TL;DR
Conveyor speed variation causes film thickness variation across the car body. Check the VFD and drive chain tension before adjusting the conveyor speed parameter.
What you might see
- film thickness variation along the length of a body panel
- conveyor speed controller alarm
- drive chain noise or slipping
- encoder feedback showing speed below setpoint
Likely causes
Conveyor drive chain stretched or links worn causing slip
Drive motor VFD fault from overload or input voltage variation
Speed encoder fault causing incorrect speed feedback to the VFD
Drive chain lubrication insufficient causing drag and speed drop
Required tools
- Contact or non-contact tachometer
- Drive chain lubricant (approved for paint booth)
- Chain tension gauge or ruler
- LOTO kit
Safety first
- Lock out the conveyor drive before inspecting or lubricating the drive chain. The chain is under significant tension and can cause crush injuries.
- Paint booth conveyors carry heavy vehicle bodies. Never reach into the conveyor path while the conveyor is energized.
Procedure
- 1
Check the VFD fault log for the conveyor drive. Note the fault code and time.
- 2
Measure the actual conveyor speed at the conveyor rail with a contact or non-contact tachometer. Compare to the programmed setpoint.[1]
- 3
Inspect the drive chain tension. A stretched chain should be tightened or replaced if link elongation is visible.[1]
- 4
Lubricate the drive chain with the lubricant type specified for the paint booth environment (typically anti-static or food-grade).
- 5
Lock out the conveyor drive and inspect the speed encoder on the drive sprocket for contamination or mounting looseness.
- 6
Restore power and verify the VFD is receiving the correct speed feedback signal at the nominal conveyor speed. If feedback is erratic, clean or replace the encoder.
Sources
Dürr Dürr EcoDryScrubber / EcoBell3 Paint Spray Booth general technical documentation, Dürr
Durr paint booth conveyor and drive system maintenance documentation (general)
More guides for Dürr Dürr EcoDryScrubber / EcoBell3
How to inspect and maintain the EcoBell3 rotary atomizer on a Durr paint system
Bell cup wear or bearing failure on the EcoBell3 rotary atomizer causes paint film defects and uneven spray pattern. Measure bell cup runout and check bearing air pressure before each production run.
How to manage overspray buildup in a Durr EcoDryScrubber / EcoBell3 paint booth
Excessive overspray buildup in the dry scrubber reduces air flow and degrades paint quality. Follow the limestone powder charge schedule and replace the filter trays before build-up reduces booth airflow below specification.
Stop fixing the same fault twice.
Dovient turns guides like this into your team's shared playbook, with AI that catches recurring issues before they break the line.