Brookfield DV3T User Manual

Brookeld Engineering Labs., Inc. Page 88 Manual No. M13-167-A0415
VII.5 Other Rheological Models
The NCA/CMA Casson Model
(1+a) √τ = 2√ τ
o
+ (1+a) √hD
(τ
=shearstress
, τ
o
=yieldstress, h =plasticviscosity,and =shearrate)
TheNCA/CMACassonmodelisdesignedbytheNationalConfectionersAssociationandthe
ChocolateManufacturersAssociationasthestandardrheologicalmodelfortheindustry.This
modeldeterminesyieldandowpropertiesunderspeciedconditionsandcloselyapproximates
theplasticbehaviorofchocolatebeforenalprocessing.
Figure VII-5
Whenchocolateisusedforenrobing,itmusthaveayieldstresshighenoughtostayinplaceonce
itenrobesthelling.Inthecaseofdecoratingchocolate,theyieldstressmustbehighenoughsoit
cankeepitsshapeonceithasbeensqueezedintoplacethroughanozzle.Formoldingchocolate,
theplasticviscositymustbelowenoughtocompletelyllthemold.
(TheNCA/CMAlistsBrookeld’sHA-springrangeviscometerwithaSmallSampleAdapter,
SC4-27spindleandSC4-13Rsamplechamberastheapprovedapparatus.)
The IPC Paste Model
h=kR
n
TheIPCPasteModelwasdevelopedforsolderpastes.Itcalculatestheviscosityofsolderpastes
at10rpm.TheIPCPasteModel requires thattheproductbetested with aBrookeldSpiral
Adapteratmultiplespeeds.MoredetailscanbefoundintheIPC-TM-650TestMethodsManual
(methods2.4.34.2and2.4.3).

Brookfield DV3T Specifications

General

Brand	Brookfield
Model	DV3T
Category	Measuring Instruments
Language	English