|Micro-molding relates to a part that is measured in microns and is no bigger than 0.5 cubic inches. Or, it can be a very small feature on a normal sized part. Micro-features include extremely thin walls, micro-fluid channels or holes. Both micro-parts and micro-features require very small tolerances, ranging from .001 inch or tighter. They also typically have complex geometries. These parts can be found in micro electronics, cell phones, telecommunications, surgical tools, hearing aids, medical devices, antennas, connectors and more. In the world of micro-molding, mission critical components often require exotic or highly engineered compounds. Materials like PEEK, PEI (Ultem®), carbon filled LCP or glass filled nylons are commonplace. Soft durometer or elastomeric resins are also prominent. Direct experience with these materials in the context of micro-molding is another part of valuable know-how needed to maximize the performance of the resin/part design combination. The term �micro� suggests that micro-molding has something to do with size-parts that weigh less than a gram. Also, micro-molding must be capable of producing thousands, millions, even billions of parts with the same precision. The combination of innovation, processing, and expert tool building together make up the elements of true micro-molding. Not every application requires microscopic parts, but could be for a small molding project that requires demanding geometry and tight tolerances, but on a slightly larger scale. For example, a part measuring about an inch long can have many micro-sized features, a .004� (.1 mm) thin wall section, a .008� (.20 mm) diameter hole, etc. These features can be extreme, but a genuine micro-molder can apply the skills and expertise from successful micro-molding to these �larger� parts. Another key ingredient for any micro-molder is the ability to perform other traditional injection molding processes at the micro scale. The demand for micro-sized lead frame and insert molding continues to grow and the same size and tolerance requirements of standard micro-molding apply to these processes as well.
The innovative technologies in micro-molding include:
Insert / Lead Frame Molding:
Lead frame packaging technology requires the combination of high quality metal lead frame companies that produce some of the most intricate designs. Manufacturing lead frame molded parts requires fabrication of a system to feed the metal lead frame into the machine and to extract the complete component from the metal after the plastic has been molded to it. Insert micro-molding is where an existing or previously manufactured part is molded in and around a wide variety of materials from metals and glass to other plastics.
Micro Over molding
Over molding often refers to any process that takes one part made of plastic, metal or other material and molds "over" it in some fashion to bind two parts in one. The ability to over mold a micro-sized part on an extremely small insert while maintaining consistency and accuracy is critical. This process is in demand for the continued success of the micro-electronics and semiconductor industries. Insert micro-molding applies to more than just metal inserts. It means being capable of molding in and around a wide variety of other materials such as ceramic, glass, fabrics, film or foil to other plastics.
Adding to the capabilities of micro-molding is the ability to mold two different materials on the same part at the same time. The two different thermoplastic resins are shot in sync so that it requires only one mold cycle. Often times this process can add valuable cosmetic or functional properties reduce labor or assist in making the part more robust.
The world of micro-optics and micro-molding seem to go hand in hand. This high-tech market sector requires micron level features and micron level tolerances. Besides a product for the telecommunications market, products like medical diagnostics, endoscope and minimally invasive surgical tools and micro sensor applications are taking advantage of these tiny lenses.