Common Faults & Troubleshooting of Rotary Tablet Press in Tablet Manufacturing

Rotary tablet press runs continuously for long hours in pharmaceutical workshops, and small mechanical or formula problems will cause massive unqualified tablets and production stop. Most factory operators only handle simple breakdowns and lack systematic troubleshooting solutions.

This technical article summarizes the 8 most frequent faults of rotary tablet press, analyzes root causes and gives operable solutions, plus standardized daily maintenance procedures to extend machine service life and reduce batch rejection rate.

Top 8 Common Tablet Press Faults & Step-by-Step Solutions

Tablet Capping & Splitting (Top Layer Separates)

1.Root Causes:

Insufficient pre-compression, air trapped inside powder granules

Over-dry raw material, low particle bonding strength

Worn punch surface with scratches

Solutions:

Increase pre-compression pressure; adjust granulation moisture; polish or replace damaged upper punches; reduce turret rotation speed properly.

Severe Tablet Weight Deviation

2.Root Causes:

Poor powder fluidity, bridging inside feeding hopper

Forced feeder speed mismatched with turret rotation

Die cavity blocked by residual powder

Solutions:

Install stirring vacuum feeder; synchronize feeder & turret PLC parameters; disassemble and fully clean dies every batch.

Material Sticking on Punches & Dies

3.Root Causes:

High moisture of herbal powder; no anti-stick polishing treatment on punch surface; insufficient lubrication.

Solutions:

Dry raw materials before compression; adopt mirror polished molds; add appropriate pharmaceutical lubricant magnesium stearate.

Tablet Hardness Unstable Batch to Batch

4.Root Causes:

Hydraulic compression pressure system leakage; inconsistent granule particle size; turret vibration at high speed.

Solutions:

Check hydraulic seal and pressure sensor; re-sieve granules to unify particle size; adjust machine base shock absorption pad.

Machine Abnormal Vibration & Loud Noise

5.Root Causes:

Uneven ground installation; loose turret fixing nut; worn transmission gear and bearing.

Solutions:

Level machine with horizontal ruler; fasten turret locking parts; replace lubricate worn bearings regularly.

Powder Flying & Dust Leakage

6.Root Causes:

Damaged sealing strip of compression chamber; negative pressure dust collector blocked.

Solutions:

Replace aging silicone sealing strips; clean dust filter cartridge every shift.

PLC Touch Screen Alarm & Automatic Shutdown

7.Root Causes:

Overload protection triggered by foreign hard blocks in die cavity; low air pressure for pneumatic feeder.

Solutions:

Stop machine and clean foreign matter; check air compressor pressure pipeline.

Low Tablet Surface Smoothness

8.Root Causes:

Rough punch inner surface; insufficient compression dwell time.

Solutions:

Repolish punch dies; extend compression holding time via touch screen parameter setting.

Standard Daily & Weekly Maintenance Schedule for Rotary Tablet Press

Daily Maintenance (After Each Production Shift)

Disassemble hopper, feeder, turret, punches and dies, clean all residual powder with purified water

Check sealing strips for damage, wipe compression chamber

Empty dust collector waste powder box

Run machine idle for 5 minutes to record running noise and pressure data

Weekly Maintenance

Dismantle transmission gearbox, replace lubricating oil

Calibrate weight detection and compression pressure sensor

Check all safety interlock emergency stop devices

Inspect punch wear degree, replace severely scratched molds in advance

GMP Cleaning Validation Tips for Rotary Tablet Press

For pharmaceutical factories with strict audit requirements:

Split all product contact parts for separate cleaning, avoid cross-contamination

Keep complete cleaning operation records, record cleaning time, operator and detergent type

Use alcohol or purified water disinfection after each batch switching

Store spare punches and dies in sealed dust-free cabinet

Conclusion

Timely troubleshooting and standardized maintenance can cut rotary tablet press failure rate by over 70%. If you encounter complex mechanical faults that cannot be solved by on-site operators, our technical team provides 24-hour online remote guidance and overseas engineer on-site repair service.

Troubleshooting FAQ

How often should I replace punch and die sets?

Depends on raw material abrasiveness; herbal formulations need replacement every 3–6 months, chemical API every 8–12 months.

Can I run the rotary tablet press continuously for 24 hours?

High-speed industrial model supports 24h continuous operation under normal maintenance; lab small models suggest 8h rest interval.

Why does the machine reject tablets automatically?

The weight detection system triggers rejection when tablet weight exceeds tolerance range; check feeder uniformity first.

What lubricant is allowed for pharmaceutical tablet press?

Only food-grade medical lubricating grease, non-toxic and no pollution to raw materials.