Features    Functionality    Software    Specifications    Options    Presster™ Benefits

Raw Data Plot    Compaction Profile    Force-Thickness Plot    Dwell Time 

  What is the Presster™?

It is a tablet press replicator designed to match compression force and dwell time of any press. It is a compaction simulator designed to mimic a punch displacement profile of any press. It is a high-speed single station tablet press with standard tooling. It is a powerhouse computer for compressibility profiles, Heckel plots, lubricant studies, etc.

The Presster™ Features are:

• Standard IPT B tooling, upper and lower compression rolls, ejection  cam, take-off bar, variable speed motor controller, tablet weight and thickness adjustments and overload protection mechanism.

• A choice of interchangeable compression rolls (and, optionally, precompression rolls) to mimic the loading pattern of any rotary tablet press, with easy changeover mechanisms.

• Instrumentation to measure precompression, compression, ejection, take-off and die wall forces, punch displacement, and press speed.

• Manual or automatic (gravity force) feed shoe mechanism.

• Computerized adjustment of depth of fill (tablet weight), lower wheel position (tablet thickness), and press speed (in terms of dwell time).

• Pentium computer and color printer for scientific reports and plots.

• State-of-the-art software with a comprehensive database of parameters for various tablet presses, to match dwell times and compression profiles.

• Comprehensive user manual, technical documentation, and validation protocol.

The Presster™ Functionality:

  Under computer control the Presster™ will

• Make tablets with up to 50 kN compression force at a user specified speed (dwell time).

• Display compression waveform and peak force, peak offset time, decompression time, dwell time, contact time, and other measurements.

• Measure punch displacement, calculate tablet volume, elastic recovery, work of compaction, and display Heckel or stress vs. strain plots.

• Allow input of tablet weight in g or mg, tablet thickness and diameter in mm or inches, and hardness in kP, SCU, or N.

• Display an array of scientific plots and reports that are widely used in formulation development.

• Display compressibility profile where each point corresponds to compression and hardness for each tablet made, or sample average. This plot can be converted into tensile strength vs. compression pressure.

The Presster™ Software:

Mouse / menu driven under Windows Windows NT. Produces reports and plots in the Excel (raw waveforms, analytical graphs, and statistics for all tablets made). Provides the means for comparing different compressibility profiles or Heckel plots, e.g. superimposing the current profile with previously collected graphs. Has a comprehensive context sensitive on-line help. Prints on demand any screen graph, report or display on the color printer.

Presster™ Standard Specifications:

Maximum compression force	50 kN
Maximum precompression force	10 kN
Maximum depth of fill	17.4 mm
Maximum tablet thickness	8 mm
Tooling	TSM/Euro, B type, any shape and size (D type is optional)
Die OD	1.1875"
Number of stations	1
Maximum punch velocity (in horizontal plane)	2.2 m/s
Minimum dwell time	5.8 ms
Minimum punch velocity (in horizontal plane)	0.055 m/s
Maximum dwell time	230 ms
Die feeding	manual or force feed shoe
Maximum output	4 tablets / minute
Drive motor nominal speed	1800 RPM
Drive motor power	7.5 HP
Electricity requirements	208-220 V, 3 phase, 30 A, 50/60 Hz
Pressure rolls diameter	7.5" - 14" (user specified)
Machine installation	on casters
Machine base width (standard)	103"
Machine base depth (standard)	32.5"
Machine height (standard)	83.5"
Machine weight (approximately)	2.5 tons (25 kN)
Computer	Pentium IV 1.3 GHz Industrial
Printer	HP Color
Standard Instrumentation measurements	Upper compression force Upper punch displacement Lower punch displacement Compaction speed
Optional Instrumentation measurements	Ejection Force Lower compression force Upper pre compression force Lower precompression force Take-Off Force Radial die wall pressure

 

   Presster™ Options:

Additional instrumentation: lower compression force, ejection force, take-off force, radial die-wall force. A variety of compression and precompression rolls to the exact diameters of the specified production presses. Additional functionality: Precompression event and force measurement, variable ejection cam angle.

Integrated 4-way tablet tester (weight, thickness, diameter, and hardness measurements).

Validation Protocol, including IQ / PQ testing and all relevant documentation. IPT D Type or any custom type tooling

 

Dwell Time Calculations for Scale-Up of Tableting Process

To compute a dwell time for any press, we use the following formula:

DT (msec) =	PHF · NP ·3,600,000
	π · PCD · TPH

Where PHF = 12.7 mm (Punch Head Flat of the TSM-B )

NP = Number of Stations

π = 3.141

PCD = Pitch Circle Diameter of the turret

TPH = press speed in terms of Tablets Per Hour

 

The following graph represents the dwell time ranges for different R&D and production presses. The fastest presses, such as Fette, can achieve dwell times of about 5 ms. All high speed production presses are normally run at dwell times well under 10 ms. This is well within the range of a Manesty Betapress or MCC Presster™, but other research presses such as Korsch XL100 or Riva Piccola do not compare. Presster™ can reach the dwell time of 5.8 ms (as calculated on the basis of 12.7 mm PHF).

 

Linear Speed Comparisons for Rotary Tablet Presses

To avoid any misunderstanding regarding the dwell time definition, it is best to compare ranges of press speeds in terms of linear speed in horizontal plane. The following graph makes such comparison clear. Note that typical production ranges of linear speed are between 1500 to 2000 mm/s.

 

It is the linear speed (rather than the changes in dwell time at the same speed, e.g. by changing tooling geometry) that has a demonstrated effect on compaction process for strain-rate sensitive products.