HAMMER – Hybridized Additive Manufacturing Machine with Error Rectification

Introduction

To make the most of Additive Manufacturing, the development of a machine that can utilize different classes of materials is advantageous. Fabrication of hybrid materials where different classes of materials are deposited simultaneously will allow parts to be produced with properties tailored to need by location. Hybridization and shape complexity promises to significantly improve the functionality of manufactured components, reduce their weight, and cut down the cost of manufacturing.
This project was focused on the design and construction of the Additive Manufacturing system exclusively to process different material classes. Developed technology would allow the fabrication of hybrid 3D components with polymeric, metallic, and ceramic sections. In addition, the system would have the ability to mix materials prior to processing thus allowing for testing novel material combinations. Moreover, HAMMER was designed to include an optical precision alignment and feedback control system that provided self-alignment of the print-heads thus offering geometrically accurate prints.
As a deposition technology, AM provides means for the development of new products for the defense and aerospace industry. Lockheed Martin Corp. is using AM for manufacturing of titanium satellite parts, GE is investigating the incorporation of the printed parts into jet engines, BAE Systems is using AM to make air intake struts and a landing gear part for Tornado fighters. Compared to conventional methods for part production, AM brings the benefit of reducing the part count, decreasing assembly times, thus reducing costs and cycle time production.
To date, AM machines can process one material (SLS, 3DP, and SLA), or several materials (FDM, Jetted Photopolymer) at the same time. However, multi-material capability simply means the ability to process the same class of material (e.g. photopolymer). To make the most of AM, the development of a machine that can utilize different classes of materials is necessary. A truly multi-material AM machine will allow components to be fabricated with properties tailored to need by location thus combining structure and function with an overall minimization of weight and cost. 
Project Goal: develop an AM system capable of processing different material classes simultaneously
Benefits: fabrication of multi-functional/hybrid components 
Results: 

• Demonstrated the ability of the system to process polymers
• Polymers with melting temperatures ranging from 135°C to over 300°C were sintered
• The density of sintered polymers depends on print-head speed; 99% dense parts were fabricated using Polyamide 6 as base material

• Demonstrated the capacity to process metals
• Copper and Iron were successfully sintered 
• Sintering metal in an alternative operation mode led to melting top layer and fabrication of near 100% dense parts
• Sintered metals had density ranging from 80% to 90%

• The tested feedback control system
• A single two-dimensional feedback system was evaluated
• The system is capable of error correction down to 8.5 µm±15 µm