Patent ID: 6770158
Filing Date: 2004-08-03
Classification: B29C,B29K,Y10T

Abstract:
A method for assessing whether a workpiece having an initial transmission of TINIT has been rendered weld-enabled as defined by a transmission drop &Dgr;PRE to a pre-processed transmission TPRE within a welding zone, the method comprising the steps of:providing a workpiece with a bulk portion and a surface extending across the bulk portion, wherein at least the surface is made from a first polymer which softens on heating; transmitting electromagnetic radiation toward the surface in the region of the expected welding zone to be tested; sensing electromagnetic radiation at a test wavelength passing through the surface of the workpiece and generating a signal representative of transmission; determining whether the sensed transmission signal is within a range of TPRE as an indication that an absorber dye possessing both strong absorption and a high extinction coefficient was deposited on or above said workpiece surface within the welding zone via a vehicle having necessary viscosity and which avoids undue interference with or occlusion of the welding zone; and certifying the workpiece weld-enabled for radiant energy welding wavelengths within a bandwidth range of the test wavelength.