Direct Digital Manufacturing

Abstract

Direct digital manufacturing (DDM) is a term that describes the usage of additive manufacturing technologies for production or manufacturing of end-use components. Although it may seem that DDM is a natural extension of rapid prototyping, in practice this is not usually the case. Many additional considerations and requirements come into play for production manufacturing that are not important for prototyping. In this chapter, we explore these considerations through an examination of several DDM examples, distinctions between prototyping and production, and advantages of additive manufacturing for custom and low-volume production.Many times, DDM applications have taken advantage of the geometric complexity capabilities of AM technologies to produce parts with customized geometries. In these instances, DDM is not a replacement for mass production applications, as customized geometry cannot be mass produced using traditional manufacturing technologies. In addition, since the economics of AM technologies do not enable economically competitive high-volume production for most geometries and applications, DDM is often most economical for low-volume production applications. Two major individual-specific medical applications of DDM will be discussed, from Align Technology and Siemens/ Phonak, as well as several other applications that make use of the unique design freedom afforded by AM techniques. This will be followed by a discussion of the unique characteristics of AM technologies that lead to DDM.

Fabrication and Characterisation of Aligned Discontinuous Carbon Fibre Reinforced Thermoplastics as Feedstock Material for Fused Filament Fabrication

“…If the material has a high specific heat capacity and high thermal conductivity, more heat initially must be added to soften the polymer. The benefit of this is that more heat can be distributed after deposition between the printed tracks to improve the polymer sintering process [ 31 ]. Having a high specific heat capacity and thermal conductivity is therefore beneficial to the FFF process.…”

“…FFF works best with polymers that are amorphous, despite their lower mechanical performance, as they have no distinct melting point and increasingly soften (lower viscosity) with increasing temperature. This means the polymer sintering process happens over a longer time when cooling down [ 31 ]. The polymer sintering process is related to material flow and the reptation time, which is the time required to create a fully welded, entangled interface.…”

Additive Manufacturing for the Aircraft Industry: A Review

“…The application of the multi-material printing technologies has been limited in the context of the aircraft industry. However, Gibson et al showed the possibility of printing a conductive wire sensor onto a turbine blade structure [35].…”

Optimization Methodology for Additive Manufacturing of Customized Parts by Fused Deposition Modeling (FDM). Application to a Shoe Heel

“…The high level of geometric freedom that additive manufacturing technologies allow [ 7 ] significantly increases possible design solutions. In this context, parametric design and optimization processes become very important [ 8 ].…”