The appearance of orange peel wrinkles (irregular bumpy textures resembling orange peel) in the coating film during the spraying process is usually related to paint leveling properties, spraying technique, or environmental conditions. The following are common causes and improvement methods:

I. Analysis of Main Causes

1. Excessive Paint ViscosityHigh viscosity leads to poor paint atomization, preventing even leveling after application.

2. Improper Spraying ParametersInsufficient spray gun pressure, incorrect spraying distance (too far or too close), or uneven movement speed.

3. Abnormal Ambient Temperature/HumidityExcessively high temperature (causing solvents to evaporate too quickly) or high humidity (moisture interference) results in poor leveling.

4. Excessively Thick or Thin CoatingWhen a single coat is too thick, solvents on the surface evaporate rapidly while underlying solvents remain, causing uneven shrinkage.

5. Unsuitable Substrate TemperatureSubstrate temperature is too high (accelerating evaporation) or too low (delaying leveling).

6. Improper Thinner SelectionThe thinner’s evaporation rate is mismatched with the spraying environment (e.g., using fast-drying thinner in high temperatures).

7. Poor Spray Gun AtomizationWorn nozzle, excessive paint flow, or clogged air cap.

II. Improvement Methods

1. Adjust Paint ConditionReduce Viscosity: Add dedicated thinner in the correct ratio to ensure paint viscosity meets technical requirements (test with a viscosity cup).

a. Filter Paint: Remove impurities or undispersed particles from the paint to prevent clogging the spray gun.

2. Optimize Spraying ProcessAdjust Spray Gun Parameters:Air Pressure: Increase pressure to improve atomization (typically recommended 0.3~0.5 MPa).

i. Spraying Distance: Maintain 15~25 cm, moving the gun vertically at a constant speed.

ii. Spraying Speed: Avoid irregular speed; ensure even coverage.

b. Apply Multiple Thin Coats: Use a “thin coats, multiple passes” method, controlling the interval between coats according to the paint’s surface drying time.

3. Control Environmental ConditionsTemperature: Control ambient temperature between 20~25°C (avoid direct sunlight or cold drafts).

a. Humidity: Maintain relative humidity below 60%~70% (pause operations if humidity is too high).

b. Ventilation: Ensure uniform solvent evaporation, but avoid strong air currents disturbing coating leveling.

4. Substrate Pre-treatmentClean the substrate surface of oil, dust, and other contaminants.

a. Control Substrate Temperature: Pre-cool in summer; pre-warm to 15~30°C in winter.

5. Select Appropriate ThinnerChoose a thinner with a matching evaporation rate based on ambient temperature: High-Temperature Environments: Use slow-drying thinner to extend leveling time.

i. Low-Temperature Environments: Use fast-drying thinner to prevent sagging.

6. Spray Gun Maintenance & AdjustmentRegularly clean the nozzle and air cap; replace worn parts.

a. Test Atomization: Conduct a test spray before starting to check for uniform paint atomization.

7. Use of AdditivesAdd leveling agents (e.g., silicone or fluorocarbon-based) to improve paint leveling.

a. Add slow-evaporating solvents (e.g., ethylene glycol monobutyl ether) to delay surface drying.

III. Quick Troubleshooting Procedure

1. Check spraying equipment parameters (pressure, spray distance, movement speed).

2. Test paint viscosity and adjust the dilution ratio.

3. Monitor ambient temperature and humidity; pause operations if necessary.

4. Conduct a small-area test spray to verify improvement before full-scale operation.

Systematic adjustment of process parameters and environmental conditions can significantly improve the orange peel issue. If the problem persists, contact the paint supplier to analyze formula compatibility.