1. Chapter 35: Surface Engineering
DeGarmo’s Materials and Processes in Manufacturing

2. 35.1 Introduction

3. Fatigue Strength as a Function of Finish
FIGURE 35-1 Fatigue strength
of Inconel 718 components after
surface finishing by grinding or
EDM. (Field and Kahles, 1971).

4. Surface Profiles
FIGURE 35-2 Machining processes produce surface flaws, waviness, and roughness that can influence the performance of the component.

5. Machined Surfaces

6. Machined Surfaces
FIGURE 35-3 (a) Terminology used in specifying and measuring surface quality; (b) symbols used on drawing
by part designers, with definitions of symbols; (c) lay symbols; (d) lay symbols applied on drawings.

7. Surface Measurement
FIGURE 35-4 (a) Schematic of stylus profile device for measuring surface roughness and surface
profile with two readout devices shown: a meter for AA or rms values and a strip chart recorder for
surface profile. (b) Profile enlarged. (c) Examples of surface profiles.

8. Surface Finish Measurement
FIGURE 35-5 Typical machined
steel surface as created by face
milling and examined in the SEM. A
micrograph (same magnification) of
a in. stylus tip has been
superimposed at the top.

9. SEM Micrograph FIGURE 35-6 (a) SEM micrograph of a U.S. dime,
showing the S in the word
TRUST after the region has been
traced by a stylus-type machine.
(b) Topographical map of the S
region of the word TRUST from a
U.S. dime [compare to part (a)].

10. Roughness
FIGURE 35-7 Comparison of surface roughness produced by common production processes.
(Courtesy of American Machinist.)

11. 35.2 Mechanical Cleaning and Finishing Blast Cleaning

12. Finishing Barrel FIGURE 35-8 Schematic of
the blow of material in tumbling
or barrel finishing. The parts and
media mass typically account for
50 to 60% of capacity.

13. Synthetic Media Geometry
FIGURE 35-9 Synthetic
abrasive media are available in a
wide variety of sizes and shapes.
Through proper selection, the
media can be tailored to the
product being cleaned

14. Vibration Finishing Tub
FIGURE Schematic diagram of a vibratory-finishing tub loaded with parts and
media. The single eccentric shaft drive provides maximum motion at the bottom, which decreases
as one moves upward. The dualshaft design produces more
uniform motion of the tub and reduces processing time

15. Media to Part Ratio

16. Part Examples FIGURE 35-11 A variety of parts before and after barrel
finishing with triangular-shaped media. (Courtesy of Norton
Company.)

17. 35.3 Chemical Cleaning

18. 35.4 Coatings

19. Organic Finishes

20. Electroplating Processes
FIGURE Basic steps in
the electrocoating process

21. Powder Coating

22. Powder Coating Systems
FIGURE A schematic of a powder coating system. The wheels on the color modules permit it to be
exchanged with a spare module to obtain the next color.

23. Electroplating Circuitry
FIGURE Basic circuit for
an electroplating operation,
showing the anode, cathode
(workpiece), and electrolyte
(conductive solution).

24. Electroplating Design Recomendations
FIGURE Design
recommendations for
electroplating operations

25. Anodizing
FIGURE The anodizing process
has many steps.

26. Nickel Carbide Plating
FIGURE (Left) Photomicrograph of nickel carbide plating produced by electroless deposition. Notice
the uniform thickness coating on the irregularly shaped product. (Right) High-magnification cross section
through the coating. (Courtesy of Electro-Coatings Inc.)

27. 35.5 Vaporized Metal Coatings

28. 35.6 Clad Materials

29. 35.7 Textured Surfaces

30. 35.8 Coil-Coated Sheets

31. 35.9 Edge Finishing and Burrs

32. Burr Formation FIGURE 35-18 Schematic showing the formation of heavy
burrs on the exit side of a milled
slot. (From L. X. Gillespie,
American Machinist, November
1985.)

33. Deburring Allowance

34. 35.10 Surface Integrity

35. Burr Prevention FIGURE 35-19 Designing
extra recesses and grooves into a
part may eliminate the need to
deburr. (From L.X. Gillespie,
American Machinist, November
1985.)

36. Surface Deformation FIGURE 35-20 Plastic
deformation in the surface layer
after cutting. (B. W. Kruszynski
and C. W. Cuttervelt, Advanced
Manufacturing Engineering,
Vol. 1, 1989.)

37. Shot Peening
FIGURE (a) Mechanism for formation of residual compressive stresses in surface by cold plastic deformation (shot peening). (b) Hardness increased in surface due to shot peening.

38. Surface Damage as a Function of Rake Angle
FIGURE The depth
of damage to the surface of a
machined part increases with
decreasing rake angle of the
cutting tool.

39. Surface Stress FIGURE 35-23 (Top) A
cantilever-loaded (bent) rotating beam, showing the normal distribution of surface stresses
(i.e., tension at the top and compression at the bottom). (Center) The residual stresses
induced by roller burnishing or shot peening. (Bottom) Net
stress pattern obtained when loading a surface-treated beam.
The reduced magnitude of the tensile stresses contributes to
increased fatigue life.

40. Fatigue Life with Surface Finish
FIGURE Fatigue life of
rotating beam 2024-T4
aluminum specimens with a
variety of surface-finishing
operations. Note the enhanced
performance that can be
achieved by shot peening and
roller burnishing.