Will the quality of imported spare parts for papermaking machinery be affected by transportation and storage conditions?

The quality of imported spare parts of papermaking machinery will be significantly affected by the transportation and storage conditions, especially the precision mechanical parts, electrical components and vulnerable materials (such as seals and alloy knives) contained in the spare parts of papermaking, which have strict requirements on environmental temperature and humidity, vibration impact and protective measures. The specific impacts and reasons are as follows:

First, the influence of transportation conditions on the quality of spare parts

Vibration, impact, temperature and humidity fluctuation and improper protection during transportation may directly lead to physical damage or performance deterioration of spare parts. Common scenarios include:

Mechanical spare parts: structural damage and accuracy failure

Precision parts (such as bearings, gears, refiner blades):

If it is not firmly fixed during transportation (such as no customized tray and no cushioning material), the metal surface may be scratched and deformed due to bumps and collisions, and even the bearing ball will fall off and the gear tooth surface will crack;

If high-precision components (such as bearings with tolerance level P5) are subjected to severe vibration, the internal clearance may become larger, abnormal sound and heat will occur during operation after installation, and the service life will be shortened.

Large parts (such as press roller and motor housing):

When transported in the open air without cover, rain and seawater (when transported by sea) may cause corrosion on the metal surface, especially on the cast iron parts that have not been rusted, which will destroy the matching accuracy (for example, the diameter of the roller body becomes larger and it cannot be installed normally).

Electrical spare parts: functional failure and short circuit risk

Control module (such as PLC, sensor, servo driver):

If there are insufficient moisture-proof measures during transportation (such as not being sealed in anti-static packaging bags and not placing desiccant), high-humidity environment (such as condensation of shipping containers) will cause the circuit board to get wet, which may be short-circuited and burned after being electrified;

Lack of electrostatic protection (e.g., unused anti-electrostatic tray) may puncture electronic components (e.g., chips), resulting in "hidden damage" of spare parts (no abnormal appearance, but it cannot work normally after installation).

Cable spare parts (such as encoder cables and hydraulic hoses):

Excessive extrusion or bending may cause the internal wire core to break, the shielding layer to break, or the inner rubber of the hose to crack, resulting in signal transmission failure and hydraulic oil leakage after installation.

Spare parts of vulnerable materials: performance degradation

Seals (such as NBR sealing ring and fluororubber gasket):

High-temperature transportation environment (such as the temperature in the container exceeds 60℃ in summer) will accelerate the aging of rubber, leading to the decrease of elasticity and the increase of hardness, which can not be effectively sealed after installation, leading to slurry leakage and oil leakage;

Alloy knives (such as paper cutters and pulper blades):

If it comes into contact with acidic/alkaline substances (such as mixed chemicals) during transportation, corrosion may occur, which may lead to passivation of the cutting edge and decrease the cutting efficiency during use.

Second, the influence of storage conditions on the quality of spare parts

Temperature and humidity control, stacking mode and protective aging in storage stage will affect the performance stability of spare parts for a long time, especially spare parts stored for a long time:

Deterioration caused by improper temperature and humidity

High temperature and humidity environment:

Metal parts (such as stainless steel filter screen and bearing seat) are prone to electrochemical corrosion and rust spots appear on the surface;

The plastic shell of electrical spare parts may be deformed at high temperature, and the internal capacitance, resistance and other component parameters drift, resulting in the decline of control accuracy;

Wood or fiber spare parts (such as some pulp screening parts) will absorb moisture and become moldy, which will affect the structural strength.

Low temperature dry environment:

Rubber and plastic spare parts (such as sealing rings and hoses) will become brittle due to low temperature, and cracks may occur after long-term storage;

If the storage temperature of hydraulic oil, grease and other fluid spare parts is too low (such as below-10℃), it may solidify and delaminate, which will affect the fluidity when used.

Physical damage caused by improper stacking and protection.

Excessive stacking pressure: if heavy spare parts (such as rollers and motors) are stacked too high, the bottom spare parts may be deformed due to load bearing; If light precision components (such as valves and sensors) are squeezed by heavy objects, the shell may be broken and the internal parts may be displaced.

Lack of dustproof measures: Unsealed spare parts (such as gear box and pump body) are exposed to dust for a long time, and dust entering the interior will pollute the lubricating oil and wear the mating surface, which may lead to sticking failure after installation.

Expired shelf life: Some spare parts (such as sealant and adhesive) have a definite shelf life, which will lead to performance failure (such as sealant curing failure).

Third, how to avoid the impact of transportation and storage on quality?

Protective measures for transportation links

Require suppliers to use customized packaging: anti-static bag+foam buffer+wooden tray (with fixed buckle) for precision parts; Heavy parts are fixed with anti-skid pads and steel belts to avoid displacement during transportation;

Clarify the transportation environment requirements: spare parts sensitive to temperature and humidity (such as electrical modules and rubber parts) are required to be transported in constant temperature containers to avoid extreme temperatures; Extra waterproof film should be wrapped when shipping to prevent seawater erosion;

Inspection immediately after arrival: unpacking to check whether the package is damaged, whether the spare parts are scratched or deformed, testing the continuity of electrical components, and claiming compensation from suppliers in time when problems are found.

Management standard of storage link

Establish a special warehouse: divide areas to store different types of spare parts (such as mechanical parts, electrical parts and wearing parts), and equip them with a thermometer (keeping the temperature at 15-30℃ and humidity at 40%-60%), a dehumidifier and a dust cover;

Classified storage rules:

Metal parts: coated with antirust oil, wrapped with antirust paper, and periodically (every 3 months) check the antirust state;

Electrical spare parts: the original packaging is sealed and stored away from strong magnetic fields and corrosive gases (such as chlorine and ammonia);

Rubber/plastic parts: Avoid direct sunlight (to prevent ultraviolet aging), and store them separately on dry and ventilated shelves, and do not contact with organic solvents (such as gasoline and alcohol);

First-in, first-out principle: according to the arrival time, spare parts with short storage time are given priority to avoid performance degradation caused by long-term storage.

To sum up, the quality of imported spare parts of papermaking machinery is closely related to the transportation and storage conditions, and it needs to be strictly controlled from the aspects of packaging specifications, environmental control, acceptance management, etc., so as to ensure the best performance of spare parts during installation and use, and avoid hidden damage or shortened service life caused by external factors.