Increasing Interlaminar Strength in Large Scale Additive Manufacturing

Roschli, Alex
Duty, Chad
Lindahl, John
Post, Brian K.
Chesser, Phillip C.
Love, Lonnie J.
Gaul, Katherine T.
Journal Title
Journal ISSN
Volume Title
University of Texas at Austin

Interlaminar strength of extrusion-based additively manufactured parts is known to be weaker than the strength seen in the printed directions (X and Y). With Big Area Additive Manufacturing (BAAM), large parts lead to long layer times that are prone to splitting, sometimes referred to as delamination, between the layers. Fiber filled materials, such as carbon fiber reinforced ABS, are used to counteract the effects of thermal expansion by increasing the strength in the X and Y directions. These fibers stay in-plane meaning that no fibers span from layer to layer, which would help counteract the weak interlaminar strength that causes splitting. A solution to this is a patent pending approach called Z-Pinning. The process involves strategically positioning voids across multiple layers that are backfilled with hot extrudate. This paper will explore the benefits and results of using Z-Pinning in large scale additive manufacturing.