Abstract: An improved laser weld process control system and method are provided. The system and method include a machine vision camera to detect a deviation between a pre-programmed laser beam toolpath and a gap centerpoint between first and second parts being welded together. The first and second parts are secured to a rotatable fixture, and the system and method cause the rotatable fixture to rotate through a corrective angle to bring the gap centerpoint into alignment with the laser beam toolpath, optionally in real time during the application of laser beam energy. The system and method can also correct for a vertical misalignment of the laser focal point due to rotation of the fixture by adjusting the vertical separation of the laser unit relative to the fixture.

Abstract: An assembly for measuring metal powder material mass flow rate during direct metal deposition. A detection strip is placed in the gas-blown metal powder material flow path. The detection strip is fixed in one end and suspended at the other end. The flowing metal powder material particles induce displacement to the detection strip. A displacement measurement sensor measures the amount of displacement of the detection strip. The amount of displacement of the detection strip gives relationship to the amount of the metal powder material flowing in the metal powder material flow path. The detection strip and the sensor are connected to a housing with a metal powder material inlet port and metal powder material outlet port and includes internal features for smooth travel of metal powder material particles.

Abstract: An assembly for rapid manufacturing of symmetrical objects by direct metal deposition is disclosed. A rotary stage provides rotational movement to an object supported by the stage around a central stage axis. Nozzles are spaced above the rotary stage for performing direct metal deposition for building an object supported by the stage. Each nozzle is independently moveable along a horizontal axis and independently pivotable, and combined, moveable along a vertical axis for providing symmetrical movement corresponding to a symmetrical deposition configuration of the object while the object is rotated around the central stage axis.

Abstract: A method of forming a valve seat of an engine head formed from a first composition includes forming a groove at a predetermined valve seat location of a bore defined by the engine head. A source of directed heat energy preheats at least the valve seat location to about a temperature of the melting point of the first composition with the source of directed heat energy. The source of directed heat energy is infused with a material having a second composition generating a melt pool upon the groove by direct metal deposition with the melt pool including the second composition. The second composition includes a heat conductivity generally equal to a heat conductivity of the first composition for providing efficient transfer of heat energy from the first composition to the second composition.

Abstract: Direct metal deposition (DMD) is used to fabricate knife edges with extended service life. A metal alloy powder is deposited along a blank and melted with a laser beam so that the powder solidifies into a strip of material having a hardness and/or wear resistance greater than that of the starting material. The piece is then finished to produce a sharp edge in the solidified material. The powder may be melted while it is being deposited, or it may be melted after being deposited. A slot or groove may be formed in the blank with the metal alloy powder being deposited into the slot or groove. A hardened steel alloy powder is deposited onto a mild steel blank. For example, a tool steel or vanadium steel powder may be deposited onto a 1018 steel blank. An invention line-beam nozzle may be used for deposition and/or powder melting.

Abstract: A direct metal deposition (DMD) process is stabilized by monitoring the temperature and the shape of the melt pool during deposition, applying a recursive least square (RLS) model estimation algorithm to adaptively identify process characteristics in accordance with the temperature and the shape of the melt pool, and delivering the process characteristics to a generalized predictive controller with input constraints to control the process. The process may be controlled by adjusting laser power or by adjusting the speed of the movement of the laser. In the preferred embodiment the temperature is monitored using a two-color pyrometer, and the shape of the melt pool is monitored by detecting the edge of the melt pool with a camera and/or photodetector.

Abstract: In a direct metal deposition system which builds up a metallic overlay on a substrate by moving the substrate relative to a laser in a metallic powder feed, the laser power is adjusted for successive layers by sensing the weld pool in a plurality of selected points in each layer and adjusting the power during successive layers to maintain a weld pool that corresponds to those achieved during deposition of a lower optimal layer. This compensates for heating of the substrate resulting from the deposition which tends to increase the pool size or temperature in the higher layers.

Abstract: A direct-metal deposition (DMD) processing stage and a 5DOF (degree of freedom) dry micro-EDM (mEDM) stage are integrated to provide the submicron scale resolution necessary for the ultra-precision processing of work pieces. The DMD processing stage includes optical feedback for dimensional control utilizing a high-power, fiber-coupled diode laser with fast response time and small beam parameter product. The electrical discharge machining (EDM) stage is a dry EDM stage using an inert gas with appropriate dielectric properties to perform the surface finishing operations. The system further includes one or more surface treatment operations to obtain a desired level of surface hardness or wear resistance and/or to minimize the distortion induced in treating the surface.