Solid freeform fabrication

Calvert, P.D. et al. (1994) in Proc. Solid Freeform Fabrication Symposium, ed. Marcus, H.L. et al. (University of Texas Press, Austin) p. 50. 

Cawley, J.D. (1999), Solid freeform fabrication of ceramics , Curr. Op. Solid State Mater. Sci., 4, 483 -89. 

The scaffolds for implants can be manufactured by mean of solid freeform fabrication (SFF), which relies on a layer-by-layer (LbL) composition of 3D materials. 

E. Sachlos and J. T. Czemuska, Making tissue scaffolds work. Review on the application of solid freeform fabrication technology to the production of tissue engineering scaffolds, Europ. Cells Mater. 5, 29-40 (2003). 

Solid Freeform Fabrication (SFF) technologies have in common the capability to build objects with comphcated 3D geometries, directly from Computer-Aided Design (CAD) files, without the necessity of tooling. SFF technologies also have in common the employment of an additive building process, in which a 3D object is built up by the repeated addition of layers of material. This is in contrast to more standard technologies which are characterized by the implementation of a subtractive fabrication process, e.g., CNC (Computer Numerical Control), where the 3D object is manufactured by calculated removal of material from a block of raw material. 

Derived from standard desktop printers, drop-on-demand techniques, such as electrohydrodynamic jet (e-jet) printing, solid freeform fabrication (SFF), or piezoelectric inkjet printing, are among a few notable examples of rapid prototyping techniques that have been developed to pattern biomaterials. With the incorporation of a user friendly computer interface, these techniques have been employed to process a number of multiplexed, biomaterial constructs without the use of masks, stamps, or any other time consuming processing equipment. The design of such constructs with minimal feature sizes in the microliter to picoliter resolution has been demonstrated and will be discussed below. 

Morissette, S., Lewis, J., and Cesarano, J., Solid freeform fabrication of aqueous alumina-polyfvinyl alcohol) gelcasting suspensions, J. Am. Ceram. Soc., 83, 2409, 2000. 

H.L. Marcus, J.J. Beaman, J.W. Barlow, D.L. Bourell, and R.H. Crawford (eds.). Solid Freeform Fabrication Symposium, University of Texas, Austin, TX, 1994. 

Liu, Z. S.Z. Erhan P.D. Calvert. Solid freeform fabrication of soybean oil-based composites reinforced with clay and fibers. /. Am. Oil Chem. Soc. 2004a, 81, 605-610. 

Liu, Z.S. S.Z. Erhan J. Xu P.D. Calvert. Development of soybean oil-based composites by solid freeform fabrication method Epoxidized soybean oil with bis or polyalkyleneamine curing agents system./. Appl Polym. Sci. 2002, 85, 2100-2107. 

Scaffolds can be fabricated by using different types of methodologies such as fiber bonding, salt leaching, gas-induced foaming, phase separation, electrospinning, solid freeform fabrication, and molecular self assembly [15, 17]. Some of the fabrication techniques are discussed below. 

Leong KF, Cheah CM, Chua CK (2003) Solid freeform fabrication of three-dimensional scaffolds for engineering replacement tissues and organs. Biomaterials 24 2363-2378... 

Rapid prototyping (RP) or solid freeform fabrication (SFF) is a relatively recent approach to forming ceramic components. There are various forms of RP techniques, but they are based on a common principle a computer directly controls the shaping process by accessing computer-aided design (CAD) files. We can thus use RP to form a 3D component without the use of a die or a mold. RP techniques are used commercially for fabrication of parts from polymers for design verification and form-and-fit applications these techniques have more recently been applied to forming parts out of ceramics. 

Solid Freeform Fabrication Symposium Proceedings (held annually. University of Texas, Austin). The formation of ceramic components by RP or SFF is a developing field. These proceedings give current information. 

Example Solid freeform fabrication (SFF) techniques such as selective laser melting (SLM) and sintering (SLS) are often prized for being much cleaner than conventional machining processes and being able to fabricate products with minimum waste (e.g., Bourell et al. 2009). 

M. Orme, C. Huang Phase change manipulation for droplet-based solid freeform fabrication, Trans. ASME - J. Heat Transf. 119, 1-6 (1997). 

Tay BY, Evans JRG, Edirisinghe MJ (2003) Solid freeform fabrication of ceramics. Int Mater Rev 48 341-370... 

Z. S. Liu, S. Z. Erhan and P. D. Calvert, Solid freeform fabrication of epoxidized soybean oil/epoxy composites with di, tri, and polyethylene amine curing agents , J Appl Polym Sci, 2004,93,356-63. 

Three-dimensional printing can be used to create resorbable devices with complex concentration profiles within the device (65). This method belongs to solid freeform fabrication methods. Both macrostructure and microstructure can be controlled. The application of this technology for the fabrication of polymeric drug delivery systems has been elucidated. 

---