Low-pressure injection molding

Explored various tube fabrication techniques, including cold isostatic pressing and low-pressure injection molding. 

We have evaluated several ceramic tube fabrication techniques. The cold isostatic approach turned out to be inadequate for the present purpose because of the difficulties to incorporate sufficient porosity in the structure. A low pressure injection molding technique was successfully developed to fabricate green tubes with lengths up to sixteen inches (Figure 2). 

SF is characterized as a plastic structure with a nearly uniform density foam core and integral near-solid skins (facings). When these structures are used in load-bearing applications, the foam bulk density is typically 50 to 90% of the plastic s unfoamed bulk density. Most SF products (90wt%) are made from different TPs, principally PS, PE, PVC, and ABS. Polyurethane is the primary TS plastic. Unfilled and reinforced SFs represent about 70% of the products. The principal method of processing (75%) is modified low-pressure injection molding. Extrusion and RIM account for about 10% each. 

C. Sundback, T. Hadlock, M. Cheney, J. Vacant , Manufacture of porous polymer nerve conduits by a novel low-pressure injection molding process, Biomaterials 24 (2003) 819-830. 

Low-pressure injection molding A term sometimes used for the process of injecting a fluid material such as a vinyl plastisol into a closed mold, using a grease gun or similar low-pressure equipment. 

The value of the pressure determines two injeetion techniques high pressure and low pressure injection molding. The high pressure injection molding process [GER 90], which is used most often, is directly inspired from the technology of injection... 

Figure 5.37. Operating principle of low pressure Injection molding machines A) medium pressure, B) low pressure...

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