Infiltration for improvement of the mech
INFILTRATION FOR IMPROVEMENT OF THE MECHANICAL AND THERMAL PROPERTIES OF 3D PRINTED PARTS
WITH PLASTER POWDER MATERIAL
Edwin Ocaña-Garzón1,2, Jorge Lino Alves2, Leonardo Santana3
1Departmento
de Ciencias de la Energía y Mecánica (DECEM), Universidad de las Fuerzas Armadas–ESPE, Sangolquí, Ecuador; 2INEGI, Faculty of Engineering University of Porto, Portugal; 3International
CNPq fellow, Faculty of Engineering University of Porto.
Keywords: Infiltration; 3D printing; powder characterization; mechanical strength; plaster moulds; rapid casting.
Introduction
Despite the fast and ongoing advances of Additive Manufacturing processes
(AM), parts printed by Binder Jetting (BJ) technology present high brittleness,
specially in ceramic materials. Thus it is a challenge to reduce it through postprocessing (PP) to create competitive mechanical and thermal strengths. One
of the most widely used PP is the infiltration, which is a way to achieve high
density parts without the large shrinkage to full density [1]. Infiltration occurs
when the liquid is drawn into the open pores of the printed part through
capillary action and solidifies. In this sense, this work proposes two objectives:
1. Characterize the 3D printer powder base material, - grain size distribution
and chemical composition - and print moulds directly for rapid casting
applications, and examining their dimensional changes and friability;
2. Analyse the main influential parameters of infiltration on the flexural and
tensile properties of 3DP parts, infiltrated with common materials.
Materials and Methods
The 3D printing material VisiJet® PXL Core with water based binder VisiJet®
PXL were printed in a 3D printer Projet 660 Pro (3D Systems, USA). The
infiltrating materials are Ethy Silicate (ES), Levasil (L), Ludos SK (LSK),
Aeordisp (AD),Ticoat-N (TN) and Zirconium Acetate (ZA).
First study: a simple geometry for
moulds with 4 different wall
thicknesses was printed, whose
internal dimensions were controlled
prior to infiltration (total immersion
at different times, see Table 1 and
2) with binders recommended for
investment casting.
Table 1. Internal average dimensions of green
mould samples (mm)
CAD Av. size by wall thickness Av.
3.0 3.5 4.0 Dev.
Dim. 2.5
A 35
34.94 34.99 34.99 35.00 0.02
B 25
24.97 24.98 25.03 24.96 0.02
a 30
30.15 30.14 30.07 30.12 0.02
b 20
20.22 20.10 20.03 20.09 0.05
H 20
20.48 20.32 20.26 20.25 0.08
Moulds were cured at RT with
forced air for 2 hours, and later
post-cured at 3 different thermal
cycles (Fig. 1). After that, Al alloy
AlSi9Cu3 was casted on them at
700 ºC and finally, their toughness
was evaluated.
VisiJet® PXL Core powder was
characterized in order to determine
the chemical composition and
particle size distribution (PSD), in a
SEM (Phenom ProXL USA) with EDS. Fig. 1. post-curing heating cycles of moulds samples.
Second study: Epoxy Resin (E), Cyanoacrylate (CY), magnesium sulphate
(MS), and drinking water (W), were used as infiltrated materials in accordance
with the methods recommended by the provider [2]. One batch was not
infiltrated (referential green specimens). Three-point bending and tensile tests
were conducted according to ASTM D790 and ASTM D638 respectively, to
obtain the maximum flexural “sfM” and tensile strengths “stM”.
Results and Discussions
For powder characterization, two types of representative particles were
identified, (spot 1 and 2), with their chemical composition (Fig. 2). Particle 1
has a similar composition of CaSO4.0.5H2O, and particle 2, contains calcium
sulphate and additives with a high carbon presence such as polyacrylonitrile
─(C3H3N)n─ [4].
The overlay curves of PSD of powder, in % volume density, are shown in Fig.
3. It can be seen that in % of equivalent volume: up to 10% have
WITH PLASTER POWDER MATERIAL
Edwin Ocaña-Garzón1,2, Jorge Lino Alves2, Leonardo Santana3
1Departmento
de Ciencias de la Energía y Mecánica (DECEM), Universidad de las Fuerzas Armadas–ESPE, Sangolquí, Ecuador; 2INEGI, Faculty of Engineering University of Porto, Portugal; 3International
CNPq fellow, Faculty of Engineering University of Porto.
Keywords: Infiltration; 3D printing; powder characterization; mechanical strength; plaster moulds; rapid casting.
Introduction
Despite the fast and ongoing advances of Additive Manufacturing processes
(AM), parts printed by Binder Jetting (BJ) technology present high brittleness,
specially in ceramic materials. Thus it is a challenge to reduce it through postprocessing (PP) to create competitive mechanical and thermal strengths. One
of the most widely used PP is the infiltration, which is a way to achieve high
density parts without the large shrinkage to full density [1]. Infiltration occurs
when the liquid is drawn into the open pores of the printed part through
capillary action and solidifies. In this sense, this work proposes two objectives:
1. Characterize the 3D printer powder base material, - grain size distribution
and chemical composition - and print moulds directly for rapid casting
applications, and examining their dimensional changes and friability;
2. Analyse the main influential parameters of infiltration on the flexural and
tensile properties of 3DP parts, infiltrated with common materials.
Materials and Methods
The 3D printing material VisiJet® PXL Core with water based binder VisiJet®
PXL were printed in a 3D printer Projet 660 Pro (3D Systems, USA). The
infiltrating materials are Ethy Silicate (ES), Levasil (L), Ludos SK (LSK),
Aeordisp (AD),Ticoat-N (TN) and Zirconium Acetate (ZA).
First study: a simple geometry for
moulds with 4 different wall
thicknesses was printed, whose
internal dimensions were controlled
prior to infiltration (total immersion
at different times, see Table 1 and
2) with binders recommended for
investment casting.
Table 1. Internal average dimensions of green
mould samples (mm)
CAD Av. size by wall thickness Av.
3.0 3.5 4.0 Dev.
Dim. 2.5
A 35
34.94 34.99 34.99 35.00 0.02
B 25
24.97 24.98 25.03 24.96 0.02
a 30
30.15 30.14 30.07 30.12 0.02
b 20
20.22 20.10 20.03 20.09 0.05
H 20
20.48 20.32 20.26 20.25 0.08
Moulds were cured at RT with
forced air for 2 hours, and later
post-cured at 3 different thermal
cycles (Fig. 1). After that, Al alloy
AlSi9Cu3 was casted on them at
700 ºC and finally, their toughness
was evaluated.
VisiJet® PXL Core powder was
characterized in order to determine
the chemical composition and
particle size distribution (PSD), in a
SEM (Phenom ProXL USA) with EDS. Fig. 1. post-curing heating cycles of moulds samples.
Second study: Epoxy Resin (E), Cyanoacrylate (CY), magnesium sulphate
(MS), and drinking water (W), were used as infiltrated materials in accordance
with the methods recommended by the provider [2]. One batch was not
infiltrated (referential green specimens). Three-point bending and tensile tests
were conducted according to ASTM D790 and ASTM D638 respectively, to
obtain the maximum flexural “sfM” and tensile strengths “stM”.
Results and Discussions
For powder characterization, two types of representative particles were
identified, (spot 1 and 2), with their chemical composition (Fig. 2). Particle 1
has a similar composition of CaSO4.0.5H2O, and particle 2, contains calcium
sulphate and additives with a high carbon presence such as polyacrylonitrile
─(C3H3N)n─ [4].
The overlay curves of PSD of powder, in % volume density, are shown in Fig.
3. It can be seen that in % of equivalent volume: up to 10% have