Tape thickness

In addition to the petrolatum tapes and those based on a laminate of p.e. or p.v.c. with an elastomeric sealant or pressure-sensitive adhesive layer, recent developments have centred around self-adhesive bituminous laminates. These tapes are commonly constructed with a p.v.c. backing, whose thickness ranges from 0 08 to 0 75 mm and a bituminous adhesive compound layer to provide a total tape thickness of up to 2 mm. In order to maintain conformability without compromising impact values, tapes may also be manufactured with a fabric reinforcement within the bituminous layer. 

Figure 7.33 Variation of tape thickness with carrier velocity and slurry viscosity. Adapted from J. S. Reed, Principles of Ceramics Processing, 2nd ed. Copyright 1995 by John Wiley Sons, Inc. This material is used by permission of John Wiley Sons, Inc.

The same procedure of firing treatment is applied to this technique as is applied to extrusion. The ratio of the freshly deposited layer thickness to the dried tape thickness is about 2. The final tape thickness depends on the shrinkage during firing. 

Cut a cotton swab in half with scissors and wrap each cut end with masking tape thick enough to seal the tube. 

This line lies slightly below the experimental result for a nontwisted tape (Fig. 11.33, curve r) because the tape thickness is not included in the analysis. There is no substantial increase in friction factor above the empty half-tube results until Re = 300. A lengthy set of correlations for the higher Reynolds number region is presented by Shah and London [194]. 

Podnt Source sped cations Aluniinuin annulus O.D. 5.4 cm Alumnmm annulus I.D. 3.8 cm Alumiimni annulus thickiiess 0.05 cm Polyester tape thickness 0.0 06 cm Filter p aper diameter 0.6 cm ... 

Recommended for products tapes, thick items such as car bumpers and garden furniture ... 

The second example concerns functionally graded cathodes, consisting of five layers of YSZ/LSM with increasing content of LSM (20-100%) (Holtappels and Bagger [2002]). The cathodes were prepared on both sides of a YSZ tape (thickness -150jum), characterized by IS and found to have a very high performance, with... 

In general, doctor blades are used for casting thicker tapes, that is, those that are 25 microns or thicker in the dried state. All ceramic substrate casting machines use a doctor blade of some sort. For these applications, the green tape thickness is usually on the order of 250 to 1000 pm (0.010 to 0.040 in.). Some of the machines produced in Japan use the "comma coating head for these thick tapes. 

As a general rule of thumb, the doctor blade coater or knife coater and the "comma coater" or other round-bottomed coating tools are used for the manufacture of tape thicknesses from 50 to > 1000 pm (0.002 to > 0.040 in.). When thinner coatings are required, the industry has turned to lip coaters, microgravure coaters, and slot-die coaters. The lip coater is used to make multilayered ceramic capacitor tapes for thicknesses of 50 pm (0.002 in) or less. For tape thicknesses 25 pm (0.001 in.) and less, the microgravure and slot-die techniques have been used very effectively. 

Because of its importance in determining tape thickness, great care must be taken to create and maintain a consistent and uniform blade gap. The doctor blade itself is usually surface ground and polished to... 

The uniformity of the blade gap from cast to cast can also be a source of variation in tape thickness (wet and dry). Many manufacturers use an adjustable mounting system for the doctor blade, which is set to height before each cast. Many of these blades are set by hand and are subject to human error. This human factor can significantly affect repeatability. To avoid this, some manufacturers simply minimize the... 

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