Advanced machining processes

Advanced machining processes

1. Advanced Machining Advanced Machining
ProcessesProcesses
Manufacturing Manufacturing
ProcessesProcesses
GOPINATH.GGOPINATH.G
MECHANICALMECHANICAL

2. OutlineOutline
Chemical MillingChemical Milling
Photochemical BlankingPhotochemical Blanking
Electrochemical MachiningElectrochemical Machining
Pulsed Electrochemical MachiningPulsed Electrochemical Machining
Electrochemical GrindingElectrochemical Grinding
Electrical-Discharge MachiningElectrical-Discharge Machining
Electrical-Discharge GrindingElectrical-Discharge Grinding
Electrical-Discharge Wire CuttingElectrical-Discharge Wire Cutting
Laser-Beam MachiningLaser-Beam Machining
Electron Beam MachiningElectron Beam Machining
Plasma Arc CuttingPlasma Arc Cutting
Water Jet MachiningWater Jet Machining
Abrasive Water Jet MachiningAbrasive Water Jet Machining
Abrasive Jet MachiningAbrasive Jet Machining

3. Examples of PartsExamples of Parts

4. Chemical MillingChemical Milling
Produces shallow cavities on a Produces shallow cavities on a
workpiece, usually to reduce workpiece, usually to reduce
weightweight
The area affected by the The area affected by the
chemical reagent is controlled chemical reagent is controlled
by masking or by partial by masking or by partial
immersionimmersion

5. Chemical MillingChemical Milling

6. Chemical MillingChemical Milling
Procedure:Procedure:
1.1.Relieve residual stresses to Relieve residual stresses to
prevent warpingprevent warping
2.2.Clean the material surfaceClean the material surface
3.3.Apply masking materialApply masking material
4.4.Remove the masking on regions Remove the masking on regions
that require etchingthat require etching
5.5.Apply the reagentsApply the reagents
6.6.Wash the partWash the part
7.7.Remove remaining maskingRemove remaining masking
8.8.Additional finishing or chemical Additional finishing or chemical
milling procedures may be usedmilling procedures may be used

7. Photochemical BlankingPhotochemical Blanking
Uses chemicals and Uses chemicals and
photographic processes to photographic processes to
remove material, usually from remove material, usually from
a thin sheeta thin sheet
Can produce complex shapes on Can produce complex shapes on
metals as thin as .0025 mm metals as thin as .0025 mm
without forming burrswithout forming burrs

8. Photochemical BlankingPhotochemical Blanking

9. Examples of PartsExamples of Parts

10. Photochemical BlankingPhotochemical Blanking
Procedure:Procedure:
1.1.Prepare the design at a Prepare the design at a
magnification of up to 100x; make magnification of up to 100x; make
a photographic negative and a photographic negative and
reduce it to the size of the partreduce it to the size of the part
2.2.Coat the blank with Coat the blank with
photosensitive materialphotosensitive material
3.3.Place the negative over the part Place the negative over the part
and expose it to ultraviolet light to and expose it to ultraviolet light to
harden the exposed harden the exposed
photosensitive coatingphotosensitive coating
4.4.Dissolve the unexposed coatingDissolve the unexposed coating
5.5.Apply the chemical reagentApply the chemical reagent
6.6.Remove the masking and wash Remove the masking and wash
the partthe part

11. Chemical MachiningChemical Machining
Design Considerations:Design Considerations:
-Avoid sharp corners, deep narrow Avoid sharp corners, deep narrow
cavities, steep tapers, folded cavities, steep tapers, folded
seams and porous workpiecesseams and porous workpieces
-Undercuts may developUndercuts may develop
-Most of the workpiece should be Most of the workpiece should be
shaped by other processes to shaped by other processes to
speed productionspeed production
-Variations may occur depending Variations may occur depending
onhumidity and temperatureonhumidity and temperature
-Computerized designs must be Computerized designs must be
converted to a format compatible converted to a format compatible
with the photochemical artwork with the photochemical artwork
equipmentequipment

12. Electrochemical Electrochemical
MachiningMachining
Uses an electrolyte and electrical Uses an electrolyte and electrical
current to ionize and remove current to ionize and remove
metal atomsmetal atoms
Can machine complex cavities in Can machine complex cavities in
high-strength materialshigh-strength materials
Leaves a burr-free surfaceLeaves a burr-free surface
Not affected by the strength, Not affected by the strength,
hardness or toughness of the hardness or toughness of the
materialmaterial

13. Electrochemical Electrochemical
MachiningMachining

14. Electrochemical Electrochemical
MachiningMachining

15. Electrochemical Electrochemical
MachiningMachining
Design Considerations:Design Considerations:
-The electrolyte erodes away The electrolyte erodes away
sharp profilessharp profiles
-It is difficult to control It is difficult to control
electrolyte flow; irregular electrolyte flow; irregular
cavities may not be formed cavities may not be formed
accuratelyaccurately
-Allow for small taper in holes Allow for small taper in holes
made this waymade this way

16. Pulsed Electrochemical Pulsed Electrochemical
MachiningMachining
A form of electrochemical A form of electrochemical
machining; the current is machining; the current is
pulsed to eliminate the need pulsed to eliminate the need
for high electrolyte flowfor high electrolyte flow
Improves fatigue life of the partImproves fatigue life of the part

17. Electrochemical Electrochemical
GrindingGrinding
Uses a rotating cathode Uses a rotating cathode
embedded with abrasive embedded with abrasive
particles for applications particles for applications
comparable to milling, grinding comparable to milling, grinding
and sawingand sawing
Most of the metal removal is Most of the metal removal is
done by the electrolyte, done by the electrolyte,
resulting in very low tool wearresulting in very low tool wear
Adaptable for honingAdaptable for honing

18. Electrochemical Electrochemical
GrindingGrinding

19. Electrochemical Electrochemical
GrindingGrinding
Design Considerations:Design Considerations:
(in addition to those for (in addition to those for
electrochemical machining)electrochemical machining)
-Avoid sharp inside radiiAvoid sharp inside radii
-Flat surfaces to be ground Flat surfaces to be ground
should be narrower than the should be narrower than the
width of the grinding wheelwidth of the grinding wheel

20. Electrical-Discharge Electrical-Discharge
MachiningMachining
Uses a shaped electrode and Uses a shaped electrode and
electric sparks to remove electric sparks to remove
metal; discharges sparks at metal; discharges sparks at
about 50-500 kHzabout 50-500 kHz
A dielectric (nonconductive) fluid A dielectric (nonconductive) fluid
removes debris and acts as an removes debris and acts as an
insulator until the potential insulator until the potential
difference is high enoughdifference is high enough
Can be used on any material Can be used on any material
that conducts electricitythat conducts electricity

21. Electrical-Discharge Electrical-Discharge
MachiningMachining

22. Electrical-Discharge Electrical-Discharge
MachiningMachining

23. Electrical-Discharge Electrical-Discharge
MachiningMachining
Design Considerations:Design Considerations:
-Design parts so that the Design parts so that the
electrodes can be made electrodes can be made
economicallyeconomically
-Avoid deep slots and narrow Avoid deep slots and narrow
openingsopenings
-Do not require very fine Do not require very fine
surface finishsurface finish
-Most of the material removal Most of the material removal
should be done by other should be done by other
processes to speed productionprocesses to speed production

24. Electrical-Discharge Electrical-Discharge
GrindingGrinding
The grinding wheel lacks The grinding wheel lacks
abrasives and removes abrasives and removes
material by electrical material by electrical
dischargesdischarges
Can be combined with Can be combined with
electrochemical grindingelectrochemical grinding
Can be used for sawing, in which Can be used for sawing, in which
the saw has no teeththe saw has no teeth

25. Electrical-Discharge Electrical-Discharge
Wire CuttingWire Cutting
The wire moves through the The wire moves through the
workpiece like a band saw, workpiece like a band saw,
removing material by electrical removing material by electrical
dischargedischarge
Dielectric fluid is applied to the Dielectric fluid is applied to the
work areawork area
The wire is generally used only The wire is generally used only
once; it is inexpensiveonce; it is inexpensive

26. Electrical-Discharge Electrical-Discharge
Wire CuttingWire Cutting

27. Electrical-Discharge Electrical-Discharge
Wire CuttingWire Cutting
Example of a wire EDM machine
Courtesy of Edison Industrial Service Center

28. Electrical-Discharge Electrical-Discharge
Wire CuttingWire Cutting
Example of a wire EDM machine
Courtesy of Edison Industrial Service Center

29. Electrical-Discharge Electrical-Discharge
Wire CuttingWire Cutting
Example of a wire used for an EDM machine
This wire has been used; the wave pattern was
formed during take-up
Courtesy of Edison Industrial Service Center

30. Electrical-Discharge Electrical-Discharge
Wire CuttingWire Cutting
Example of cores removed from a part using wire
EDM to create the cavity in a high-pressure nozzle
Holes were drilled in the interiors so that the wire
could be strung through
Courtesy of Edison Industrial Service Center

31. Laser-Beam MachiningLaser-Beam Machining
Uses a concentrated beam of Uses a concentrated beam of
light to vaporize part of the light to vaporize part of the
workpieceworkpiece
Usually produces a rough Usually produces a rough
surface with a heat-affected surface with a heat-affected
zonezone
Can cut holes as small as .005 Can cut holes as small as .005
mm with depth/diameter ratios mm with depth/diameter ratios
of 50:1of 50:1

32. Laser-Beam MachiningLaser-Beam Machining

33. Laser-Beam MachiningLaser-Beam Machining

34. Laser-Beam MachiningLaser-Beam Machining
Example of a part cut by laser-beam machining
Splatter marks appear where the laser first cuts into
the material

35. Laser-Beam MachiningLaser-Beam Machining
Design Considerations:Design Considerations:
-Non-reflective workpiece Non-reflective workpiece
surfaces are preferablesurfaces are preferable
-Sharp corners are difficult to Sharp corners are difficult to
produce; deep cuts produce produce; deep cuts produce
taperstapers
-Consider the effects of high Consider the effects of high
temperature on the workpiece temperature on the workpiece
materialmaterial

36. Electron Beam Electron Beam
MachiningMachining
Vaporizes material using Vaporizes material using
electrons accelerated to 50-electrons accelerated to 50-
80% the speed of light80% the speed of light
Produces finer surface finish and Produces finer surface finish and
narrower cut width than other narrower cut width than other
thermal cutting processesthermal cutting processes
Requires a vacuum; generates Requires a vacuum; generates
hazardous X rayshazardous X rays

37. Electron Beam Electron Beam
MachiningMachining

38. Electron Beam Electron Beam
MachiningMachining
An electron beam in a very low-pressure
atmosphere of helium

39. Plasma Arc CuttingPlasma Arc Cutting
Uses plasma (ionized gas) to Uses plasma (ionized gas) to
rapidly vaporize materialrapidly vaporize material
Material removal rates are much Material removal rates are much
higher than those for laser higher than those for laser
beam machining and electron beam machining and electron
beam machining; produces beam machining; produces
good surface finish and thin cut good surface finish and thin cut
widthwidth

40. Plasma Arc CuttingPlasma Arc Cutting

41. Plasma Arc CuttingPlasma Arc Cutting
Close-up view of a plasma arc

42. Plasma Arc CuttingPlasma Arc Cutting

43. Electron Beam Machining Electron Beam Machining
and Plasma Arc Cuttingand Plasma Arc Cutting
Design Considerations:Design Considerations:
(in addition to those for laser-(in addition to those for laser-
beam machining)beam machining)
-Parts should match the size of Parts should match the size of
the vacuum chamberthe vacuum chamber
-Consider manufacturing the Consider manufacturing the
part as a number of smaller part as a number of smaller
componentscomponents

44. Water Jet MachiningWater Jet Machining
A pressurized jet of water cuts a A pressurized jet of water cuts a
groove in the materialgroove in the material
Effective for many nonmetallic Effective for many nonmetallic
materialsmaterials
Cuts can be started at any Cuts can be started at any
location; does not produce location; does not produce
heat; produces very little heat; produces very little
burringburring

45. Water Jet MachiningWater Jet Machining

46. Water Jet MachiningWater Jet Machining

47. Abrasive Water Jet Abrasive Water Jet
MachiningMachining
The water jet contains abrasive The water jet contains abrasive
particles; this increases the particles; this increases the
material removal ratematerial removal rate
Can cut metallic, nonmetallic, Can cut metallic, nonmetallic,
and advanced composite and advanced composite
materialsmaterials
Suitable for heat-sensitive Suitable for heat-sensitive
materialsmaterials

48. Abrasive Jet MachiningAbrasive Jet Machining
A high-speed jet of dry air, A high-speed jet of dry air,
nitrogen or carbon dioxide nitrogen or carbon dioxide
carries abrasive particlescarries abrasive particles
Good for cutting hard or brittle Good for cutting hard or brittle
materialsmaterials
Can be used for deburring, Can be used for deburring,
cleaning, or removing oxides cleaning, or removing oxides
or surface filmsor surface films

49. Abrasive Jet MachiningAbrasive Jet Machining

50. SummarySummary
Advanced machining processes Advanced machining processes
offer alternatives where offer alternatives where
conventional procedures would conventional procedures would
be insufficient or uneconomical be insufficient or uneconomical

51. The End