Rapid Prototyping Facility Laboratory Presentation
Overview Introduction Data Preparation Material Machine Process Demo Crane hook assembly
Introduction Direct Laser Sintering Process Theoretical Basics Advantages Application
Direct laser Sintering Process Uses a Laser beam to selectively sinter one layer of powder at a time to produce plastic and metal prototypes Input geometry is in STL file format The part is sliced with a particular layer thickness and each sliced geometry is sintered by selective scanning of laser beam over a heated powder bed
Theoretical Basics STL file representation of geometry using triangles obtained by tessellating a solid model Slicing Creating contours of sections of the geometry at various heights in the multiples of layer thickness
Theoretical Basics Laser Sintering Using a laser beam to melt the powder and allow densification of powder to form solid dense part
Advantages Ability to make functional prototypes No support structure is required Capability to handle wide variety of material. Living hinges and Snap fit components are possible Capability to make rapid tooling applications
Application For form fit testing For conceptual models Medical applications Tooling applications Patterns for investment casting Varied applications
Data preparation Magics RP-Tools PSW
Information flow
RP Process CAD System Magics RP STL file Reverse Engineering STL File EOS RP Tools EOSINT P380 SLI file CT & MRI Scan data PSW Data Processing
Magics RP Error Fixing of STL file Part placement and orientation Shrinkage Compensation
STL file Optimum number of triangles More triangles more accuracy but large file size Errors in STL file Bad edges, noise shells, flipped triangles, intersecting and overlapping triangles Fixing STL files Using Magics Fix wizard Bad.stl
STL file error fixing using Magics
Flipped Triangles When the normal is pointing at the wrong direction (the inside), the triangle is called a flipped triangle
Bad Edges Original file Stitch tolerance was too small Still near bad edges visible Stitch tolerance was too high Deformations of the part
Noise Shells
Holes Planar Ruled Freeform A simple hole A "rule" is needed to fill the hole correctly When a freeform surface is needed
Bad Edges & Intersecting Triangles
Double Surfaces Angle Tol
Unifying Shells 1 Shell 2 Shells 2 Shells Body 1 first.stl
Placement Procedures Part should not be placed near the edge of the platform Parts should be placed near the centre of the platform Part should not be placed within 6mm height from the platform Part to Part gap should be 5mm
Orientation Procedures Orient parts as flat as possible Orient cylindrical parts with its axis perpendicular to building plane Orient two mating parts in assembly such that their axis are parallel in build volume
Orientation & Placement Use Translate & Rotate Toolbutton to Orient and Place the part
Shrinkage Compensation Scaled up After Shrinkage Part intended Part fired Part Obtained Shrinkage Factor for Scaling the part up X 3.1 % Y 3.1 % Z 1.6 %
Applying Shrinkage Factor Use the Scale toolbutton to apply the shrinkage factor
EOS RP Tools Part Slicing File error Fixing Skin & Core generation
Part Slicing using RP-Tools Creating Sliced contours with layer Thickness 0.15mm Repairing Sliced layer contours
SliFix Sli File Repair
SliFix
SliFix
Skin & Core Generation The skin can be fired Trapped material can be removed by providing hole on any one surface
PSW 3.0 Part Placement Machine Control software
Material, Machine & Process PA2200 EOSINT P380 PSW
Material Polyamide 12 Particle size approx 40 50 µm Crystalline polymer Details Name Polylaurinlactum Melting Point - 180 o H N O (C12 H23 N O)x
EOSINT P380 Plastic Laser Sintering Machine Manufactured by EOS gmbh, Germany Build Volume 320 x 320 X 600 mm 3 Materials Polyamide Glass filled Polyamide Alumide Prime cast
Process Basics
Process Basics
Process Basics
Process Basics
Optical Unit
Characteristics of CO 2 Laser Continuous wave laser Wavelength 10.16µm Maximum power 60 watts Diameter of curing zone 0.6mm
Laser Parameters Laser power Beam Speed Beam offset Hatch spacing Hatch Pattern
Hatch spacing & Beam speed
Skywriting
Sorted with skywriting
Unsorted with skywriting
Updown Skin
Hatching Pattern
Beam Compensation for Hatching
Powder bed properties Powder bed heating using four infra red heating lamps Determination of powder bed temperature Powder bed temperature 173 180 o C
Post processing Part is allowed to cool inside the machine for 5 to 7 hours After the part cools the part is cleaned in shot blasting machine It can dyed and glued.
Case Study Crane Hook Assembly
Assembled view of Crane Hook
Exporting STL files Binary or ASCII Chord height = 0 Angle Control = 1
Orienting & Placing in Magics
Sliced Hook in RP-Tools
Contours and Hatch lines in PSW
Thank you Queries?