Double Press or Impression
This problem involves only those punches, which have a monogram or other engraving on them. Where the punch makes double impressions on a tablet surface during the ejection process.
Cause
- Free rotation of either upper punch or lower punch during ejection of a tablet.
Remedies
- Use keying in tooling, which can prevent punch rotation.
- Newer presses have anti-turning devices, which also prevent punch rotation.
Cracking
Small or fine cracks observed on the upper and lower central surface of tablets, or very rarely on the sidewall are referred to as Cracks‘.
Causes
- Too dry granules.
- Large size of granules.
- Air entrapment.
Remedies
- Reduce granule size. Add fine powders.
- Improve granulation. Add dry binders.
- Moisten the granules properly and add proper amount of binder.
- Use tapered die.
- Use special take-off.
