CBAM: Composite-Based Additive Manufacturing

CBAM-made Carbon Fiber Reinforced Plastic (CFRP) Parts

How CBAM works

Feed fiber

sheet into inkjet

printer.

17 GSM areal

weight for

nonwoven

sheets:

• Carbon

• Fiberglass

Load CAD

slices into

printer and use

600DPI inkjet

system to print

aqueous fluid

layer shape of

object on fiber

sheet

Deposit polymer

powder onto

printed sheet

which sticks to

where the sheet

is wet from print

fluid.

Powder particle

approximately

50 to 100 micron

Air knife and

vacuum to

remove dry

powder; only

powder stuck to

the print fluid

remains based

on weight

calculation of

20% carbon

and 80%

polymer

Stack sheets in

order, heat to

melting T° of

polymer, and

compress stack

to final part

height.

200◦C nylon 12

400◦C PEEK

Compaction

pressure 100 -

150 psi

Abrasive removal

of un-bonded

portions of sheet

fibers to net final

part.

60psi, 12 CFM

Abrasives

• Walnut shells

• Silicon carbide

#320

• Aluminum

Oxide #220

STEPS

Step 1 Step 2 Step 3 Step 4 Step 5 Step 6

Step 1

Print image on fiber sheets Step 2

Heat & Press

Step 3

Remove Part

4 Impossible Objects Confidential

Nonwoven Composite Materials

A nonwoven is a highly porous fiber sheet with tuneable properties

• Nonwoven composite veils and mats are composed of:

– Long (> 1’’ length) chopped engineered fibres

– Uniform, random fibres orientation

– Held together with a polymer binder

• Fiber type dictates properties, typical examples:

– Carbon, glass, aramid, polyester, metal-coated carbon, thermoplastics

Non-woven fiber veils

• Carbon Fiber

• Kevlar

• Fiberglass

Polymers Matrix Materials

• HDPE

• Nylons

• PEEK

• PEI and TPU (under evaluation)

NOTE:

PEI is a flame retardant resin has UL94 V0, V2 and 5VA ratings an is RoHS compliant

Option for a open material system allowing for third party materials

Kevlar

Carbon Fiber

Fiberglass

Build materials options

Co

st

Dri

ve

n

Pe

rfo

rma

nc

e D

rive

n

amorphous crystalline

Engineering

Polymers

High Performance

Polymers

PET PBT

POM PUR

PC PPE

Commodity

Polymers

PA4.6

PPA

PPS

LCP

FPs

PEEK

PA12

PA11

PAI

PPSU

PEI

PES

PSU

PAR PA612 Transp. PA

PA6 / PA66

PI

PVC

ABS

PS SAN

PE

PP

PMMA

PMMI

PMI

PE-LD PE-HD

High Performance Material Focus

Thermal Properties

0

50

100

150

200

250

300

350

PEEK PPSU PEI PPA PA66 PA12

Tg Tm HDT A HDT B

Tem

pera

tur

(°C

)

PEEK Material Properties

Key Properties:

• Excellent chemical, mechanical &

thermal resistance

• Low water absorption, dimension

stability & constant material properties

over a wide temperature & humidity

range

• Excellent sliding friction behavior,

minimal abrasion

• Outstanding chemical and hydrolysis

resistance

• Low tendency to form stress cracks and

low creep at high load

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CBAM Microstructure

CT Scan – courtesy of

Carbon Fiber/PEEK Tool

Standard void content ranges from 1 to 10%

PMC Microstructure

500X

100X

X Z

Baseline Material Properties

11

Test standard Test standard measurement Carbon+ Nylon 12 Carbon+ PEEK

Mechanical Properties

ASTM D256 Notched Impact 7.1 KJ/m2 49.3 KJ/m2

ASTM D4812 Unnotched Impact 18.8 KJ/m2 13.2 KJ/m2

ASTM D638 Tensile 102.6 Mpa (14.8 ksi) 131.9 Mpa (19.1 ksi)

ASTM D638 E-modulus 9.22 Gpa (1337.4 ksi) 12.74 Gpa (1847.7 ksi)

ASTM D638 Poisson's ratio 0.44 0.32

ASTM D638 Elongation % 1.20 1.04

ASTM D695 Compression 7802 psi 23500 psi

ASTM D790 Ultimate Flexural Strength 131.5MPa (19.1 ksi) 176.7 MPa (25.6 kpsi)

ASTM D790 Flex modulus 9.05 Gpa (1312 ksi) 12.43 Gpa (1802 ksi)

Thermal Properties

ASTM D648 HDT 332°F (167°C) 315°C - 340°C

ASTM D5470 Thermal transmission 1mm with sic oil 4.01 K/W 5.39 K/W

ASTM D5470 Thermal conductivity transmission 1mm with sic oil 0.279 W/mk 0.223 W/mk

ASTM E831 CTE - below softening point 176.7 µm/m°C 65.5 µm/m°C

ASTM E831 CTE - above softening point 389.2 µm/m°C 246.9 µm/m°C

Thermal Properties

Density 1.1 g/cm3 1.4 g/cm3

Part Tolerance Analysis

Part Tolerance

Part surface finish & feature detail

• Great feature detail

• Parts can be post processed to a Surface finish Roughness Ra of 20 micro-inches (µin)

Light weight structures

• 50% lighter than aluminum part

• Enables integrated part designs

• Self aligning assembly features

• Capability to incorporate text into parts

• Improves product performance

Monolithic Structures

• Design freedom to combine multiple components

• Capability to build variable wall thicknesses

• Capability to make parts with various fine to large feature details

• Various build material options

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Enclosure Cases

EMI enclosure cases – Fiberglass/PA12 • Transparent to radio EMI/RFI transmissions • Non-conductive • High dielectric capability • Very light weight 1.1 g/cm3

Electronics Enclosures – Carbon/PEEK • Electrical Conductivity • High temperature resistance • Static dissipation • Chemical resistance • Very light weight 1.4 g/cm3

Multi-functional structures

Glass fiber layer

Carbon fiber layers

Non-conductive glass fiber layer

Conductive carbon fiber layers

• Upper and lower surface made with nonwoven carbon

• Sandwich structure is 17 gsm nonwoven fiberglass

• Nylon 12 thermoplastic as the matrix material

• Demonstrates conductive and insulative material properties

• Provides capability to tailor electrical and mechanical part properties

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Tooling Applications

• Drill guides

• High temperature tooling

• High temperature 350◦ F Composite fabrication tools

(ORNL CRADA)

• Metal forming

CBAM Model One Pilot System

• 12” x 8” min. up to 12” x 18” build envelope

• Print speeds of 6 -10 sheets/minute

• Robust electronics

Impossible Objects Confidential

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Thank you for your time.