The hydraulic fluid (liquid grease or hydraulic oil) is pressurized by a piston
and expands the plastic expanding sleeve, reinforced by glass fiber (GFK)
or by carbon fiber (CFR), to the locating hole size of the workpiece.
The sleeve can be expanded to max. 1% of its diameter.
The workpiece can be chucked either directly with the expanding sleeve or
indirectly, using a cylindrical intermediate sleeve with slots on both sides.
For transmitting high torques the intermediate sleeves are provided with a
positive driver. Sets of interchangeable intermediate sleeves are available
for adaptation to different hole sizes.
Properties of HYKS expanding mandrels
The ingenious design and the direction of fiber flow of the GFK and CFK expanding
sleeves permit accurate cylindrical and round expansion to within 0.005 mm over
the full chucking range.
The expanding sleeve compensates for any radial run-out of the workpiece in the
hole diameter so that any deformation of the external contour is precluded at all
chucking pressures.
The snug fit of the expanding sleeve in the hole of the workpiece results in
optimum damping during machining. It also minimizes noise and substantially
increases tool life.
The expanding mandrels may be used for rotating or stationary work and can be
operated by means of hydraulic or air cylinders, directly by the hydraulic system
of the machine or even mechanical functions assures consistently high true running
and linear accuracy.
Applications
Röhm HYKS expanding mandrels with diameters of 20 mm or more are available in
virtually any length and for any type of mounting and chucking diameter. The larger
sizes have a light metal core to reduce weight. Expanding mandrels of this type are
mainly used for thin-walled cylindrical parts, such as cylinder liners in the automotive
industry, light metal cylinders for a variety of applications and tubes requiring a high
true-running accuracy on the outside diameter.
Other applications include jigs and fixtures as well as gauging and inspection
equipments.
![[HYKS Hydraulically Operated Expanding Mandrels]](mandrel04.jpg)
![[HYKS Hydraulically Operated Expanding Mandrels]](mandrel05.jpg)
