Daniel T. Buckley Manager of R&D American GFM · Directed Fiber Oldest method P4/P3 and variations Slurry Rimfire Bentley Magnetic Carbon Fibre ... Carbon Fiber Very thick preforms

Daniel T. Buckley Manager of R&D American GFM

Preforming goes back about 75 years Invented by Ivan Brenner All Liquid Composite Molding Processes “Closed Mold Processes” RTM, SRIM, VARTM, High Pressure RTM, ETC. RTM Lite, Resin Infusion, RFI Wet Compression Molding Mid to High Volume Structural, Semi-Structural and non Structural

Reduce Cost Repeatable and Accurate Laminate Schedules Reduction of Manual Labor Faster Molding Cycle Use of Hot Molds Use of Closed Molds to eliminate VOCs Efficient use of expensive Molding tooling Compression Molding Mid to High Volume Predictable Molding Process

Directed Fiber Oldest method P4/P3 and variations Slurry Rimfire Bentley Magnetic Carbon Fibre CompForm and MatForm

Thermo/Thermal Forming Many Variations on Theme Powdered Binders

Thermoplastic or Thermoset Binders

Factory supplied preformable mats and fabrics

CompForm Visable Light or UV Light Cure Carbon Fiber Specific Processes

Single Bladder, Double Bladder Diaphragm, Vacuum forming, Pressure/presser

foot/roller, etc. Binders Liquid, Powder/Melt and String Thermoset Binders Epoxy, Urea, Resol, Acrylate, UP, Epoxy Acrylate, etc.

UV and Visible light curable Thermoplastic Binders PBT, PET, Epoxy, etc.

Tackifiers Staples and Tape

Oldest Preforming Method Variations

P4, P3, Powdered and String Binders

Brenner/CompForm

Budd Slurry

Dow Flame Spray

RIMFIRE

Complements of MFG

Brenner/CompForm

Courtesy OCF

Pre weighed

chopped fibers are

dispersed in water.

Air is bubbled up

from bottom to

keep fibers

dispersed. weighed chopped fibers are

dispersed in water.

Chopped fibers

are collected by

perforated screen

as it is moved

vertically through

water until screen

is above water

and can be

removed for

drying.

Spare Tire Well

Preform

Courtesy of Bentley

Molded Spare

Tire Well

Courtesy of Bentley

Low cost input materials-Rovings Isotropic Properties P3,4 etc. capable of some Anisotropy Very low trim scrap Low to Mid Volume Fractions/Slurry Low to High Volume Fractions/P’s Deep draw possible, male tooling In Mold—Rimfire, onto Gelcoat In Mold-Bentley Magnetic Carbon Fibre In Mold-Various flame/hot melt binder Preform and mold in same tool Relatively Fast Deposition Rates

Isotropic Properties Difficulty getting Anisotropy High Energy Use Mid to High Volume Fractions difficult Large Volume Fraction Variations Randomized Process High loft and loft control, Inside Radii Bridging, Outside Radii Blocking Rimfire, Fast Loft increases with thickness Deposition Rates can be slow

Poor Shape Definition on side away from screen

Thickness/Weight/Volume Fractions limited by Air Movement

Some Binders Systems Non Compatible with Matrix Resins

Some Binder Systems Migrate during Molding

Some Binder Systems foul the Preforming Equipment and ducting

Can be messy around equipment

Heat/Form/Cool process

Heating Typically IR Ovens

Binder releases when heated above Melt Temperature

Thermoformable Continuous Strand Mats typically use Thermoplastic Binders (PBT)

Various NCF Fabrics supplied with various Thermo Process capable Binders

Typically Binder applied during Weaving/Stitching

Some Carbon fabrics with Epoxy based Binder

Binders can be applied at Molders Location

Courtesy OCF

Standard Materials Available Some Thermal Forming NCF Fabrics Available Some Woven Fabrics Available Isotropic Properties with Continuous Strand

Mats Relatively Fast Processing Times Relatively Low Cost Equipment Glass and Carbon manual preforming

possible Different Types of Binders can be Used

Courtesy of Plasan

BMW i3

Limited Material Selection but getting Better Volume Fractions Energy due to Heating/Cooling Very Thick or Very Thin Preforms Isotropic Properties with mats Draw or Depth Thinning During Draw Springback

Conformability/Drapability

Wrinkling, Folding and Bunching

High Cost of Material

With High Temp Molding the Binder can release and not hold fibers in Place during infusion

Thermoformable CSM Expensive for Properties

Supply of Thermoformable Mat is Limited

Can be Very High Trim Scrap

Sometimes Binder Migrates during elevated Temperature Molding Processing

Binder Compatibility

Courtesy of Fiber Innovations

Custom braided sleeve products and Some Standardized Products

Historically Both are relatively expensive Historically, Typically for Low Volume Great Physical Properties Various Anisotropy All different kinds of Fibers and hybrids Z Direction Reinforcing Tailored Fiber Placement is very Material efficient

and getting faster with new technology Tailored Fiber Placement can be combined with

larger preforms made from NCF Fabrics Not rigid preforms but can be

Fiber Orientation and Geometry

Optimized for Product Properties

Tailored Fiber Placement

LayStitch Fiber Printer

www.LayStitch.com

www.TailoredFiberPla

cement.com Phone: +1 (248) 346

5146 - e-mail:

[email protected]

http://www.laystitch.com/http://www.laystitch.com/http://www.laystitch.com/http://www.laystitch.com/http://www.laystitch.com/http://www.tailoredfiberplacement.com/http://www.tailoredfiberplacement.com/

Needle

Thread


www.LayStitch.com

www.TailoredFiberPlacement.com

Phone: +1 (248) 346 5146

e-mail: [email protected]

http://www.laystitch.com/http://www.laystitch.com/http://www.laystitch.com/http://www.laystitch.com/http://www.laystitch.com/http://www.tailoredfiberplacement.com/

Material Optimization

Topological Optimization


www.LayStitch.com

www.TailoredFiberPlacemen

t.com

Phone: +1 (248) 346 5146

e-mail:

[email protected]

http://www.laystitch.com/http://www.laystitch.com/http://www.laystitch.com/http://www.laystitch.com/http://www.laystitch.com/http://www.tailoredfiberplacement.com/http://www.tailoredfiberplacement.com/

Uses Light cure for Fiberglass Materials

Special Matrix Resin Specific Binders for Carbon Fiber Very thick preforms and Opaque Materials

Target Markets are Automotive and Higher Volume Applications

Very High degree of Process Flexibility

Process easily Automated

Process can provide Net Shape Preforms

Infusion Stable Binders

From AGFM

Light Cure is Very fast Cure is maximum of 18 to 20 seconds Cure can be in 1-3 second range

Very Energy Efficient No lights used except during cure step

No Heating required in Process Therefore Low Cost Composite Tooling

Works on all Fiberglass Materials Engineering Fabrics Continuous and Chopped Strand Mats All Veils

Energetic Stitching Complex Preforms Lighting can be on Tooling Surface Eliminates High Intensity Lights Single side or Two side Lighting Lighting can come on with Tooling Closed

Flexible Cell Designs Binders are Compatible with all common

Matrix Resins Can Preform behind and onto skins Works with Directed Fiber Preforming

From AGFM

Extremely Fast cure Cycles Possible Typically User Determines Binder % Liquid Binder is 100% Solids, no VOCs User can Determine Binder Location Matrix Resin BinderCompatibility Complex Preforms Selective Curing Complex Shapes Low Energy Cure

Virtually any Reinforcing Material

Conformability of Certain Materials

High Volume Fractions

Cores and Fasteners

Anisotropy determined by Material Selection and Laminate Schedule

Preform Assembly for very Difficult Shapes or Impossible Shapes

Preforms to any Thickness

Single Step Thickness Limited

Anything Opaque

Liquid Binder Application

Cost of High Intensity Lighting

Very Deep Draws can be slower or require Male Preforming tooling

or require Separate preforms

Binder Cost Relatively High

Net Shape is when the Preform fits the Molding Tool with no material outside the Mold Cavity

Net Shape fits the molding tool such that the parting line is closed

Net Shape provides molded parts that do not have to be trimmed except for flash

Net Shape provides parts that are essentially ready to be used

Net Shape eliminates most or all secondary operations

Net Shape virtually Mandatory for High Volume

Net Shape Yields High Degree of Accuracy in the Molded Part

Net Shape Keeps the Parting Line Sealed

Net Shape allows High Molding Pressure and Closed parting lines

Net Shape allows High Resin Holding Pressures

Net Shape allows Control over Mold Vacuum

Net Shape requires Accurate Trimming/Cutting

Net Shape Cutting Machinery is Expensive Net Shape Cutting/Trimming adds Step Net Shape requires accurate Near Net Shape

Preforms Net Shape Requires stable Preforms to

prevent fiber distortion during Cutting/Trimming

Net Shape Preforms to be stable during Handling

Courtesy of Ford

Motor Company

Courtesy of Ford Motor

Company

From AGFM

4 Layers 24 oz Woven Roving

From AGFM

Saertex,Chomarat, Syncoglass, Owens Corning, Etc

Pros Simple Shapes do not Require Preforming Essentially a Sandwich Construction Different Core Materials Available Easy Infusion

Cons High Cost to Performance Ratio Draw Limits and Thinning Low Volume Fractions High resin content between mats in center

From AGFM

Simple Shapes Do not Require Preforming Unless fiber stabilization required for infusion

Numerous Different constructions available Can be Stitched Fabrics or Woven Fabrics Good for Structural Applications Excellent for Preforming using Binders for

Stabilization Varying levels of Conformability Available in all kinds

of Fibers Hybrids Available Available in various fiber orientations Available in multiple axial orientations Excellent Physical Properties

Can be Expensive

Difficult to Handle Manually

Some Constructions do not conform well

Often Lose fiber alignment during Handling

Can Lose fibers during Handling

Fiber Alignment and Density changes during forming

Density changes can make infusion difficult Dry spots

Racetracking

Courtesy of Bentley

From AGFM

Courtesy of Plasan

From AGFM

Conformability is the most Important Criteria for Preforming any Roll good Material

During Preforming, Densities and Thickness Change Locally

Failure to conform creates numerous molding and infusion problems

To Model Flow, the Conformability needs to be known

During Preforming Fiber Orientation changes as a function of the shape

To Model Mechanical Properties the Fiber Orientation in 3D needs to be known

Complements of Textechno

GmbH, contact:

[email protected]

mailto:[email protected]


GmbH, contact:

[email protected]

m

mailto:[email protected]:[email protected]


GmbH, contact:

[email protected]

mailto:[email protected]

Non Elastic Reinforcing Materials do not Stretch

Fibers must Move, Shear or Break during Preforming of Roll Good Materials

The above Problems create Dry Spots, Non-Fills, Racetracking and/or integrity Problems in the Molded Part

From AGFM

Courtesy Citroen

Material follows the contour created by the through plane forming pressure

Areas of high fiber stress are created

Springback is the tendency to relieve the stress

All fiber reinforcing materials spring back to some degree depending on construction

To Control Race-tracking and resin rich areas the tooling must compensate

Courtesy of Bentley

Typically Thermo/Thermal processes are used to melt Binders, thermoset or thermoplastic

Preform can be Stabilized by either Cooling Binder or curing Binder

Tackifiers are often used but do not produce a rigid preform

Light Cure has very limited application with Carbon Fiber Single layer or with Fiberglass

Usually Woven or Stitched Fabrics but can be Directed Fiber

Bentley Developed adding Metal to Fibers and using Magnetic tooling to hold Directed Fibers in Place

Courtesy of Plasan

Look at Local and Global Properties Let Properties Drive Decisions Chopped Fibers vs. Continuous Fibers Random Fiber vs. Oriented Fibers Anisotropy vs. Isotropy

Material Selection, 3D Shape and Laminate Schedule drive Preform Process Selection

Model Fabric Conformability to verify material selection

Model Fiber Density and Orientation for correct Flow modeling

Model Flow to verify molding process

Performance Reinforcing Materials Selection Conformability Net Shape? Cores and fasteners?

Cost Volume Driven Reinforcing Materials Cost Preforming Process Trim scrap

Quality Quality/SPC Capable Process Low Scrap

Documents

Daniel T. Buckley Manager of R&D American GFM · Directed Fiber Oldest method P4/P3 and variations Slurry Rimfire Bentley Magnetic Carbon Fibre ... Carbon Fiber Very thick preforms