Problems on this page:
Anodic film too thin
Hits OEE: Quality
Symptoms: Coating thickness measurements are below the specification.
Current density or time too low
Check the rectifier settings and the time in the tank against the recipe.
Poor electrical contact on the jigs
Check the jig contacts and clean or replace worn contact points.
Electrolyte temperature too high
Check the tank cooling; a warm bath dissolves the film as it grows.
Rectifier output lower than displayed
Check the rectifier current with a calibrated meter.
Prevention: Film thickness measured on samples from each load.
Uneven colour after dyeing
Hits OEE: Quality
Symptoms: Dyed parts show patchy or different shades within a load or between loads.
Film thickness uneven across the load
Check the jig spacing and the current distribution.
Dye bath concentration or temperature off
Check the dye concentration, temperature and pH.
Time between anodising and dyeing varying
Keep the transfer time the same for each load.
Alloy or surface finish different
Check the material and the pre-treatment of the parts.
Prevention: Colour checked against a reference sample for each load.
Poor sealing
Hits OEE: Quality
Symptoms: Seal quality tests fail, or dyed parts bleed colour.
Seal bath temperature too low
Check the seal bath heating and its temperature control.
Seal time too short
Check the time in the seal tank against the film thickness being sealed.
Seal bath contaminated
Check the bath chemistry and replace it when out of limits.
Rinse before sealing not enough
Check the rinse before the seal tank, since carried-over acid spoils the seal bath.
Prevention: Seal quality tested on samples from each shift.
Burning or pitting on parts
Hits OEE: Quality
Symptoms: Parts show burnt areas or pits after anodising.
Current too high at the start
Use a current ramp at the start of the cycle.
Bath agitation poor
Check the air or pump agitation so heat is carried away from the part surface.
Contaminated electrolyte
Analyse the bath for dissolved aluminium and other contamination.
Bad jig contact causing arcing
Check the jig contacts and tighten loose parts on the jig.
Prevention: Defects recorded per load.
Bath temperature control failing
Hits OEE: Availability
Symptoms: The electrolyte runs too warm, so loads are held or the current has to be reduced.
Chiller not keeping up with the heat load
Check the chiller output and the load being run against its capacity.
Heat exchanger or cooling coils fouled
Clean the heat exchanger or coils on the set interval.
Circulation pump failing
Check the pump flow and its seals.
Temperature sensor drifting
Check the bath sensor against a reference thermometer.
Prevention: Bath temperature logged against every load.
Hoist or crane faults
Hits OEE: Availability
Symptoms: The automatic hoist stops between tanks, and loads wait in the wrong solution.
Position sensors dirty or corroded
Clean the position sensors and protect them from fumes.
Drive or brake fault
Check the hoist drive and brake.
Program or recipe error
Check the line program for the recipe that stopped.
Wheels, chains or ropes worn
Inspect the mechanical parts on the maintenance plan.
Prevention: Hoist faults recorded with the tank position where they happened.
Chemical leaks and splashes
Hits OEE: Availability
Symptoms: Acid or caustic leaks from tanks or pipework, or splashes reach the walkways.
Tank lining damaged
Inspect tank linings and repair damage before it leaks.
Valves and fittings leaking
Replace leaking valves and fittings with parts rated for the chemical.
Fume extraction over the tanks weak
Check the extraction airflow over each tank.
Protective equipment not used
Make the required protective equipment available at each tank and check it is worn.
Prevention: Tanks, pipework and extraction inspected weekly.
Rinse water problems
Hits OEE: Quality
Symptoms: Parts show stains or drag-out marks from poor rinsing.
Rinse flow too low
Check the rinse water flow to each rinse tank.
Rinse water quality poor
Check the conductivity of the rinse water.
Drain time over the tank too short
Extend the drain time so less solution is carried over.
Rinse tanks contaminated
Change the rinse when conductivity reaches its limit.
Prevention: Rinse conductivity logged each shift.
Guidance only. Always follow lockout/tagout and your site's safe-work procedures, and verify against OEM manuals before acting.
Related equipment guides: electroplating line · parts washer · chiller · reverse osmosis system · overhead crane
Stop the same fault coming back
Recurring anodising line stops usually trace to a cause you cannot see by hand. The partner we recommend is Fabrico: it tracks OEE and downtime live from PLCs, IoT sensors or AI cameras; where cameras are fitted, the video of a stop sits next to its machine data so the cause can be reviewed; and a technician opens the work order from the stop in the same system. Data is hosted in the AWS EU region, and Fabrico and the company behind it hold ISO/IEC 27001, ISO/IEC 20000-1 and ISO 9001.
Book a Fabrico demo
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Related tools: full troubleshooting directory · OEE calculator · downtime cost · MTBF / MTTR · glossary
Methods that cut recurring stops: the six big losses · root cause analysis · preventive vs predictive maintenance · TPM · SMED & changeover