Unit 3 - Additive manufacturing processes

Question 1

STL - Stereolithography

Answer 1

• tank with a liquid photosensitive or a heat-sensitive polymer
• a build platform which is height-adjustable, moves downwards as the construction progress
• laser with X/Y coords, supplies energy for polymer chemical reaction
• finished component is lifted out of the liquid polymer > additional uv or heat then cleaning

accuracy up to 50um

oldest and mature process

Question 2

SLS - selective laser sintering

Answer 2

metals or sand
metallic powder particles are externally covered with plastics

1. laser in X/Y melting and cross linking the plastic coating to bond the powder
2. platforms lowers step by step after each layer and new powder is spread
3. repeat untill component is finished
4. heat treatment: sintering furnace, high temperatures burn off plastics and create atomic bonds between metal particles

Question 3

SLM - selective laser melting

Answer 3

metal is melted layer by layer

Question 4

SEBM - selective electron beam melting

Answer 4

must work under vacuu, metal is melted

Question 5

FDM - fusion deposition melting

Answer 5

is an additive manufacturing process in which a component is built up layer by layer from a meltable plastic (thermoplastic)

build platform (Z)
one or more injection heads + heated nozzle
head draw in the material from a material spool
electrically heated nozzle, melt plastics and place layer by layer

Question 6

MJM - Multi-jet modeling and PJM - poly-jet modeling

Answer 6

liquid plastic or wax is applied as a layer to build a platform or to a previous layer using a print head, like a inkjet printer
plastics can be UV sensitive
multiple nozzle
liquid or base material is sprayed in fine drops to build the layer

Question 7

3DP - 3d printing process

Answer 7

powder is dispensed onto the building platform in thin layers
bonding agent is injected into the powder layer with a Piezo injector
bonding agent turns the powder layer into a solid material
component is build up layer by layer

umbonded powder remains in the building space, stabilizing the component, performs a support function

metals, ceramics, sand, plastics

can produce molds for casting processes

Question 8

LLM - Layer laminated manufacturing or LOM - layer object modeling

Answer 8

building material is cut out and applied layer upon layer or later to the underlying layer using adhesive technology or polymerization

paper, plastic films, metal foils, stell aluminium or titanum

Question 9

SMS - selective mask sintering

Answer 9

plastic powder is applied layer byy layer to the build platform
selectively melted by means of a planar infrared (IR) emitter
mask are used to exclusively direct the IR to the area that needs to be melter
survace layer is melted and bondend to the underlying layer

mask pattern created layer by layer
> glass plate is coated with toner, pattern allows the light to pass where needed and don’t pass in other areas
glass plate automaticcaly cleaned and re-covered