In a system for laser welding work pieces along a collapsing weld
interface, methods and apparatus include providing welding pads and/or
stop projections on either or both of the work pieces to control the
manner or amount of collapse. Preferably, the stop projections exist a
separation distance from the weld interface while the welding pads exist
at and form a portion of the weld interface. Buffers are taught between
the weld interface and stop projection. The work pieces may comprise
inkjet printhead lids and bodies. In another aspect, the invention
teaches methods of laser welding inkjet printhead lids and bodies
according to whether the inkjet printhead body embodies a mono or color
ink body type and especially includes selective control of one or more
laser light sources to illuminate the inkjet printhead lid in a specific
pattern of light.