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Our Technologies: Rapid Prototyping (RP), Rapid Tooling (RT), and Rapid Manufacturing (RM) Technologies

1.                  B. Z. Jang, E. Ma and C. J. Wang, “Apparatus and Process for Freeform Fabrication of Fiber Reinforced Composite Objects,” U.S. Patent 5,936,861 (Aug. 10, 1999).

2.                  J. S. Yang, L. W. Wu, E. J. Ma and B. Z. Jang, “Apparatus and Process for Freeform Fabrication of Composite Reinforcement Preforms,” U.S. Patent No. 6,214,279 (April 10, 2001).

The first item in our RP/RT/RM product line is the composite layer manufacturing (CLM) machine. The continuous fiber reinforced composite material, as a class of engineering materials, is known to possess superior strength, stiffness, toughness, corrosion resistance and many other desirable characteristics.  This class of materials is used in a broad range of industry sectors, including aerospace (e.g., aircraft structures), transportation (various ground vehicles), infrastructure (bridges, chemical facilities, communications towers), and sporting goods (tennis rackets, fishing rods, and golf clubs).                A CLM machine is capable of rapidly producing composite-based parts (including prototypes, tools, and structural components). The CLM method entails impregnating a continuous fiber tow with a solidifying matrix resin to form a pre-impregnated tow or “towpreg”.  The towpreg is then dispensed from a nozzle and deposited onto a support platform to form multiple layers of a part in a point-by-point and layer-by-layer fashion according to a computer-generated deposition path file.  Successive layers solidify essentially immediately upon deposition and adhere to one another to build up a 3-D part.  This method converts a computer-aided design (CAD) model directly into a 3-D physical object of high structural integrity without part-specific tooling or human intervention.

            The advantages of the CLM technology over other types of RP technologies or composite manufacturing technologies are summarized below:

(1).       More realistic prototyping:  A composite prototype part being similar in composition, micro-structure and properties to the final production part can be fully evaluated to verify its fit-form-function (not just fit-form) before mass production begins.  This could help eliminate the possibility of producing a large number of parts only to find out that these parts do not meet the technical requirements.

(2).       Reduction in time from design to production:  The CLM, as a rapid prototyping technology, can dramatically curtail the length of time required to proceed from a CAD to a final part. Use of this technology could reduce tool-making time and cost, and provide the opportunity to modify mold or die design (if necessary) without incurring high costs and lengthy time delays.

(3).       Cost-effective for low-volume production of complex-shaped components:  The CLM has great potential as a cost-effective production process particularly if the number of parts needed at a given time is relatively small.  It is envisioned that, in some defense and aerospace applications, one would only need to produce a limited number of final products at a time: e.g., rockets, tactical vehicles, and missiles.  Every tactical vehicle will contain a large number of components, for instance.  Because tooling is very expensive, it would not be economical to make a tooling (mold or die) for a component if only a small component count is needed.  Hundred of millions of US dollars will be saved by using the CLM technology to avoid repeated tooling design and fabrication.

(4).       Instant supply of needed parts:  The CLM technology has the capability of producing custom manufactured parts on demand.  Such a capability is essential to meeting industry’s needs to reduce unnecessary inventories of spare parts while ensuring availability of parts when and where needed.  Many structural elements in existing vehicles, weapons, or other functional machineries that need to be replaced, repaired or restored are “one-of-a-kind”.  The CLM provides a fast, cost-effective approach to automated fabrication of lower number-count components and/or complex-shaped components.

(5).       Increase alternate design selection:  The CLM technology places a minimal constrain on the type of materials that can be selected to make a composite part.  Functionally gradient and hybrid composites are well within the fabrication capability of a CLM machine.  The ability and flexibility of a CLM machine to make parts of intricate-shape and large dimensions makes this technology suitable to integrating several closely spaced components into a sub-system.  This will reduce the total part count of a vehicle system and significantly curtail the costs associated with the design, tooling, and manufacturing of otherwise a large number of parts.

(6).       Accessible to customers for interactive collaboration:  The CAD file used in a CLM machine can be transmitted back and forth between a part user (military or civilian personnel), a designer, and a fabricator (where a CLM machine is located) through various modern communications means (PC, e-mail, and web based).  A CLM machine can be used to cost-effectively make a smaller or full-scale concept model, allowing a customer to evaluate the form-fit-function requirements of a part.  This effective communication practice will help ensure the customer satisfaction and deliver first quality parts.

(7).       Integration of design, manufacturing, simulation, and analysis for “Life Cycle Engineering”: The towpreg deposition path executed by a CLM machine may be dictated by a CAD design, which is composite mechanics based.  Existing simulation approach can be integrated to impart additional performance prediction and failure analysis capabilities throughout the life cycle of a composite part.  These capabilities will facilitate structural problem identification and provide reliable clues based upon which a problem can be corrected in time at the location of the structure.

            These highly desirable attributes make the CLM technology second to none when it comes to the RP/RT/RM technology.

 The CLM Technology for Scaffold Fabrication:  A primary goal of tissue engineering research is the development of effective techniques to repair, replace, or regenerate damaged or diseased tissues by manipulating cells, creating artificial implants, or synthesizing laboratory-grown substitutes.  The purpose of using a scaffold is to support cells, which, after being seeded into the scaffold, cling to the interstices of the scaffold and replicate, produce their own extra-cellular matrices, and organize into the target tissue.  In many potential applications (e.g., cartilage, bone and tendon regeneration), mechanical integrity (stiffness and strength) of a scaffold is a critical factor that affects the success or failure of the implanted scaffold.  Specifically, in vivo, the scaffold structure should protect the inside of the pore network proliferating cells and their extracellular matrix from being mechanically overloaded for a sufficiently long period of time.  However, most of the state-of-the-art techniques and the associated materials used do not provide scaffolds with adequate mechanical integrity.

            Nanotek Instruments, Inc. has pioneered the composite layer manufacturing (CLM) technology that provides an orthopedic or plastic surgeon with the capability of designing and automated-fabricating a scaffold of high strength for tissue engineering. 

How does it work?  The CLM involves

(1)        acquiring a digital model of a 3-D scaffold of a desired shape and dimension for a given patient through computer-aided design (solid modeling), MRI and/or CT scanning. 

(2)        converting the digital model in a layer-wise data format, to control signals that drive a material-dispensing head to dispense and deposit a resin-preimpregnated continuous fiber tow (towpreg) in a point-by-point, line-by-line and layer-by-layer fashion to form a desired macro-porous 3-D scaffold in a net-shape fashion.