Rapid Prototyping

1
Rapid Prototyping

• A short introduction to stereolithography on
  campus

2
Uses of Rapid Prototyping

• Diagnostic tool
• pre-operative planning
• improve product quality
• reduce time-to-market
• communication
• early design flaw detection
• functional prototypes

3
File Management

• Object must be a skin or solid
• STL (stereolithography files)
• triangles connected at vertices
• SLC (Stereolithography contour files)
• successive cross-sections taken at ascending Z
  direction intervals

4
Popular Systems

• Stratasys
• MedModeler
• Z Corp
• Z402
• 3D Systems
• SLA-250

5
Stratasys FDM MedModeler

• CT/MRI data
• plastic or wax anatomical parts
• ABS or medical grade ABS
• SLC or STL
• 10x10x10 in
• /- 1 pixel 0.030 (/-0.762mm)

6
Z Corp Z402

• Concept modeling
• ZP11 powder starch and cellulose based
• STL files
• 8x10x8 in
• /- 0.005 in x y axis
• /- 0.010 in z axis

7
3D Systems SLA-250/40

• HeCd laser
• Cibatool SL5170 epoxy-based resin
• STL or SLC files
• 10x10x10 in.
• /- 0.005

8
Prototype Building

• STL or SLC file needed
• Rhino, ProEngineer
• Object must be polygon and have thickness
• Object must be in positive space
• Resin cannot be trapped
• Maestro
• building support structures

9
Building Process

• Laser moves across top of vat containing liquid
  photopolymer
• Beam transforms liquid to solid
• Completed layer dips into vat

10
Recoating Process

• Platform lowered to next slice on Z plane

11
Recoating Process

• Combination of elevator and recoater blade
  movements

12
Waiting Process

• Zwait due to critical circle diameter(CCD)
• Laser cuts next cross section

13
Post Processing

• Remove support structures
• Two step cleaning process
• Acetone bath
• 2-Propanol wash
• Cure in UV oven

14
Polymerization

• Liquid resin (Cibatool SL5170) converted to solid
  polymer upon exposure to UV light
• Photopolymer
• Photoinitiator absorbs laser energy, forms
  reactive cationic species, initiate
  polymerization process
• Epoxy based monomers and oligomers polymerize
  upon exposure to cationic species