinery spare parts is reliable?

To judge whether the quality of imported spare parts for papermaking machinery is reliable, we need multi-dimensional comprehensive evaluation such as channel traceability, physical verification, technical parameter matching, qualification document verification, etc., combined with the particularity of spare parts in papermaking industry (such as high wear resistance, corrosion resistance and high precision requirements), the specific methods are as follows:

I. Check the qualification of suppliers and the legitimacy of channels

Confirm the regularity of channels

Direct supply from the original factory or authorized agent: give priority to the domestic branches or official authorized agents of equipment manufacturers (such as Weimeide, Voith, Metso, etc.), and require the original power of attorney (including the scope of authorization and the validity period, which can be verified by the original factory in official website).

Qualification examination of traders: If the goods are purchased by a third-party import trader, it is necessary to check its business license (business scope includes "import of machinery, equipment and accessories"), past import cases (such as customs declaration of similar paper spare parts) and cooperation certificates with overseas suppliers (such as agency agreements) to avoid purchasing from unqualified "parallel importers" or middlemen (there may be risks of refurbished parts and assembled parts).

Beware of "counterfeit trap": For high-value spare parts (such as refiner blades, hydraulic valve groups and control system modules), you can directly contact the original equipment factory, provide supplier information and spare parts number, and the original factory will confirm whether it is produced or authorized to supply.

Verification of import compliance documents

The supplier is required to provide a complete customs clearance documents, including:

Certificate of origin (to prove that the spare parts are produced in the country where the brand belongs, such as Germany and Finland, etc., so as to avoid "OEM domestic" pretending to be imported);

Import declaration form (check commodity name, model, country of origin and importer information to ensure consistency with the purchase contract);

Commercial invoice and packing list (corresponding to the physical model and quantity, and the invoice amount is consistent with the customs declaration, so as to avoid the quality risk caused by underreporting).

Second, physical quality detection and parameter matching

Appearance and logo inspection

Brand identification: Original spare parts usually have clear brand logo, lettering of model and production batch number (such as laser marking, the font is neat and not easy to wear), and the logo of counterfeit parts may be vague, easy to fall off or the font is not standardized.

Material and technology:

Metal parts (such as blades and bearing seats): check whether the surface is smooth, crack-free, rust-free, and the edges are burr-free (the dimensions can be measured by calipers, and the comparison error with the drawings is within the allowable range, such as ±0.02mm);

Seals (such as rubber sealing rings): observe whether there is aging, hardening, bubbles and good elasticity (it can rebound quickly after being pressed by hand);

Electrical components (such as sensors and motors): check whether the terminal is firm, whether the shell is damaged, and whether the parameters such as voltage and power on the label are consistent with the equipment requirements.

Technical parameters and adaptability verification

Check the key parameters of spare parts against the equipment manual or original factory drawings:

Mechanical parts: such as inner diameter/outer diameter/width of bearings, tolerance grade (such as P5 precision), module, number of teeth and tooth profile of gears;

Wear-resistant parts: for example, the material hardness (above HRC55) and tooth angle (consistent with the original parts, otherwise the pulping concentration may be unstable) of the refiner's grinding disc;

Hydraulic/pneumatic components: such as cylinder diameter, stroke and working pressure of the oil cylinder (matching with system pressure to avoid cylinder explosion).

For precision components (such as servo motors and PLC modules), it is possible to connect test equipment to run with electricity, and check whether it responds normally (such as whether the motor speed is stable and whether the modules can communicate normally).

Third-party inspection (for high-risk spare parts)

For bulk purchase or high-value spare parts (such as imported stainless steel filter screen and alloy cutter), samples can be taken and entrusted to professional testing institutions (such as SGS and National Paper Machinery Quality Supervision and Inspection Center) for testing:

Material composition analysis (such as whether it is 304 stainless steel, high-speed steel and other designated materials through spectrometer detection);

Performance test (such as hardness test of blade, temperature and pressure resistance test of seal, no-load current test of motor).

Third, quality assurance and after-sales verification

Warranty clause and after-sales commitment

Require the supplier to specify the warranty period: original spare parts usually provide 6-12 months warranty (some core components such as motors can reach 18 months), while OEM parts or replacement parts have a shorter warranty period (3-6 months), so it is necessary to indicate in the contract that "replacement is free in case of non-human damage".

After-sales support ability: Ask the supplier whether they can provide technical services (such as installation guidance and troubleshooting). For complex spare parts (such as control system modules), it is necessary to confirm whether they can contact the original factory technicians to assist in debugging remotely.

Refer to industry word-of-mouth and cases

Consult peer enterprises (such as paper mills with the same equipment model) to find out their feedback (such as service life and failure rate) on purchasing spare parts of this brand;

Check the customer evaluation of suppliers (such as industry forums and cooperation case lists), and give priority to suppliers with cooperation experience in large paper enterprises (such as spare parts suppliers who have cooperated with groups such as Nine Dragons and Liwen).

Four, long-term use verification (auxiliary judgment)

For the installed spare parts, the quality can be judged by monitoring the operation data, such as the running temperature of the bearing (normally ≤70℃, and the abnormal temperature rise may be due to insufficient accuracy or material problems), the wear speed of the blade (compared with historical data, if excessive wear occurs in a short time, the material may not meet the standard), and the stability of the electrical components (such as whether the sensor signal fluctuates frequently).

Through the above steps, the risk of inferior imported spare parts can be avoided from the source, the purchased spare parts can be ensured to adapt to the equipment and have reliable performance, and finally the equipment downtime loss and maintenance cost can be reduced.