Branson Ultrasonics Corporation

David A Grewell

Donald C Lovett

Jeffrey L Frantz

Paul A Rooney

Justin R Bickford

A laser imaging apparatus having a laser source outputting a laser beam and an electronic display device. The electronic display device is positioned downstream from the laser source. The electronic display device is operable to selectively polarize a discrete portion of the laser beam to define a modified portion and an unmodified portion. A polarizing filter is then positioned downstream from the display device so as to prevent passage of either the modified portion or the unmodified portion of the laser beam therethrough so as to define an imaging beam having a specific pattern.

Electronic masking laser imaging system

The present invention is directed to a method and apparatus using a light guide for directing a laser beam to a weld zone. The light guide includes an entrance end, an exit end and a flexible body therebetween. The entrance end of the light guide is operatively coupled to a laser source such as a diode and is adapted to receive and communicate the laser radiation through the light guide. The light guide is formed of a flexible material to permit the exit end of the light guide to be spaced from and aligned with complex two-dimensional and three-dimensional weld zone configurations. The internal reflection of the light guide contains the laser radiation therein as it passes from the entrance end and through the exit end of the light guide. The light guide and corresponding methods of welding parts permit laser welding of complex geometric configurations.

Light guide for laser welding

An inflatable bladder system for applying generally uniform pressure to parts being welded to insure proper contact at the welding interface includes a first sheet that is generally transparent to electromagnetic radiation to allow such radiation to pass therethrough. This electromagnetic radiation serves to heat the parts to a temperature sufficient to create a weld. The inflatable bladder also includes a second sheet that is also generally transparent to electromagnetic radiation. The second sheet is coupled to the first sheet to create a sealed volume therebetween. Fluid is selectively introduced into the sealed volume in order to expand the bladder into engagement with the parts being welded to exert a generally uniform pressure thereon.

Transparent pressure bladder

A laser joining system deforms a workpiece projection based on collapse of the projection to a predetermined displacement. The laser joining system has a laser system for generating a predetermined level of laser radiation based on radiation control signals. An actuation system directs the laser radiation to the projection and contacts the projection with a laser head based on forced control signals. The actuation system also generates position feedback based on a position of the laser head, wherein the position feedback includes a reference position of the laser head. The joining system further includes a controller communicating with the laser system and the actuation system. The controller generates the radiation control signals and the force control signals based on the position feedback. When the projection collapses to a predetermined displacement with respect to the referenced position, one of the radiation control signals causes the laser system to discontinue generation of the laser radiation. Controlling laser radiation on the basis of collapse distance allows improved consistency and reduced rework costs.

Distance mode control for laser welding

A laser diode array comprises a plurality of substantially parallel spaced metal plates, each plate having a laser diode mounted upon one side of the plate. The plates are supported electrically insulated from one another on mounting means. The diodes, connected electrically in series, when energized illuminate an oblong workpiece area disposed a certain distance opposite the array. In a preferred embodiment, the mounting means comprises flexible rod means passing through respective apertures of the plates, thus enabling the array to assume a curved configuration, thereby enabling the array to illuminate a straight as well as a curved oblong workpiece area.

Laser diode array

A filter for absorbing electromagnetic radiation which is used in heating a welding zone wherein a first part is joined to a second part. The filter includes a solid material for absorbing undesired wavelengths of radiation from a heating source before the radiation reaches the welding zone. The filter also has a housing which contains a chamber within which a fluid is placed. The fluid cools the solid material and also may absorb undesired wavelengths of radiation from the heating source before the radiation reaches the welding zone. A heat exchanger is connected to the filter in order to cool the fluid during the filtering process.

Welding method and apparatus

An ultrasonic processing method is disclosed wherein during the processing time interval the motional amplitude and engaging force of the resonating horn and thereby the power and engaging pressure to the workpiece is varied to improve weld strength and decrease weld cycle time. The variation in motional amplitude and engaging force may be in response to a process condition such as a change in dimensions of the workpiece, a sharp rise in the transducer power curve, or in response to the lapse of a predetermined time interval.

Simultaneous amplitude and force profiling during ultrasonic welding of

A method of welding two thermoplastic workpieces (W) together along a predetermined weld line during a weld cycle utilizing a high frequency vibration sonic or ultrasonic welding apparatus. This welding apparatus includes an electroacoustic transducer (18) which transmits such vibrations to a horn (19) which is dimensioned to be resonant with the horn being brought into forced engagement with at least one of the workpieces to be welded. The method comprising the steps of bringing the workpieces into bearing relation against one another along the weld line. Then the electroacoustic transducer is energized so as to resonate the horn with a desired motional amplitude. Forceful contact is established between the horn and one of the workpieces. Then, the forceful contact between the horn and the one workpiece is maintained throughout the weld cycle. The motional amplitude of the horn is varied in accordance with a desired motional amplitude profile.

Method for processing workpieces by ultrasonic energy

For accurately determining, in real time, the collapse of a thermoplastic workpiece processed in a press, such as an ultrasonic welding apparatus or a vibration welding apparatus, a two-phase method is used. In the calibration phase signals are generated which are responsive to the yielding or displacement of the movable press portion relative to the substantially stationary portion arising from forced engagement of the workpiece within the press. The force responsive displacement value is stored. In the subsequent workpiece processing phase, when the workpiece collapses due to the softening and flowing of thermoplastic material as the workpiece is coupled to vibrations, the previously stored force responsive displacement value is recalled as a correction signal and subtracted from the newly obtained displacement signal related to the same force. The result of the subtraction is a true on-line signal indicative of the collapse of the workpiece as it occurs.

Method of determining the collapse of plastic parts

An expert system for a welding machine has an installed knowledge base concerning weld problems and preferred solutions. Trial welds are made from which input data concerning weld quality is obtained. The expert system applies predetermined rules and historic confidence levels to determine changes in weld parameters to attempt to correct any weld defects.

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Waterbury, CT, United States of America

David A Grewell