TL;DR
Punch sticking means material is adhering to the punch face. Inspect punch surface quality, verify lubrication, and check product moisture before adjusting compression force.
What you might see
- tablet material adhering to punch faces
- punch pulling or tearing tablet on ejection
- weight variation increasing over run
- punch face showing discoloration or pitting
Likely causes
Inadequate magnesium stearate or lubricant level in the blend
Punch face pitting or scoring providing nucleation sites for adhesion
High product moisture content at ambient conditions causing tackiness
Compression force too high driving material into microscopic punch surface defects
Required tools
- Magnifying glass or loupe (10x)
- Punch cleaning solvent per formulation compatibility
- LOTO kit
- Moisture analyzer
- Torque wrench (for punch cam rail fasteners)
Safety first
- Pharmaceutical dust from the tablet press can be potent or sensitizing. Wear the correct respiratory PPE as specified in the product SOP.
- Lock out the press main drive and dust extraction before removing punches. The turret rotation hazard is severe.
- Cleaning solvents used inside the press must be compatible with GMP residue limits. Use approved solvents only.
Procedure
- 1
Stop the press. Lock out and tag out the main drive and dust extraction.
- 2
Remove a set of punches from the turret. Inspect each punch face under magnification for pitting, scoring, or buildup.[1]
- 3
Clean the punch faces with an appropriate non-scratching solvent. Re-inspect for embedded particles.
- 4
Check the punch lubrication system. Verify the lubricant spray or dry wipe system is operating and reaching the punch faces.[1]
- 5
Sample the blend for moisture content. High moisture (above the formulation limit) is a direct sticking driver.
- 6
Review the compression force setpoint. Reduce by 5 percent and run a short trial to see if sticking improves.
- 7
Replace any punches with visible surface damage. Surface damage cannot be corrected by polishing in the field.
Sources
Fette Compacting Fette FE 1200i / 3090 Tablet Press general technical documentation, Fette Compacting
Fette FE 1200i / 3090 tablet press general punch maintenance and sticking remediation procedures (general)
More guides for Fette Compacting Fette FE 1200i / 3090
How to diagnose main drive overload on a Fette FE 1200i / 3090 tablet press
Main drive overload usually means a mechanical jam, a broken punch, or a drive fault. Inspect the turret and punch set before attempting a restart.
How to fix out-of-spec weight variation on a Fette FE 1200i / 3090 tablet press
Weight variation on a rotary tablet press is most often a feed system or fill depth problem. Check the feed frame paddles, hopper level, and die fill depth before adjusting.
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