Mass single side

Hot-bar soldering is best suited for low-thermal-mass, single-sided surface-mount assemblies. Each component type requires its own hot-bar bonding head assembly. These can be expensive, with the price dependent on the complexity, materials of construction, precision required, and overall size of the bonding head. 

The test principle is such that the extraction of migratable substances from a sample of the plastics is determined as the mass of non-volatile residue after evaporation of the solvent following immersion. Test specimens of at least 1 dm2 (single side considered) are immersed in the extraction solvent at the specified test conditions and then... 

As a special case (1.192) is also used for the situation of single side mass transfer where hA = h and hB = 0. It then follows from (1.192) that... 

Multilayer boards are formed by adding unetched, single-sided laminates on either side of an etched single or multilayer laminate by using an interface of partially cured resin and (usually) glass mats. In the mass-lamination approach, large arrays of boards can be produced, although the technique is usually limited to about ten layers. 

As in the case of the Sieverts technique, the appearance of the sample density on the bottom line in Eq. (7.13) implies a sensitivity of the result to sample density and increased buoyancy forces with samples of low density. Equation (7.14) shows that the best outcome is with matched sample and tare-weight densities as well as matched masses, thus cancelling the buoyancy force on the sample. At the opposite extreme, the single-sided balance (or a double-sided balance with grossly mismatched sample and tare-weight densities) requires careful calibration with an inert gas as discussed in Section... 

Kinetics of mass transfer prevents a growing crystal from achieving the thermodynamically possible value of the distribution coefficient. Figure 8.2-12 shows that the impurities enrich close to a growing crystal surface (phase boundary Ph). Due to the single-sided mass transfer, impurity i enriches near the growing phase boundary to y,. The definition of the thermodynamic distribution coefficient... 

Matsushita Electric Industrial introduced Pb-free wave soldering to mass production of videocassette recorders (VCR) in 1999. The single-sided PWB assembled with Sn-Cu eutectic solder for a VCR is shown in Figure 12. In August 2000, Nissan Motors released a lead-free soldered, keyless entry component produced by wave soldering with a Sn-Ag-Cu alloy. 

Mass-production wave soldering began on one production site in mid-1998 with Sn-5Bi-2Sb-lAg solder on single-sided printed boards with a wide variety of surface-mounted and through-hole-mounted components. The wave soldering process is very stable and has a first-pass defect rate of only 30 ppm. Industrial reflow soldering began on another site in early 1999, with no details available about process stability or yield. 

To calculate the force exerted by a single molecule, we use Newton s second law of motion force is equal to the rate of change of momentum of a particle (Section A). Momentum is the product of mass and velocity so, if a molecule of mass m is traveling with a velocity vx parallel to the side of the box that we are calling x, then its linear momentum before it strikes the wall on the right is mvx. Immediately after the collision, the momentum of the molecule is mvx because the velocity has changed from vx to —vx. 

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