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RAPID PROTOTYPING

Plastic

Selective laser sintering

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WHAT IS RAPID PROTOTYPING?

Its is a automatic process of construction of physical objects

using additive manufacturing technology.

Additive manufacturing is defined as a process of joiningmaterials to make physical objects from 3-D model data,

usually layer upon layer.

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RP PROCESS FLOW

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RAPID PROTOTYPING TECHNOLOGIES

Rapid Prototyping

Technologies

3-D printing(3-DP)Laminated Object

Manufacturing(LOM

Stereo lithography(SLA)

Fused Deposition

Modeling(FDM)

Selective Laser

Sintering (SLS)

Electron Beam

Melting(EBM)

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SELECTIVE LASER SINTERING(PLASTICS)

It is a additive manufacturing technique that uses sintering process

to make physical objects.

In this process high powerCO2 laser selectively fuses plastics

powder material by scanning crossections generated from 3-Dmodel of a part on the surface of powder bed.

After each cross-section is scanned, the powder bed is lowered by

one layer thickness, a new layer of material is applied on top, and

the process is repeated until the part is completed.

This process is carried out in a air tight chamber in the presence of

INERT gas (N2 ).

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SLS PROCESS DIAGRAM

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STEPS INVOLVED IN THE SLS

Step 1: Create a CAD model of the object.

Step 2: Convert the CAD model into STL(Standard Triangulation

Language) format.

Step 3: Slice the STL file into thin crossections layers. Step 4: Construct the model one layer over other to from a object,

X-Y dimensions are controlled by scanner and Z dimension is

controlled by the movement of the piston.

Step 5: Now cleaning and finishing is done of the prepared model.

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MATERIAL USED

Two type of plastic materials are sent by the company namely:

Dura form PA.(100kgs)

Dura form GF.(105kgs)

Materials supplied

DuraformPolyamide(PA)

100kgs.

Duraform GlassFilled(GF)

105kgs.

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DURAFORM POLYAMIDE(PA)

Features:

Excellent surface resolution and feature detail.

Easy to process

Good chemical resistance and low moisture absorption.

Benefits:

Prototypes withstand functional testing.

Produce durable end use parts without tooling.

Machinable and paintable for demonstration.

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Properties Value

Density 0.59g/cm3 .

Average particle size 58m.

Moisture absorption(24hrs) 0.07%

Melting point 184o C.

Tensile strength, Yield 43MPa.

Tensile strength, Ultimate 1586MPa

Flammability HB

Properties

Duraform polyamide(PA) contd.

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DURAFORM POLYAMIDE(PA) CONTD.

Applications

Housings and enclosures.

Impellers and connectors.

Dashboards and grilles. Snap fit designs

Functional prototypes.

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DURAFORM GLASS FILLED(GF)

Features

Excellent mechanical stiffness.

High temperature resistance.

Dimensionally stable.

Easy to process.

Good surface finish.

Benefits

Good load bearing capacity at high temperature.

Machinable and paintable for demonstration.

Improved isotropic shrinkage due to glass filler.

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DURAFORM GLASS FILLED(GF)

CONTD.Properties Value

Density 0.84g/cm3 .

Average particle size 48m.

Moisture absorption(24hrs) 0.22%

Melting point 185o C

Tensile strength, Yield 27MPa

Tensile strength, Ultimate 26MPa

lammability

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SLS MACHINE PARAMETERSParameters Value

Model Number sProTM 60 HD Base(3d systems).

Material Duraform PA (100 kgs) Duraform GF

(105 kgs)

Scanning speed. 6m/s.

Build speed . 35mm/hr, 1L/hr.

Build volume 381mmx340mmx457mm.

Container volume 57 ltrs.

Laser power/type. 30W CO2 .

Inert gas . Nitrogen with 9 LPM.

Layer thickness . 0.08mm, 0.1mm and 0.15mm

Control & part preparation

software.

L54.4 Sinter/BuildSetUp.

Coolant Mixture of Distilled water and Glycol.

Input data file format STL.

Operating system Windows XP.

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SLS MACHINE REQUIREMENTS

Requirements Value

Space 2077x1429x2040mm.

Electrical 240V, 12.5KVA, 50/60Hz, 3-Phase.

Ambient Temperature 16o C-27o C.

Chiller 200-240V, 13A, Single phase.

Relative Humidity

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KEY POINTS FOR SLS

Continuous inert gas supply.

Continuous power supply.

Continuous coolant supply.

Continuous material supply. Preheating of the bed.

Laser/scanning head calibration time to time.

Dust free and temperature controlled environment for machine.

Skilled manpower.

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RP APPLICATIONS

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RP BENEFITS

Visualization , verification, iteration, and design optimization.

Communication tool for simultaneous engineering.

Form fit function tests.

Marketing studies of consumer preferences.

Metals prototypes fabricated from polymer parts.

Tooling fabricated from polymer parts.