Additive Manufacturing - 3D-Printing Technologies Flashcards
3D-Printing (Powder)
Binder Jetting
Ink-jet printing heads move accross a powdered material in a scanning pattern, distributing a liquid inorganic binder and ink to “glue” the powder particles in the shape of each layer.
3D-Printing (Photopolymer)
Material Jetting
Ink-jet printing heads ejects micro-droplets of molten plastic or wax material onto a stationary platform which is cured by UV light
3D Printing- Method
- Inkjet printing heads move across a powdered material in a scanning pattern ejecting droplets of an adhesive bonding material into the required cross section shape
- Lowering the platform with the powder bed by the slice thickness after each new layer is formed at the surface
- The unbonded powder remains loose and acts as a support structure for overhanging or fragile features
- Post process e.g. heat treatment to strengthen the part by solidification
3d Printing- Process Characteristics
-Layer thickness 0.1mm
Vertical build speed 5-28mm/hr
-Prototype often porous with a slightly grainy surface
-May lack in strength; sinter or infiltrate with a hardener (wax, glue, or metal) to increase strength
-Parts can be sanded, drilled, tapped, painted and electroplated
-Accuracy 300x450 or 600x540
3D Printing- Materials
-Plastic- or starch based powders (ABS)
-Ceramic-, glass- or metal-based powders (e.g stainless steel)
-Special powders for
Direct metal casting- Blend of foundry sand, plaster and additives
Investment casting- mix of cellulose, speciality fibres and additives
Elastomeric properties- mix of cellulose, speciality fibres and additives
3D Printing- Applications
- concept models
- parts for limited functional testing
- colour models for FEA and other engineering related applications
- architectural & landscape models
- colour industrial design models, especially consumer goods & packaging
- castings
Pros of 3D Printing
- Good range of materials (metal, polymer and ceramics)
- Two material method allows for a number of different binder-powder combinations and various mechanical properties
- Quick processing time
- No support structure required
- realistic, multi-coloured models, complex geometries with intricate, small, and detailed features
- good for secondary operations (parts can be sanded, drilled, tapped, painted and electroplated)
- Office friendly( quiet, safe, odour-free, easy to use)
Cons of 3D Printing
- Accuracy and surface finish fair
- Fragile prototypes- may require strengthening
- Post processing is often required to strengthen the part (enhance mat
- Overall process time is extended by binder to set and the part to fully solidify while in the machine
3D Jetted Photopolymers- Materials
- Acrylics based photopolymer (UV curable) with transparent , coloured, opaque, flexible, and rigid properties
- Wax support material
3D Jetted Photopolymers- desired properties
- Simulate production plastics (ABS etc) for material properties such as toughness, dimensional stability, detail visualisation, biocompatible
- Simulate rubber-like material properties such as flexibility and durability
- Simulate polypropylene-like appearances (flexibility, strength, toughness, low water absorption rate)
3D Jetteed Photopolymer - Appication
- concept development
- design validation
- form and fit analysis
- moulding and foundry casting patterns
- pattern for investment casting
Pros of 3D Jetted Photopolymer
- Small layer thickness eliminating the stair effect common to complicated curved surfaces
- Quick processing time; adjustable resolution
- Coloured printing
- Multi-material printing
- End use parts
- Office friendly (quiet, safe, odour-free, easy to use)
Cons of 3D Jetted Photopolymer
- Accuracy and surface finish fair
- Fragile prototypes- may require strengthening
- Post processing is often required to strengthen the part (enhanced mechanical and structural properties)
3D Jetted Photopolymer- Method
- Inkjet printing heads ejects micro-droplets of molten plastic or wax material onto a stationary platform
- Continuous or drop on demand (DOD) approach
- Build and support material is ejected simultaneously via separate jets
- Curing of the photopolymer build material using a UV flood lamp (mounted on the ink-jet heads)
3D Jetted Photopolymer- Characteristics
Layer thickness- 16-32micrometers
- Gel like support structure can be easily removed by water jetting
- Accuracy 20-85 micrometers for features smaller than 50micrometers; roughly equal to 200micrometers for larger model sizes
