Question

sls: moving parts
use the information below to answer the question.
sls printing can be used to make moving parts. there is no support structure other than the powder that is in the powder bed.
moving part considerations
consider the thickness of the shafts and the mass to avoid over - sintering. in general, if the print has a shaft that is less than 1 cm in diameter, there can be a clearance of 0.15 mm on each side. the mass will not build up too much heat, so it wont over - sinter. if the shaft needs to be 1 cm, the clearance will be 0.25 mm on each side. it is important to note that there will still be powder in between and it can over - sinter.
reduce surface area
to avoid over - sintering moving parts, a redesign that reduces the surface area and contact is a good choice. there will be much less heat build - up, and the possibility of over - sintering is reduced greatly. the clearance in the center will be 0.4 mm, and an escape hole can be put in to allow the powder to get out.
which of the following is true about selective laser sintering (sls)?

• it requires a tree - shaped support structure.
• it does not have post - processing steps.
• it can be used to make moving parts.
• it uses a resin - based material.

Explanation:

• Analyze each option:
• "It requires a tree - shaped support structure": The text says "There is no support structure other than the powder that is in the powder bed", so this is false.
• "It does not have post - processing steps": The text doesn't mention post - processing, but we can't conclude it has none. Also, the main info is about making moving parts, so this is not supported.
• "It can be used to make moving parts": The text clearly states "SLS printing can be used to make moving parts", so this is true.
• "It uses a resin - based material": SLS typically uses powder - based materials (like nylon powder), not resin - based. Resin is used in SLA (Stereolithography) more commonly, so this is false.

Answer:

It can be used to make moving parts.