Pasta Extruder Troubleshooting: Causes & Fixes

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Problems on this page:

White spots or streaks in the pasta Die pressure too high Pasta cracking after drying Uneven length or shape Dough sticking in the premixer Barrel or head temperature unstable Long die changes Screw or gearbox wear

White spots or streaks in the pasta

Hits OEE: Quality

Symptoms: Extruded pasta shows white spots, streaks or an uneven colour.

Semolina not fully hydrated

Check the water dosing and the mixing time in the premixer.

Vacuum in the mixer too weak

Check the vacuum level; air left in the dough shows up as white spots.

Water temperature varying

Check the temperature of the dosing water.

Flour particle size changed

Check the semolina specification of the new lot.

Prevention: Pasta colour checked against a reference sample each shift.

Die pressure too high

Hits OEE: Performance

Symptoms: Extrusion pressure rises, output falls and the motor load climbs.

Die inserts blocked with dough

Clean the die and its inserts, and check the cleaning method removes all dried dough.

Dough too dry

Check the water dosing against the recipe.

Dough temperature too low

Check the cooling water on the barrel and the head.

Screw worn so it compacts unevenly

Measure the screw and barrel clearance at the next planned stop.

Prevention: Die pressure and motor load trended per product.

Pasta cracking after drying

Hits OEE: Quality

Symptoms: Pasta cracks or checks after the dryer, or breaks in the pack.

Drying too fast for the shape

Check the dryer temperature and humidity profile for the product.

Dough moisture too high leaving the extruder

Check the water dosing and the moisture of the extrudate.

Cooling after the dryer too sudden

Check the cooler conditions at the dryer exit.

Air in the dough

Check the mixer vacuum.

Prevention: Cracks checked on samples after the dryer.

Uneven length or shape

Hits OEE: Quality

Symptoms: Cut pieces vary in length, or the shape is deformed.

Cutter knife dull or set wrong

Sharpen or replace the knife and set its gap to the die face.

Cutter speed not matched to extrusion speed

Check the cutter speed setting for the product.

Die inserts worn or damaged

Inspect the inserts and replace damaged ones.

Flow uneven across the die

Check the die for partly blocked holes.

Prevention: Piece length and shape checked on samples.

Dough sticking in the premixer

Hits OEE: Availability

Symptoms: Dough builds up in the premixer or the feed to the screw and the line stops.

Water dosing too high

Check the dosing pump and the flow meter.

Paddles worn

Check paddle clearance and condition.

Cleaning interval too long

Clean the premixer on the schedule set for the product.

Feed to the screw blocked

Check the transfer between mixer and screw.

Prevention: Premixer build-up checked at each changeover.

Barrel or head temperature unstable

Hits OEE: Quality

Symptoms: Dough temperature at the die swings, and the product surface changes.

Cooling water flow low

Check the cooling water supply, valves and filters on the barrel and head.

Temperature control valve sticking

Service the valve and check its actuator.

Sensor fault

Check the sensor against a reference.

Screw speed changed

Compare the screw speed with the recipe.

Prevention: Dough temperature at the head logged per shift.

Long die changes

Hits OEE: Performance

Symptoms: Changing to another shape takes long and the first product is out of specification.

Next die not cleaned and ready

Clean, inspect and stage the next die before the run ends.

No settings stored per shape

Store the screw speed, water dosing and cutter settings per shape.

Die change done without lifting aid

Use a die trolley or lifting aid; dies are heavy and the head is hot.

Start-up waste high

Follow a written start-up sequence for each shape.

Prevention: Die change time recorded per shape.

Screw or gearbox wear

Hits OEE: Availability

Symptoms: Output drops or the gearbox gets noisy and hot.

Screw flights worn

Measure the screw and plan its rebuild or replacement.

Gearbox oil low or old

Check the oil level and change it on schedule.

Thrust bearing wearing

Check the thrust bearing temperature and noise.

Running at high pressure for long periods

Find the cause of high die pressure.

Prevention: Gearbox oil and screw wear checked on the maintenance plan.

Guidance only. Always follow lockout/tagout and your site's safe-work procedures, and verify against OEM manuals before acting.

Related equipment guides: extruder · mixer / agitator · dough sheeter · vacuum pump · cooling tunnel

Stop the same fault coming back

Recurring pasta extruder 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.

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Methods that cut recurring stops: the six big losses · root cause analysis · preventive vs predictive maintenance · TPM · SMED & changeover