ULTRASONIC WELDING

SolidState

Welding

Electrical

Chemical

Mechanical

Friction

Pressure UltrosonicWeld

Flow chart of solid state welding

Definition of Ultrasonic Welding“Ultrasonic welding is solid state

welding process , where in coalescence is produce by local application of high frequency vibratory energy to the workpiece as they held together under pressure ”

 

Ultrasonic Welding Mechanism

A static clamping force is applied perpendicular to the interface between the work pieces.

The contacting sonotrode oscillates parallel to the interface.

Combined effect of static and oscillating force produces deformation which promotes welding. Anvil

Mass

Sonotrode tip

Clamping force

wedge Transducer

Force

workpiece

10-75 KHz

Principle of Ultrasonic Welding

Anvil

Mass

Sonotrode tip

Clampingforce

wedge Transducer

Force

WeldmentVibration

*In US welding, frictional heat produced by the ultrasonic waves and force is used for joining process.*US waves(15to60 kHz) are transferred to the material under pressure with a sonometer. Welding times are lower than 3 s. -*It can proceed with or without the application of external heat.

Types of US welding

• Spot Welding

• Ring Welding

• Line Welding •- Linear Sonotrode

• Continuous Seam Welding - Roller Sonotrode

.Types of Ultrasonic

Welding

ultrasonicspot-type welding machine

Lateral DriveUltrasonicWelder

Ultrasonic Welding Interfacial Interaction

Localized temperature rises resulting from interfacial slip and plastic deformation.

Temperature is also influenced by power, clamping force, and thermal properties of the material.

Localized Plastic DeformationMetallurgical phenomena such as

recrystallizing, phase transformation, etc..... can occur.

Extreme InterpenetrationNickel Foil (top) to Gold-Plated Foil

Local Plastic FlowDark Regions are Trapped OxideNickel Foil (top) to Molybdenum Sheet

Very Little Penetration, Thin Bond Line, Fiber FlowMolybdenum Sheet to Itself

Advantages of Ultrasonic WeldingNo heat is applied and no melting occurs.Heat affected zone is minimized. Minimum surface deformation.Very thin materials can be weld.No defect due to arc , gases ,filler metal.Welding of glass is also possible.Pressures used are lower, welding times are

shorterDissimilar metal can be weld.

Limitations of Ultrasonic WeldingRestricted to join thin welding.Process is limited to lap joints.Competitively not economics.Material being may weld to the anvil

and tip only.

Applications of Ultrasonic Welding Computer and electrical industriesdelicate

circuits,  Junctions of wire harnesses ,  flash drives and computer disks, Semiconductor devices

Aerospace and automotive industriesinstrument panels, door panels, lamps, air ducts, steering wheels, and engine components

Medical industry hospital gowns , sterile garments, masks, transdermal patches,  dialysis tubes, pipettes

Packaging industryEncapsulation and Sealing containers, tubes packaging, hermetic sealing.

Starter motor armature with wires joined in commutator slots by

ultrasonic weldingUltrasonically welded

Helicopter access door.

Wire Harnessing