Welding

Fabrication (sculptural) process that joins materials .This is often done by melting the workpieces and adding a filler material (usually metals or thermoplastics, that causes coalescence ) to form a pool of molten material (the weld pool) that cools to become a strong joint, with pressure sometimes used in conjunction with heat, or by itself, to produce the weld. This is in contrast with soldering and brazing, which involve melting a lower-melting-point material between the workpieces to form a bond between them, without melting the workpieces .

Different energy sources can be used for welding

A gas flame

An electric arc

A laser

An electron beam

Friction force

Ultrasound waves

Types of welding processes

·                  Arc

·                 Gas welding

·                 Resistance

·                 Energy beam

·                 Solid-state

One of the latest amoung is UITRASONIC welding that includes high frequency waves

Making of Ultrasonic Weld:

 ultrasonic welding process

The theoretical method of doing(making) an ultrasonic weld is un-complicated, the interactions of the var weld parameters are vital and may be understood. When manufacturing an ultrasonic weld,

there are 3 primary variables that depends are:

• TIME (the period of applied ultrasonic vibration)

• AMPLITUDE (the longitudinal displacement of the vibration)

• FORCE (the compressive force applied in perpendicular (normal) to the direction of vibration)

Power needed initiating and maintaining vibration (motion) throughout the weld cycle is givens as:

P = F x A

Where:

P = Power (in watts)

F = Force (in psi)

A = Amplitude (in microns) 

Force = (Surface Area of the Cylinder) X (Air Pressure) X (Mechanical Advantage ) 

Energy is calculated as:

E = P x T

Where:

E = Energy (in joules)

P = Power (in watts)

T = Time (in seconds)

Thus the complete ‘Weld to Energy’ process is defined as:

E = (F x A) x T

A well designed ultrasonic metal welding system can compensate for normal variations within the surface conditions of the metals by delivering the required energy value to the metal. This is often achieved by permitting time (T) to regulate & to suit the condition of the materials and deliver the required energy.

Steps how Ultrasonic Welding Works:

Step 1: The parts to be welded are placed into a locating holderjaw

Step 2: The ultrasonic tool descends (to apply a clamping pressure between the weld parts.)

Step 3: The tool then vibrates at a frequency 1 – 40 KHz. (The weld parts are thus scrubbed together under pressure causing surface oils and oxides to be removed & dispersed)

Step 4: The base metals are then mechanically intermixed causing a metallurgical bond between the parts. The parts are immediately welded . There is no hold time or curing time .

In Ultrasonic welding electrical power supply is applied to a Transducer at a frequency of 50 to 60 Hz, into a high frequency electrical supply operating at 20, 30 or 40 KHz. Here transducer converts electrical energy into mechanical energy. This electrical energy is supplied to the converts, which converts to mechanical energy at ultrasonic frequencies.

Step 5:  Thus the pieces to be weld are tested for surety

Ultrasonic welding processes produces a localized temperature rise (due to the combined effects of elastic hysteresis+interfacial slip+plastic deformation). The weld interfaces reach around 1/3 the temperatures required to melt the metals.

As the temp. does not reach the melting point of the material, the physical properties of the welded material are safed( preserved thus no danger of any mechanical or metallurgical bad effects). As the ultrasonic welding method is an exothermic reaction , as welding time will increases similarly weld temperature changes. metals up to 2.5 mm thick have been welded

The ultrasonic vibrating unit consists of following main components:

Frequency converter

Booster

Horn or sonotrode,

      Pneumatic Press /Actuator

Ultrasonic power supply, and

     

      holding fixture

      This was my first post hope you like it....stay tuned for further up dates.

Special events alert  happen in INDIA.

WELD INDIA 2014 Exhibition

Now Goes Beyond Welding.

      10-12 April 2014,NEW DELHI, INDIA     

A single place where you can get solution of welding all under one roof like  Welding act, Cutting, Fabrication, Manufacturing, Precision Metal Forming, Chemical Coating, Metallurgy Materials, Testing & Robotics processes & have Training & Education about  them. 

Weld India 2014

The Indian Institute of Welding has announced in association with FABTECH (That is one of the world's largest metal forming, fabricating, welding & finishing exhibitions that is best in world of Exhibitions.).

Weld India 2014 will provide an opportunity of not only bringing Companies in Welding Technology covering Arc Welding , Solid State Processes , Brazing , Soldering , Adhesive Bonding , Plastic Welding , Metallurgy , Material Testing Techniques including NDT , Health & Safety , Robotics & Automation , Beam Processes & Special Processes including Nano Joining etc. but also large group of user industry ranging from fabrication and construction to metal coating and other relavent fields , all under one roof to provide for a comprehensive insight into technology and markets.

its aim is to attract the prospective Indian consumers and gain a foothold in the 'India of the Future". 
presently, the IIW International Congress 2014 (IIW IC 2014) is also being organised by the Indian Institute of Welding which will host about 700 delegates from India and abroad . It is expected about 200 high quality technical papers will  be presented at IIW IC 2014.
I hope we meet  you at WELD INDIA 2014 , Pragati Maidan, New Delhi...and reap the benefits of it together ... !!!