Stripe Formation in Powder Coating: Causes and Remedies

Stripe formation during application is a common issue in automated powder coating systems, negatively affecting both visual quality and process reliability.

🚩 Common Causes

• Stroke timing and conveyor speed not synchronized: The double stroke time of the gun must be shorter than the time it takes the part to pass through the spray zone. Otherwise, stripes appear.
• Incorrect number of moving guns: Too few or too many guns, or improper gun sequencing, leads to uneven powder application.

🛠️ Effective Actions

• Check sinusoidal program: Ensure a smooth, clean motion path of the gun axis to maintain synchronization.
• Optimize stroke time: Confirm that double stroke time (up and down) is shorter than the part’s spray zone transit time.
• Adjust number of guns: Match the number and distribution of guns to the part geometry and conveyor speed.

✅ Benefits of Optimized Process Control

• Uniform powder coverage with no visible stripes
• More efficient powder use and less rework
• Stable process quality and greater repeatability

🔗 Further Information

More technical details and control parameters are available in GEMA’s “Stripe Formation” section under Tips & Tricks – especially for automatic systems.