Hardware spray painting production line

The hardware painting process is to apply a layer of paint film on the surface of the hardware to beautify, prevent corrosion and rust.

The specific process is as follows:

1.Hardware surface treatment: including rust removal, grinding, cleaning, etc.

2.Primer treatment: Primer can enhance the surface adhesion and anti-corrosion and anti-rust capabilities of hardware.

3.Intermediate coating: Intermediate coating can increase the color, gloss and hardness of hardware.

4.Topcoat treatment: Topcoat can protect the intermediate coating and increase the beauty and durability of hardware.

product details

Production Line Overview

This spray painting line is specially designed for spraying the surface of hardware parts, and is suitable for the automatic spraying of metal products (such as screws, brackets, shells, etc.). The production line adopts a modular design, integrating pre-treatment, spraying, curing and quality inspection processes to achieve efficient, environmentally friendly and stable continuous production, meeting the quality requirements of industrial-grade spraying.

Process flow

1.Pretreatment stage

lOil removal and degreasing: Use alkaline cleaning solution (pH 9-11) or ultrasonic cleaning equipment to remove oil and impurities from the surface of hardware.

lPhosphating treatment (optional):To enhance the adhesion between the substrate and the coating, zinc/iron phosphating process is used to form a 5-10μm phosphating film.

lWashing and drying: Three-stage countercurrent water washing to remove residual liquid medicine, and hot air circulation drying (temperature 80-120℃, time 5-10 minutes).

2.Spraying stage

lElectrostatic spraying: High-voltage electrostatic spray gun (voltage 60-90kV) is used to adsorb liquid paint evenly.

lAir spraying (optional): For complex structural parts, use a high atomization spray gun (pressure 0.3-0.6MPa) for make-up spraying.

lRobot spraying (optional): 6-axis robotic arm carrying spray gun, programmed control path, accuracy ±0.5mm, suitable for high precision needs.

3.Curing stage

lHeat curing: by gas/electric heating oven, set temperature 80-150°C (liquid paint), time 15-30 minutes.

lUV curing (optional): UV light curing coatings are rapidly cured in 30-60 seconds under the irradiation of UV lamps (wavelength 320-400nm).

4.Cooling & Quality Control

lForced cooling: air cooling system to cool down the temperature to below 40℃ to avoid deformation of the workpiece.

lQuality inspection: automated inspection of coating thickness (±5μm), adhesion (scratch method ≥4B), gloss (60° incidence angle) and appearance defects.

Core equipment components

Device name	Technical parameter	Functional description
Hanging Conveyor Chain	Chain speed 0.5-5m/min adjustable, load 10kg/station	Continuous conveying of workpieces, supports start-stop speed regulation.
Paint booth	Negative pressure design, filtration efficiency ≥ 98% (HEPA + activated carbon)	Dust-proof and explosion-proof, centralized waste gas treatment
Oven	Hot air circulation, temperature control accuracy ±2℃, power 50-100kW	Even heating to avoid coating bubbles or discoloration
PLC control system	Siemens / Mitsubishi PLC, touch screen human-machine interface	Real-time monitoring of temperature, speed, pressure and other parameters

Precaution

√Surface treatment of hardware should be thorough: oil, oxides, rust, etc. on the surface of hardware should be removed, otherwise it will affect the adhesion and quality of the coating.
√The primer should be even: the primer should be evenly coated without any omission or overlapping, otherwise it will affect the quality of the coating.
√The intermediate coating should be transparent: the intermediate coating should ensure the transparency, otherwise it will affect the color and gloss of the hardware.
√The top coat should be fully dry: the top coat should be fully dry, otherwise it will affect the quality and durability of the coating.
√Choose the right coating: different hardware needs to choose different coatings, otherwise it will affect the quality and effect of the coating.