Short fiber process

An alternative process is to feed continuous fiber into the extruder instead of pellets. This process was originally operated by Turner Brothers Asbestos, who sold the know-how to 

Norsk Hydro. The process supposedly does less damage to the reinforcement, although in practice, there would appear to be little advantage. 

There are two types of machines that can be used for injection molding—one fitted with a plunger and the other a screw type injection unit, the latter being preferred for carbon fiber applications. Section 17.9.2 explains the functions of the individual parts of an injection molding machine and describes the terminology used for this application. 

The process is similar except carbon fiber reinforced thermoplastic polymer pellets are used. 

Brittleness Burn Marks Discoloration Flashing Sink marks Short shots Splay Sticking roughness long term Remedial action 

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With respect to Fig. 8.32, the nominal wall thickness (W) can vary from 0.045 to 0.250 in for preform-molded parts, 0.080 to 0.500 in for SMC-molded parts, and 0.060 to 1.000 in for BMC parts. The process can handle variations of 100% for preform molded parts, even more for BMC and SMC (300%) however, the transition between wall thicknesses must be gradual. Wall thickness variations of 0.010 in can be anticipated. In general, these processes can handle tolerances nearly as tight as those for the short-fiber processes. 

Dry-Laid Pulp. A principal objective of using air to form webs from natural and synthetic fiber pulps is to produce relatively lofty, porous stmctures from short fibers, without using water. Early technical developments in air-laid pulp processing were made by Kroyer in Denmark. 

Recycled paper contains more fines, short fibers, and anionic trash. This will increase demand for process chemicals such as drainage aids and both wet- and dry-strength additives (43). 

Whiskers are short fibers, usually a single crystal with an aspect ratio of 10/1 or greater. They have high strength but are difficult to process. Their applications so far has been limited SiC whiskers are reported as random reinforcement for ceramics and in alumina cutting tools. CVD is a common production method.O Beside SiC, the following whiskers have recently been produced by CVD ... 

Processing Aspects of Short Fiber-Rubber Composites.371... 

Processing Aspects oe Short Fiber-Rubber Composites... 

Short fiber incorporated rubber compounds can be processed in a way similar to that of conventional mbber compounds. Proper dispersion of the fiber in the rubber matrix is the primary objective. 

Though short fiber-reinforced mbber composites find application in hose, belt, tires, and automotives [57,98,133,164] recent attention has been focused on the suitability of such composites in high-performance applications. One of the most important recent applications of short fiber-mbber composite is as thermal insulators where the material will protect the metallic casing by undergoing a process called ablation, which is described in a broad sense as the sacrificial removal of material to protect stmcrnres subjected to high rates of heat transfer [190]. Fiber-reinforced polymer composites are potential ablative materials because of their high specific heat, low thermal conductivity, and ability of the fiber to retain the char formed during ablation [191-194]. 

Short-fiber composites fabrication of, 26 766 Short fiber metal-matrix composites, casting process for, 76 168 Short fiber web layering systems, 77 504 Short oil alkyds, 2.T48 Short random fiber reinforcement,... 

Toughness maps for short fiber composites can also be established in a similar manner, but no such maps have been reported. The difficulty stems from the large number of material and process variables that are used to fabricate these... 

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