Lecture 8 part1 - Other polymer and non-metal processes Flashcards
What are the 3 methods are in this category ?
- Extrusion-based systems
- Jetting methods
- Lamination
Extrusion-based systems - The process
What are the 5 stages of this method?
- Molten plastic extruded through a nozzle to create cross-section
- Plastic filament supplied to heated extrusion nozzle
- Plastic melts and is extruded in appropriate cross-sections
- Chamber heated to just below Tm of the plastic
- Support structures for overhanging geometries
_Extrusion-based system - Post Processing _
What can removing support structures entail?
1) Breakaway supports – manual removal
2) Soluble supports – dissolve in ‘water-based’ solution
- May need to apply temperature, agitation etc.
- Can be best to manually remove majority of supports first
3) Varying choice of support structures (experience is
key)
_Extrusion-based system - Post Processing _
What comes after removing support material?
what does this entail?
Smoothing/finishing
Finishing touch smoothing station
• Semi-automated smoothing of parts
• Solvent-based process – claims to reduced surface
roughness to one-tenth, with no reduction in accuracy
_Extrusion-based systems - Advantages _
What are 5 advantages of these types of systems ?
- Office friendly – no hazardous materials (but can be loud/hot!)
- Some companies (e.g. Materialise) starting to make use of this for heating their facility
- Several available materials, some of which, compare with traditional materials
- Coloured materials (only one at a time)
- Range of systems available (size, speed, cost etc.)
- Soluble supports
_Extrusion-based systems - Limitations _
What are 4 limitations of this technique ?
- Slow production of parts with large cross-sections
- Mechanical properties, particularly in z direction
- Surface finish can be poor
• Support structures not always as easy to remove
as you might think…
Extrusion-based systems - other comments
what has this technology made major advances in ? (2 areas)
- Surface finish (as-produced and with finishing)
- Mechanical properties (especially z-direction)
Other Systems (1)
Give an example of one of these other systems?
……….. ..-.. Bio-………..
What is it specifically designed for ?
what are 3 advantages of this ?
- Envisiontec 3-D Bio-plotter
• Designed specifically for processing of bio-materials
for Computer-Aided Tissue Engineering
• Range of temperatures
• Several materials in one build
• Different methods of hardening, depending on build material
Other systems (2)
What is another example of these other systems ?
Hewlett-Packard ……….. … ………..
What was it ?
what was it’s issue ?
- Hewlett-Packard Designjet 3D systems
• Basically a re-branding of small Stratasys system
• Exciting development – for many years the
community had hoped for a big printing company to
become involved
• Scale (production, distribution etc.)
• Technical expertise
• Only lasted ~2 years before agreement
was discontinued
• A question of demand?
Other systems (3)
another example of this is ………. ……….
What is the price range of these systems ?
Where are these available ?
Personal systems
- Defined as costing <$5,000
- E.g. Bits from Bytes
- Makerbot Industries
- RepRap
- Fab@Home
• Now available to buy on the
High Street
• Some self-assembly, some
ready-made
Other systems (4)
What is the target market of personal AM systems?
What are teh general features of these systems
Range of machines aimed at home use
(occasionally office use)
• Education/outreach
• Hobbyists
Variety of systems, but some commonality:
• Small (desktop-size)
• Easy to use
• Often comes with deliberately user-friendly software
Other systems (5)
give an example of a personal system
what are its features ?
When buying this system - what are the two options?
• Fab@Home – the first example!
• (58 out of 66 units in 2007)
• 3D printers to make at home
• Low cost, syringe-based system, almost any material
can be processed
• Two options:
• Buy complete self-assembly kit
• Download blueprints and buy components yourself
• All information is free (remember Hod Lipson from
before?)
• Exchange of ideas and
improvements is encouraged
• As more people use the kits,
the better the systems become
Applications (1)
What are the 3 types of tooling this is used in ?
- Assembly tools etc.
- Ergonomically produced assembly aids
- Improved handling/balance improvement
- Weight reduction (e.g. 72% reduction through sparse-fill techniques)
- Carbon fibre lay-up
- Vacuum casting
• Porosity helps!
Applications (2)
How is this method used in Measurement/inspection
RapidFit
– originally started as a packaging solution
• Fixtures to package a complex part for transit
Progressed to use for measurement/inspection
• ‘If it doesn’t fit, it’s out of spec’
Applications (3)
What are the reasons for this being used in space ?
- Weight restrictions in space travel prevent carrying spare parts for repair
- Ultimately require production of spare parts and redesign on-board spacecraft
- Liquid/powder based systems unsuitable
- FDM tested under microgravity conditions to determine potential for use in space
