Advanced machining processes such as electrical discharge machining (EDM), electrochemical machining, laser beam machining, waterjet cutting, and abrasive jet machining can produce intricate parts with complex geometries and tight tolerances. EDM works by using electric sparks to erode materials and is often used for dies and molds. Electrochemical machining uses electrically charged chemicals to remove material. Laser beam machining uses a focused laser beam to cut or drill holes in materials like non-metallics. Waterjet cutting uses a high-pressure stream of water, sometimes with an abrasive, to cut through materials. These advanced processes allow for parts to be made that would be difficult or impossible with traditional machining techniques

1. Advanced Machining Processes

2. Parts Made by Advanced Machining Processes
Examples of parts produced by advanced machining processes. (a) Samples of parts
produced from waterjet cutting. (b) Turbine blade, produced by plunge EDM, in a
fixture to produce the holes by EDM. Source: (a) Courtesy of Omax Corporation. (b)
Courtesy of Hi-TEK Mfg., Inc.
(a)
(b)

3. General
Characteristics
of Advanced
Machining
Processes

4. Chemical Milling
(a) Missile skin-panel section contoured by chemical milling to improve the stiffness-to-
weight ratio of the part. (b) Weight reduction of space-launch vehicles by the chemical
milling of aluminum-alloy plates. These panels are chemically milled after the plates first
have been formed into shape by a process such as roll forming or stretch forming. The
design of the chemically machined rib patterns can be modified readily at minimal cost.

5. Chemical-Machining
(a) Schematic illustration of the chemical-machining process. Note that no forces or
machine tools are involved in this process. (b) Stages in producing a profiled cavity by
chemical machining; note the undercut.

6. Surface
Roughness
and
Tolerances
in
Machining
Surface roughness and tolerances obtained in various machining processes. Note the wide
range within each process (see also Fig. 23.13). Source: Machining Data Handbook, 3rd ed.
Copyright © 1980. Used by permission of Metcut Research Associates, Inc.

7. Parts Made by Chemical Blanking
Various parts made by chemical blanking. Note the fine detail.
Source: Courtesy of Buckbee-Mears, St. Paul.

8. Electrochemical Machining
Schematic illustration of the electrochemical machining process.

9. Parts Made by Electrochemical Machining
Typical parts made by electrochemical machining. (a) Turbine blade made of nickel
alloy of 360 HB. Note the shape of the electrode on the right. (b) Thin slots on a 4340-
steel roller-bearing cage. (c) Integral airfoils on a compressor disk.

10. Knee Implants
(a) Two total knee replacement systems showing metal implants (top pieces)
with an ultra-high molecular-weight polyethylene insert (bottom pieces). (b)
Cross-section of the ECM process as applies to the metal implant. Source:
Courtesy of Biomet, Inc.

11. Electrochemical-Grinding Process
(a) Schematic illustration of the electrochemical-grinding process. (b) Thin
slot produced on a round nickel-alloy tube by this process.

12. Electrical-Discharge Machining Process
(a) Schematic illustration of the electrical-discharge machining process. This is one of the most widely
used machining processes, particularly for die-sinking applications. (b) Examples of cavities produced by
the electrical-discharge machining process, using shaped electrodes. Two round parts (rear) are the set of
dies for extruding the aluminum piece shown in front (see also Fig. 19.9b). (c) A spiral cavity produced by
EDM using a slowly rotating electrode similar to a screw thread. (d) Holes in a fuel-injection nozzle made
by EDM; the material is heat-treated steel. Source: (b) Courtesy of AGIE USA Ltd.

13. Stepped Cavities Produced by EDM Process
Stepped cavities produced with a square electrode by the EDM process. The
workpiece moves in the two principle horizontal directions (x – y), and its motion is
synchronized with the downward movement of the electrode to produce these
cavities. Also shown is a round electrode capable of producing round or elliptical
cavities. Source: Courtesy of AGIE USA Ltd.

14. The Wire EDM Process
Schematic illustration of the wire EDM
process. As many as 50 hours of machining
can be performed with one reel of wire, which
is then discarded.

Metal removal rate :
MRR  4 104
ITw
1.23
where
I  current in amperes
Tw  melting temperature of workpiece, C

15. Wire EDM
(a) (b)
(a) Cutting a thick plate with wire EDM. (b) A computer-controlled wire
EDM machine. Source: Courtesy of AGIE USA Ltd.

16. Laser-Beam
Machining (LBM)
(a) Schematic illustration of the
laser-beam machining process.
(b) and (c) Examples of holes
produced in nonmetallic parts by
LBM. (d) Cutting sheet metal
with a laser beam. Source: (d)
Courtesy of Rofin-Sinar, Inc.

17. General Applications of Lasers in Manufacturing

18. Electron-Beam Machining Process
Schematic illustration of the electron-beam machining process.
Unlike LBM, this process requires a vacuum, so workpiece size is
limited to the size of the vacuum chamber.

19. Water-Jet
Cutting
Process
(a) Schematic illustration of the water-jet machining process. (b) A computer-controlled
water-jet cutting machine cutting a granite plate. (c) Examples of various nonmetallic
parts produced by the water-jet cutting process. (Enlarged on next slide). Source:
Courtesy of Possis Corporation

20. Nonmetallic Parts Made by Water-Jet Cutting
Examples of various nonmetallic parts produced by the water-jet cutting process.
Source: Courtesy of Possis Corporation

21. Abrasive-Jet Machining
(a) Schematic illustration of the abrasive-jet machining process. (b) Examples of parts
produced through abrasive-jet machining, produced in 50-mm (2-in.) thick 304 stainless
steel. Source: Courtesy of OMAX Corporation.
(b)

22. Case Study: Stent Manufacture
The Guidant MULTI-LINK TETRATM
coronary stent system.
Detail of the 3-3-3 MULTI-LINK
TETRATM pattern.
Evolution of the stent
surface. (a) MULTI-LINK
TETRATM after lasing. Note
that a metal slug is still
attached. (b) After removal
of slag. (c) After
electropolishing.