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Chapter 37: Surface Engineering

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Presentation on theme: "Chapter 37: Surface Engineering"— Presentation transcript:

1 Chapter 37: Surface Engineering
DeGarmo’s Materials and Processes in Manufacturing

2 37.1 Introduction

3 Surface Profiles FIGURE 37-1 Machining processes produce surface flaws, waviness, and roughness that can influence the performance of the component.

4 Machined Surfaces

5 Machined Surfaces FIGURE 37-2 (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.

6 Surface Measurement FIGURE 37-3 (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.

7 Surface Finish Measurement
FIGURE 37-4 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.

8 SEM Micrograph FIGURE 37-5 (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)].

9 Roughness FIGURE 37-6 Comparison of surface roughness produced by common production processes. (Courtesy of American Machinist.)

10 Surface Deformation FIGURE 37-7 Plastic
deformation in the surface layer after cutting shown in a micrograph at 120X.

11 Surface Damage as a Function of Rake Angle
FIGURE 37-8 The depth of damage to the surface of a machined part increases with decreasing rake angle of the cutting tool.

12 Fatigue Strength as a Function of Finish
FIGURE 37-9 Fatigue strength of Inconel 718 components after surface finishing by grinding or EDM. (Field and Kahles, 1971).

13 Shot Peening FIGURE & 11 (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.

14 37.2 Abrasive Cleaning and Finishing

15 Finishing Barrel FIGURE 37-12 Schematic of
the blow of material in tumbling or barrel finishing. The parts and media mass typically account for 50 to 60% of capacity.

16 Synthetic Media Geometry
FIGURE 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

17 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

18 Media to Part Ratio

19 Part Examples FIGURE 37-15 A variety of parts before and after barrel
finishing with triangular-shaped media. (Courtesy of Norton Company.)

20 37.3 Chemical Cleaning

21 37.4 Coatings

22 Organic Finishes

23 Electroplating Processes
FIGURE Basic steps in the electrocoating process

24 Powder Coating

25 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.

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

27 Electroplating Design Recomendations
FIGURE Design recommendations for electroplating operations

28 Anodizing FIGURE The anodizing process has many steps.

29 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.)

30 37.5 Vaporized Metal Coatings

31 37.6 Clad Materials

32 37.7 Textured Surfaces

33 37.8 Coil-Coated Sheets

34 37.9 Edge Finishing and Burrs

35 Burr Formation FIGURE 37-22 Schematic showing the formation of heavy
burrs on the exit side of a milled slot. (From L. X. Gillespie, American Machinist, November 1985.)

36 Deburring Allowance

37 Burr Prevention FIGURE 37-23 Designing
extra recesses and grooves into a part may eliminate the need to deburr. (From L.X. Gillespie, American Machinist, November 1985.)

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