Scale-Up Calculator Tutorial - mcc-online.com

1 Tutorial for Scale-Up Calculator , Version Page 1 of 24 Scale-Up Calculator Tutorial The MCC Tableting Calculator Press speed is a major factor in tableting, and yet the commonly used measures of press speed (such as RPM, tablets per hour, dwell time, linear speed, etc.) do not take into account significant differences in press and tooling geometry, press deformation, tablet thickness, or depth of fill. Scale-Up of tableting process involves shorter die feeding times (can affect tablet weight), smaller consolidation times (may lower compactibility), and faster ejection (can create cracks or lamination). At the same production rate, duration of tableting events depends on roll diameter, pitch circle diameter, number of stations, punch geometry, length of feed frame and the angle of ejection ramp. On the other hand, the speed of various tableting events becomes a limiting factor in press productivity.

2 However, the same consolidation time will, most probably, ensure the same tablet quality, or, at least, bring the process to a close proximity of the target. To properly Scale-Up a formulation based on consolidation time: During a new formulation development, evaluate the minimum consolidation time at which tablets of a satisfactory quality can be produced ( the maximum compaction speed). Calculate at what speed (RPM) different production presses can offer the minimum satisfactory consolidation time, and what tablet output can be expected from different presses at that speed. Algorithms and formulas of the MCC Tableting Calculator are based on extensive list of published papers and on our own investigations into the geometry and dynamics of tableting. Some sources are listed in in the c:\sc folder created on your computer after software installation (you will need an Adobe Acrobat Reader to access this file). We suggest that you read this file in its entirety before proceeding with this Tutorial .

3 Please note that sometimes the resulting fields are blank. Than means that not all press parameters are available in the database for calculations. If you need to calculate Measurement Control Corporation Process Analytical Instrumentation, Monitoring and Control 13D Great Meadow Lane, East Hanover, New Jersey 07936, Tel: (800) 504-9010 Web Address: Tutorial for Scale-Up Calculator , Version Page 2 of 24 compaction variables for such a press, please contact MCC for more information. We will try to find the missing press parameters and update the database. In the reports, when a calculated field is blank, this may also mean that the press can not reach the requested velocity ( , it is outside the range of attainable speeds for this particular tablet press). The Tableting Calculator Algorithms Consolidation time Ts calculation are based on geometrical parameters such as roll diameter, pitch circle diameter, punch geometry, depth of fill and in-die tablet thickness.

4 Calculation formulas are based on the analysis of Rippie and Danielson (1981) and represent extension of work by Mu os Ruiz et al, (1992). Calculation of vertical punch displacement Zs during consolidation time is based on depth of fill Hf and in-die thickness Hi. Calculations of Consolidation time Ts take into account a correction for press deformation if the rate of deformation is known. A new, more accurate expression for dwell time calculation takes into account the rotational motion of the punches. A proper formula to calculate decompression (relaxation) time is used for estimation of all periods of the compaction event and the entire contact time. Definitions Feeding Time, Tf. Time when the die is fed with powder. Consolidation (Solidification) Time, Ts. The portion of Contact Time when punches are changing their vertical position in reference to the rolls decreasing the distance between their tips. Dwell Time, Td.

5 The portion of Contact Time when punches are not changing their vertical position in reference to the rolls. Decompression (Relaxation) Time, Tr. The portion of Contact Time when punches are changing their vertical position in reference to the rolls increasing the distance between their tips before losing a contact with the rolls. Compression Time, Tp. The portion of Contact Time before the decompression period begins (Tp = Ts + Td). Contact Time, Tc. Time when both punches are moving having their tips in contact with the material that is being compacted, and their heads are in contact with the pressure rolls (Tc = Ts + Td + Tr). Ejection Time, Te. Time when the tablet is being ejected from the die Tutorial for Scale-Up Calculator , Version Page 3 of 24 Total Time, Tt. Time required to produce one tablet on a press (including time between tablets). Feeding Efficiency Factor Ef = Tf/Tt, where Tf is a feeding time.

6 Consolidation Efficiency Factor Es = Ts/Tt, where Ts is the time required to perform work of consolidation. Ejection Efficiency Factor Fe = Te/Tt, where Te is the time required to eject a tablet. About Dwell Time Dwell time is defined as a portion of the contact time when punches are not changing their vertical position with respect to the rolls, that is, when a flat portion of the punch head is in contact with the rolls. Note that dwell time (unlike contact time) as defined does not depend on the roll diameter. The notion of dwell time is largely misused or misunderstood. In fact, it should be used as a yardstick, a measure of linear (that is, tangential or angular) velocity and therefore it will depend on the punch geometry. The speed comparisons based on the dwell time assume that the punch has a flat head. The velocity then is the dwell time divided by the length of that flat portion. For the same linear velocity, the smaller is the punch head flat, the smaller is the dwell time.

7 To everyone s surprise, dwell time for dome-shaped punch heads is practically zero by definition, regardless of press linear velocity or RPM. That is why, compared to dwell time, linear velocity is a better measure of press speed. Calculations of dwell time in the MCC Tableting Calculator are based on a length of a punch head flat. By default, this value is conventionally set at mm (R3, radius of the punch head flat = mm). Since the flat portion is surrounded by a curvature, some published sources use different values. You can change the length of the flat portion of the punch head by adjusting the R3 parameter on the MCC Tableting Calculator screen. How to use the MCC Tableting Calculator for Scale-Up In order to properly Scale-Up a strain-rate sensitive formulation, you have to match not only force and tooling, but consolidation time (the most important factor), dwell time (linear speed) and contact time (depends on roll diameter) as well.

8 In their seminal paper, Mu oz Ruiz et al. (1992) have described a failed attempt to Scale-Up a particular granulation from Korsch PH106 to Manesty Betapress. The failure was surprising since the Scale-Up of the product from a single punch machine to a 6 station Korsch Pharmapress was conducted without any evidence of compaction problems . The granulation turned out to be strain-rate sensitive, and further analysis indicated that it is not possible to obtain the same dwell times on the Korsch PH106 and Manesty Betapress. Let us use the MCC Tableting Calculator to forecast such Scale-Up problems. The easy way to learn the basics is to use the Tableting Calculator Wizard. It is self-explanatory. Tutorial for Scale-Up Calculator , Version Page 4 of 24 To follow the problem as outlined in the above mentioned paper, use the Wizard as follows: At Step 1, select Korsch PH106 6-station press from the list of tablet presses.

9 At Step 2, make sure the Match radio buttons indicate Td , that is, the Tableting Calculator is set to match dwell time, or linear speed. Note that your choices are mimicked on Panel 1 of the Tableting Calculator . At Step 3, move the speed slider all the way to the right to indicate the highest value, namely, 32,400 TPH, or 90 RPM, or 471 mm/sec horizontal punch velocity (linear speed). At Step 4, select Manesty Betapress 16 station press. Note that your choice is mimicked on Panel 2 ( The Matching Panel ) of the Tableting Calculator . Finish the Wizard and look at the panels . For clear comparison, on both panels set R3 = , d = , F = , Hf = 6 mm, Hi = 3 mm (these parameters affect either Consolidation time, or Dwell Time, or both). For the Korsch PH106 press, the Panel 1 on the left indicates Consolidation Time Ts = ms, Dwell Time Td = ms, Relaxation Time Tr = ms, and Contact Time Ts = ms. Tutorial for Scale-Up Calculator , Version Page 5 of 24 Note that ?

10 Data means missing data (in this case, missing information on the feed frame and ejection). Now, on the Matching Panel 2, the Manesty Betapress 16 station machine is selected. Tutorial for Scale-Up Calculator , Version Page 6 of 24 In general, each time you click on Panel 2, the program will try to match the selected parameter ( , dwell time) between the primary press (Panel 1) and secondary press (Panel 2). The same ms dwell time (same Horizontal Velocity or linear speed) for Betapress corresponds to 37,751 TPH, or RPM, which is almost the lower limit of Betapress speed. Thus, the lowest speed of Betapress can match the highest Korsch PH106 speed in terms of dwell time, but this is highly impractical. Other compaction values are: Ts = ms, Td = ms (matching the Korsch), Tr = ms, Tc = ms. Even at this matching speed, the tablets would probably be somewhat harder on the Betapress because of a larger contact time.