Rigid molding

Eject rigid molded article from cavity or force... 

General purpose Rigid moldings. Ttays, boats, tanks, boxes, luggage, seating. 

The molds in a RIM-process plant are located in a separate assembly, which has devices for opening and clamping a mold and, in some cases, for changing it. The pressure in the RIM-process is considerably lower than in traditional injection molding of thermoplastics thus, the requirements for the mold material are less rigid. Molds may be made from aluminum or reinforced plastics, since high-strength steel is not necessary. 

L-V-345, Vinyl Chloride Polymer and Copolymer Rigid Molded Plastics, October 2, 1952 L-L-31, Laminated Thermosetting Sheets, Rods, and Tubes, November 4, 1952. 

FIGURE 5.5.32 Schematic of nanoimprint hthography (NIL). (1) A rigid mold is pressed into a thermoplastic resist, heated above its glass transition temperature, to create an imprint. (2) The mold is removed, leaving behind the patterned resist. (3) An anisotropic etch removes the residual resist and transfers the pattern into the substrate. (From S. Y. Chou et al., J. Vac. Sci. Technol, B, 14, 4129, 1996.)... 

Spider to support rigid mold part "and enaple filling... 

General purpose Rigid moldings, craze resistant... 

Soft-template technique offers advantage of scalability [39]. In hard-template method, a porous membrane of inorganic or polymeric material serves as a rigid mold for chemical or electrochemical replication of stracture. This method provides an easy marmer for production of 1-D nanostractures, but with difficulties of scale up. Hard templates such as silica or carbon spheres are also ideal for synthesis of hollow strac-tures (11 Chen et al. 2003). Classical examples where the template enables the control of morphology of a-Fe Oj nanoparticles can be found in literature (Table 1). 

The earliest molds that have been found are rigid and made of mineral materials such as clay or plaster. Even today, rigid molds made of these materials or organic resins are frequently used if models without undercuts are to be reproduced. 

Modem chemistry has created a number of new mold-making materials with improved performance. These include organic resins for rigid molds as well as thermoplastic vinyl rubbers, polyurethane elastomers and, finally, RTV-2 silicone rubbers. The latter have become more and more used, in spite of their relatively high price, because they are the only materials that offer the ideal combination of properties essential for high-performance molding applications. 

High conversions and molecular weights are obtained because reversible reactions and side-product removal is not an issue. In RIM processes, liquid monomers are mixed using impinging jets and must quickly flow into the mold before the reacting mixture becomes too viscous. The complete cycle time for injection, reaction and umnolding (so that the mold can be used to make the next product) is often only 30-60 s. RIM is used to produce rigid molded polyurethane automobile parts and polyurethane foam seat cushions [3j. 

ABS is a common thermoplastic used to make light, rigid, molded products such as pipe, automotive body parts, wheel covers, enclosures, and protective head gear. It is also used in 3D printing technology. 

Epoxies—Molded, Extruded High performance resins (cycloaliphatic diepoxides) Cast, rigid Molded Glass cloth laminate Epoxy novolacs Cast, rigid Glass cloth laminate 1.24 1.7 1.97 1.22 1.97... 

A common hypothesis in injection molding simulation is to assume an infinitely rigid mold. However, in reality, the high cavity pressure can lead to mold deflection due to mold compliance. Experimental investigations (Leo and CuveUiez 1996 Delaunay et al. 2000b) have shown that the mold elastic deformation can play a significant role in the pressure-time history. 

Near-net-shaped composite parts with a good surface finish and close dimensional tolerances can be produced since the reinforcing preform is compacted between the two sides of a rigid mold with gel-coated surfaces. Complicated shapes with ribs, channels and tapered thickness can be obtained however, skilled preforming labor is needed. 

The thermal expansion core variation proceeds according to the conventional RTM process except for the insertion of a foam core along with the preform into the rigid mold. After resin injection the entire mold is tempered leading to an expansion of the foam core. The suppression of the preform causes higher fiber volume fractions and a better impregnation of fibers [68]. 

Undercut. A protuberance or indentation that impedes withdrawal from a two-piece, rigid mold any such protuberance or indentation, depending on the design of the mold. 

Mold Opening - Part ejection once it becomes sufficiently solidified and rigid, Mold is opened and the part is ejected, after which the mold is closed again to begin the next cycle. 

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