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Niro Pharma Systems Leading Technologies Delivering Competitive Advantages. FLAT SURFACE ON PUNCH HEAD. REPRESENTATION OF UPPER PUNCH. DWELL LENGTH/TIME DIFFERENCE AT PRE-COMPRESSION WITH OR WITHOUT ACTIVE COURTOY PRE-COMPRESSION COMPENSATOR. Definition used:
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Niro Pharma Systems Leading Technologies Delivering Competitive Advantages
FLAT SURFACE ON PUNCH HEAD REPRESENTATION OF UPPER PUNCH DWELL LENGTH/TIME DIFFERENCE AT PRE-COMPRESSION WITH OR WITHOUT ACTIVE COURTOY PRE-COMPRESSION COMPENSATOR • Definition used: Dwell length starts when 100% of the pre-compression force is achieved and ends when the pre-compression force starts to drop. Dwell length is independent of press speed and therefore used in this presentation. When the press speed is know the Dwell Time can be calculated. Without the active Courtoy air compensator, 100% of the pre-compression force is achieved ONLY when the pre-compression roller dwells on the flat surface of the punch head.
PRE-COMPRESSION FORCE TIME UPPER PUNCH CONTACT WITH PRE-COMPRESSION ROLLER WITHOUT ACTIVE COURTOY AIR COMPENSATOR REPRESENTATION OF UPPER PRE-COMPRESSION ROLLER 1 1 REPRESENTATION OF UPPER PUNCH Initial contact between punch and Upper Pre-compression roller.
PRE-COMPRESSION FORCE TIME UPPER PUNCH CONTACT WITH PRE-COMPRESSION ROLLER WITHOUT ACTIVE COURTOY AIR COMPENSATOR 2 2 The punch is forced into the die: the pre-compression force increases.
PRE-COMPRESSION FORCE TIME UPPER PUNCH CONTACT WITH PRE-COMPRESSION ROLLER WITHOUT ACTIVE COURTOY AIR COMPENSATOR 3 3 Start of Dwell Length The roller starts to dwell on the flat of the punch head and then the downward stroke of the punch has ended. The pre-compression force will remain constant until the roller leaves the punch head flat surface. This point marks the beginning of the dwell at 100% of the pre- compression force.
PRE-COMPRESSION FORCE TIME UPPER PUNCH CONTACT WITH PRE-COMPRESSION ROLLER WITHOUT ACTIVE COURTOY AIR COMPENSATOR 4 4 Start of Dwell Length During the contact between the roller and the flat of the punch head the pre-compression force will remain at 100%.
PRE-COMPRESSION FORCE TIME UPPER PUNCH CONTACT WITH PRE-COMPRESSION ROLLER WITHOUT ACTIVE COURTOY AIR COMPENSATOR 5 5 Start of Dwell Length End of Dwell Length The roller ceases to dwell on the flat of the punch head. The pre-compression force will drop very fast and is a function of the elastic recovery of the pre-compressed tablet.
PRE-COMPRESSION FORCE TIME Start of Dwell Length End of Dwell Length UPPER PUNCH CONTACT WITH PRE-COMPRESSION ROLLER WITHOUT ACTIVE COURTOY AIR COMPENSATOR 6 Total dwell time on Non Courtoy Press 6
COURTOY PNEUMATIC COMPENSATOR air cylinder air pressure:P piston surface: Spiston dead stop piston upper pre-compression roller upper punch reaction force of the compressing powder on the punch INCREASED DWELLTIME DUE TO DISPLACEMENT SYSTEM P is controlled and kept constant by a proportional valve Spistonis the calculated surface of the piston. Therefore the force applied to the yoke by the air pressure is F=P x S piston = constant The image above shows the Top Pre-Compression Roller Assembly on a Courtoy Pharma press. The yoke that holds the pre-compression roller can slide up and down in the cylinder. The constant air pressure in the cylinder holds the yoke against its dead stop as long as the pressure in the cylinder exceeds the reaction force from the powder transferred through the punch to the yoke. When the reaction force from the powder equals the force applied to the yoke by the air-pressure but the punch stroke on roller is not completed, the roller will move upwards for a distance equal to the vertical component of the stroke.
COURTOY AIR COMPENSATOR 1 PRE-COMPRESSION FORCE 1 TIME Initial Contact between Punch and Upper Pre-compression roller.
PRE-COMPRESSION FORCE TIME COURTOY AIR COMPENSATOR 2 2 The punch is forced into the die: the pre-compression force increases.
PRE-COMPRESSION FORCE TIME COURTOY AIR COMPENSATOR 3 3 Start of Dwell Length At this point the reaction force from the tablet equals the air pressure x the compensator surface in the air compensator. This will end the downward stroke of the upper punch and initiate the roller to movement upwards. The roller starts to dwell on the flat of the punch head. The pre-compression force will remain constant until the roller leaves the punch head flat surface. This point marks the beginning of the dwell at 100% of the pre- compression force.
PRE-COMPRESSION FORCE TIME COURTOY AIR COMPENSATOR CONSTANT FORCE COMPRESSION ROLLER MOVEMENT 4 Start of Dwell Length 4 Pre-Compression force can NOT increase: roller is pushed up!
PRE-COMPRESSION FORCE TIME COURTOY AIR COMPENSATOR CONSTANT FORCE COMPRESSION MAXIMUM ROLLER MOVEMENT CALLED DISPLACEMENT OCCURS WHEN PUNCH AND ROLLER CENTERLINES ALIGN 5 Maximum roller movement is called DISPLACEMENT Start of Dwell Length 5
PRE-COMPRESSION FORCE TIME COURTOY AIR COMPENSATOR CONSTANT FORCE COMPRESSION ROLLER MOVEMENT 6 Precompression force is maintained….. Start of Dwell Length 6
PRE-COMPRESSION FORCE TIME Total dwell lengthon NON COURTOY presses Total dwell lengthonNON COURTOY presses COURTOY AIR COMPENSATOR TOTAL DWELLLENGTH 7 ROLLER BACK INTO LOWEST POSITION, READY FOR NEXT PUNCH Start of Dwell Length End of Dwell Length 7
Standard dwell length Extended Dwell length using Courtoy Compensator CALCULATION OF DWELL LENGTH EXTENSION Dwell length extension using Courtoy Compensator R² = (R-d)² + (D/2)² (D/2)²= R² - R² + 2dR – d² d² almost = 0 D/2 = (2dR)½ D = 2(2dR)½ Calculated example on Courtoy Modul Roller diameter = 240 mm so R= 120 mm Average displacement ~ 0.25 mm D = 2x(2x0.25x120) ½ = 15.5mm For B TSM tooling Flat on punch head is max 9.3 mm. Dwell length without displacement = 9.3 mm Dwell length with displacement =9.3+ 15.5= 24.8mm almost 200% increase !!!!!!. Dwell time is a function of the press speed and increases with the same % as Dwell length.
ADVANTAGES OF EXTENDED DWELL TIME • Higher production output for dwell time sensitive products. • Leads to better de-aeration and uniform distribution of the granule in the die and punch cups prior to final compression of the tablet. • Higher hardness, for equal disintegration time. • Reduced risk of capping, better bonding of layers on Bi-layer tablets.
EXTENDED PRE-COMPRESSION PROFILE WITH ACTIVE COURTOY AIR COMPENSATOR PRE-COMPRESSION PROFILE WITHOUT ACTIVE COURTOY AIR COMPENSATOR P.S. Above curve is valid for presses set to achieve equal pre-compression force.