One of the many challenges for human exploration in space is the ability to repair or replace damaged parts and structures on orbit. A space based manufacturing center, utilizing a solid freeform fabrication (SFF) process capable of producing components from metal and composite materials, offers the most practical solution. To accomplish this, an SFF process must overcome the challenges of micro-gravity and zero-gravity environments. Equipment mass, complexity, power requirements, feedstock material containment, system handling and safety, and the ability of a single machine to produce objects from multiple materials are all issues that need to be addressed in the employment of an SFF system for in space application.

Metal deposition processes such as EB round wire feedstock fusion, or laser powder fusion are providing metallurgical bonding to the substrate but require a liquid metal pool to be present on the substrate during the deposition. The extra heat necessary for carrying this molten pool has a significant negative impact on additive metal deposition and its potential applications, causing a high degree of part distortion, undesirable dilution, and in some instances cracking. HRT’s precision metal deposition (PMDä ) process provides capabilities for low heat input manufacturing and repair of three-dimensional structures. The patented PMDä process fuses solid metal flat wire onto a substrate without the need to create a molten pool of metal, unlike other laser metal deposition processes. As a result, HRT's metal deposition process produces metal parts with an order of magnitude less heat input per unit volume deposited than competing technologies.

This low heat input process will reduce system’s power requirements, its footprint and mass when compared with other metal deposition SFF processes under consideration. The PMDä process allow for 100% utilization of feedstock material during part fabrication as oppose to a reported 20% - 30% utilization of powder deposition processes. It removes the complexities of powder containment, recycling and safety associated with in-space powder fusion processes. The PMD™ system integrates deposition, grinding and machining into a single process system for net shape fabrication. The fully integrated PMD™ technology will be effective in both micro-gravity environments as well as zero gravity environments.