Bubble stability is reduced by turbulence caused by the cooling air stream when it hits the bubble. This is particularly evident for high air exchange rates.  The sizing cage offers the function of a shock absorber.  It reduces movement that the bubble would otherwise incur, and prevents the bubble from losing stability. The sizing cage also provides the ability to artificially hold the frost line to a lower level when cage height adjustment is provided.  This benefit has been cited as the main reason for installing a sizing cage because a higher production rate is achieved on IBC and non-IBC lines alike. New woolen, silcone, or carbon fiber roller style cages are now the preferred choice when wanting to run scratch free film.  Contact us about getting a quote on this cost effective option.