3D MODEL OPTIMIZATION FOR HYBRID LAYER PRINTING

Authors:

Electronics 2012

*Eduardas Lukošiūnas*Violeta Bulbenkienė

*Arūnas Andziulis**Janis Harja

*Klaipeda university, Department of Informatics Engineering**Ventspils University College

2012 June 18th1 Electronics 2012

Introduction In todays modern manufacturing the use of

virtual models in prototype development has been increased. There is much software being used for creating 3D objects, such as: AutoCAD, 3ds Max, SolidWorks and others.

Hybrid Layered Manufacturing (HLM) is a Rapid Manufacturing (RM) process that builds metallic object prototypes from 3D virtual objects, through a combination of additive and subtractive processes.

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Hybrid Layered Manufacturing

Hybrid manufacturing consists of rapid printing that uses Gas Metal Arc Welding (GMAW) technology for layered deposition and computer numerical control (CNC) technology.

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Disadvandages One of the main disadvantages is creating an accurately flat

layer surface, to make it suitable for other layers. Nowadays HML cannot create a flat surface. This problem is

solved by milling a surface to make it flat. This kind of process takes a lot of time and needs to be improved.

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3D modeling of a printable object

The shape of a 3D model is rough and inaccurate, because it is divided in thick layers. The rough surface would later be trimmed by using CNC method.

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Bead shape calculation

During the printing a bead is created with a parabolic shape, therefor it‘s difficult to make a flat surface from these kind of beads.

c+ax=y 2

h=c; w

4h -=a

2

2

xw

2-1h=y

t

ww

v

rvwh

43

2 =A

2

wh3

2 =A

(1)

(2)

(3)

(4)

(5)

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Calculation of a distance between beads (1)

2

2

2

1

21:

21:

pxw

hyp

xw

hyp

222

2: Rmy

pxc

(6)

(7)

(8)

In order to get a flat surface we need to calculate a distance between bead trajectories. The distance needs to be small enough to make beads collide with each other to create a small amount of extra material for filling the gap between beads

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Calculation of a distance between beads (2)

22

2

2

22

2

2

2

22

2

4

084

2

4,

02

8

2

02

88

pkR

w

hkhm

w

hkm

w

hkh

pk

w

hkhkA

w

hkmy

px

dx

dymypx

w

hkx

w

h

dx

dy

AA

(9)

(11)

(10)

(12)

(13)

(14)

Modern three-dimensional printing equipment requires additional software packages, apart from those used in modeling. Such programs have their own structure, and some even in their own language. CNC milling equipment has its own language, whose structure is similar to the simulation code for SolidWorks software. While it is used for CNC calculations, it can as well be used for using those calculations to print beads by applying some changes in the code.

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Trajectory estimation

Calculated bead trajectories.

convertTo $ PolyMeshObject$.name = "voxell"modPanel.addModToSelection (Vol__Select ()) ui:on$.modifiers[#Vol__Select].level = 2$.modifiers[#Vol__Select].type = 1$.modifiers[#Vol__Select].invert = on$.modifiers[#Vol__Select].Volume = 3$.modifiers[#Vol__Select].node = $model2voxelmodPanel.addModToSelection (DeleteMesh ()) ui:onmodPanel.addModToSelection (Shell ()) ui:on$.modifiers[#Shell].outerAmount = 0.95

Part of the program code which is used for printing layers

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3D layer surface in 3ds max

Experimental studies were conducted in a virtual environment. For this reason 3ds Max software was used. According to the process parameters - bead printing speed, - wire cross-section radius and – wire pushing speed, visualisation of the collided beads was calculated.

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Conclusions After analysis and calculation to get a flat surface layer an

algorithm was written. A 3D prototype model was created, which was used for experimental testing. Experiments have shown that it is possible to get a close to flat surface layers by using these process parameters: By using them we could calculate a distance between trajectories

This distance is the most optimal in order to obtain a smooth surface.

Due to gravity, surface tension force and electromagnetic force, the surface is not completely smooth, but close to being flat. To obtain a completely smooth surface, the CNC milling can be used to remove a small portion of the layer.

.

mm/s. 0,9=vmm/s; 5,5=v wt

mm. 1.71p

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Thank you for listening

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