Machining and rapid prototyping

advantages of additive manufacturing

super fast

can build complex shapes

little to no waste other than throwing away prototype or failures

types of additive manufacturing

FDM (normal) 3d printing usually PLA or ABS

SLA (stereolith) uses UV to cure liquid resin - USUALLY ACRYLIC/EPOXY

SLS uses laser beam to fuse together powder

Direct metal laser melting - melt cross sections that fuse together then lower bed and add new powder layer and repeat.

STL-files

files made from the cad model using regular polygons or traingles to approximate the shape of the design to a certain degree of accuracy

main thing to consider with additive manufacturing

design orientation in building - to produce strongest build consider that printer adds layer by layer and so your product should be oriented in order to reduce the amount of overhangs.

(also generally 45* lattices are stronger than horizontal lattices.)

types of machining (not traditional etc)

generating = shape of workpiece determined by toolpath - tool shape usually simple

forming = shape of workpiece determined by shape of tool

where do u perform turning

= lathe

two main types of workpiece holders in turning

faceplate

3-jaw chuck

types of turning cuts other than the obvious

Contour turning = just making a non linear shape

form turning = tool is already shaped as you want it (forming)

Drilling = making hole parallel to axis

boring/reaming = making hole parallel to axis BIGGER

knurling = grip texture

where do you perform drilling

drill press

types of drill cuts

boring/reaming = make holes bigger

countersinking = make countersink for screws

tapping = making thread space for screws

counterboring/reaming = just mkaes a stepped hole

centering = make primary hole to drill in correct place

milling definition

a machining process in which a workpiece is fed past a rotating cylindrical tool with teeth

types of milling cuts

conventional = workpiece is smaller than the mill cutter!!

end = most versatile/common

surface contouring = contouring i.e. non linear shaping just like lathe

types of non-conventional machnining

mechanical

electrical

thermal

chemical

water jet cutting + pros and cons (K)

high pressure water used to cut narrow slits

GOOD FOR THE ENVIRONMENT and

no heat affected zone which significantly impacts thin materials so this is perfect for them

but

further down the hole water jet loses intensity so thinning of hole AKA KERF ANGLE

abrasive water jet

same ad water ejt but with abrasive particles

STILL GOOD FOR ENVIRONMENT and same negatives

thermal energy process + pros and cons

locally removes material by fusion or vaporisation

good for rlly temp resistant materials

but leaves a bad surface finish and so requires other processes

only applicable to some materials

laser cutting + pros and cons

cons:

burn marks as well

kerf as well

There is a max thickness that the machines can handle

only compatible with certain materials

electrical discharge machining + wire cutting

both tool and workpiece submerged in conductive fluid, current flows into workpiece through fluid from tool causing enough heat to remove a mslal amounut of material NO MATTER HOW HARD THE MATERIAL AS LONG AS ITS CONDUCTIVE.

pros:

any conductive material/hardness

REALLY COMPLEX SHAPES that cannot be made otherwise

and high accuracy

no mechanical working stress on workpiece or tool

cons:

environmentally unfriendly - liquid is full of liquid and cant be thrown away as u normally would

only diff between two is one acts like band saw other acts like mill.

Plasma arc cutting

conductive work piece - electeic arc made between electrode and workpiece - the arc must go through/be made of an ionised gas which is also provided by the electrode.

other gases can be used to confine the arc and increase accuracy.

pros: (comp to laser cutting)

for thicker materials

faster

cheaper!

cons:

leaves bigger marks

less accurate - uneven edges from resolidified material

workpiece must conduct