Print thickness measurement

Parker and Lenhard (1989) and Lenhard and Parker (1988) have developed equations that relate the apparent product thickness measured at a well under equilibrium conditions with the product and water saturations in a vertical column of soils adjacent to the well. By integrating the product saturation curve with respect to elevation, an equivalent depth of LNAPL-saturated pores is obtained. This process has been implemented in a computer program called OILEQUIL. The result is reported as a total oil depth in a vertical profile. The water and oil saturation curves with elevation can also be produced and printed in graphical or tabular form. 

Instead of the simultaneously extmded polymer film, a pre-extmded or laminated film can be laminated on the substrate (e.g., paper or paper board). In this case, the extruder can be used to extrude the polymer providing adhesion (e.g., Ecoflex ) in a thin layer between the polymer coating film or laminate and the substrate. Another option is to apply a dispersion or heat in the laminator (Fig. 10, 4) to obtain adhesion. After thickness measurement and second subsequent corona treatment, substrate and polymer coating are wound on a winder (Fig. 10, 6) in order to obtain rolls for transport to subsequent processes (e.g., printing, cutting, cup forming, box making). 

There are two basic approaches to measuring print thickness off-contact and contact. Off-contact systems may be used to measure wet, dry, or fired films, whereas contact systems may only be used on dry or fired films. The simplest noncontact method is to focus a high-powered metallurgical microscope with a narrow depth of field on the substrate, mark a reference, and refocus the microscope on the top of the film. The print thickness is the distance the object lens must be moved. This method is somewhat inaccurate as the profile of the print is nonuniform, allowing the thickness to vary considerably across the print. 

Analysis of these physical thickness measurements of solder joints provides the information required for process characterization and improvement. For instance, variations in average solder thickness or volume for the solder joints across a single assembly or from assembly to assembly provide insight into the quahty level of the paste printing process as well as sources of defects. 

FIGURE 8.15 Conductor test pattern serving various fimctions (a) pads for adhesion, wettability, solder leach resistance, and wire bondability (p) serpentine pattern for measuring print thickness and resistivity and (c) pattern for print resolution. 

Stiffness of the films and sheeting can be measured as the tensile modulus of elasticity. Droop or drape tests may be used, particularly for multilayer products. The stiffness is strongly influenced by thickness (to the third power) and temperature, and is important to the processing of film in printing, coating, or end use appHcations where it affects the "hand" of the product. 

The characteristics of interior paints that require testing and analysis include hiding and appearance, package stabiHty, adhesion, spatter resistance, flow and leveling, color and sheen uniformity, touch-up, stain removal, burnish resistance, and block and print resistance. A popular test that assesses the wet abrasion resistance of an interior paint is to measure its scmb resistance. A mechanical device is used to scmb a paint film of a specified thickness with a standard bmsh and abrasive cleanser suspension. The number of scmb cycles (back and forth movements of the weighted bmsh) at various end points (first cut through, or 50% removal of the film) is then recorded. Scmb resistance usually holds steady or decreases slightly as PVC is increased, but drops quickly once the CPVC is exceeded in a paint formulation. 

Silver is often preferred as an undercoat for rhodium by reason of its high electrical conductivity. A further advantage of silver in the case of the thicker rhodium deposits (0-0025 mm) applied to electrical contacts for wear resistance is that the use of a relatively soft undercoat permits some stress relief of the rhodium deposit by plastic deformation of the under-layer, and hence reduces the tendency to cracking , with a corresponding improvement in protective value. Nickel, on the other hand, may be employed to provide a measure of mechanical support, and hence enhanced wear resistance, for a thin rhodium deposit. A nickel undercoating is so used on copper printed connectors, where the thickness of rhodium that may be applied from conventional electrolytes is limited by the tendency of the plating solution to attack the copper/laminate adhesive, and by the lifting effect of internal stress in the rhodium deposit. 

Figures 2 through 9 are design charts for ultraviolet stabilized polycarbonate under blast load. Charts are provided for pane thicknesses of 1/4, 3/8, 1/2, and 1 inch for pane areas up to 25 ft at pane aspect ratios (pane length to width ratios) of 1.00, 1.50, 2.00 and 4.00. The charts relate the peak experienced blast overpressure capacity, B, for convenient pane dimensions across the spectrum of encountered blast durations. Depending on the orientation of the window to the charge, the blast overpressure may either be incident or reflected. The pane dimensions (measured across the span from the gasket centerline) peak blast capacity at 1000 msec, B, static frame design pressure, r, and the required bite are printed to the right...

Figure 12 shows the CTL-based sensor element. The platinum ribbon wire (0.2 mm in width and 0.02 mm in thickness) is spot-welled on the screen-printed substrate as heater lead wires, and the sensor chip is suspended on a plastic frame by the lead wires. In order to measure the catalyst temperature, very thin thermocouple wires are fixed on the substrate using ceramic cement. 

The first miniaturized electrochemical device for measuring glucose in whole blood was a mediated system produced in thick-film technology by screen printing [73]. This disposable, single-shot system is produced and actually marketed widely by the company Medisense. Several other companies are now following with similar approaches [74,75]. 

The target consists of a printed circuit board with two circuits. One circuit is exposed. The second circuit is protected and is used to compensate for the effect of elevated temperature on the electrical resistance of the circuit. The target is removed from the chamber 1 h after the start of a test and the reduction of the electrical resistance of the exposed circuit is measured. The target is then exposed to an atmosphere of 23°C and relative humidity of 75% for 24 h. The electrical resistance is measured again after the 24 h post-test exposure. The electrical resistance measurements are converted to the equivalent reductions in metal thickness, C, and C2 respectively, expressed in nanometers. 

Strontium-90 beta sources to measure the thickness of paper in paper manufacture and also to discharge static electricity by ionizing the air in high-speed printing operations... 

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