LMD-W – Additive process with 100 percent material efficiency

Lateral wire feed for stable and efficient processes

LMD-W-20-L

Smart processing module for wire-based laser deposition welding

© Fraunhofer IPT

The Fraunhofer IPT has developed a smart laser module for wire deposition welding, which can be easily integrated within existing process chains, handling systems or machine tools. Thanks to its robust design and intelligent sensor system, it can even be combined with industrial robot systems.

Laser deposition welding with wire or "Laser Metal Deposition – Wire". LMD-W for short, is particularly suitable for integration into existing production lines due to the easy to handle additive material wire.

Modular design for cost-effective integration into existing systems

The cost-effective welding head “LMD-W-20-L” can be easily retrofitted due to its modular design. It works with common laser optics and therefore it does not require complex custom-made beam guidance systems. With the built-in sensors, it is possible to detect typical faults in the running process so that the causes can be analyzed during machining and compensated for by the control system.

Lateral wire feed for stable and efficient processes

A lateral feed of the wire at a steep angle of 20 degrees to the optical axis ensures stable processes with high melting efficiency. Available wire materials include various types of steel, nickel- and titanium-based alloys as well as numerous special materials. The Fraunhofer IPT is investigating the suitability of other alloys in several research projects.

LMD-W – Additive process with 100 percent material efficiency

A special feature of wire-based laser deposition welding is its quasi 100 percent material efficiency, since the supplied material is completely melted and applied to the component surface in layers. With appropriate CAM support and multi-axis process control, additional functional elements in hybrid design can be built on existing components and repairs and modifications can be carried out. A wide range of wire filler materials can not only be processed very cost-effectively, but also close to contour, resulting in high-quality components.

Technical Specifications

Dimensions

Height: 843 mm
Width: 373 mm
Depth: 201 mm

Weight

Total weight: 38 kg
Wire feeding motor: 2.8 kg
Optics: 6.9 kg
Zero-point clamping system: 3.4 kg (not included in total weight)

Wire feeding motor

Compatible are common wire feeding motors e.g. by the companies A. Binzel Schweisstechnik GmbH & Co. KG or Dinse GmbH. Currently in use is an Abicor Binzel MF1 30 with corresponding wire feeding system for wire diameters of 1.2 mm.

Laser optics

Compatible are common laser optics ≤ 2" with external dimensions (width x depth) smaller than 80 mm x 80 mm and a focusing focal length of approx. 250 mm. Currently a Laserline OTS 5 laser optics is applied for high power diode lasers. The optics enables coaxial observation of the process zone by a CCD camera. The OTS 5 optics generates a round laser spot with a diameter of 2.1 mm. The optics is equipped with an LLD-D fiber plug and a protective glass.

Wire feeder

The wire is fed at an angle of 20° to the optical axis. This arrangement permits forehand welding. The wire feed motor is aligned and at a small distance from the process zone, so that a kink-free and friction-reduced wire feed into the process zone is possible. The wire feed is cooled with water through an independent channel. In addition, the temperature of the replaceable wire nozzles is monitored.

Shielding gas

The shielding gas is also supplied at an angle of 20° to the optical axis and is positioned opposite to the wire. The shielding gas nozzle partially encloses the wire nozzle. The wire nozzle and inert gas nozzle thus stabilize each other. This provides high rigidity to the LMD-W-20-L in the area of the wire and inert gas supply, thus increasing the precision and quality of the metal deposition. The shielding gas guidance contains two shielding gas channels so that different shielding gases can be connected. Pressure and temperature are also monitored. The inert gas supply is also cooled with water via a separate channel.

Positioning and handling

The LMD-W-20-L can, for example, be picked up by a handling system via a zero-point clamping system. Two eyebolts can be mounted on the head side to allow the use of a crane. There is an individually adaptable connection plate for cable towing on the head side. The two large doors swinging out to the side enable convenient operation of the optics, positioning system and wire feed motor. The positioning system enables precise relative positioning of the laser spot and wire.

Force measurement and sensor technology

The LMD-W-20-L is equipped with a force measuring system with which the process forces can be recorded and stored in a database. If a defined force is exceeded, the system can interrupt the welding process and stop the handling system. In this way, potential component defects can be detected and, if necessary, the process be stopped before their occurrence. In addition, this system offers effective collision and wire adherence detection. During metal deposition, the process forces are visualized in color on the front side of the system. In addition to the process forces, the temperature values and the inert gas pressure for a possible database are also recorded and monitored by the integrated electronics.