Multiple Independent Extrusion Heads for Fused Deposition Modeling

Fused Deposition Modeling is a rapid prototyping technique in which miniature extruders melt filaments of polymeric materials. The extruder is mounted to an X/Y stage, and a computer controls the machine so that the polymer is deposited in only the appropriate locations. Material is deposited on one layer at a time so that the desired shape is built from the bottom up. While Fused Deposition Modeling has many advantages, it is poorly suited for large parts or for parts with thick walls due to the amount of time that is required to fabricate them. One strategy to reduce the build time is to implement multiple independent extrusion-heads. This thesis addresses various issues and concerns that arise while designing a multiple independent extrusion-head Fused Deposition Modeling system. The greatest design challenges and most critical issues are identified, and then solutions are presented. Physical samples and experiments verify feasibility when possible. Suitable material deposition strategies have been formulated to allow multiple independent extrusion heads to work simultaneously to reduce build time while allowing for a larger build envelope. These strategies produce parts that have nearly identical mechanical properties as those made on a single-head machine. This work seeks to provide information that is useful for designing a multiple independent extrusion-head Fused Deposition Modeling, regardless the number of extrusion heads or machine configuration. Implementing multiple independent extrusion heads will greatly reduce the fabrication time while allowing for a larger build envelope.