JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 55

repair TECHNOLOGY

Automated repair preparation
and post-machining of composites
This paper focuses on the reworking of fibre-reinforced plastic (FRP) components during manufacturing as well as the repair of such structures while in
service. It gives a summary of adaptive machining in the field of composites
and showcases the achieved results as well as current developments.
Dr. ClAus Bremer
President
BCT GmbH

P

reliminary studies have shown that milling is more effective
than laser ablation and water jetting for composite material
removal. To achieve perfect preparation of the repair area, all
aspects of scarfing by milling must be examined meticulously. Various milling strategies and new milling tools have been developed
and optimized. In any case, the milling process requires a very accurate tool path referring to the as-is geometry of the component
to be scarfed.

3D scanning
Every adaptive machining process starts with the capture of component geometry. One of the goals of the system development was
to be able to machine a repair scarf without any prior knowledge of
a part's nominal geometry, e.g. through CAD data. Hence, a precise
measuring process lies at the core of the adaptive milling process.
A wide variety of tactile measuring methods and optical scanning
systems are available for this purpose - from the classic machine-integrated tactile probe to the robot-guided structured light scanner.
During the design of an adaptive machining system and process,
the specified accuracies and the geometrical task description are
decisive. Optical scanners are the devices of choice for large-scale
CFRP structures, which are to be milled in three dimensions over
their entire surface.
A second important aspect is the decision as to whether geometrical

data capture should be integrated into the numerically-controlled
(NC) equipment or whether a separate scanning system would be
more advantageous. If separate units are used for scanning and for
NC machining, additional expenses and effort may be required for
materials handling and, possibly, for fixtures and component referencing as well.
In general, machine-integrated scanning is the preferred system
configuration for large and floppy components.
While an overwhelming variety of scanning technologies is available for separate scanning units, the possibilities for machine-integrated geometrical data capture are currently largely limited to
touch-trigger probes. To remedy this situation, a solution has been
developed that permits 6-axis scanning with line scanners in 5-axis
NC machines - here the spindle is used as the sixth controlled axis
- as well as for industrial robots (Figure 1). With this solution, process-integrated scanning of components can be performed.
As the laser line scanner has a relatively small focus area, a precise
distance to the surface to be scanned must be maintained in order
to attain precise measurements. To generate the scanning path, a
rough geometrical model of the component is needed. A point laser

Focus
Issues and context
Throughout the manufacturing, reworking and repair of FRP
components, unavoidable deviations from nominal shape play
a decisive role. For several decades, geometrically-adaptive
machining technology has been used successfully in the manufacture and repair of aero-engine and turbine components. This
technology has now been transferred and adapted to the needs of
the composite sector.

Fig. 1: Line scanning
as part of a mobile
milling machine on a
composite helicopter
fuselage

No108 October 2016

/ jec composites magazine

55



Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #108 - October 2016

Cover
Edito
Opinion: BOI Thaïlande
Contents
NEWS
In brief
Agenda
JEC Conferences 2017
BUSINESS
Merging
Basalt
MANUFACTURING
Biocomposite
Green Materials
3D Printing
Feature Wind energy RECORD BEATING INDUSTRY
Resin
Performance
Recycling
Recycling
Offshore
Process
Design
Market
SOLUTIONS
Marine
Infrastuctures
Construction
Pavilion
In the world
TECHNOLOGY
Simulation
Repair
Index
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - BckCovAd
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - Cover
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 2
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - Edito
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - Opinion: BOI Thaïlande
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 5
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - Contents
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 7
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - In brief
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 9
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - Ad1
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - Ad2
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - Agenda
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - JEC Conferences 2017
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 12
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - Merging
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 14
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - Basalt
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 16
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 17
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 18
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - Biocomposite
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 20
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 21
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - Green Materials
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 23
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 3D Printing
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 25
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 26
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - Resin
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 28
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 29
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - Performance
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - Recycling
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 32
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - Recycling
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - Offshore
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - Process
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 36
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - Design
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - Market
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 39
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 40
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - Marine
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 42
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 43
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - Infrastuctures
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 45
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - Construction
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 47
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - Pavilion
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 49
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - In the world
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 51
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - Simulation
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 53
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 54
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - Repair
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 56
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 57
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - Index
JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 59
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