Laser based additive manufacturing

Question 1

Is additive manufacturing a primary or a secondary process?

Answer 1

A primary process. The work piece will need secondary shaping before it is finished.

Question 2

What are the three different classifications of lased based manufacturing?

Answer 2

Additive Subtracting Joining

Question 3

What is Stereolithography?

Answer 3

A scan head moves a laser beam over a vat of photosensitive resin, curing the resin.

Question 4

What might the key components of a Stereolithography manufacturing set up?

Answer 4

Question 5

What is 3D laser lithography?

Answer 5

There is a substance transparent to laser light. The laser is focused onto a point in the substance, causing it to solidify due to 2 photon absorption.

Question 6

What is selective laser sintering?

Answer 6

Often used with polymers. The powder is is heated to just below the glass transition temperature. The laser adds the extra heat needed.

Up to 4 lasers can laser a workpiece at once.

Question 7

What are the componets of a selective laser sintering set up?

Answer 7

Question 9

What is selective laser melting?

Answer 9

Like selective laser sintering, however the material is complety melted together, giving a very high part density

Question 10

What are the main componets of selective laser melting?

Answer 10

Question 11

What is laminated object manufacture?

Answer 11

A laser cuts out sheets of material. A hot roller then bonds the sheet to the work piece beneith.

Question 12

What is laser engineering net shaping?

Answer 12

The moving laser head contains a laser and powder delivery nozzles. The power is deposited as the laser moves around. It can be used to add material to repair things.

Question 13

What are the key componets of laser engineering net shapping?

Answer 13

Question 14

What are some of the materia issued of additive manufacturing?

Answer 14

• Limited range of materials avaliable.
• Anisotropic properties. There can be inconsistant joining of different adjacent layers of material. The orientation of the part also has an effect on material properties.

Question 15

What is a voxel?

Answer 15

The smallest amount of 3D space a CAD design is split up into. The

Question 16

What are process optimisation issues with additive manufacturing?

Answer 16

Errors due to poor slicing or tessellation of the CAD.

Poor calibration.

Finishing errors

Part build errors. A sintering laser has a non zero diameter.

Question 17

What are some of the orientation constraints of AM?

Answer 17

To maximise strength, snaps and pegs should be built in the XY plane.

Fine features should be built facing up to give better feature definition.