Material Extrusion-Debinding-Sintering as an Emerging Additive Manufacturing Process Chain for Metal/Ceramic Parts Construction

Hybrid Fabrication of Zirconia Parts with Smooth Surface Texture and Tight Tolerances

“…Among the seven families of AM processes defined by ISO 52900 [9], material extrusion (MEX) is seen as very promising [10]. This technology enables the shaping of green composite parts made of almost any type of ceramic material (oxide and non-oxide) at a 40% lower cost than the conventional route [11,12]. Variations exist among MEX printers depending on the composite feedstock used to manufacture the part: it can be filaments, pastes or even pellets [13][14][15].…”

“…Indeed, these feedstocks have been used since the 1970s in the CIM industry [16] and present many advantages such as lower price, higher availability, lower brittleness and no preheating required [14,17]. The ceramic content of such composite feedstock can reach up to 60%vol [12]. The process that relies on machines fitted with an extrusion screw and uses pellets is called PAM (pellet additive manufacturing).…”

“…This motivates the integration of the milling tool and spindle directly in the AM printer to obtain a hybrid machine that combines the additive and subtractive processes [28,29]. This architecture enables the surfaces to be finished progressively when they are still reachable and the production of parts with the same characteristics as those finished by milling during the green state [12]. Moreover, hybrid machines allow larger nozzle diameters to be selected since the imperfections of the printing process will be corrected by the milling operation [11].…”