Page 37 - 2010-2022 hose manufactureing ability and guide

MANUFACTURING METHODS

Chapter 2

The principal methods used to manufacture hose will be described and illustrated in this chapter. The
three basic methods: (1) non-mandrel, (2) flexible mandrel, and (3) rigid mandrel, describe how the various
components of the hose are supported during processing into a finished product. The processing equipment
used to fabricate the three typical hose components (tube, reinforcement, and cover) as discussed in Chapter 1
will be characterized herein. The advantages and disadvantages of each of these techniques will be
overviewed with special consideration given to application, working pressure, diameter, production volume,
and cost. Finally, rubber hose vulcanization techniques will be reviewed.

Hose manufacturing methods have been Essentially, the non-mandrel technique
evolving for over 100 years. Some of the older involves extruding the tube, applying the
techniques are still in use but with a variety of reinforcing, and extruding the cover in the
optimizations for specific needs. In addition, unsupported mode (without a mandrel).
advanced concepts are continually being Frequently low pressure air is used inside the
introduced for improved efficiency by a tube for minimal support, keeping the tube from
diversified array of well-qualified equipment flattening during the reinforcing process. In
manufacturers. some cases, especially 1" to 2" ID, the tube may
be extruded with air injection along with an
THREE BASIC METHODS OF MAKING internal lubricant to prevent adherence to itself.
HOSE
The non-mandrel tube extrusion process can
Hose is manufactured in the unvulcanized
state by forming a cylindrical tube over which a be done continuously, if appropriate handling
reinforcement and cylindrical cover are applied. equipment is available, thus providing excellent
In its uncured form, a hose tube will often need length patterns for the finished product. In
recent years with improvements in die design
support to maintain proper internal diameter
(ID) and dimensional tolerances while being and cooling, dimensional control of non-
processed through the various stages of mandrel rubber tube is approaching that of
flexible mandrel style.
manufacture. Thus, the three basic methods of
making hose have evolved: (1) non-mandrel, (2) Most smooth bore thermoplastic hoses are
flexible mandrel, and (3) rigid mandrel. In extruded non-mandrel. The higher rigidity of
methods (2) and (3), the mandrels are used for most thermoplastics eliminates the need for
support and as dimensional control devices for mandrel support. In addition, with advanced
the hose tube during processing. Then after the cooling and dimensional sizing equipment,
hose building and, if necessary, the thermoplastic tube dimensions can be
vulcanization are complete, the mandrels are maintained quite accurately.
removed, inspected and recycled.
Flexible Mandrel Style
Non-mandrel Style
When moderate tube processing support is
The non-mandrel method of manufacture is needed and more accurate dimensional
generally used for lower working pressure (less tolerances are a concern, flexible mandrels may
than 500 psi), smaller diameter (2" and under), be utilized. These mandrels are rubber or
textile reinforced products not requiring thermoplastic extrusions, sometimes with a wire
stringent dimensional tolerances. Typical hose core to minimize distortion. This style process
products in this category would include garden, may be used for mid-range working pressures
washing machine inlet, and multipurpose air (up to 5000 psi) with ID’s of 1/8" to 1-1/2".
and water styles.

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