Swaging or Crimping?

Definitions ~

"Stem"  is an externally serrated steel tube which fits inside the bore of the hose or pipe.

"Ferrule"  is an internally serrated steel tube which fits over the outside of the hose or pipe.

"Internal Swaging"  is the process by which the stem is internally expanded to compress the hose material against the ferrule to provide grip. Internal swaging also provides a full flow area through the bore of the end fitting significantlyreducing the possibility of bacteria becoming trapped between the end ofthe fitting. This is particularly suitablefor food grade hose assemblies. Internal swaging is achieved by pulling a hardened tool of larger diameter, (commonly known as (dolly) down the inside of the stem in order to expand it. The compressive force exerted on the hose by the coupling causes the hose material to flow into the serrated cavities of both tail and ferrule thus providing a secure mechanical bond.

"External Swaging"  is the reverse of internal swaging in that it is the act of compressing the ferrule onto the hose material in order to compress it against the stem to provide grip. External swaging is achieved by pushing the hose and end fitting assembly through a hardened steel die whose inside diameter is smaller than the external diameter of the ferrule. Similar in principle to internal swaging, the external diameter of the ferrule is permanently reduced such that the resulting compressive force exerted onto the hose causes it to flow into the serrated cavities of both stem and ferrule thus providing a secure mechanical bond.

"Dual Swaging"  is a concept exclusively developed by Shand UK in order to attach end fittings onto high pressure flexible hose or pipe. Dual swaging is achieved by the act of compressing both the stem and the ferrule onto the hose material in order to provide a secure method of attachment. Both internal and external swaging by themselves are perfectly suitable for low to medium pressure applications, i.e. less than 100 Bar working pressure, but for higher pressure applications up to say 1,000 Bar, it is essential to dual swage. Dual swaging is effectively internal and external swaging combined. The aim is to compress both stem and the ferrule onto the hose in order to provide the necessary grip. It is essential when dual swaging to compress both the inside and outside diameters of the hose or pipe by similar amounts in order to minimise the disruption to the reinforcing layer usually positioned towards the centre of the hose or pipe wall.

"External Crimping"  provides a similar method of attaching end fittings as external swaging and the end fittings used are essentially the same. External crimping is the act of compressing the hose ferrule onto the hose material in order to compress it against the stem and is achieved by a multi-segmented external die. Similar in principle to external swaging, the external diameter of the ferrule is permanently reduced such that the resulting compressive force exerted onto the hose material causes it to flow into the serrated cavities of both stem and ferrule thus providing a secure mechanical bond.