When encountering a leak in a rotary tablet press, first stop the machine and check the leak location. Then, address the leak point specifically (die hole, feeder, pressure roller and guide rail, tablet ejection mechanism) to avoid affecting tablet quality, wasting materials, or damaging the equipment.
Step 1: Emergency Stop and Clean Up
- Immediately press the emergency stop button to cut off the power supply, preventing the leak from spreading or the equipment from jamming due to material accumulation.
- Use a clean brush or compressed air (low pressure) to clean up any leaked powder, preventing it from entering equipment gaps (such as pressure roller bearings and transmission components) to avoid wear and tear on parts or decreaed accuracy during subsequent operation.
- If the leaked material contains oil (such as lubricating grease seeping out), wipe it clean with a specialized cleaning agent to prevent contamination of subsequent materials.
Step 2: Troubleshooting and Solutions for Leaks in Different Areas
Leaks in rotary tablet presses are mostly concentrated in four core areas, which need to be checked and addressed one by one:
1. Excessive Clearance Between Die and Punch (Most Common Leakage Point)
- Troubleshooting: Observe whether the leaking material seeps out from the edge of the die orifice, or whether there is continuous powder accumulation around the die orifice during tableting. This is usually caused by an excessive clearance between the punch (upper punch, lower punch) and the die orifice (the normal clearance should be ≤0.03mm).
- Solution: Replace worn punches or dies, ensuring the outer wall of the punch is smooth and free of scratches, and that it fits tightly with the die orifice; If the die orifice is worn (the inner wall becomes rough), replace the die ring to avoid continuous leakage due to the inability to adjust the clearance.
2. Feeder Malfunction or Improper Installation
Solution:
- Adjust the feeder height to ensure the gap between the scraper and the turntable surface is controlled at 0.1-0.2mm (measured with a feeler gauge), ensuring the scraper can evenly scrape material into the die hole;
- Replace worn feeder scrapers. If the scraper is deformed, correct it to prevent material leakage due to the scraper not fitting snugly against the turntable.
3. Abnormal Fit Between Pressure Roller and Guide Rail
- Troubleshooting: Material leakage accompanied by abnormal noise from the pressure roller, burrs on tablets, or weight fluctuations may indicate excessive clearance between the upper or lower pressure roller and the guide rail, causing the punch to wobble during tableting and material to overflow from the die hole.
- Solution: Loosen the pressure roller fixing screws, adjust the pressure roller position to ensure a tight fit between the pressure roller and the guide rail (no noticeable wobble during operation), then tighten them again; If the pressure roller bearing is worn, replace it with a new bearing to prevent pressure roller eccentricity from causing punch instability.
4. Misalignment between the tablet ejection mechanism and the die hole
- Troubleshooting: Leakage from the tablet ejection scraper, or tablets failing to exit the die hole smoothly, may be due to a misalignment of the scraper with the edge of the die hole, causing material leakage as the turntable rotates.
- Solution: Adjust the angle and position of the scraper to ensure it accurately scrapes the pressed tablets from the die hole without excessive gaps between it and the turntable surface. Clean any material residue from the scraper. Replace worn scrapers to prevent material accumulation and leakage due to ineffective tablet ejection.
Step 3: Post-treatment Test Run
- After repairing the leak, run the equipment under no-load to observe whether each component (punch, pressure roller, feeder) operates smoothly without abnormal friction or noise.
- Introduce a small amount of material for a test run to check if the tablet weight and hardness are uniform and if there is no leakage from the die hole or any mating parts. Resume mass production only after confirming everything is normal.
- Record the causes and solutions for material leakage, and regularly inspect easily worn parts (punch, scraper, pressure roller) and replace aging parts in advance to reduce the recurrence of material leakage.