Mold insert

The practice of molding inserts in place is usually employed to provide good holding power for plastic products, but there are drawbacks to this method. It normally takes a pin to support the insert, and since this pin is small in relation to the cored hole for the insert, it is easily bent or sheared under the influence of injection pressure. Should the insert fall out of position, there is danger of mold damage. Also, the hand placement of inserts contributes to cycle variation and with it potentially product quality degradation. Some of these problems can be overcome by higher mold expenditures,... 

M 18] [P 17] If the filled liquid channels and bridges can be fixed by, e.g., freezing, polymerization or sol-gel reactions, a mold insert could be formed which would allow one to transfer the fluidic network structure as real channels into plastic or other materials [102],... 

Fig. 2. Mold insert in nickel for membrane micropump made by LIGA technique using multiple irradiation...

Most of the plastisols are used in open molding. It is a very simple process to use. A measured amount of plastisol is poured into an open mold cavity. The mold and plastic are heated to gel and fuse the plastisol. The mold is then cooled so that it solidifies. It is stripped from the mold. Inserts can be placed in the liquid plastic before it is fused inserts can also be inserted in the mold before pouring. Two or more colors can be placed in different parts of the mold. 

When tool steels of high hardness are used they are supplied in the soft annealed condition (hardened mold inserts for cores, cavities, other molding surfaces and gibs, wedge locks, etc are typically hardened to a... 

G. Komarek and K. R. Komarek, Briquetting roll structure with mold inserts , US Patent 3 077 634, 1963. 

Micromolding, for example, using mold inserts machined by precision techniques. 

The plastic molding process may be combined with deep etch X-ray lithography to fabricate microstructures with different shapes in the third dimension" In the first step, only the upper part of a very thick resist layer is patterned with the embossing technique using a mold insert fabricated by the standard LIGA process. The relief structure obtained by this first patterning process is subsequently exposed to synchrotron radiation through a precisely... 

Figure 5. Two-Shot Process First shot molded insert.

For cavity and inplace molding plastisols are mainly used. Fluids are ideal for the encapsulation of intricate mold inserts. They can be poured into place by gravity or injected at low pressures, thus enabling relatively low cost, lightly constructed molds to be used. Due to the problems inherent in solvent or volatile removal, the plastisols have this field nearly to... 

Fig. 31 Mold plate with wood veneer embossing (left) and explosively embossed steel mold insert with holographic surface stmctures (right)...

Copper-nickel-zinc alloys Copper-nickel-zinc alloys (also known as German silver ), which have a high mechanical and corrosion resistance, are mainly used for machining of optical mold inserts for injection molding of plastics. 

Moreover, ultraprecision grinding, often with ELK), is used for small batch production of physical and astronomical instrumentation. In the wafer industry, ultraprecision grinding is of increasing importance for the fabrication of large (300 mm diameter) silicon wafers. It is hoped that the future development of ultraprecision grinding will also stimulate the fabrication of microstructured optical mold inserts for the mass production of next generation illumination devices. 

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