Process parameters

Bultmann's Roll Compaction-site
on Dry Granulation

Characterization checklist for Roller Compaction equipment selection
(taken and adapted from: Walzenkompaktierung, M. Bultmann; ISBN 3-xxxxxxxx-x in preparation)

Property / feature units explanation value / data

Vendor / model specify n/a

Roll diameter [mm]

Roll width [mm]

different roll surfaces available smooth polished
smooth satinated
knurled
other (please specify) to accommodate different draw in properties

variable gap system yes / no variable gap systems are prerequisite for constant porosity = high quality

all unit sizes available (from lab size to production size yes / no to cover all steps without major equipment change

all unit sizes use same roll diameter yes / no ease of scale up

all unit sizes use same design yes / no ease of scale up: no change in design related parameters

max. throughput¹ [kg/h]

min amount of powder [g] for development porposes: the less the better

quasi contained production zone by default while area still visible (e.g. perspex door) yes / no health and safety issues, facilitate cleaning but still allowing observation of process

flanges /ports easily attachable to inlet and outlet yes / no allow switch to contained operation or from small scale development to full production easily

contained version available (containment has to be proven by data !) genuine by vendor
third party working with vendor
not at all total solution from vendor provides best overall performance

relative roll position inclined
vertical
horizontal
horizontal: might cause issues with material flowing through the gap by itself: poor
vertical: different draw in angles at the rolls: poor

designed for reduced surfaces (pay attention to nuts, covers, sealings, welding seams) yes / no sophisticated design implies reduction of welding seams (milled from solid block preferred), avoidance of nuts and bolts, covering of them wherever possible, tight sealings between drive shafts and housing

WIP available yes / no facilitates cleaning (under contained conditions); health and safety

CIP available yes / no provides cleaning (under contained conditions); health and safety

number of augers 2 / 1 two auger systems provide high flexibility from predensification to aeration of powder. Widens range of processable material

predensifying augers no / yes predensification should not be forced by default by auger design

cooling of rolls available yes / no widens range of processable materials to products with low melting point / low degradation temp.

working²(!) rim roll sealing available yes / no rim rolls provide more uniform porosity distribution across ribbon; but must be a real working rim principle. Ribbons must show plain sharp edges

adjustable speed ratio between augers yes / no allow high flexibility from predensification to aeration of powder. Widens range of processable material

torque control for feed auger yes / no allows to provide material of constant predensification to tamping screw

recycling of fines necessary no / yes uncompacted) fines should not occur right after compaction (optimization of formulation necessary or machine not working properly).Fines will occur after milling of course, but recycling them is not suggested for several reasons

automatic gap control with adjustable(!) PID parameters yes / no automatic mode provides constant gap at constant force. PID parameters must be adjustable to offer potential for adaption to product if necessary

Granulation unit attached yes / no reduces processing steps, facilitates containment

low speed³ granulation plus granulator speed plus angle of rotation plus direction adjustable yes / no high milling speeds produce lots of fines. Granulator movement should be adjustable to match individual needs / throughput

ease of rotor sieve distance adjustment (reproducibility !) fool proof … hard to adjust, not adjustable rotor sieve distance becomes important under certain circumstances. distance adjustment should be made easy and reproducible

mesh sizes available please specify

conidur sieves available as standard option yes / no conidur sieves provide more cutting action and can help to reduce fines. On the other hand through put is limited

Sample theif/chute for ribbons yes / no necessary for drawing ribbons

sample thief/chute for granules yes / no necessary for drawing granule samples

Different agitator shapes available yes / no widen range of processable material (aeration or just movement instead of predensification in feeding hopper)

creeping mode with(!) ramp yes / no saves material (especially relevant for development); fast steady state

tip mode for each drive individually selectable yes / no relevant for cleaning

rolls and tamping auger reverse tip mode available yes / no required in case of clogging

full instrumentation of all(!) drives (speed, torque, temperature); similar for hydraulic pump yes / no better process understanding, ease of trackin process, usable for QbD, PAT

Data export function yes / no tracability and evaluation of process and parameters; necessary for development

dynamic (!) force calibration (force exerted on powder) yes / no truly displays the actual force on the powder leaving all other influencing factors beside (oil leakage, bear friction, lever bending…)

dynamic (!) gap calibration yes / no assure that gap display is accurate for all force settings

(proven!) spare time delivery instant .. the faster the better, of course

CFR 21 / 11 compliant yes / no self explaining

through the wall assembly available yes / no save lab space, facilitate cleaning and maintenance in high potent production zones

experience available within own company yes / no roll er compaction is a complex topic. advantage of inhouse experience is self explaining

machine displays the actual force exerted on the powder (rather than hydraulic pressure or a force measured somewhere in the machine) yes / no anything else doesn't make much sense. actual force on the powder facilitates scale up

consistent with internal equipment and process of choice documents) yes / no self explaining

[1] using Avicel PH101 + 0.5% MgSt; ribbon porosity ~20%
[2] ribbons must not be pressed through/over rims
[3] to give an impression: Quadro Comil(TM) for example is high speed; oscillating granulators are usually low speed

Property / feature	units	explanation	value / data
Vendor / model	specify	n/a
Roll diameter	[mm]
Roll width	[mm]
different roll surfaces available	smooth polished smooth satinated knurled other (please specify)	to accommodate different draw in properties
variable gap system	yes / no	variable gap systems are prerequisite for constant porosity = high quality
all unit sizes available (from lab size to production size	yes / no	to cover all steps without major equipment change
all unit sizes use same roll diameter	yes / no	ease of scale up
all unit sizes use same design	yes / no	ease of scale up: no change in design related parameters
max. throughput¹	[kg/h]
min amount of powder	[g]	for development porposes: the less the better
quasi contained production zone by default while area still visible (e.g. perspex door)	yes / no	health and safety issues, facilitate cleaning but still allowing observation of process
flanges /ports easily attachable to inlet and outlet	yes / no	allow switch to contained operation or from small scale development to full production easily
contained version available (containment has to be proven by data !)	genuine by vendor third party working with vendor not at all	total solution from vendor provides best overall performance
relative roll position	inclined vertical horizontal	horizontal: might cause issues with material flowing through the gap by itself: poor vertical: different draw in angles at the rolls: poor
designed for reduced surfaces (pay attention to nuts, covers, sealings, welding seams)	yes / no	sophisticated design implies reduction of welding seams (milled from solid block preferred), avoidance of nuts and bolts, covering of them wherever possible, tight sealings between drive shafts and housing
WIP available	yes / no	facilitates cleaning (under contained conditions); health and safety
CIP available	yes / no	provides cleaning (under contained conditions); health and safety
number of augers	2 / 1	two auger systems provide high flexibility from predensification to aeration of powder. Widens range of processable material
predensifying augers	no / yes	predensification should not be forced by default by auger design
cooling of rolls available	yes / no	widens range of processable materials to products with low melting point / low degradation temp.
working²(!) rim roll sealing available	yes / no	rim rolls provide more uniform porosity distribution across ribbon; but must be a real working rim principle. Ribbons must show plain sharp edges
adjustable speed ratio between augers	yes / no	allow high flexibility from predensification to aeration of powder. Widens range of processable material
torque control for feed auger	yes / no	allows to provide material of constant predensification to tamping screw
recycling of fines necessary	no / yes	uncompacted) fines should not occur right after compaction (optimization of formulation necessary or machine not working properly).Fines will occur after milling of course, but recycling them is not suggested for several reasons
automatic gap control with adjustable(!) PID parameters	yes / no	automatic mode provides constant gap at constant force. PID parameters must be adjustable to offer potential for adaption to product if necessary
Granulation unit attached	yes / no	reduces processing steps, facilitates containment
low speed³ granulation plus granulator speed plus angle of rotation plus direction adjustable	yes / no	high milling speeds produce lots of fines. Granulator movement should be adjustable to match individual needs / throughput
ease of rotor sieve distance adjustment (reproducibility !)	fool proof … hard to adjust, not adjustable	rotor sieve distance becomes important under certain circumstances. distance adjustment should be made easy and reproducible
mesh sizes available	please specify
conidur sieves available as standard option	yes / no	conidur sieves provide more cutting action and can help to reduce fines. On the other hand through put is limited
Sample theif/chute for ribbons	yes / no	necessary for drawing ribbons
sample thief/chute for granules	yes / no	necessary for drawing granule samples
Different agitator shapes available	yes / no	widen range of processable material (aeration or just movement instead of predensification in feeding hopper)
creeping mode with(!) ramp	yes / no	saves material (especially relevant for development); fast steady state
tip mode for each drive individually selectable	yes / no	relevant for cleaning
rolls and tamping auger reverse tip mode available	yes / no	required in case of clogging
full instrumentation of all(!) drives (speed, torque, temperature); similar for hydraulic pump	yes / no	better process understanding, ease of trackin process, usable for QbD, PAT
Data export function	yes / no	tracability and evaluation of process and parameters; necessary for development
dynamic (!) force calibration (force exerted on powder)	yes / no	truly displays the actual force on the powder leaving all other influencing factors beside (oil leakage, bear friction, lever bending…)
dynamic (!) gap calibration	yes / no	assure that gap display is accurate for all force settings
(proven!) spare time delivery	instant ..	the faster the better, of course
CFR 21 / 11 compliant	yes / no	self explaining
through the wall assembly available	yes / no	save lab space, facilitate cleaning and maintenance in high potent production zones
experience available within own company	yes / no	roll er compaction is a complex topic. advantage of inhouse experience is self explaining
machine displays the actual force exerted on the powder (rather than hydraulic pressure or a force measured somewhere in the machine)	yes / no	anything else doesn't make much sense. actual force on the powder facilitates scale up
consistent with internal equipment and process of choice documents)	yes / no	self explaining