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16 Cards in this Set
- Front
- Back
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What material formats can be used in RP of metals?
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Mainly powder, but can use solid and UC
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What types of metal RP are there?
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Direct and Indirect, Indirect processes include 3DP infiltrated with metals, and SLS using a polymer coated metal powder.
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What are the problems with indirect metal RP?
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Can ruin the accuracy of the part
Difficult to do for large parts Involves long periods at high temperatures, which takes alot of energy, and can sinter the powder or dissolve the part You are only really producing a metal composite |
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Describe the direct powder bed process
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Using a method similar to SLS, metal powder is melted by a laser in slices. Unmelted powder supports the layers above it. The powder feed system is the same as SLS. For all powder bed systems, there are stringent materials requirements.
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What characteristics does the MMT system for metal RP from 3D Systems have?
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Uses commonly supply material
Powder bed is heated Highly controlled environment which allows reactive metals to be used |
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What characteristics does the EOS system for metal RP have?
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Materials supplied directly from EOS
An upgrade is available for use with reactive metals |
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What characteristics does the concept laser system for metal RP have?
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A solid state laser
Can be used with steels, titanium, aluminium or nickel alloy |
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What characteristics does the Phenix system for metal RP have?
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Can build metallic or ceramic parts
Offer smaller machines for dentistry |
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What characteristics does the Arcam system for metal RP have?
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No laser, electron beam is used instead.
Build envelope heated to 800 degrees Gives excellent metallurgy but a poor surface finish Scanning is relatively quick, but parts must be cooled slowly Post processing is required |
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What are the advantages of powder bed?
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Controllable environment
Geometric freedom Fully recycleable Produces parts with similar properties to wrought parts |
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What are the limitations of powder bed?
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Support structures dissapate heat, and require removal
Can't use graded materials Can mix materials easily Waste filters can cause fire hazards due to the temp of the material |
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What considerations should be made for materials used?
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Powder must be spherical
Powder size must be right to allow the feed system to work while providing a good density |
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What problems can the materials cause?
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Quality material is very expensive
The powder can become atomised and create trapped pockets of gas Metal purity must be maintained |
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Describe a powder feed metal RP system
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Essentially 3D laser welding, laser creates a pool of molten material powder is fired out of nozzle into the pool. Most systems are mounted on multiple axis machines to provide better geometry
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What are the advantages of a powder feed metal RP system?
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Can be used with graded materials
Can be added to existing structures, used for repairs No supports |
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What are the disadvantages of a powder feed metal RP system?
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Very expensive, in the order of $1m
Lack of supports limits geometry |
