Lecture 2 part 1 Flashcards
What are the 5 Stages of Pre-processing?
1) Design stage considerations
2) .stl file preparation/repair
3) Orientation/nesting
4) Support structures
5) Machine set-up
What are the 2 stages of Post-processing?
1) Support removal*
2) Surface finish*
*Process-dependent
Fill in the gaps
Pre- and post-processing
Often ….-……., or simply ignored, when talking about AM
Can add ….. and ……. to the production process. In some cases, not considering these things can be
catastrophic!
If you are in the position to buy one or more systems, find out about these things first! :
- E.g. if specialist ……….. materials are required, what is the cost of these?
- Do you need extra ………..? How much ……….-space is needed? Any special …………… requirements?
over-looked
cost, time
cleaning
equipment, floor
atmospheric
Pre & Post processing
What part of the Generic process chain is not pre & post processing ?
Fill in the gaps
Pre-processing starts at the ………. stage. You cannot effectively design something if you don’t understand the restrictions of the ……………… processess
Consult the AM …………… and use their experience to optimise your designs for AM. This will save a lot of time and effort in the process.
design
manufacturing
technician
When choosing an AM system and/or material , what are 6 things to consider ?
1) Accuracy required
2) Mechanical Properties ( cheaper processes may give lower properties, but does this matter?)
3) Surface finish (may also incluse colouring procedures)
4) Number of parts required
5) Component size and complexity (particularly ,how easily can you remove support material)
6) Total cost per part (including pre- and post processing!)
Fill in the gaps
Once you know which system/material combination
you will use, some considerations will be:
• Minimum achievable ……. …..
• Minimum ….. thickness
• Smallest …………. …… diameter etc.
• What mechanical properties will you obtain, and how
…………. are these?
• What ….. - ………….. considerations do you need to be aware of?
• E.g. ………… structures, ……….. removal
feature sizes
wall
reproducable hole
homogeneous
post- processing
support , powder
.stl files
sketch the flow diagram from CAD to AM
.stl files
What do .stl files do , what shape does it use and what is lost when using this file?
approximates the surface of 3D models
Uses a series of tessellated trianges - each triangle is defined by its normal and 3 vertices
Colours layers and other CAD data is lost , only coordinatesof the vertices are in this .stl file. Therefore the file sizes is relatively small.
.stl files
sketch a diagram of high and low tolerances with .stl circles
Fill in the gaps
.stl
File sizes are directly related to the ………. of ………
May also have an effect on the ….-………….. time (bear in mind how accurate your system is)
Many CAD packages can import .stl files - mainly for what ? What is the limitation of this?
The most widely used .stl package/viewer software is….
What are the uses of this software ?
viewing, limited modification
Magics from Materialise
tooling, slicing and support generation
Magics Software
What is its most important function ?(Arguably)
Why does it have this function ?
checking and repairing
.stl files often have a variety of errors which cause problems in the build (common for surface models less so for solid models)
This software can identify and help fix errors
Magics software
what does this software do with common errors?
what other function is there for dealing with errors?
repaired automatically
manual repair
not all errors are catestrophic
Common errors with.stl files are
………… normals / flipped ……….. :
The ……….. of each triangle/facet is crucial. Each triangle has a …….. which should face outward.
If the ……….. is pointing in the wrong direction i.e. to the inside of the part, it is considered inverted or flipped and must be corrected
Inverted, triangles
orientation
normal
normal
