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Where foam fits in medical design
volume of void space lets the foam filter with relatively little air resistance or pressure drop. Despite porosities ranging from 3 to over 100 pores per linear inch, urethane foams have high tensile strength and tear resistance. As a result, they can be cut or molded into complex shapes without
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MICRO:Process Equipment-CMP Consumables, by Douglas W. Cooper, p.53 (July '99)
rotating roller "brushes," while the product itself is rotated and sprayed. Commonly made of a high-porosity foam such as polyvinyl acetal (PVA), the brushes help dislodge ultrafine slurry particles and direct the contaminated rinsewater away from the product surface. Figure 1 shows a schematic
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Tight seals for the long haul
. High. Low. Good. Excellent. Sealed. Excellent. 1. Pycnometer is a testing device that measures excluded volume. 2. ASTM D-570-98 Standard Test Method Water Absorption of Plastics. 3. Gurley porosity determines airflow through a foam from top to bottom. Poron cellular urethane 4701-41, for example
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Car designers are "hip" to aluminum castings
that pack well, such as brake calipers and steering knuckles. Bodycote says HIP works well for most investment, sand, and permanent mold (gravity die) casting. High-pressure die and lost-foam castings can, however, have surface porosity and trapped air pockets that HIP may not be able to get out
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PLASTICS REFERENCE GUIDE
in demanding power-train environments. The brown, one-component FastGasket 5964 features low durometer and high elongation for applications in antilock-brake modules, timing-belt covers, and connectors. FastGasket 5965 is a black, one-component, water-resistant foam that doubles in size during
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PSAs perform in assembly
that is coated with silicone on both sides protects the PSA side and allows for difficult-to-bond substrates such as low permeability foams and high density polyethylene foams. Uses include non-slip steel pads and sound damping materials. Double-coated PSAs ensure dimensional stability to laminated material
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Optimized deaeration
losses that are attributable to high air / gas contents during paper manufacturing are generally speaking poor formation, porosity and printability, specks, pinholes / holes, and strength losses. In a mill environment many factors have brought about a rise in gas contents:. Optimized deaeration
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Expanded PTFE Polymer Keeps Electrical and Electronics Cables Clean and Flexible
. Polyethylene foam is another common dielectric material, but its density can vary from wire to wire or along the length of a single wire. Because dielectric constant varies with density, controlled-impedance cables with this form of insulation often have lower high-frequency electrical signal integrity. ePTFE