Kathy C. Chuang, Joseph E. Grady, Steven M. Arnold, and Robert D. Draper

Glenn Research Center, Cleveland, Ohio

Eugene Shin

Ohio Aerospace Institute, Brook Park, Ohio

Clark Patterson and Tom Santelle

Rapid Prototyping+Manufacturing (rp+m), Avon Lake, Ohio

Chao Lao, Morgan Rhein, and Jeremy Mehl 

Glenn Research Center, Cleveland, Ohio

A Fully Nonmetallic Gas Turbine Engine

Enabled by Additive Manufacturing

Part II: Additive Manufacturing and Characterization of

Polymer Composites

NASA/TM—2015-218749

June 2015
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Kathy C. Chuang, Joseph E. Grady, Steven M. Arnold, and Robert D. Draper

Glenn Research Center, Cleveland, Ohio

Eugene Shin

Ohio Aerospace Institute, Brook Park, Ohio

Clark Patterson and Tom Santelle

Rapid Prototyping+Manufacturing (rp+m), Avon Lake, Ohio

Chao Lao, Morgan Rhein, and Jeremy Mehl 

Glenn Research Center, Cleveland, Ohio

A Fully Nonmetallic Gas Turbine Engine

Enabled by Additive Manufacturing

Part II: Additive Manufacturing and Characterization of

Polymer Composites

NASA/TM—2015-218749

June 2015

National Aeronautics and

Space Administration

Glenn Research Center

Cleveland, Ohio 44135
Acknowledgments

The authors would like to thank Drs. Mike Dudley and Koushik Datta from NASA Aeronautics Research Institute for their 

continuous support and encouragements. In addition, we would like to thank Michael Vinup, Natalie Wali and Don Weir of 

Honeywell Aerospace for providing component CAD fi les, and the following collaborators for their contribution in terms of 

material characterization and mechanical testing efforts for this report: Pete Bonacuse, GRC-LMA, Joy Buehler/LMA-VPL, 

Chris Burke/LM-SLI, Chris Kantzos/GRC, LERCIP intern, Rich Martin/LMA-CSU, Linda McCorkle and Daniel Scheiman/

LMN-OAI, D. Jordan McCrone/ LMA-VPL, Bob Pelaez/GRC-FTH, Larry Smith/FTC-Jacobs, Tim Ubienski/FTH-SLI, Nathan 

Wilmoth/LMA-VPL and rp+m staffs.

Available from

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This report is available in electronic form at http://www.sti.nasa.gov/ and http://ntrs.nasa.gov/
NASA/TM—2015-218749 1 

A Fully Nonmetallic Gas Turbine Engine Enabled by 

Additive Manufacturing 

Part II: Additive Manufacturing and Characterization 

of Polymer Composites 

Kathy C. Chuang, Joseph E. Grady, Steven M. Arnold, and Robert D. Draper 

National Aeronautics and Space Administration 

Glenn Research Center 

Cleveland, Ohio 44135 

Eugene Shin 

Ohio Aerospace Institute 

Brook Park, Ohio 44142 

Clark Patterson and Tom Santelle 

Rapid Prototype Plus Manufacturing (rp+m) 

Avon Lake, Ohio 44012 

Chao Lao,*

 Morgan Rhein,* and Jeremy Mehl*

National Aeronautics and Space Administration 

Glenn Research Center 

Cleveland, Ohio 44135 

Abstract 

This publication is the second part of the three part report of the project entitled “A Fully Nonmetallic 

Gas Turbine Engine Enabled by Additive Manufacturing” funded by NASA Aeronautics Research Institute 

(NARI). The objective of this project was to conduct additive manufacturing to produce aircraft engine 

components by Fused Deposition Modeling (FDM), using commercially available polyetherimides—Ultem 

9085 and experimental Ultem 1000 mixed with 10% chopped carbon fiber. A property comparison between 

FDM-printed and injection molded coupons for Ultem 9085, Ultem 1000 resin and the fiber-filled composite 

Ultem 1000 was carried out. Furthermore, an acoustic liner was printed from Ultem 9085 simulating 

conventional honeycomb structured liners and tested in a wind tunnel. Composite compressor inlet guide 

vanes were also printed using fiber-filled Ultem 1000 filaments and tested in a cascade rig. The fiber-filled 

Ultem 1000 filaments and composite vanes were characterized by scanning electron microscope (SEM) and 

acid digestion to determine the porosity of FDM-printed articles which ranged from 25 to 31%. Coupons of 

Ultem 9085, experimental Ultem 1000 composites and XH6050 resin were tested at room temperature and 

400 °F to evaluate their corresponding mechanical properties. A preliminary modeling was also initiated to 

predict the mechanical properties of FDM-printed Ultem 9085 coupons in relation to varied raster angles and 

void contents, using the GRC-developed MAC/GMC program. 

1. Introduction 

Additive manufacturing (AM) has gained considerable attention recently, because of the promise of 

being able to produce net shape 3D components layer by layer directly by automated machines. This is 

especially true for complex shape polymer parts and low production volume components, which are not 

 

*

NASA Glenn Research Center, academy intern 2014. 
NASA/TM—2015-218749 2 

economical to produce by injection molding. In addition, AM offers quick turn-around time for specialty 

parts and shortened production and testing cycle for components. This project concentrated on Fused 

Deposition Modeling (FDM) technique (Fig. 1) in which a polymer filament is melted and then deposited 

in successive layers to build a 3D component according to a computer-aided design (CAD) file (Ref. 1). 

The state-of-the art of FDM are populated with commercial acrylonitrile butadiene styrene (ABS), 

polycarbonate (Ref. 2) and polyamides such as Nylons for use as prototyping at the temperature around 100 

to 125 °C (212 to 257 °F). 

One objective of the project was to develop additive manufacturing approaches for polymeric aircraft 

engine components and conduct testing on coupons as well as built parts, such as acoustic testing in a wind 

tunnel. The Ultem 9085 polyetherimide filament is one of the commercial polymers marketed by Stratasys 

for use in FDM with a glass transition temperature (Tg) of 186 C (367 °F). Ultem 9085 is certified by FAA 

as flame retardant polymer for use in aircraft cabin. This project used Ultem 9085 as the baseline polymer 

for printing demonstration components, such as acoustic liners and a perforated engine access door. 

Furthermore, this project also strived to advance the FDM process into building polymer composites for 

aircraft engine parts. These additively manufactured components were tested in rigs and results have been 

presented in the first part of the report (Ref. 3). The Ultem 1000 with 10% AS4 carbon fiber was chosen as 

the candidate fiber-filled polymer filaments for this project, because Stratasys is making it available for the 

first time as an experimental filament under the State funded Ohio Third Frontier research project. Ultem 

1000 is a homopolymer with higher Tg (217 °C, 423 °F) than that of Ultem 9085 which is a blend of 

polycarbonate and Ultem 1000 with lower viscosity and cost suitable for injection molding. 

Figure 1.—Schematic of Fused Deposition Modeling (FDM) process. 
NASA/TM—2015-218749 3 

 (a) Perforated engine access door 

(Ultem 9085) 

(b) Acoustic liner and components 

(Ultem 9085) 

(c) Composite 

vanes 

Ultem 1000/fiber 

Figure 2.—FDM printed polymer components. 

2. Experimental 

All the FDM printing was performed at Rapid Prototype Plus Manufacturing (rp+m), using Stratasys’ 

open source Fortus 400 or 900 mc FDM machines. The experimental XH6050 resin and carbon-fiber-filled 

Ultem 1000 filaments were supplied by Stratasys under the Ohio Third Frontier Program—Advanced 

Materials for Additive Manufacturing Maturation. The Ultem resins and composites were printed between 

375 to 420 °C (707 to 788 °F). The specific engine components were selected by Honeywell Aerospace. 

Using Ultem 9085, a perforated engine door (Fig. 2(a)), an acoustic liner and its demonstration components 

(Fig. 2(b)) with 93 °C (200 °F) use temperature were printed by FDM at 375 °C in one piece, simulating 

the Aramid honeycomb structures bonded with epoxy composite face sheet. Additionally, composite vanes 

(Fig. 2(c)) with use temperature up to 204 °C (400 °F) were printed at 420 °C, using Ultem 1000 filled with 

10% chopped AS4 carbon fibers. Rig testing conditions and results of acoustic liner and composite inlet 

guide vane (IGV) are described in details in the first part of the report (Ref. 3). 

3. Results and Discussion 

3.1 Property Comparison of FDM and Injection Molding 

A mechanical property comparison between FDM-printed and injection-molded coupons of Ultem 

9085, Ultem 1000 and the carbon-fiber-filled Ultem 1000 are shown in Table 1. These data indicated that 

Ultem 9085 (printed at 0° raster angle), displayed about 87% of tensile strength and 64% of modulus, as 

compared to the injection molded counter parts, due to the presence of inherent porosities within the FDMprinted test coupons. The porosity of FDM-printed Ultem 9085 was about 5 to 8%, depending on the 

orientation of the layup. The mechanical strength of FDM generated specimens also relied on the built 

direction, the thickness of the filaments, the tool path generation and the air gap between raster in the filled 

pattern. In general, the FDM generated structures are more brittle and have lower elongation than the 

injection molded counterparts (Ref. 4). 

3.2 Initial Characterization of Carbon Fiber Filled Ultem 1000 Composites and Filaments 

The initial tensile strength of 10% AS4 fiber-filled Ultem 1000 composites (first batch ever made from 

Stratasys) was only about 70% of Ultem 9085 resin as printed by FDM (Fig. 3), which was much lower 

than expected. The printing of 45° raster angle reduced the strength by 80 to 86% as opposed to 0°. Further 

investigation by acid digestion indicated that the porosity of fiber-filler Ultem 1000 vanes are unusually 

high, ranging from 23 to 26% (Table 2). The printing orientation did not exhibit much difference in terms 

of porosity. However, the porosity measurement based on the integration of optical microscope images 

(Fig. 4) ranged from 29 to 34% (Table 3), which was even higher than the 23 to 26% porosity obtained by 

acid digestion. 
NASA/TM—2015-218749 4 

TABLE 1.—PROPERTY COMPARISON OF ULTEM 9085 AND ULTEM 1000 BY INJECTION MOLDING VS FDM 

esin type 

Properties 

Ultem 9085 

injection 

molded 

(Sabic data) 

Ultem 9085 

FDM printed 

(Stratasys data) 

0°

Ultem 9085 

FDM rp+m 

(GRC tested) 

45°

Ultem 1000 

injection 

molded 

(Sabic data) 

Ultem 1000+10 wt% 

AS4 chopped C-fiber 

FDM rp+m (GRC tested) 

0°/45°

Tensile strength 

(MPa) 83 72 620.1 110 500.9/440.3 

Tensile modulus 

(MPa) 3,432 2,200 2,23012 3,579 2,90148/224846 

Flexural strength 

(MPa) 137 115 922 165 tbd 

Flexural modulus 

(MPa) 2,913 2,500 1,90141 3,511 tbd 

Compression 

strength (MPa) n/a 104 tbd n/a tbd 

Compression 

modulus (MPa) n/a 1,930 1,89032 n/a tbd 

*No Ultem 1000 filament for FDM is commercially available. 

Figure 3.—Tensile properties of Ultem 9085 and fiber-filled Ultem 1000 as received. 

TABLE 2.—POROSITY OF FIBER-FILLED ULTEM 1000 COMPOSITE VANES BY ACID DIGESTION 
NASA/TM—2015-218749 5 

TABLE 3.—POROSITY OF COMPOSITE VANES BASED ON OPTICAL MICROSCOPE IMAGES 

Figure 4.—High resolution of optical micrographs (left) and images of pore, fiber and matrix (right) of a 

 FDM-printed composite vane. 

To understand the origin of high porosity in the FDM-printed fiber-filled Ultem 1000 composites, an 

effort was initiated to investigate the as-received thick Ultem 1000 filament filled with 10% chopped AS4 

carbon fibers, which was fed into the FDM machine. The fiber-filled Ultem 1000 filaments were produced 

by mixing 6 mm AS4 chopped fibers with Ultem 1000 in an extruder, cut into pellets, and then re-extruded 

into filaments at Stratasys. As shown in Figure 5, the longitudinal section (a) revealed that the chopped 

fibers were aligned with the filament axis, and significant amounts of the fibers were further chopped into 

average length of 2 to 3 mm during the extrusion process. The cross section (b) to (e) indicated that there 

were little voids present in the as-received filaments in this segment of initial investigation. 

Separately, thin filaments of fiber-filled Ultem 1000 extruded from the liquefier of Stratasys’ Fortus 

400 mc FDM machine at 420 C were collected and analyzed, since these thin filaments were used directly 

for FDM printing. As shown in Figure 6, the FDM extruded thin filaments were full of voids in the form of 

blisters, due to the sudden exposure to extreme high heat. 

The acid digestion values in Table 4 confirmed that this segment of as-received thick fiber-filled 

filament analyzed had no porosity as confirmed by the photomicrographs in Figure 5. The fiber content was 

9% by weight which was very close to the original formulation of 10% chopped fibers. However, the thin 

FDM-extruded filaments were found to have about 31% of porosity, which was closer to the image analysis 

result of 33% porosity than that of 24 to 26% porosity by acid digestion of the printed vane. 

Vmy1

Hmy1

High resolution optical micrographs Images assigned for pore, fiber and matrix 
NASA/TM—2015-218749 6 

(a) Longitudinal section of fiber filled filament (b) Cross section 

 

(c) Cross section #1 (d) Cross section #2 

after removing ~1 mm 

(e) Cross section #3 

after removing ~2 mm 

Figure 5.—Photomicrographs of 10% AS4 fiber filled Ultem 1000 filaments (as received-thick). 

 

 (a) Cross section#1 (b) Cross section #2 

after removing ~1 mm 

(c) Cross section #3 

after removing ~2 mm 

Figure 6.—Photomicrographs of 10% AS4 fiber filled Ultem 1000 filaments (FDM-extruded-thin). 

TABLE 4.—POROSITY OF FIBER-FILLED ULTEM 1000 FILAMENTS 

*Thick filament—as received and fed into FDM machine; thin filament—extruded from FDM machine. 

 

Balance

Mc,  g Vc,  cc c,  g/cc Mf, g Mm, g Vf, cc Vm, cc Vp, cc

Filament, thick 0.2753 0.2084 1.3209 0.0254 0.250 0.014 0.1968 ‐0.003 9% 7% ‐1.2%

Filament, thin 1 0.0582 0.0645 0.9029 0.0054 0.053 0.003 0.0416 0.02 9% 5% 30.9%

thin 2 0.0583 0.0653 0.8924 0.0054 0.053 0.003 0.0417 0.021 9% 5% 31.6%

FWF,

wt%

FVF,

v%

porosity,

v%

After drying

Sample ID Pycnometer Acid digestion

From Theor. Density
NASA/TM—2015-218749 7 

Thermogravimetric analysis (TGA) with Fourier Transform Infrared Spectroscopy (FTIR) was carried 

out to investigate the origin of blistering. As shown in Figure 7, the major weight loss shown in TGA up to 

300 °C (572 °F) corresponded to water shown in FTIR, which indicated that some water was trapped inside 

the filament, which was more difficult to remove than the surface water. Additionally, Figure 8 indicated that 

Ultem 1000 resin pellet contained 0.375% of water, and the fiber-filled Ultem 1000 filament had 0.593% of 

water whereas separate TGA analysis had indicated that the chopped fiber contained 0.25% of water. These 

two curves indicated that other than water loss, the Ultem resin and filament are very stable until about 

500 °C (932 °F). However, the thin fiber-filled filament showed not only the loss of surface water around 

100 °C (212 °F), but also some other weight loss due to degradation, as it had been exposed to the sudden 

high temperature of 420 °C (788 °F) at the liquefier in the FDM machine during the melting process. This 

first lot of the fiber-filled Ultem 1000 filament seemed to be solid but brittle whereas the thin filament 

appeared to be fragile and extremely porous. 

Figure 7.—TGA-FTIR analysis of the fiber-filled Ultem 1000 filament. 

Figure 8.—Thermogravimetric analysis of and fiber-filled Ultem 1000 filament and resin pellet.
NASA/TM—2015-218749 8 

3.3 Development and Evaluation of Drying Processes for Fiber-Filled Ultem 1000 Filaments 

(1) To improve the quality and mechanical properties of FDM-printed composites, an initial drying of 

as-received filament at 185 °C (365 °F) was carried out to remove the water from fiber-filled Ultem 1000 

in an air-circulation oven for 12 hr; this was followed by the printing two cubes by FDM (Fig. 9). The dried 

thick filaments and FDM-spun thin fibers seemed shrunken and more ductile than the corresponding asreceived filaments and un-dried FDM-spun thin filaments. The resulting printed cubes contained much 

lower porosity (13.6 to 17.4%) than that of the vanes (23 to 26%) as indicted in Table 2. 

(2) A second drying trial for fiber-filled Ultem 1000 was conducted at 204 °C (400 °F) for 22 hr. SEM 

micrographs in Figure 10 showed that the dried thick filaments still had large pores of voids which were 

formed by the trapped water, air or other gases within the filaments during extrusion and drying (Fig. 10(a)), 

as well as the small pores of fiber pull-out at the fracture surface. Furthermore, Figure 10(b) revealed that the 

porosity of FDM-spun thin filaments was much higher than the thick filaments as confirmed by acid digestion 

values listed in Table 5. The severe porosity of thin filaments were the results of volume expansion of trapped 

water vapors, air bubbles or other gases generated from the degradation of Ultem 1000 resin exposed to the 

sudden high liquefying temperature of 420 °C (788 °F) used to spin it within the FDM machine. 

Figure 9.—Picture and micrograph of fiber-filled Ultem 1000 filaments and printed cubes. 

(a) Thick filament after drying at 204 C (400 F) for 22 hr 

(b) FDM-spun thin filaments derived from 204 C dried thick filaments 

Figure 10.—SEM of fiber-filled Ultem 1000 filament after drying at 204 °C for 22 hr. 
NASA/TM—2015-218749 9 

(3) A third drying process was conducted in a desiccant system at 149 °C (300 °F) for 12 hr and 

characterized along with another section of as-received thick carbon-filled Ultem 1000 filaments as a repeat 

to investigate the uniformity and porosity of the experimental composite filaments supplied by Stratasys. 

As shown in Table 5, the porosity of the fiber-filled Ultem 1000 thick filaments as-received for the second 

trial was 15.3% which is much higher than the void-free in the initial as-received filaments. This clearly 

indicated that the porosity of experimental fiber-filled Ultem 1000 filaments varied considerably from 0 to 

15.3%, and the porosity remained at 15% even after drying at 149 °C for 12 hr (Fig. 11). The 

photomicrographs in Figure 10 confirmed that as-received fiber-filled Ultem 1000 filaments exhibited some 

porosity this time, in contrast to the void-free segment shown in Figure 4 previously. Since the moisture 

content of the as-received Ultem 1000 composite filaments was only 0.6%, including 0.2% moisture from 

as-received chopped fibers, the voids shown in the as-received fiber-filled Ultem 1000 thick filaments could 

either come from moisture trapped inside or the air bubbles introduced during the extrusion process. 

Nevertheless, after drying at various conditions, all the FDM-extruded thin filaments still displayed 

consistent porosity of ~25%, which is similar to porosity of printed composite vanes, but lower than the 

30% porosity detected in the FDM-extruded thin filaments derived from the undried thick filaments (Table 

5). This fact clearly indicated that once the moisture pore or air bubbles formed within the filaments, they 

are much more difficult to remove than surface water. 

TABLE 5.—POROSITY OF VARIOUS DRIED FIBER-FILLED ULTEM 1000 FILAMENTS 

 
NASA/TM—2015-218749 10 

As-Received Filament Dried Filament 

(300 °F in a Desiccant)

Original 

 

FDM 

Extruded 

 

Figure 11.—Optical Micrographs of as-received and dried fiber-filled Ultem 1000 filaments. 

3.4 Mechanical Properties of FDM-Printed Ultem Resins and Fiber-Filled Ultem 1000 

Tensile tests of FDM-printed Ultem 9085, Ultem 1000, XH6050 and fiber-filled Ultem 1000 coupons 

were conducted at room temperature and 204 °C (400 °F) as listed in Table 6. Figure 12 showed that Ultem 

1000/C-fiber composite printed with the dried FDM filament showed the highest modulus while Ultem 

9085 resin showed the highest toughness and strength at room temperature. The carbon fiber reinforcement 

Ultem 1000 was estimated to increase the tensile strength by 23% and modulus by 38% while the strain-tofailure ration dropped by 55%, back-calculated based on XH6050 data of injection-molded versus FDMprinted. Regardless of test temperature, Ultem XH6050 showed inferior properties than either Ultem 1000 

composites or Ultem 9085 (Tg = 186 °C), despite of its higher Tg (245 °C). XH6050 also showed significant 

losses in toughness and strength at 204 °C (400 °F). Thermal analysis results in Table 7 showed that 

substantial moisture still trapped within the composites even after drying. 

More specifically, drying FDM filament prior to FDM-printing improved the room temperature (RT) 

properties of Ultem 1000 composites considerably, as indicated by the reduced porosities of FDM-extruded 

thin filaments from 30 to 24% after various drying conditions (Table 5), especially 45° samples, even 

though its residual moisture content was still high. As shown in Figure 13, the 0° sample, showed ~8% 

increase in modulus, ~3% increase in strength, but ~11% decrease in strain-to-failure. The 45° sample 

displayed ~26% increase in modulus, ~20% increase in strength, but ~2.4% decrease in strain-to-failure. 

At 204 °C which is near Ultem1000’s Tg (217 °C), all the properties decreased considerably due to the 

softening of the resin. 
NASA/TM—2015-218749 11 

TABLE 6.—MECHANICAL PROPERTIES OF ULTEM 9085, ULTEM 1000, 

XH6500, FIBER-FILLER ULTEM 1000 

*No Ultem 1000 filament for FDM is commercially available 

Figure 12.—Tensile properties of FDM-printed Ultem resins and 

fiber-filled Ultem 1000. 

Data

Source

Injection Molded n/a 3,432 ± n/a 83 ± n/a 72 ± n/a n/a ± Sabic

FDM by Stratasys 0° 2,200 ± n/a 72 ± n/a 6.0 ± n/a n/a ± Stratasys

FDM by rp+m ± 45° 2,230 ± 12 62 ± 0.1 6.1 ± 0.4 0.38 ± 0.02 GRC

ULTEM 1000 Injection Molded n/a 3,579 ± n/a 110 ± n/a 60 ± n/a n/a ± Sabic

FDM by rp+m 0° 2,901 ± 48 50 ± 0.9 2.4 ± 0.1 0.33 ± 0.01 GRC*

FDM by rp+m ± 45° 2,248 ± 46 44 ± 0.3 2.8 ± 0.1 0.39 ± 0.01 GRC*

FDM by rp+m 0° 3,132 ± 20 52 ± 2.0 2.1 ± 0.0 0.35 ± 0.02 GRC*

FDM by rp+m ± 45° 2,835 ± 177 53 ± 1.8 2.7 ± 0.1 0.34 ± 0.02 GRC*

Injection Molded n/a 3,511 ± n/a 96 ± n/a 25 ± n/a n/a ± Sabic

FDM by rp+m 0° 2,069 ± 190 36 ± 4.7 2.2 ± 0.3 0.33 ± 0 GRC*

FDM by rp+m ± 45° 1,938 ± 105 35 ± 4.8 2.2 ± 0.5 0.38 ± 0 GRC*

FDM by rp+m 0° 1,920 ± 94 11.4 ± 0.5 5.2 ± 3.4 0.32 ± 0.08 GRC*

FDM by rp+m ± 45° 1,456 ± 143 9.3 ± 0.5 5.2 ± 3.7 0.33 ± 0.04 GRC*

FDM by rp+m 0° 1,951 ± 119 11.4 ± 1.3 9.2 ± 3.7 0.30 ± 0.06 GRC*

FDM by rp+m ± 45° 1,197 ± 82 5.8 ± 2.3 43.5 ± 7.8 0.35 ± 0.03 GRC*

FDM by rp+m 0° 1,497 ± 26 9.4 ± 0.6 0.65 ± 0.1 0.34 ± 0.1 GRC*

FDM by rp+m ± 45° 1,367 ± 123 8.2 ± 1.1 0.6 ± 0.1 0.41 ± 0.1 GRC*

* All GRC testing used 0.2 in/min CHS and averaged out of three repeat runs.

ULTEM 9085

ULTEM 1000 + 10wt%

AS4 C‐fiber:  

As‐received filament

ULTEM 1000 + 10wt%

AS4 C‐fiber:  

Dried filament at 300°F

Material Process Printing

Orientation

Tensile Properties at RT (23 °C)

Modulus

MPa

Strength

MPa

Strain‐to‐

Failure, %

Poisson's

Ratio

Tensile Properties at 400 °F (204 °C)

ULTEM XH6050

ULTEM XH6050

ULTEM 1000 + 10wt%

AS4 C‐fiber:  

As‐received filament

ULTEM 1000 + 10wt%

AS4 C‐fiber:  

Dried filament at 300°F
NASA/TM—2015-218749 12 

TABLE 7.—THERMAL ANALYSIS OF FIBER-FILLED ULTEM 1000 COMPOSITES 

 

Figure 13.—Tensile properties of as-received and dried fiber-filled Ultem 1000 composites. 

3.5 Characterization of Ultem 9085 and XH6050 Neat Resin Filaments 

A detailed characterization effort was undertaken to understand why FDM-printed fiber-filled Ultem 

1000 composites exhibited an average of 25% porosity whereas Ultem 9085 exhibited only 5 to 8% porosity 

due to inherent FDM process. Acid digestion of as-received Ultem 9085 neat resin filaments showed 1.8 to 

3.5% porosity while XH6050 had none, but registered negative porosity because of errors in small quantity 

analysis (Table 8). In contrast, optical micrograms in Figure 14 indicated that both as-received Ultem 9085 

filaments and thin filaments extruded at 375 °C by FDM exhibited no porosity. However, optical 

microscope image of the thin XH6050 filaments extruded at 410 °C by FDM revealed substantial voids due 

to blistering, but no porosity in the as-received thick filaments. The discrepancy of two methods depends 

on the segments of the filaments analyzed in each technique, and subjected to variable porosity. Compared 

to low porosity of neat resin filaments such as Ultem 9085 and XH6050, the fiber-filled Ultem 1000 

composite filaments with varied porosity of 0 to 15% clearly warranted more process improvement. 

Thermal analysis (Table 9) of Ultem 9085 and XH6050 revealed that there were 0.3 to 0.4% weight loss 

between 100 to 300 °C due to moisture presence in these two resin filaments as received, which are common 

among all the moisture sensitive polyetherimides. 

Total

Heat

Rev.

Heat Td, °C Wt%

RT‐100 °C

Wt%  

100 ‐ 300 °C

Wt%

@ 750 °C

Char

yield

Horizonal vane, top 214 217 556 0.298 0.389 42 58

Horizonal vane, bottom 213 213 560 0.326 0.340 42 58

Vertical vane, top 213 217 558 0.332 0.303 42 58

Vertical vane, bottom 213 217 556 0.261 0.479 41 59

As‐received Filament 563 0.074 0.580 40 60

FDM‐spun Filament 550 0.500 0.574 40 60

As‐dried Filament 214 217 563 0.110 0.471 41 60

FDM‐spun Filament 213 215 560 0.403 0.178 37 63

DR 1 213 216 559 0.325 0.078 44 56

As‐dried Filament 565 0.050 0.199 43 57

FDM‐spun Filament 557 0.313 0.387 43 57

As‐received Filament 215 220 554 0.094 0.331 42.5 57.5

As‐dried Filament 214 216 554 0.062 0.374 42.2 57.8

As‐dried & extruded 215 546 0.154 0.438 45.9 54.1

149 °C (300 °F) dried filaments but in a desiccantsystem, received @ 12/8/14

Sample ID

mDSC Tg,  °C TGA (under N2 gas)

1st Gen Composite Vanes (received @ 6/18/14)

185°C dried filament  and cubes (samples received @ 8/25/14)

204.4 °C (400 °F) dried filament (samples received @ 10/17/14)

RT 

204°
NASA/TM—2015-218749 13 

TABLE 8.—ANALYSIS OF ULTEM 9085 AND XH6050 RESIN FILAMENTS BY ACID DIGESTION 

Sample 

ID 

Sample 

conditions 

Drying Mass 

(g) 

Pycnometer Density 

(g/cc) 

Porosity 

(%) T (°C) t (hr) Volume (cc) 

Ultem 9085 As-received 

Filament 

120 24 0.3972 0.302 1.3152 1.85 

165 24 0.3963 0.3066 1.2926 3.54 

Extruded 

Filament 

120 24 0.0743 0.0505 1.4713 –9.80 

165 24 0.0742 0.0506 1.4664 –9.43 

Ultem XH6050 As-received 

Filament 

120 24 0.3353 0.2492 1.3455 –3.50 

165 24 0.3356 0.249 1.3478 –3.68 

Extruded 

Filament 

120 24 0.1021 0.0766 1.3329 –2.53 

165 24 0.1024 0.0764 1.3403 –3.10 

Ultem 9085 Ultem HX6050 

As-Received 

thick filament 

FDM—Extruded 

thin filament 

Figure 14.—Optical micrographs of Ultem 9085 and XH6050 resin 

filaments. 

TABLE 9.—THERMAL ANALYSIS OF ULTEM 9085 AND XH6050 

*mDSC stands for modulated Differential Scanning Calorimetry (DSC). 

Total

Heat

Rev.  

Heat Td, °C Wt%RT‐100 °C

Wt%

100‐300°C

Wt%

@ 750 °C

Neat resin (manufacturer data) 186

As‐received filament 181 183 501 0.02044 0.3307 53

As‐received and extruded filament 177 184 501 0.09342 0.6288 55

Neat resin (manufacturer data) 247

As‐received filament 243 246 554 0.1116 0.4376 48

As‐received and extruded filament 244 556 0.06844 0.1781 54

Ultem 9085

Ultem XH6050

mDSC Tg,  °C TGA

Sample types
NASA/TM—2015-218749 14 

3.6 Computational Modeling of 3D Printing of Ultem 9085 by FDM 

The object of this effort is to develop numerical models for generation of mesostructure of the printed 

product to account for the voids, raster angles of each layer that are inherently associated with the FDM 

process. The immediate goal is to enable the prediction of mechanical properties based on void contents 

and raster angles; however, the ultimate goal seeks to predict mechanical performance of the FDM printed 

components. 

Modeling of Fused Deposition was performed using MAC/GMC program developed by Dr. Steven 

Arnold et al., at NASA Glenn for general composite applications. The repeat unit cell is shown in red in 

Figure 15. 

In order to predict ultimate tensile stress of a specific material with corresponding parameters, such as 

varying raster angle and void percentage, the “failure sub-cell” capability was added and implemented in 

the MAC/GMC input file. The model utilizes user-defined material properties, such as EA, ET, VA, VT, GA, 

CTE, and K, to compute the outcome according to desired orientation of the raster angle. It enables user to 

define limitation by either providing stress, strain, or both level where ultimate tensile stress occurs. Using 

known experimental strain data, the model is able to define the strain criteria for both materials in the axial 

load direction. During execution, the MAC/GMC code attempts to match user-defined failure criteria on 

each iteration. If the criteria are met, the code execution comes to a halt. Otherwise, it continues until the 

criteria are met or matches the defined iteration number. To incorporate another capability to the 

MAC/GMC model for the materials of interest, an adjustment was made to the input file for the Ultem 9085 

model. After re-evaluating the model, and revised simulated thermo loading, the error between the 

calculated and experimental Young’s modulus decreased drastically. 

For example, different FDM print orientations were compared to injection molding processed 

Ultem 9085 while maintaining the same void amount for each orientation. Furthermore, mechanical and 

thermal loadings were implemented via the code to obtain tensile responses of each raster angle. Figure 16 

showed the results of tensile response of Ultem 9085 at 135 °C, flat built with axial loading.

Theoretical Cross Section of FDM Processed Components 

 

Figure 15.—Unit cell of 3D printing by FDM (Ref. 5). 

 

Resin 

Void 
NASA/TM—2015-218749 15 

The simulated data of Tables 10 to 14 and Figures 17 to 20 continue to show interesting optimal 

mechanical properties at the 15° raster angle for Ultem 9085 and fiber filled Ultem 1000 composites and 

should be investigated further. As America Makes already collected a comprehensive database under 

contract on b-based allowable for FDM-printed Ultem 9085 specimens. Conceivably, one would be able to 

develop modeling techniques for FDM process that can be verified with the experimental mechanical data 

such as Ultem 9085. Hopefully, the computational modeling will one day be expanded into real capability 

for predicting performance of FDM printed parts. 

TABLE 10.—CALCULATED TENSILE MODULUS OF INJECTION MOLDING PROCESSED MATERIALS 

100% density 

Materials Tensile modulus (Gpa) Tensile strength (Mpa) 

Ultem 9085 1.72 83.83 

Ultem 1000 composite 25.1 493.21 

*Simulated at 135 °C. 

TABLE 11.—CALCULATED TENSILE MODULUS OF ULTEM 9085 NEAT RESIN 

AT VARIED DENSITY AND RASTER 

Tensile modulus (Gpa) 

Raster angles 96% density 92% density 85% density 75% density 70% density 

0/90° 1.66 1.56 1.38 1.10 0.95 

15° 1.65 1.59 1.44 1.21 1.09 

30° 1.64 1.53 1.33 1.03 0.87 

45° 1.62 1.49 1.25 0.90 0.73 

70° 1.62 1.48 1.25 0.90 0.72 

*Simulated loading speed 5 mm/min at 135 °C. 

TABLE 12.—CALCULATED TENSILE MODULUS OF ULTEM 9085 RESIN AT 

VARIED DENSITY AND RASTER ANGLE 

Ultimate tensile strength (Mpa) 

Raster angles 96% density 92% density 85% density 75% density 70% density 

0/90° 78.79 73.79 65.08 50.46 42.05 

15° 77.94 76.42 70.00 59.97 54.54 

30° 79.17 74.35 65.86 51.79 43.68 

45° 77.59 71.07 60.27 43.50 35.18 

70° 77.66 71.70 61.20 44.07 35.41 

*Simulated loading speed 5 mm/min at 135 °C. 

TABLE 13.—CALCULATED TENSILE MODULUS OF ULTEM 1000 COMPOSITE AT 

VARIED DENSITY AND RASTER 

Tensile modulus (Gpa) 

Raster angles 96% density 92% density 85% density 75% density 70% density 

0/90° 8.76 8.28 8.06 7.43 6.64 

15° 15.89 15.03 14.92 14.02 12.54 

30° 7.69 7.27 6.99 6.34 5.67 

45° 4.14 4.14 3.61 3.12 2.78 

70° 3.13 2.96 2.67 2.26 2.01 

*Simulated loading speed 5 mm/min at 204 °C. 

TABLE 14.—CALCULATED TENSILE MODULUS OF ULTEM 1000 COMPOSITE 

AT VARIED DENSITY AND RASTER ANGLE 

Ultimate tensile strength (Mpa) 

Raster angles 96% density 92% density 85% density 75% density 70% density 

0/90° 170.18 161.17 156.72 145.19 129.95 

15° 276.08 271.84 257.36 241.19 216.10 

30° 174.74 166.35 161.65 136.50 124.22 

45° 89.74 83.97 73.78 59.95 49.04 

70° 83.11 77.85 68.11 55.66 53.31 

*Simulated loading speed 5 mm/min at 204 °C. 
NASA/TM—2015-218749 16 

Figure 16.—Modeling of Ultem 9085 tensile properties. 

Figure 17.—Tensile modulus at different void percentage in a specimen. 

Figure 18.—Ultimate tensile strength at different void percentage in a sample. 

y = 237,000.71x ‐ 216.62

R2 = 0.95

‐1000

0

1000

2000

3000

4000

‐0.01 0 0.01 0.02 0.03 0.04 0.05 0.06 Stress (psi)

Axial Strain (in/in)

ULTEM 9085 Tensile Stress v. Strain at

135 °C

Strain from

h

0.00

0.50

1.00

1.50

2.00

4% 8% 15% 25% 30%

Tensile Modulus

(GPa)

Void Percentage

Ultem 9085 Tensile Modulus vs. Void

Percentage

± 15°

0/90°

± 30°

± 45°

± 70°

0.00

50.00

100.00

4% 8% 15% 25% 30%

Tensile Strength

(MPa)

Void Percentage

Ultem 9085 Tensile Strength vs. Void

Percentage

0/90°

± 15°

± 30°

± 45°

± 70°
NASA/TM—2015-218749 17 

Figure 19.—Void percent versus tensile modulus for Ultem 1000 composite. 

Figure 20.—Trend for void percentage versus ultimate tensile strength for Ultem 1000 composites. 

4 Summary and Conclusions 

To advance the state-of-the-art in additive manufacturing via Fused Deposition Modeling (FDM) 

beyond the commonly used ABS, polycarbonate and Nylons as prototyping for 100 to 125 °C use, this 

project aimed at producing aircraft engine components by FDM, using Ultem 9085 and cabon fiber-filled 

Ultem 1000 composite filaments with higher temperature (130 to 175 °C) capability. 

A perforated access engine door and acoustic liners simulating conventional honeycomb structures, 

were printed with Ultem 9085 to modulate the sound wave and reduce noises. Composite engine inlet guide 

vanes were printed using Ultem 1000 filled with 10% AS4 chopped fibers as a reinforcement to eliminate 

the need for machining when using conventional polymer prepregs to make vanes. Preliminary data 

indicated that the FDM-printed Ultem 9085 exhibited about 84% of its original strength and 64 percent of 

its original modulus compared to its injection-molded counter parts. The incorporation of 10% chopped 

fiber into Ultem 1000 increased the tensile strength by 23% and modulus by 38%, but also made the 

resulting composites more brittle. The experimental fiber-filled Ultem 1000 filaments (as received) 

contained 0 to 15% varied porosity. However, the FDM extruded thin filaments and FDM printed Ultem 

1000 composite vanes exhibited ~25% porosity, due to the volume expansion of trapped moisture, air or 

other gases generated form degradation at elevated printing temperature of 420 °C by FDM. In contrast, the 

0.00

5.00

10.00

15.00

20.00

4% 8% 15% 25% 30%

Tensile Modulus

(Gpa)

Void Percentage

Ultem 1000 composite Tensile Modulus vs.

Void Percentage

± 15°

0/90°

± 30°

± 45°

± 70°

0.00

50.00

100.00

150.00

200.00

250.00

300.00

4% 8% 15% 25% 30%

Tensile Strength

(MPa)

Void Percentage

Ultem 1000 composite ultimate Tensile

Strength vs. Void Percentage

0/90°

± 15°

± 30°

± 45°

± 70°
NASA/TM—2015-218749 18 

Ultem 9085 resin filament is a high quality commercial product that manufactures 3D objects with 5 to 

8% porosity inherently associated with the FDM process, when printing at 375 °C. The tensile properties 

of the new experimental Ultem XH6050 FDM resin is inferior to Ultem 9085, even though its Tg is roughly 

60 °C higher than that of Ultem 9085. 

In summary, this project proved the feasibility of printing integrated complex aircraft parts with polymers 

by FDM. FDM printing compared favorable to bonded honeycomb structures with face sheets in acoustic 

liners. However, printing composite parts by FDM is still considered experimental, as in the case of this effort 

to print Ultem 1000 composite vanes. Incorporation of 10% of chopped fibers into Ultem 1000 raised the 

viscosity significantly that affected the compounding efficiency in the extruder, resulting in high porosity in 

the extruded filaments and FDM-printed composite objects. In light of conventional polymer composites with 

65% fiber content, additive manufacturing only looks favorable for printing intricate parts that are difficult to 

manufacture by conventional methods. In order to increase the fiber content and reduce porosity in polymer 

composites, it might be worthwhile to look into printing composite structures using thermoset polyimides 

with higher temperature performance and lower viscosity by selective laser sintering (SLS) for future works. 

The modeling of the FDM process using Ultem 9085 was intended to correlate the mechanical performance 

of FDM-printed objects with void contents and variation with different raster angles within each layer using 

GRC-developed MAX/GMC program for composites. The rough matching between mechanical test results 

and modeling prediction in this brief work is encouraging. Recent establishment of b-based allowable of 

Ultem 9085 in America Makes’ contract report as an industrial database (Ref. 6) offers an excellent 

opportunity to verify computer modeling with mechanical properties of FDM-printed test coupons. The 

ultimate goal to predict the performance of FDM-printed parts by computational modeling is achievable 

through refinement of modeling. 

References 

1. Ludmila Novakova-Marcincinova, Ivan Kuric: “Basic and Advanced Materials for Fused Deposition 

Modeling Rapid Prototyping Technology,” Manuf. and Ind. Eng., 11(1), 25–27 (2012), ISSN 1338–

6549. 

2. Water C. Smith and Richard W. Dean: “Structural Characteristics of Fused Deposition Modeling 

Polycarbonate Material,” Polymer Testing, 32(8), 1306–12 (2013). 

3. Joseph E. Grady, William J. Haller, Phil Poinsatte, Michael C. Halbig, Sydney Schulo, M. Singh, Don 

Weir, Natalie Wali, Michael Vinup, Michael G. Jones, Clark Patterson, and Tom Santelle, “A Fully 

Non-Metallic Gas Turbine Engine Enabled by Additive Manufacturing: Part I: System Analysis, 

Component Identification, Additive Manufacturing, and Testing of Polymer Composites,” NASA TM2015-218748 Glenn Research Center, Cleveland, OH (2015). 

4. Angnes Bagsik and Volker Shoppner: “Mechanical Properties of Fused Deposition Modeling Parts 

Manufactured with Ultem 9085,” ANTEC Conference Proceedings, May 1–5, Boston, MA (2011). 

5. A. Sherif El-Gizawy, Joseph Cardona, Brian Graybill: “An Integrated Approach for Characterization 

of Properties and Mesostructure of Fused Deposition Modeling Ultem 9085 Products,” SAMPE 

Conference Proceedings, 55, May 17–20, Seattle, WA (2010). 

6. America Makes contract report (2014): “Maturation of Fused Deposition Modeling (FDM) Component 

Manufacturing (4003),” by Rapid Prototype Plus Manufacturing (rp+m).