Process Development for Manufacturing of Cellular Structures with Controlled Geometry and Properties

Pinto, Paulo; Peixinho, Nuno; Soares, Delfim; Silva, Filipe

doi:10.1590/1516-1439.286614

Paulo Pinto

Centre for Mechanical and Materials Technologies – CT2M, Universidade do Minho, Azurém, 4800-058 Guimarães, Portugal

Nuno Peixinho ^**e-mail: peixinho@dem.uminho.pt

Centre for Mechanical and Materials Technologies – CT2M, Universidade do Minho, Azurém, 4800-058 Guimarães, Portugal

Delfim Soares

Centre for Mechanical and Materials Technologies – CT2M, Universidade do Minho, Azurém, 4800-058 Guimarães, Portugal

Filipe Silva

Centre for Mechanical and Materials Technologies – CT2M, Universidade do Minho, Azurém, 4800-058 Guimarães, Portugal

*e-mail: peixinho@dem.uminho.pt

Figures (19)
Tables (9)

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Figure 1
Developed geometries used in this study.

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Figure 2
Spiral model (H=8.0mm; Revolutions=4; Ø_section=0.5mm).

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Figure 3
Prototype metal foam structure and final dimensions.

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Figure 4
Shematic of lost wax casting procedure [(a) and (b)] used to obtain the metallic specimens of the development geometry and the metal foam prototype (c).

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Figure 5
Detail of metallurgical analysis zones in sample according to the distance from pouring size.

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Figure 6
Prototyped model cells in defined sample zone 1 a), zone 2 b) and zone 3 c) for the wall section diameter of 0.4 mm. The arrow shows the pouring direction.

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Figure 7
Metal sample cell in defined zone 1 a), zone 2 b) and zone 3 c) for the wall section diameter of 0.4 mm and pouring temperature of 635 °C. The arrow shows the pouring direction.

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Figure 8
Average cellular perimeter of resin samples and metallic samples casted at different initial mold temperatures.

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Figure 9
Production steps of the three-dimensional metal foam prototype started with the CAD model design (a); was followed by the production of the resin model in a stereolitography laser machine (b); and ended with the casted sample (c).

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Figure 10
Geometry changes occurring in the manufacturing steps (CAD-Resin-Metal)of the smaller holes [d1 variation – (a)] and larger holes [d2 variation (b]) in the cellular structure.

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Figure 11
Microstructure of a sample with a wall section diameter of 1mm, poured at a temperature of 635 °C in a mold at 350 °C.

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Figure 12
Microstructures of samples poured at 635 °C in a mold at 350 °C for different wall section diameters: (a) 0.4 mm, (b) 0.7 mm and (c) 1mm - [Zone 2].

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Figure 13
Eutectic silicon numeric fraction variation of samples poured at 635 °C in a mold at 350 °C for different sample wall section diameters: 0.4 mm, 0.7 mm and 1.0 mm - [Zone 2].

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Figure 14
Microstructures of samples poured at 635 °C with a section diameter of 0.7mm for different mold temperatures: (a) 300 °C, (b) 350 °C and (c) 400 °C - [Zone 2].

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Figure 15
Eutectic silicon numeric fraction variation of samples poured at 635 °C with a section diameter of 0.7mm for different mold temperatures: 300 °C, 350 °C and 400 °C - [Zone 2].

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Figure 16
Microstructures of a sample with a section diameter of 0.7 mm, poured at 635 °C, in a mold temperature of 350 °C assessed in different zones: (a) Zone 1; (b) Zone 2 (c) Zone 3.

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Figure 12
Microstructures of samples poured at 635 °C in a mold at 350 °C for different wall section diameters: (a) 0.4 mm, (b) 0.7 mm and (c) 1mm - [Zone 2].

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Figure 13
Eutectic silicon numeric fraction variation of samples poured at 635 °C in a mold at 350 °C for different sample wall section diameters: 0.4 mm, 0.7 mm and 1.0 mm - [Zone 2].

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Figure 14
Microstructures of samples poured at 635 °C with a section diameter of 0.7mm for different mold temperatures: (a) 300 °C, (b) 350 °C and (c) 400 °C - [Zone 2].

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Figure 15
Eutectic silicon numeric fraction variation of samples poured at 635 °C with a section diameter of 0.7mm for different mold temperatures: 300 °C, 350 °C and 400 °C - [Zone 2].

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Figure 16
Microstructures of a sample with a section diameter of 0.7 mm, poured at 635 °C, in a mold temperature of 350 °C assessed in different zones: (a) Zone 1; (b) Zone 2 (c) Zone 3.

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Figure 17
Representative figure of broken sample with 0.7mm section diameter.

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Figure 18
Stress-Strain curve of samples poured at 625 °C into a mold temperature of 350 °C for different section diameters.

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Figure 19
Average tensile strength for different section diameters (0.4mm, 0.7mm and 1.0mm) and different mold temperatures (300 °C, 350 °C and 400 °C).

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Table 1
Composition of the A413.1 aluminium alloy (wt.%) (according to the manufacturer).

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Table 2
Composition of the DC 500 resin (wt.%) (according to the manufacturer).

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Table 3
Composition of the R&R Ultra-Vest gypsum (wt.%) (according to the manufacturer).

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Table 4
Number of samples used in each type of study.

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Table 5
Prototype oversizing percentage resulted from the prototype process comparing with the CAD models.

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Table 6
Spiral length metal filling with different initial mold temperatures.

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Table 7
Measurements for the diameters d1, d2 and their variation percentage for the various productions steps.

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Table 8
Eutectic silicon average length of samples poured at 635 °C in a mold at 350 °C for different section diameters: 0.4 mm, 0.7 mm and 1.0 mm - [Zone 2].

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Table 9
Eutectic silicon average length of samples poured at 635 °C with a section diameter of 0.7mm for different mold temperatures: 300 °C, 350 °C and 400 °C - [Zone 2].

*Element*	Si	Cu	Fe	Mg	Mn	Zn	Ni	Al
Wt. %	11.0-13.0	1.0	1.0	0.10	0.35	0.40	0.50	balance

*Element*	*Multi-functional acrylic monomers*	*Crystalline Silica* *Cristobalite*	*Radical photoinitiator*
wt.%	70-90	10-30	0.5-3

*Element*	*Crystalline Silica Quartz*	*High molecular polyol*	*Calcium Sulfate* *Hemihydrate*
wt.%	< 50	> 30	< 40

	Number of samples
Type of study	Fluidity			Metallurgical properties			Mechanical Properties			Geometrical Analysis
Method	Length measurement			Optical Microscope			Tensile Tests			Optical Microscope
Mold Temperature (ºC)	300	350	400	300	350	400	300	350	400	350
Ø _section = 1.0 mm	-	-	-	1	1	1	3	3	3	1
Ø _section = 0.7 mm	-	-	-	1	1	1	3	3	3	1
Ø _section = 0.4 mm	-	-	-	1	1	1	3	3	3	1
Spiral	1	1	1	-	-	-	-	-	-	-
Prototype Metal Foam	-	-	-	-	-	-	-	-	-	1

Mold Temperature (ºC)	300		350	400
Spiral length [mm]	23.56		31.41	62.83

	d1	d2
CAD Model	1.74 mm	4.00 mm
Resin Model	1.64 mm	3.65 mm
Metal Model	1.79 mm	3.81 mm
CAD-Resindiameter variation	-5.7%	-8.9%
Resin-Metaldiameter variation	+9.1%	+4.6%
CAD-Metaldiameter variation	+2.9%	-4.7%

Wall section diameter [mm]	0.4	0.7	1.0
Average length of eutectic Silicon [µm]	9.21 ± 3.61	18.23 ± 6.95	19.39 ± 7.36

Mold Temperature [ºC]	300	350	400
Average length of eutectic silicon [µm]	16.20±7.06	18.23±6.95	24.89±11.57

[1] *e-mail: peixinho@dem.uminho.pt

Prototype internal perimeter cell oversizing [%]
Øsection = 0.4 mm	Øsection = 0.7 mm	Øsection = 1.0 mm
+8.5	+17.1	+24.4

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Process Development for Manufacturing of Cellular Structures with Controlled Geometry and Properties