CHAPTER 30 Brazing, Soldering, Adhesive-Bonding, and Mechanical-Fastening Processes

Brazing Figure 30.1 (a) Brazing and (b) braze welding operations.

Typical Filler Metals for Brazing Various Metals and Alloys

Furnace Brazing Figure 30.2 An example of furnace brazing: (a) before, (b) after. Note that the filler metal is a shaped wire.

Induction Brazing Figure 30.3 Schematic illustration of a continuous induction-brazing setup, for increased productivity. Source: ASM International.

Joint Designs Used in Brazing Figure 30.4 Joint designs commonly used in brazing operations. The clearance between the two parts being brazed is an important factor in joint strength. If the clearance is too small, the molten braze metal will not fully penetrate the interface. If it is too large, there will be insufficient capillary action for the molten metal to fill the interface.

Brazing Design Figure 30.5 Examples of good and poor design for brazing.

(a) Figure 30.6 (a) Screening or stenciling paste onto a printed circuit board: 1. Schematic illustration of the stenciling process; 2. A section of a typical stencil pattern. (continued) Stenciling

(b) Wave Soldering (c) Figure 30.6 (continued) (b) Schematic illustration of the wave soldering process. (c) SEM image of wave-soldered joint on surface-mount device.

Types of Solders and their Applications

Joint Designs Used in Soldering Figure 30.7 Joint designs commonly used for soldering. Note that examples (e), (g), (i), and (j) are mechanically joined prior to being soldered, for improved strength. Source: American Welding Society.

Typical Properties and Characteristics of Chemically Reactive Structural Adhesives

General Properties of Adhesives

General Properties of Adhesives (cont.)

Adhesive Peeling Test Figure 30.8 Characteristic behavior of (a) brittle and (b) tough adhesives in a peeling test. This test is similar to the peeling of adhesive tape from a solid surface.

Joint Designs in Adhesive Bonding Figure 30.9 Various joint designs in adhesive bonding. Note that good designs require large contact areas between the members to be joined.

Configurations of Adhesively Bonded Joints Figure 30.10 Various configurations for adhesively bonded joints: (a) single lap, (b) double lap, (c) scarf, (d) strap.

Rivets Figure 30.11 Examples of rivets: (a) solid, (b) tubular, (c) split (or bifurcated), (d) compression.

Design Guidelines for Riveting Figure 30.12 Design guidelines for riveting. (a) Exposed shank is too long; the result is buckling instead of upsetting. (b) Rivets should be placed sufficiently far from edges to avoid stress concentrations. (c) Joined sections should allow ample clearance for the riveting tools. (d) Section curvature should not interfere with the riveting process. Source: J. G. Bralla.

Metal Stitching and a Double-Lock Seam Figure 30.13 Various examples of metal stitching. Figure 30.14 Stages in forming a double-lock seam.

Crimping Figure 30.15 Two examples of mechanical joining by crimping.

Spring and Snap-In Fasteners Figure 30.16 Examples of spring and snap-in fasteners used to facilitate assembly.