Lecture 4 part 1 Flashcards
What is the defintition of Additive Manufacturing?
The additive manufacture of end-use products or components directly from 3D Computer Aided Design (CAD) data without the need for any tooling – Hopkinson et al
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Additive Manufacturing is a process of ———- geometry ——– by ———
Additive Manufacturing is a process of creating geometry layer by layer
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Additive manufacturing is directly comparable to ——— ———– techniques
Currently there are —- core types of Additive processes available, all provide ———— ————- and opportunities
Additive manufacturing is directly comparable to Rapid Prototyping techniques
Currently there are 5 core types of Additive processes available, all provide different functionality and opportunities
What are some of the major advantages of AM
Design freedom - Anything that can be modelled using 3d CAD can be manufacture
Geometrical complexity/optimisation
Personalisation/customisation - economic manufacture of one unit - Body fitting - Medical implants
Multiple free-moving assembilies - AM textiles - Strandbeest (Theo Jansen)
Part consolidation - integrated fastners - live hinges - springs…
Large scale and small scale AM possible - 3d printed concrete for construction - micro-scale lithography (Nanoscribe)
What Design for Manufacture considerations are removed?
No tooling consideration - CAD is the tool
No part extraction
Draft angles not required
Re-entrant geometry achievable
Rapid Prototyping vs Additive Manufacturing
Rapid Prototyping (RP)
- Create a likeness of a part/component
- Prototype for evaluation purposes
- DfM and DfAM considerations
Additive Manufacturing (AM)
- Creating the end-use part/component
- Direct manufacture
- DfAM considerations
What are the main stages of the AM design process?
What are the main three sections of the detailed design process?
3D modelling
- High quality CAD data
DfM/DfAM Considerations
- RP or AM
Process selection
- Build materials
- Build volumes and part size
- Resolution and accuracy
- Costs
Why do you have to check the geometry of your STL file?
Errors can be created in the conversion of the CAD file to the triangular surface matrix
Geometry may no longer be “watertight”
Any errors you may have made in your CAD data will have carried over
What are some DfM/DfAM considerations?
Minimum feature size (mm)
Part seperation (mm)
Tolerencing and accuracy
- Three dimensional
Design for tighter tolerances
Hollow-out parts (Shelled)
Support structures?
- Requirements, placement and removal
Powder removal?
- Enclosed volumens and conformal channels
What are some general rules when thinking about minimum feature size?
Process specific – check
–General rule ≈ Ø0.8mm
–Jetting & Metal processes ≈ Ø0.1 – 0.2mm
–Height = one layer, typically 0.1 – 0.2 mm
If you were to ask me to do something for love, what wouldnt I do?
THAT
If you are adding text to your print out, what are some general rules?
Pick a simple font style
Print it as large as you can for your design
When building parts that need to be separated what is the general rule for part spacing?
Ensure parts do not fuse during build
–Process specific & Geometry specific
–General rule ≈ 0.4mm (min)
What should you keep in mind to avoid tolerencing and accuracy issues in 3D builds?
- Tolerances are process specific ≈ +/- 0.2mm
–Repeatability is an issue…
–Build all ‘mating’ parts in the same build!
It is possible to design for tighter tolerences in certain processes
What does ribbing do for YOUR structure?
Increases structural integrity
- Use the design freedom to add in appropriate places
