Rapid Prototyping Facility. Laboratory Presentation

Transcription

1 Rapid Prototyping Facility Laboratory Presentation

2 Overview Introduction Data Preparation Material Machine Process Demo Crane hook assembly

3 Introduction Direct Laser Sintering Process Theoretical Basics Advantages Application

4 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

5 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

6 Theoretical Basics Laser Sintering Using a laser beam to melt the powder and allow densification of powder to form solid dense part

7 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

8 Application For form fit testing For conceptual models Medical applications Tooling applications Patterns for investment casting Varied applications

9 Data preparation Magics RP-Tools PSW

10 Information flow

11 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

12 Magics RP Error Fixing of STL file Part placement and orientation Shrinkage Compensation

13 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

14 STL file error fixing using Magics

15 Flipped Triangles When the normal is pointing at the wrong direction (the inside), the triangle is called a flipped triangle

16 Bad Edges Original file Stitch tolerance was too small Still near bad edges visible Stitch tolerance was too high Deformations of the part

17 Noise Shells

18 Holes Planar Ruled Freeform A simple hole A "rule" is needed to fill the hole correctly When a freeform surface is needed

19 Bad Edges & Intersecting Triangles

20 Double Surfaces Angle Tol

21 Unifying Shells 1 Shell 2 Shells 2 Shells Body 1 first.stl

22 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

23 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

24 Orientation & Placement Use Translate & Rotate Toolbutton to Orient and Place the part

25 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 %

26 Applying Shrinkage Factor Use the Scale toolbutton to apply the shrinkage factor

27 EOS RP Tools Part Slicing File error Fixing Skin & Core generation

28 Part Slicing using RP-Tools Creating Sliced contours with layer Thickness 0.15mm Repairing Sliced layer contours

29 SliFix Sli File Repair

30 SliFix

31 SliFix

32 Skin & Core Generation The skin can be fired Trapped material can be removed by providing hole on any one surface

33 PSW 3.0 Part Placement Machine Control software

34 Material, Machine & Process PA2200 EOSINT P380 PSW

35 Material Polyamide 12 Particle size approx µm Crystalline polymer Details Name Polylaurinlactum Melting Point o H N O (C12 H23 N O)x

36 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

37 Process Basics

38 Process Basics

39 Process Basics

40 Process Basics

41 Optical Unit

42 Characteristics of CO 2 Laser Continuous wave laser Wavelength 10.16µm Maximum power 60 watts Diameter of curing zone 0.6mm

43 Laser Parameters Laser power Beam Speed Beam offset Hatch spacing Hatch Pattern

44 Hatch spacing & Beam speed

45 Skywriting

46 Sorted with skywriting

47 Unsorted with skywriting

48 Updown Skin

49 Hatching Pattern

50 Beam Compensation for Hatching

51 Powder bed properties Powder bed heating using four infra red heating lamps Determination of powder bed temperature Powder bed temperature o C

52 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.

53 Case Study Crane Hook Assembly

54 Assembled view of Crane Hook

55 Exporting STL files Binary or ASCII Chord height = 0 Angle Control = 1

56 Orienting & Placing in Magics

57 Sliced Hook in RP-Tools

58 Contours and Hatch lines in PSW

59 Thank you Queries?