Laser powder forming, also known by the proprietary name (laser engineered net shaping) is an

additive manufacturing 3D printing or additive manufacturing is the construction of a three-dimensional object from a CAD model or a digital 3D model. It can be done in a variety of processes in which material is deposited, joined or solidified under computer ...

technology developed for fabricating metal parts directly from a computer-aided design (CAD) solid model by using a metal powder injected into a molten pool created by a focused, high-powered

laser A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word "laser" is an acronym for "light amplification by stimulated emission of radiation". The firs ...

beam. This technique is also equivalent to several trademarked techniques that have the monikers direct metal deposition (DMD), and laser consolidation (LC). Compared to processes that use powder beds, such as

selective laser melting Selective laser melting (SLM) is one of many proprietary names for a metal additive manufacturing (AM) technology that uses a bed of powder with a source of heat to create metal parts. Also known as direct metal laser sintering (DMLS), the ASTM ...

(SLM) objects created with this technology can be substantially larger, even up to several feet long.

Method

A high power laser is used to melt metal powder supplied coaxially to the focus of the laser beam through a deposition head. The laser beam typically travels through the center of the head and is focused to a small spot by one or more lenses. The

X-Y table {{Unreferenced, date=May 2009 X-Y tables, also known as cross working tables or coordinate tables, help provide horizontal motion for automated machinery such as assembly robots in manufacturing facilities. Robotic arms and other automated machiner ...

is moved in raster fashion to fabricate each layer of the object. The head is moved up vertically after each layer is completed. Metal powders are delivered and distributed around the circumference of the head either by gravity, or by using a pressurized carrier gas. An inert shroud gas is often used to shield the melt pool from atmospheric oxygen for better control of properties, and to promote layer to layer adhesion by providing better surface wetting.

Other techniques

This process is similar to other 3D fabrication technologies in its approach in that it forms a solid component by the layer additive method. The LENS process can go from metal and metal oxide powder to metal parts, in many cases without any secondary operations. LENS is similar to

selective laser sintering Selective laser sintering (SLS) is an additive manufacturing (AM) technique that uses a laser as the power and heat source to sinter powdered material (typically nylon or polyamide), aiming the laser automatically at points in space defined b ...

, but the metal powder is applied only where material is being added to the part at that moment. It can produce parts in a wide range of

alloy An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductilit ...

s, including

titanium Titanium is a chemical element with the Symbol (chemistry), symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resista ...

, stainless steel,

aluminum Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It h ...

, and other specialty materials; as well as composite and functionally graded materials. Primary applications for LENS technology include repair and overhaul,

rapid prototyping Rapid prototyping is a group of techniques used to quickly fabricate a scale model of a physical part or assembly using three-dimensional computer aided design ( CAD) data. Construction of the part or assembly is usually done using 3D print ...

rapid manufacturing 3D printing or additive manufacturing is the construction of a three-dimensional object from a CAD model or a digital 3D model. It can be done in a variety of processes in which material is deposited, joined or solidified under computer ...

, and limited-run manufacturing for aerospace, defense, and medical markets. Microscopy studies show the LENS parts to be fully dense with no compositional degradation. Mechanical testing reveals outstanding as-fabricated mechanical properties. The process can also make "near"

net shape Near-net-shape is an industrial manufacturing technique. As the name implies, the initial production of the item is very close to the final, or ''net'', shape. This reduces the need for surface finishing. By minimizing the use of finishing methods ...

parts when it is not possible to make an item to exact specifications. In these cases post-production process like light machining, surface finishing, or

heat treatment Heat treating (or heat treatment) is a group of industrial, thermal and metalworking processes used to alter the physical, and sometimes chemical, properties of a material. The most common application is metallurgical. Heat treatments are al ...

may be applied to achieve end compliance. It is used as finishing operations.

References

External links

Sandia National Laboratory LENS article.
{{3d printing 3D printing processes Laser applications