Sinter molding

Compression molding method called coining is used for parts that are too complicated to be produced by machining. In coining, a sintered molding is heated to the melting point, then it is quickly pressed into a mold cavity and held under pressure until it solidifies.4... 

Figure 9.29. The powder metal process (a) pi ad rig powder in die (b) compacting powder to 90% density tc) sintering molding to full density at higher temperature.

DuPont uses oxydianiline and pyromellitic dianhydride (Fig. 3.42) to produce a series of Kapton films (Table 3.46), Vespel sintered moldings (Table 3.47), and Pyralin lacquers... 

See also fluidized-bed coating, rotational molding, centrifugal molding, slush molding, and sinter molding. 

Polyimides are also obtained in one step in the reaction of diisocyanates with tetracarboxylic acid dianhydrides. As an example, BTDA is reacted with a mixture of 2,4-TDI and MDI in DMF (93). This copolyimide, PI 2080, is used as a high temperature fiber and it is also sinter molded into solid shapes with exceptional mechanical properties. From PMDI and benzophenone-tetracarboxylic acid dianhydride polyimide foams with outstanding thermal properties and flame resistance are produced (94). Pol5fimides derived from p-phenylene diisocyanate (PPDI) or naphthalene diisocyanate (NDI) and pyromellitic dianhydride or BTDA are also synthesized using DMAc as solvent (95). 

Silicon Carbide Sintered Moldings and a Method for Producing Said Moldings, U. S. Patent No. 4,110,386. 

Skiving skiv-ipi vf skived skiving [prob. of Scand origin akin to ON skifa to slice] (ca. 1825) Slicing off a thin layer. Skiving is the method by which veneers are cut from logs and by which polytetrafluoroethylene film is produced from cylindrical bars of ram-extruded or sinter-molded resin. PTFE film is made in this way because, unlike most thermoplastics, it cannot be directly extruded into film. 

The uneven heat baiance in the moid is often a reason for distorted parts. Using thermal imaging cameras, which are now affordable, hot spots in the mold, can be seen and valuable support for the optimization, not only for the warpage, is provided. The intensification of the temperature control, by pulsed cooling or sintered mold inserts, for example, often leads to significant cycle time reductions. 

Compositions for the production of sintered molded parts are composed of a metallic, ceramic, and polymer material and a compaction aid. The latter is a mixture of a poly(glycol), and a montan wax (3). 

R. Lindenau, K. Dollmeier, and V. Arnhold, Composition for the production of sintered molded parts, US Patent 7 524 352, assigned to GKNM Sinter Metals GmbH (Radevormwald, DE), April 28,2009. 

---