TABLETTING PROBLEMS & POSSIBLE CURE

In tabletting, it’s unavoidable to have one or a few problems but those problems can be cured with certain ways. Below are problems in tablet finished product along with their possible causes and cures:

PROBLEM	POSSIBLE CAUSE	CURE
Inconsistent Weight	Variation in punch length (lower)	Replace or regrind to length
	Inconsistent granule	Improve granule / mixing technique
	Empty feed frame	Check hopper / feeder, ensure granule flows freely
	Punch holding plugs	Replace
	Dirt under weight adjustment ramp	Remove ramp, clean
	Incorrect setting of feeder paddle speed	Adjust as required
	Incorrect setting of feeder inlet bowl	Adjust as required
Tablet stick to upper punch	Damaged upper punch	Refurbish or replace punches
	High moisture level in granule	Dry granules in oven or F.B.D., sieve and lubricate
	Lack of, or insufficient lubricant	Add or increase lubricate
Double impression	Worm punch holding pads	Replace
	Excessive tamping force	Increase tablet thickness
Flash' on tablet edge	Worm punch or die	If possible reverse die or replaace badly won punches
	If tapered dies are being used tablet compressed in taperd section of die	Increase upper punch penetration
Variation in thickness / hardness	Worn pressure roll	Replace
	Variation in upper or lower punch lengths	Replace or regrind to length
	Inconsistent granule	Improve granule
	Overload pressure, setting set too close to tabletting pressure	Reset
Safety overload pressure release operating	Damaged punches (burr on tip)	Refurbish or replace
	Excessive pressure	Reduce pressure, i.e. increase tablet thickness or reduce fill
	Overload set to close to tabletting pressure	Reset overload
Lower punch	Mtl stuck to punch or die	Check for worn punches and dies
	High moisture level in granules	Dry granules in oven or F.B.D., sieve and lubricate
Top of tablet is split / cracked	Damaged punches	Refurbish or replace
	Granules maybe too dry	Add moisture, remix, granulate, lubricate
Tablets breaking on take off	Take off plate incorrectly set	Check and reset
	Lower punch ejection	Check and reset
	Insufficient load at compression point	Increase pressure, check overload
	Speed too high for particular material	Reduce speed until acceptable  tablet is obtained
	Not enough binder	Increase
	Granules too dry	Increase moisture level
	Insufficient feed to dies (soft tablets)	Check hopper and flow of material
	Feeder height incorrectly set	Check and reset
Tablets binding in die	Worn dies	Reverse or replace
	High moisture level in granule	Dry, sieve and lubricate or reduce fill
	Lack of, or insufficient lubricant	Increase
Tablets split in half (lamination)	Take off plate incorrectly set	Check and reset
	Lower punch ejection incorrectly set	Check and reset
	Speed too high	Reduce speed
	Insufficient feed to die	Check hopper and flow of material
	Worn / damaged punches	Refurbish or replace
	High moisture level in granules	Dry in oven or F.B.D., sieve and relubricate
	Not enough binder in mix	Increase
	Excessive pressure	Increase tablet thickness
	Granules too dry	Increase moisture level
	Burr or punch tips	Refurbish or replace
	Feeder height incorrectly set	Check and reset
Loss of material	Feed frame / pedestal height incorrectly set	Check and reset
	Upper punch penetration set too high	Check and reset
	Worn lower punches or dies	Replace
	Tail over die / scraper set / worn	Check, reset or replace
	Recirculating channel worn or missing	Replace
	Indequate dust control unit	Overhaul or replace
	Excessive flow of material to feed frame	Reduce flow

The cures that have been explained are merely a guide because there are many cures that can also solve the same problem/s. One of the most critical parameters that has to be assured is how to make a proper mass that will suit the specification of the finished product the best.