Micro injection molding

When compared to the reciprocating-screw IMM, the advantages of the two-stage IMM include (1) consistent melt quality, (2) ram action in the accumulator that provides high injection pressure very fast, (3) very accurate shot-size control, (4) product clarity, and (5) easily molded very thin-walled parts. Its disadvantages include higher equipment cost and increased maintenance. See injection molding, micro-. 

Figure 4. Injection molded micro fluidic system using the tool number 3 (material polypropylene).

Recently, the telecommunication industry has undergone rapid expansion, and a strong consumer trend towards smaller and lighter telecommunication devices, such as cellular phones and notebook computers, is indicated. Small connection sockets and chip carriers are micro-injection-molded parts requiring the high flowability, high mechanical properties and dimensional stability of LCPs. These merits are now thought to be another application field for LCPs in the electronics industry. 

The special issue of micro injection molding applied for polymer heat exchangers will not be considered here. Additionally, for MEMS-like systems discussed above, other techniques, mostly based on etching, e.g. deep reactive ion etching (DR1E), are applied [20, 71, 86]. These techniques allow for future mass production of the small-scale (sub-watt fuel processors) devices to which they are applied. 

A 7] The fiber-coupled spectrometer is actually designed for applications with hand-held devices. A combination of micro injection molding and an electroforming process allows the production of a high-performance but low-cost device. The optical grating is, for example, replicated in plastic to reduce costs. 

The process of injection molding (IM) is used principally for processing unreinforced or glass fiber reinforced thermoplastics (TPs) and thermosets (TSs) (Figure 4.1). Up to at least 90wt% of all plastics processed are TPs. There are many different types or designs of IM machines (IMMs) that permit molding many different products based on factors such as quantities, sizes (such as auto bumpers to medical micro products), shapes (simple to complex), product performances, and/or economics.1,150>157,173 176 476... 

Figure 9.7. TEM Images of (a) Solid PLA-MWCNT Nanocomposite at 500 nm (Inset-a magnified view of agglomerated MWCNTs at 100 nm) (b) Microcellular PLA-MWCNT Nanocomposite at 500 nm (arrow indicates micro cell formed during microcellular injection-molding) (c) Solid PLA-MWCNT Nanocomposite at 100 nm and (d) Microcellular PLA-MWCNT Nanocomposite at 100 nm. Reprinted with permission from S. Pilla et al.. International Polymer Processing, XXII, p. 418,2007, 2007, Polymer Processing Society.

The first device integrated a microstructured multichannel plate fabricated by micro-injection molding from a two-component liquid silicon rubber material (Silopren LSR 4070) with an appropriately interfaced and temperature-controlled housing, as shown in Figure 3.1a. 

P. Deng, K. Liu, L. Zhang, H. Liu, T. Wang, J. Zhang, Micro and macro injection molded parts of isotactic polypropylene/polyethylene blends Shear-induced crystallization behaviors and morphological characteristics. J. Macromol. Sci. Part B Phys. 53, 24-39 (2014)... 

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