1. Prepare the surface and check grounding
Cleaning and pretreatment address contaminants such as oils, rust, and manufacturing residues. The appropriate method depends on the metal, its condition, and the required coating performance. Your preparation system must suit the components entering production.
The component also needs effective grounding, an electrical connection to earth through its supporting arrangement. Poor contact between the component, jig, and hanger can contribute to insufficient powder deposition. Check these connections before assuming that poor coverage requires more powder. Red Line’s troubleshooting guidance identifies them as potential causes of low coating thickness.
2. Maintain consistent powder feeding
Many hopper-fed systems use fluidisation: compressed air suspends powder particles, helping the powder flow into the feed system and towards the gun.
Lumpy powder or poor fluidisation calls for checks on powder condition and air quality. Red Line’s support guidance identifies old or moist powder, along with moisture and oil contamination in the compressed air supply, as possible causes.
Colour-change frequency also influences equipment selection. Our PC202IF seeds directly from the supplier’s carton, removing the need to empty and clean a hopper. Other powder-contact parts still require cleaning to prevent colour contamination. Discuss your colour-change schedule alongside production volume when comparing feed arrangements.
3. Charge the powder through electrostatics
Electrical attraction is central to the powder coating machine’s working principle.
In a corona-charging gun, a high-voltage electrode ionizes the surrounding air. Ions attach to powder particles, charging them so they are attracted towards the grounded component. The nozzle shapes the powder cloud; the electrode creates the charging conditions.
Deep recesses and internal corners can be harder to coat because the electric field restricts powder penetration. This is called the Faraday cage effect.
If your components have these features, discuss them with the supplier. Red Line’s guidance for poor corner coverage includes checking grounding and reducing charging voltage. Maximum voltage is not the appropriate setting for every application.
4. Control deposition and measure thickness
Powder flow, air pressure, gun distance and application time affect deposition. Excessive air velocity can blow powder away, while insufficient floor application time can leave the coating too thin.
Manual systems rely on an operator to guide the gun. Automatic arrangements use mounted guns. Our A202/X supports both fixed guns and guns mounted on moving reciprocators.
The quality benchmark is film thickness, measured against the coating specification. Suitable gauges measure cured thickness; other instruments assess uncured powder or predict cured thickness. Checking before curing can help identify application problems while correction is less involved. Visual coverage alone should not replace measurement.
5. Manage overspray and recovered powder
Powder that misses the component becomes overspray and can be collected through suitable recovery equipment. Powder management matters because particle-size distribution affects fluidisation, transport, charging and deposition.
Contamination also needs attention. Our PC202 incorporates online sieving to remove dust and fibres before spraying, with a published nominal sieving capacity of 60-90 kg/hour. This measures powder-handling capacity, not finished components per hour. When comparing powder coating equipment, ask what each capacity figure represents and how it relates to your production requirements.
6. Cure the coating and inspect the result
The component enters the separate oven, where thermoset powder flows and crosslinks. Proper curing depends on the metal temperature and time at the required temperature, not simply the oven’s air-temperature setting. Temperature profiling helps verify the conditions experienced by the component.
Your inspection checks should include:
- Thickness: Compare cured film measurements with the specified range.
- Cure: Check the metal temperature profile against the powder manufacturer’s cure schedule.
- Adhesion: Where required, use the specified test and acceptance criteria. Cross-hatch testing is one established method.
Choose equipment around your application
Before discussing a machine, prepare details of your components, production volume, colour-change frequency and coating specification. Ask how the proposed setup addresses each requirement.
At Red Line, our range includes manual and automatic machines, direct carton-feed equipment, and models with integrated sieving. Share your application requirements with our team to discuss appropriate equipment for your powder coating process.