Automated Fiber Placement - SME - Home · Automated Fiber Placement (AFP) ... Material outage,...
Transcript of Automated Fiber Placement - SME - Home · Automated Fiber Placement (AFP) ... Material outage,...
Automated Fiber Placement A Buyer’s Perspective Looking At
The Future
Burak Uzman - ALA Group
Prof. Zafer Gurdal - TU of Delft
SME Manufacturing With Composites Conference 10/23/2012
Photo Courtesy of ElectroImpact
2
Contents
Purpose and Scope
Definition of AFP In the context of this presentation
System Architecture
Heads and Tows
AFP vs Hand Layup - Cost Savings
AFP – Investment Decision
About Productivity and Rates
Productivity Analogy
Productivity and Laydown Rates
How To Increase C-Rate?
What is Next?
New Engineering Tools
ALDO and OLGA by ADOPTECH
Automation of Inspection
Conclusions
3
Automated Fiber Placement (AFP)
Purpose of this presentation
To provide a new entrant buyer’s perspective
Economics of AFP
Process parameters that affect economics of AFP
Quantitative study of AFP productivity
Introduction to fiber steering and new design tools for AFP parts
Scope
Limit discussion to AFP machines that lay down slit tape.
No discussion on Automated Tape Layup (ATL), Pick and Place, and
dry fabric placement type systems.
No discussion of vendor specific AFP solutions or machine types.
ALA Group Proprietary Information
4
AFP System Architecture
Ref: US Patent 8,151,854
Vertical Axis Gantry
Type AFP Machine Photo Courtesy of Ingersoll Machine Tool Inc
Horizontal AFP Machine Photo Courtesy of Ingersoll Machine Tool Inc
Robotic Arm AFP System
Photo Courtesy of Coriolis Composites
5
AFP – Heads and Tows
Manufacturers Offer Three Types of Head Design;
Fixed Head
The head can’t be replaced in a production environment. The
spools are inside a creel house fixed to the machine.
Manually Replaceable Head
The head can be replaced by hand. Head replacement is not
automated.
Manually Replaceable Head
by Automated Dynamics
AFP Head
Spools
Tow
Path
Modular Head
The spools are on the head, and
the head replacement is automated
ElectroImpact Modular Head
6
AFP – Heads and Tows
Tapes and Tows
Initial material form was towpreg.
Now almost everyone uses slit tape material that is made by slitting a wide
roll of uni directional tape into narrower strips.
Tow Width can be ½”, ¼” or 1/8”.
Tow Width is determined by
Part contour, head clearance
Minimum steering radius (e.g. laying up a spar)
Available machine type (½” vs ¼” machine)
Aircraft OEM’s cert. database
Number of Tow Lanes on a head are determined by;
Head clearance – how easily the head can get in and out
Manufacturer’s preference
Productivity and Reliability – Relationship between number of tows and
laydown rate can be counterintuitive.
7
Merits of AFP – Cost Savings
AFP vs Hand Layup; $6 Million investment with 30 lbs/hr laydown rate.
Potential Cost Savings of AFP is around $16/lbs for solid laminates where price
metric is between $200/lbs to $310/lbs.
The catch: To recover the investment in 7 years, the manufacturer has to produce
around 35,000 lbs of composite laminates via AFP per year
Below 25,000 lbs/yr the investment has negative NPV.
ALA Group Proprietary Information
~10 lbs/hr
Below a certain laydown rate AFP is
more expensive than hand layup per
pound of structure.
As the laydown rate goes down so
does the NPV
More on laydown rates later…….
Asymptote: y = Cost of Slit Tape
8
The AFP Investment Decision
We Should Not Lose Sight of The Total Solution and Total Cost
Footprint Cost – Part of the Return on Assets (RoA) math for the corporate
finance dept. Some GMs are measured by revenue per square feet.
Foundation – some machines are heavier than others. Some require more
expensive foundations to achieve the same performance
Headstock/tailstock – some machines can eliminate the need for these
Tooling - Tool string can change drastically based on the type of machine bought.
Cost of additional heads for systems with changeable heads.
Installation costs
Software
Warranty
Cost of Spare components
Cost of Repair and Maintenance
Tech Support Cost
ALA Group Proprietary Information
9
Productivity - Analogy
One can think of an AFP System like a very expensive
office printer;
Paper jams, Printer Out of Paper, Ink Cartridge out of Ink…
Notice that the equipment never breaks down with a part
failure.
Process reliability versus machine reliability.
AFP process is similar, we run into similar issues;
Material outage, material reload, resin buildups, fuzz balls,
cutter breakage, miscut tows, twisted tows, tow
breakage…etc…etc
AFP System productivity is highly dependent on how quickly we
can resolve the issues between the spool and the head roller, as
much as it is dependent on the frequency of such events.
Ref:
http://www.freeimageslive.co.uk/free_stock_im
age/printer-problem-jpg
Ref: US Patent 7,353,853
ALA Group Proprietary Information
11
Laydown Rates
ALA Group Proprietary Information
A-Rate (typical 120 lbs/hr)
Course Length
Off-Course
Movement
Linear
Speed/Acceleration
Number of Lanes (n)
B-Rate (typical 60 lbs/hr)
• MTTR
• Machine Design Features
• Failure Rate (λ)
• Number of Lanes
• Machine Design
• Material
C-Rate (typical 15 lbs/hr)
• Tool Load and Setup
• In-Process Inspection
• In-Process Fixes Tow Breakage
Tow Twist
Cutter Failure
Dropped Tow
Fuzz Balls
18 in 36 in 60 in 96 in 144 in
acc (g) acc (in/sec^2)
0.01 3.84 16% 22% 28% 36% 44%
0.05 19.2 35% 49% 62% 72% 80%
0.1 38.4 49% 66% 76% 84% 89%
0.2 76.8 66% 80% 87% 91% 94%
0.4 153.6 80% 89% 93% 95% 97%
Vmax = 1600 IPMCourse Length (in)
Vavg/Vmax
Hypothetical Laydown Rates for
Machines with Various Number of Tows
and Individual Lane Availabilities.
12
Laydown Rate Limiters
ALA Group Proprietary Information
C-Rate
B-Rate
A-Rate
Theoretical Max-Rate
Rate Loss Due to Finite
Course Length
Rate Loss Due to Off-
Course Movement
In-Process Inspection Time
Sample Part
AFP Machine
16 Tow Lanes
½” Tows
1600 IPM
Acc: 0.2g
Lane Availability: 97%
Inspection: 6.3 min/layer
Part
210 lbs
80 layers
1020 courses
Avg. Course: 59”
13
How To Increase C-Rate and Profitability?
C-Rate determines the number of AFP Systems a manufacturer must
purchase to support rate production. Plus more….
A lower than expected C-Rate has major business implications for the
manufacturer;
Negative NPV for the investment and the production program.
Satisfying customer contract requirements most likely to require additional
capital investment (Cap-X)
Purchase of additional AFP Systems.
Purchase of additional cure fixtures/tools to be purchased.
Additional Floor space/facilities.
C-Rate is dominated by the time spent on inspection and fixes.
Develop an AFP System Qualification Process to reduce inspection
ALA Group Proprietary Information
14
What is Next?
Where AFP pays off;
Increase Productivity and Reduce Capital Investment
Place material with high accuracy in a repeatable/consistent fashion
Fabricate intricate parts – geodesic stiffened panels
Fabricate advanced structural configurations
What Is Next with AFP?
New Engineering Tools
Automation of Inspection
Cooperative tow placement
Automated 3D weaving/braiding
ALA Group Proprietary Information
15
New Engineering Tools
New Engineering Tools Are Needed To Exploit
Individual Tow Manipulation and Steering
Capabilities of AFP.
Potential to reduce weight through the flexibility to
tailor the stiffness distribution of each ply.
Design (CAD) - How to document each tow’s 3D
shape? How do we check?
Analysis (FEA) - Can no longer assign MAT2 or
PCOMP to entire surfaces.
Producability - Tow buckling, wrinkling, shifting,
overlaps…
Engineering for Fiber Steering requires the Design,
Analysis and Producability Assessment Cycle to be
integrated.
ALA Group Proprietary Information
Parallel Steering
Limited Tailoring,
Limited Weight
Reduction
Shifted Steering
Ply with tow drops
and tow adds
Significant tailoring
16
Laminate Design Software by
ADOPTECH
ADOPTECH has developed a suite of composite design and analysis
optimization software modules.
Specifically suited for fiber-placed composite structures is a two step
optimization process utilizing ALDO and OLGA modules.
ALDO: Advanced Laminate Design Optimization
Structural weight optimization using FEM and other analysis tools.
Reduces complexity of design variables and number of analyses.
OLGA: Optimization of Laminates Using Genetic Algorithm
Optimizes stacking sequence, creates layup schedules and generates
blended laminate designs.
Incorporates manufacturing constraints and structural optimization
results.
ALA Group Proprietary Information
17
ALDO by ADOPTECH
Enables design optimization of different zones of the same part
Provides ideal stiffness distribution over the surface of the part.
Constant regions or variable stiffness solutions
Evaluates material failure, vibration, buckling aspects.
Gradient-based optimization provides fast convergence
Fiber orientation and stacking sequence no longer design parameters
Utilizes commercial FEM (NASTRAN) or customized analyses
Rectangular plate under shear buckling – 4 Design Zones
After 8 Iterations - Optimum
Thickness and Stiffness For
Each Design Zone
ALA Group Proprietary Information
18
OLGA by ADOPTECH
Genetic Algorithm for stacking sequence design
• Software converts the stiffness matrices to laminate stacking sequences
• Discrete variables not a hindrance
• Global search for optimal layup
• Customized ply configurations and laminate rules allowed
• Manages (Blends) stacking sequence transitions between design zones
• Includes manufacturing process constraints
“Blind Blending” solution minimizes number of unique ply/layer definitions
• Matches stiffnesses to optimal results from ALDO
• Includes production cost and time estimates from manufacturing packages
ALA Group Proprietary Information
19
Automation of Inspection
In-process inspection time is significant!!! Directly affects floor to floor
rates, and profitability of the program
In-process inspection automation will likely to require technology
development in areas that are not core to the machine builders’
capabilities;
Machine Vision and Artificial Intelligence based software development
Markers/tracers in slit tape material
Multi spectral sensors development to sense multiple physical phenomena attributable
to composite materials
The Boeing Company already has a few patents in this area;
US7678214, US7807002, US6871684, US8158210, US7688434, US7555404,
US8184281, US7039485, US7171033, US7193696, US7236625….
20
Increased Accuracies and Precision
For the advanced applications of AFP to become feasible, placement
and cut length tolerances need to be below 0.010”
Collaborative Tow Placement – Increasing Availability and Laydown
Rates
Multiple machines placing material on the same part at the same time.
Parallel system increases system availability, laydown rate linearly proportional to
number of lanes deployed.
Zone responsibility for each machine requires; precise splicing on long courses and
tight tolerances on tow-to-tow gaps/overlaps.
Automated Weaving/Braiding
Increase damage tolerance of the composite part by automated 3D weaving/braiding.
Can be done with splicing – requires significant improvement in cut length accuracy
Research with existing technology shows promising results.
ALA Group Proprietary Information
21
Conclusions
The technology has just overcome its “trough of disillusionment” in the
technology adoption hype cycle. Significant road ahead.
Functioning prototypes of the 90s are being replaced by first and second
generation products.
There will be new technologies, higher productivities, less expensive solutions,
new machines, new machine vendors. The business sure will change.
Gartner Group’s Hype Cycle For
Emerging Technologies
ALA Group Proprietary Information