7 research outputs found
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Precast Concrete Models Fabricated with Big Area Additive Manufacturing
The traditional process of making precast concrete molds requires significant manual
labor. The molds are made using hardwood, cost tens of thousands of dollars, and take weeks to
build. Once built, a mold will last 5-10 pulls before becoming too heavily degraded to continue
use. With additive manufacturing, the same mold can be built in eight hours, post-machined in
eight hours, costs about $9000, and is projected to last nearly 200 pulls. Oak Ridge National
Laboratory has been working with Big Area Additive Manufacturing (BAAM) to fabricate
concrete molds for a new high-rise apartment complex in New York. The molded pieces will
form structural window supports for the hundreds of windows in building façade. The magnitude
of window molds is where additive manufacturing can shine when producing the geometry. This
paper will discuss the methods and findings of using BAAM to replace conventional precast
concrete pattern making.Mechanical Engineerin
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Using Post-Tensioning in Large Scale Additive Parts for Load Bearing Structures
One of the perennial problems with additive manufacturing (AM) is the lack of inter-laminar bond
strength between the layers, also known as z-strength. This can make the use of AM fabricated
parts in load bearing applications problematic. This problem can be solved in some applications
with post-tensioning. The use of post-tensioning in structures can be used to ensure that layer
interfaces only see compressive stresses. This method is commonly used to strengthen concrete
structures since concrete is weak in tension while strong in compression. This paper explores the
successful application of post-tensioning to improve z-strength of large structures made with Big
Area Additive Manufacturing (BAAM) where loads are significant. Theory and examples are
presented herein.Mechanical Engineerin
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Increasing Interlaminar Strength in Large Scale Additive Manufacturing
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.Mechanical Engineerin
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Fieldable Platform for Large-Scale Deposition of Concrete Structures
Oak Ridge National Laboratory’s Manufacturing Demonstration Facility is developing
a novel, large-scale additive manufacturing, or 3D printing, system. The Sky Big Area Additive
Manufacturing (SkyBAAM) system will ultimately be a fieldable concrete deposition machine
with pick and place abilities that will allow for full-scale, automated construction of buildings.
The system will be implemented with existing construction equipment meaning conventional
cranes will be used to suspend the print head. SkyBAAM will be cable-driven by four base
stations and suspended from a single crane. The elimination of a gantry system, found
commonly in large-scale additive manufacturing systems, will enable SkyBAAM to be quickly
set up with minimal site preparation. The medium-scale version of SkyBAAM is currently in
development. The system design, cable stiffness analysis, and tactics for freezing rotational
degrees-of-freedom (DOF), detailed in this paper, will provide a basis for the final, large-scale
version of the SkyBAAM system.Mechanical Engineerin
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Exploration of a Cable-Driven 3D Printer for Concrete Tower Structures
Researchers at Oak Ridge National Laboratory’s Manufacturing Research Demonstration
Facility (MDF) are currently developing a cable-driven concrete additive manufacturing (AM)
system called SKYBAAM. This system is a novel solution for 3D printing large structures using
concrete. The current research focuses primarily on proof of concepts for the cable driven
system, material selection, material pumping solutions, and the concrete extruder design.
Looking forward from the success of the current research, this paper investigates the feasibility
of using the SKYBAAM on a larger scale, specifically for extremely tall tower structures. The
current system design presents challenges at a larger scale, and so the primary focus of this paper
is to investigate new designs of a platform that would support large-scale SKYBAAM
operations. Additionally, this paper will discuss the resulting deflections that can be expected
due to machine operation and wind-loading. Excessive structural deflections could lead to loss
of printing accuracy, or even a complete failure of the print, so it is important to establish that
acceptable deflections can be reasonably achieved on these large-scale tower structures.Mechanical Engineerin
Using Big Area Additive Manufacturing to directly manufacture a boat hull mould
Big Area Additive Manufacturing (BAAM) is a large-scale, 3D printing technology developed by Oak Ridge National Laboratory's Manufacturing Demonstration Facility and Cincinnati, Inc. The ability to quickly and cost-effectively manufacture unique moulds and tools is currently one of the most significant applications of BAAM. This work details the application of a BAAM system to fabricate a 10.36 m (34 ft) catamaran boat hull mould. The goal of this project was to explore the feasibility of using BAAM to directly manufacture a mould without the need for thick coatings. The mould was printed in 12 individual sections over a five-day period. After printing, the critical surfaces of the mould were CNC-machined, the sections were assembled, and a final hull was manufactured using the mould. The success of this project illustrates the time and cost savings of BAAM in the fabrication of large moulds
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Pick and Place Robotic Actuator for Big Area Additive Manufacturing
Oak Ridge National Laboratory’s Manufacturing Demonstration Facility has created a system that works
in tandem with an existing large-scale additive manufacturing (AM) system to ‘pick and place’ custom
components into a part as it is printed. Large-scale AM leaves a layered surface finish and is typically post-processed through 5-axis CNC machining. Each surface must be accurately recorded into a laser tracking
system. This process can be simplified with the use of fiducials, small location indicators placed on the surface
of a part. Additionally, the ability to monitor an AM tool via wireless sensors is advantageous to gauge part
health as it is fabricated and later used. The ‘pick and place’ system allows thermocouples, fiducials, and other
sensors to be accurately placed throughout the tool as it is fabricated. This solution has the potential to reduce
time, labor, and cost associated with fabricating, post-processing, and using AM parts.Mechanical Engineerin