Micromolding
“Donna Bibber, technical partner of microPEP (East Providence, RI), which specializes in micromanufacturing, says the definition for micromolding that she uses is fairly common in the industry. It means parts made from a fraction of a plastic pellet, weighing only fractions of a gram. “You need magnification to see their features or details,” adds Bibber.” (http://www.devicelink.com/mtprecision/archive/08/09/004.html 7/31/1009)
More on Micromolding One form of micromolding is used to form a micro to nano sized structure is based on solidifying a casting fluid onto a mold having a corresponding surface structure. The molding of micro-structures with high aspect ratio's in the micron and sub-micron range is difficult because of mechanical fragility, distortion and anchoring of those structures during mold release. Injection molding, pressure molding, hot embossing, slip casting, cross linking of the product on the mold are used. The mold structures of grooves, ridges and wells are fabricated using laser drilling, spark erosion, photo lithographic and anisotropic etching techniques. (Van Rijin et al, US Patent 7,531,120, 5/12/2009)
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The demand for micro-lenses is changing from mm to microns. Problems of crosstalk and the final assembly are becoming more difficult. Applications include refractive or diffractive lenses, reflectors, Bragg gratings, interferometers, fiber-optics, optical attenuators, polarizers, compensators, rotators, splitters and combiners. Jacobowitz et al have developed a wafer-scale apparatus based on a mold plate of micro-cavities formed by reactive ion etching and filled by an automated fluid-injection and defect-inspection system. Candidate resins include epoxies, acrylics, cycloolefins, polycarbonates, and polyimides. (RDC 8/30/2008)
Jacobowitz, Buchwalter, DeCusatis, Gruber and Shih, US Patent 7,399,421 (7/15/2008)
Micro-Injection Molding
Phase Separation Casting
Processing
Ultrasonic Micromolding
Recent US Patents
10/28/2008
7,442,028
Molding Apparatus and Molding Method
Seki of Canon has developed a method for forming micropatterns by pressing using at least two support members to prevent brittle fracture in the materials such as silicon or silica. (RDC 9/24/2010)
Recent Journal Articles
Fabrication of Polyethylene Superhydrophobic Surfaces by Stretching-Controlled Micromolding
(p 295-300) Macromolecular Materials and Engineering 294 #5 (2009)
Feng, Huang and Qian showed that superhydrophobic polymer films can be formed using a stainless rolling mold with randomly proportionally spaces microholes.
Review Articles
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