JEC COMPOSITES MAGAZINE - Issue #130 - September/October 2019 - 33

Developments in filament winding software

together with the winding program itself
via a high end controller. This can eliminate
all manner of failure possibilities die to user
errors and is highly attractive in quality lead
industries such as automotive, aerospace and
defence.

Woven tape
used on a 90 degrees
bended elbow

Accurate control of twist & shear is very important with wide fabric tapes

Winding machine
control and configuration
There is a huge diversity of Control systems
used on winding machine, most are as
G-code type controllers that also find use in
CNC Milling and turning machines. As well
as the CNC style controllers are as many
motion systems with their own proprietary
languages, for example Kuka Robots is KRL
(Kuka Robot Language) and ABB Robots
use the RAPID language.
Coupled to this, there is also are range of
mechanical configurations with between 2
and 6 degrees of motion freedom, standard
lathe type configurations, Articulated Robot
arms and machines with swinging arm axes.
To cope with this diversity and other practical
considerations such as the materials being
wound, Cadfil has several user selectable
control strategies. The control output gener-

ated for the machine is a combination of the
chosen control strategy and a user configuration file. For maximum flexibility in Cadfil
we created out own configuration language
this allows a user to be able to configure and
output style and format for pretty much any
type of winding machine and controller.
A big advantaged of this system is that customers can have several totally different winding machines but can just by the selection of
the appropriate machine configuration can
make programs for the same set of wining
patterns on any of the machines. Some users
take full advantage of the huge flexibility and
possibilities of this configuration by making
the winding programs highly integrated into
the manufacturing quality system so that
things such as materials types and batches,
tooling selected for the winding machine,
label printing, oven settings etc. are all tied

Developments in
pipe fitting winding
A good case study in the interaction of
machine design and flexible software control
strategy can be demonstrated by looking at
the winding of Pipe elbow fittings. Figure3
shows a 600mm Diameter pipe elbow with
a 90 degrees bend. One of the challenges
of winding such parts is achieving good
axial strength. It is very easy with high angle
(hoop) winding to achieve a very high radial
burst pressure. However, if pressure tested
with enclosed endcaps, we have significant
bending forces trying to 'snap' the elbow
and to counter this efficiently we need some
low angle winding. Low angle winding is not
physically possible as the fibres just bridge
across the inside of the bend. One good
solution is to use woven (0/90) fabric tapes.
With the part in the picture is very practical
to wind high angles with 200mm wide tapes
and this gives optimal fibre directions for the
principle stresses whist maintaining continuous filaments in the hoop direction and very
long fibre filaments in the axial direction. A
further benefit is that we also get a high rate of
material application for a shorter production
time. There is however a technical challenge:
Wide woven tapes are quite difficult to handle
on the rapidly changing double curvature of
a pipe bend. The tape needs to be precisely
controlled on the payout roller. It is very easy
to get shear in the tape which grossly distorts
the transverse fibres and causes both ripples,
gaps and large angle variations.
A second problem is if the tape needs to be
kept central to the rollers as deviation to the
edges can make the tape fold over on itself and
also decreases the accuracy and consistency
of application to the mandrel. Tape twisting
can also lead to a similar set of problems.
An illustration Twist and shear can be seen
in the TSW diagram, Cadfil can analyse and
output this information on a position by
position basis for any chosen control strategy.
When this was compared with the working
parameters of using the tapes it leads to the

N°130 September - October 2019

/ jec composites magazine

JEC COMPOSITES MAGAZINE - Issue #130 - September/October 2019

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #130 - September/October 2019