3.5: Rapid Prototyping

What is rapid prototyping?

the production of a physical model of a design using 3 dimensional CAD data

Additive vs subtractive?

additive manufacturing: building object by adding material

subtractive manufacturing: removing material to create object

why are rapid prototyping techniques additive?

• relatively inexpensive

• doesnt waste materials- doesnt waste cost

• allows for substantial amount of complexity within internal areas of a part

stereolithography

optical fabrication/ photo-solidification/ solid free-form fabrication/ solid imaging

form of 3d printing that uses a liquid bath of resin combined with an ultraviolet laser

• laser hits liquid + hardens it to form structure of object

LOM

Laminated object manufacturing: takes sliced CAD data from 3d model + cuts out each layer from roll of material using a laser or plotter cutter

sliced layers then glued together

what is slicing?

translated 3d model from computer to machine

FDM

fused deposition modelling

• additive

• lays down materials in layers (additive)

• plastic/metal filament fed through heated extruder nozzle which moves back and forth along a platform

SLS

selective laser sintering

• additive

• high power laser fuses small material particles (glass, ceramic, plastic, metal) into a mass that has a desired 3d shape

advantages of rapid prototyping

• decrease development time

• decrease costly mistakes

• increase number of product variants (quick to produce- increases productivity)

• increase product complexity (some difficult shapes may not be possible by hand)

• increase effective communication (tangible model easier to explain)

• provide concept proof- required to attract funds (easier to explain)

disadvantages of rapid prototyping

• fails in replication of real product/system because different manufacturing technique + material used- therefore looks, feels made differently

• made so quickly that important developmental stages could be ignored to quickly get a cheap working model

• many problems are overlooked resulting in endless rectifications and revisions

• may not be suitable for large sized applications (have to make so many parts)

• not high performing for high standard users