Selective Laser Sintering (SLS): Does SLS use laser-hardened liquid resins to build models, or does it fuse powdered materials layer by layer?
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ACorrect
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BIncorrect
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CTrue only for photopolymers
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DTrue when using support baths
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EDepends solely on layer thickness
Answer
Correct Answer: Incorrect
Explanation
Introduction / Context:Selective Laser Sintering (SLS) is a powder-bed fusion additive process. A laser scans and fuses particles (thermoplastics like PA12, elastomers, or even metal variants in related processes) layer by layer. The claim that SLS uses laser-hardened resins describes stereolithography (SLA), not SLS.
Given Data / Assumptions:
- We are comparing SLS (powder) and SLA (liquid photopolymer).
- Both use layer-wise fabrication with lasers, but materials and physics differ.
- Supports: SLS often relies on surrounding powder for support; SLA needs explicit support structures.
Concept / Approach:In SLS, a recoater spreads a thin layer of powder; the laser fuses selected regions. The build lowers, a new layer is spread, and the process repeats. In SLA, a UV laser (or projector) cures liquid resin by photopolymerization. Confusing these leads to incorrect expectations about surface finish, mechanical properties, and post-processing.
Step-by-Step Solution:
Identify medium: SLS uses powder; SLA uses liquid resin.Identify mechanism: SLS fuses/sinters particles via thermal energy; SLA cures via photochemistry.Infer implications: SLS supports are implicit (powder); SLA requires designed supports.Conclude: the statement equating SLS with laser-hardened resins is incorrect.Verification / Alternative check:Observe build chambers: SLS has powder cakes; SLA has resin vats. Datasheets list nylon/elastomer powders for SLS vs photopolymers for SLA.
Why Other Options Are Wrong:Options claiming photopolymers, support baths, or layer thickness as determinants confuse process fundamentals.
Common Pitfalls:Expecting SLA-like glossy surfaces from SLS; overlooking powder recycling and thermal management; mishandling unsintered powder during depowdering.
Final Answer:Incorrect