Concrete Block Machine Troubleshooting: Causes & Fixes

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Problems on this page:

Block height or density varying Cracked or broken blocks Mould wear and sticking Vibration system faults Board handling jams Hydraulic faults Mould change slow Surface finish poor

Block height or density varying

Hits OEE: Quality

Symptoms: Blocks vary in height, weight or strength across the board or between cycles.

Mould filling uneven

Check the feed drawer stroke and agitator so the mould fills evenly.

Vibration not even across the mould

Check the vibrator motors, their timing and the mould table mounts.

Mix moisture varying

Check the moisture of the mix coming from the mixer.

Mould and tamper head worn

Measure the mould and tamper head and plan their replacement.

Prevention: Block height and weight checked on samples each hour.

Cracked or broken blocks

Hits OEE: Quality

Symptoms: Blocks crack when stripped or in curing.

Stripping too fast or uneven

Check the stripping speed and the level of the tamper head.

Mix too dry or too wet

Check the water content of the mix.

Production boards warped

Check the boards and replace warped ones.

Curing chamber conditions wrong

Check the curing temperature and humidity.

Prevention: Broken blocks counted per board.

Mould wear and sticking

Hits OEE: Availability

Symptoms: Material sticks in the mould, and blocks come out deformed.

Mould worn beyond tolerance

Measure the mould openings and plan the replacement.

Release oil spray not working

Check the oil spray nozzles and their timing.

Mix too wet

Check the moisture of the mix.

Mould cleaning skipped

Clean the mould at the end of every shift.

Prevention: Mould measured weekly.

Vibration system faults

Hits OEE: Availability

Symptoms: Vibrators fail, or loose parts shake on the machine.

Vibrator bearings worn

Check vibrator bearing temperature and noise, and replace worn bearings.

Mounting bolts loose

Tighten bolts to the maker torque; vibration loosens them quickly.

Rubber buffers worn

Replace the rubber buffers under the mould table.

Vibrator motor fault

Check the vibrator motors and their supply.

Prevention: Bolts and buffers checked daily.

Board handling jams

Hits OEE: Availability

Symptoms: Production boards jam in the board feeder, conveyors or stacker.

Warped or broken boards

Take warped boards out of circulation.

Sensors dirty with concrete dust

Clean the board sensors on a set interval.

Conveyor chains worn or slack

Check the chains and their tension.

Stacker timing out of step

Check the stacker timing against the machine cycle.

Prevention: Board jams recorded by position.

Hydraulic faults

Hits OEE: Availability

Symptoms: Machine movements are slow or weak.

Hydraulic oil running hot

Check the oil cooler and the oil level.

Filter blocked

Change the filter and check its indicator.

Pump worn

Check the pump output and pressure.

Valve sticking from dirty oil

Service the valve and check the oil cleanliness.

Prevention: Hydraulic oil and filters checked on the maintenance plan.

Mould change slow

Hits OEE: Performance

Symptoms: Changing mould and tamper head takes long and holds up production.

Next mould not staged

Stage the mould and tamper head next to the machine before the change.

No lifting aid

Use a crane or mould change cart; moulds are heavy.

Settings not stored per product

Store vibration, feed and height settings as a recipe per product.

Many bolts to undo

Use quick clamping where the machine allows.

Prevention: Mould change time recorded.

Surface finish poor

Hits OEE: Quality

Symptoms: Block faces are rough, open or patchy.

Aggregate grading too coarse

Check the grading of the aggregate in the mix.

Face mix layer too thin or uneven

Check the face mix drawer and its setting.

Vibration time too short

Check the vibration time in the recipe.

Mix moisture too low

Check the water content.

Prevention: Faces checked against the approved sample each hour.

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

Related equipment guides: concrete batching plant · hydraulic system · conveyor · palletizer · mixer / agitator

Stop the same fault coming back

Recurring concrete block machine 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