CAMT CAMT Machine Calibration & Process Parameters 2

Question 1

How does increasing nozzle temperature in FDM printing generally affect interlayer adhesion?

Accepted Answer

Higher temperatures generally improve interlayer adhesion up to a material-specific maximum

Answer

Higher extrusion temperatures increase polymer chain mobility and diffusion across layer interfaces in FDM, improving interlayer bonding strength up to the point where material degradation begins.

Question 2

In laser powder bed fusion, what is the primary effect of increasing laser power on the melt pool?

Accepted Answer

It increases melt pool size and depth, improving fusion but risking keyhole porosity at excess levels

Answer

Higher laser power in LPBF enlarges and deepens the melt pool, improving powder fusion and part density, but excessive power creates keyhole defects from vapor cavity formation beneath the melt pool.

Question 3

What is Volumetric Energy Density (VED) in laser powder bed fusion, and why is it a key process parameter?

Accepted Answer

Energy delivered per unit volume of powder, directly controlling fusion quality and porosity

Answer

VED quantifies energy delivered per unit powder volume (Power ÷ [Scan Speed × Hatch Spacing × Layer Thickness]), serving as the primary predictor of part density, microstructure, and defect level.

Question 4

How does increasing print speed in FDM typically affect the trade-off between productivity and part quality?

Accepted Answer

Higher speed increases throughput but typically reduces dimensional accuracy, surface finish, and layer adhesion

Answer

Increasing FDM print speed reduces build time but can degrade dimensional accuracy, surface finish, and interlayer bonding due to inconsistent material flow rates and reduced interlayer dwell time.

Question 5

What is 'hatch spacing' in laser powder bed fusion, and how does it affect part density?

Accepted Answer

The lateral distance between adjacent laser scan tracks, affecting melt pool overlap and density

Answer

Hatch spacing is the lateral offset between adjacent laser scan tracks; smaller spacing increases melt pool overlap, improving density and reducing porosity, but increases scan time per layer.

CAMT - Certified Additive Manufacturing Technician Practice Test

CAMT - Certified Additive Manufacturing Technician Practice Test

CAMT CAMT Machine Calibration & Process Parameters 2