Dominos

Question 1

What is the FDM?

Answer 1

• a robot controlled extruder moves in two principal directions over a table, which can be raised and lowered as required.
  -the extruded head is heated and extrudes a polymer filament through a small orifice at a constant rate.
  -the head follows a predetermined path the extruded polymer bonds to the previously deposited layer

Question 2

explain FDM -working principle?

Answer 2

-filament spoon
-the filament is led to the extruder
-the extruder uses torque and a pinch system to feed and retract the filament in precise amounts
-A heater block melts the filament to useable temperature
-the heated filament is forced out the heated nozzle at a smaller diameter
-the extruded material is laid down on the model where it is needed
-the print head is moved in the correct X/Y/Z position

Question 3

analyse the pressure assisted systems for FDM

Answer 3

-low viscocity
-lower accuracy
-longer production
-compatible with living cells for medical applications

Question 4

analyse screw assisted systems?

Answer 4

-high viscosity materials
-higher accuracy
-shorter production time]-not compatible with living cells for medical applications

Question 5

FDM advatages and limitations?

Answer 5

Build speed- dependent on feed rate and plotting speeds
accuracy - limited to 0.078mm in high-cost printers
Part anisotropy - isotropic properties in x-y plane are possible

Question 6

What is VAT photopolymerization?

Answer 6

It requires the user of a a laser (normally ultraviolet but gamma rays, electron beams) to scan the surface of the resin promoting a chemical reaction and transforming it into a solid.