To overcome 1) the high levels of porosity due to coating material vaporization and entrapment into the weld, 2) spewing of molten base metal from the weld leaving holes and pits in the weld, and 3) humping effects when oblong beam configurations are used at higher weld speeds to weld coated materials, the present invention features an energy source (10) with multiple separated energy beams (24, 26) (formed by using multiple separate beam sources or manipulation of a single beam (14) into separated multiple energy beams (44, 46) using wedge mirror (18) and parabolic focusing mirror (20)) that produces high quality (porosity free) lap welds in a weld stack (50) of layered materials (30, 32) coated with coating material (28, 28', 34, 34') with zero gap at interface (38) during the welding process. An energy source (12) with multiple, separated energy beams (24, 26) extends the beam keyhole and increases the time and conditions available for vapor/gas to diffuse less violently through the molten weld pool.

Disclosed herein is a laser welding system having a travel path to carry a first blank and a second blank. An upstream clamp assembly and a downstream clamp assembly are positioned on the travel path and each of the upstream and downstream clamp assemblies are movable to an open position to allow the first blank to pass through the upstream clamp assembly to a first location within the downstream clamp assembly. A laser welding source is directed at a weld location on the travel path between the upstream and downstream clamp assemblies. At least one locating means is operable to locate the first weld edge adjacent the weld location. A first displacement means displaces the first weld edge against the locating means. The downstream clamp assembly is movable from the open position to a closed clamped position to clamp the first blank with the first weld edge adjacent the weld location. The locating means is operable to be withdrawn from the travel path. The upstream clamp assembly is movable from the open position to an intermediate position, which is selected to guide the second blank to pass through the upstream clamp assembly in a substantially coplanar relationship with the first blank so that the second weld edge makes contact with, but not past, the first weld edge. A second displacement means displaces the second blank to a location adjacent the weld location where the second weld edge abuts the first weld edge. The upstream clamp assembly is movable from the intermediate position to a closed clamped position to clamp the second blank and the--the laser welding source is operable to fuse the first and second weld edges blanks together.

Disclosed herein is a laser welding system having a travel path to carry a first blank and a second blank. An upstream clamp assembly and a downstream clamp assembly are positioned on the travel path and each of the upstream and downstream clamp assemblies are movable to an open position to allow the first blank to pass through the upstream clamp assembly to a first location within the downstream clamp assembly. A laser welding source is directed at a weld location on the travel path between the upstream and downstream clamp assemblies. At least one locating means is operable to locate the first weld edge adjacent the weld location. A first displacement means displaces the first weld edge against the locating means. The downstream clamp assembly is movable from the open position to a closed clamped position to clamp the first blank with the first weld edge adjacent the weld location. The locating means is operable to be withdrawn from the travel path. The upstream clamp assembly is movable from the open position to an intermediate position, which is selected to guide the second blank to pass through the upstream clamp assembly in a substantially coplanar relationship with the first blank so that the second weld edge makes contact with, but not past, the first weld edge. A second displacement means displaces the second blank to a location adjacent the weld location where the second weld edge abuts the first weld edge. The upstream clamp assembly is movable from the intermediate position to a closed clamped position to clamp the second blank and the the laser welding source is operable to fuse the first and second weld edges blanks together.

Motorized slides are inserted between the end of a robot arm and a robot tool/sensor arrangement to provide additional positioning ability. A control unit of the slides cooperates with the control unit of the sensor to maintain the tool correctly positioned over a feature while the robot arm moves following a programmed path. The control unit of the sensor has look-ahead and additional buffers from which corrected information is determined to compensate for robot teaching inaccuracies, calibration and robot arm response errors. A sensor with two distinct probing zones is used to get information about the position of the tool tip and of the feature to assist in calibrating the sensor/tool relation.