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Seam Welding Machines
Offered in 50 to 200 KVA capacity, available in longitudnal / circumferential
and universal versions. Percision built, sturdy design and robust construction
suitable for high production and uninterrupted service in the manufacturing
of drums, barrels, silence, fuel tanks, transformer radiator, water heater & auto rims, etc.
These machines are always made to specific customer requirement with highly sophisticated & leak proof joints.
Standard Rating :
50,75,100,150 and 200 KVA
Construction :
The main frame of the machine is of heavy rigidly re-inforced & robust welded steel construction. It combines a compact streamlined appearance with maximum resistance to mechanical deflection. The welding transformer is enclosed in the main frame and is easily accessible, for inspection.
Standard Throat Depths (mm.) :
280, 460 & 600 (other throat available on request)
Normal Working Height :
900 (mm)
Welding Transformer :
Transformer of a special type, water cooled, having core of high grade electrical steel, primary and secondary coils of solid electrolytic copper of ample section, heavy duty class ‘F’ insulated, impregnated and tropicalised suitable for withstanding continuous temperature of 140º C.
Current Control :
Transformer primary coils provided with taps brought out to tap change links for adjustment for welding current in a 6 step from 50 to 100%. Tap change links are enclosed behind machine door and are easily accessible for variation of welding heat.
Cooling System
Transformer, secondary connections, arms and electrode wheels are water cooled. Internet water cooling piping with flow adjusting values for each circuit and discharge to an open drain pot for visual observation of flow are provided in the machine.
Electrode
Circular disc type top and bottom welding Electrodes.
Electrode Control System
Upper electrode is actuated by hand lever to provide electrode force.
Electronic Controls
Seam welders are provided with solid-state electronic controls housed in a well-designed sheet steel cabinet. The standard design of the cabinet is suitable for mounting it on the sidewall of the machine; floor mounting shall also be provided a request. The control knobs and panel are elegantly arranged, provided maximum convenience to the operator. The front panel is protected from misuse by providing a transparent guard door. All internal wiring is easily accessible for servicing. The circuit design is versatile enough for almost all type of requirements and consists of the following facilities.
A squeeze time control to select the delay between initiation of the foot switch and the start of the weld. Timing is adjustable from 2-25 cycles, continuous
Synchronous (digital) timing control of 1-9 cycles “ON” and 0-9 cycles “OFF” both in steps of one cycles each.
Heat control circuit based on phase shifted firing of thyristors which enable continuous adjustment of current between 10% to 100% of then value available from welding transformer.
High power switches device consisting of 2 Thyristors connected in inverse parallel mounted on water-cooled heatsinks. The sizes of the thyristors are chosen to watch the KVA of the transformer and the devices are of ample capacity to withstand momentary overloads. Protection devices for high voltage surges and a thermoswitch (for inhibiting the operation if the temperature of the thyristor pad rises above a preset limit) are incorporated.
Hold time to provide a delay between stoppage of weld and separation of electrode wheels. Range of adjustment is 1-9.
Weld Initiation
By means of operators foot switch connected to a low voltage safe initiating circuit.
Motor Drive System
Machine can be supplied with either A.C. or D.C. motor drive system as per customers choice.
D.C. Motor driven system consists of an infinitely variable speed, reversible D.C. Motor, variac, rectifier & protective
fuses system with reduction gear unit to provide stepless speed variation.
A.C. Motor driven system consists 3-phase induction motor speed as constant.
Note : Machine shall be supplied with A.C. MOTOR DRIVE SYSTEM AS STANDARD
UNLESS SPECIFIED otherwise by the customer.
Serivice Requirements
Customer to provide the following service facilities :-
Power Supply
For Transformer : 415 V, Single phase, 50 cycles (suitable for connection
to 2 lines of 3 phase supply). Main supply cable for transformer connection.
Disconnect switch with fuses of recommended rating. For Motor : 415 V,
3 phase, 50 cycles or 230 V, single phase, 50 cycles or 230 V, single
phase, 50 cycles for D.C. motor drive, depending on the drive system selected
supply cable 1.5 sq. MM 4 core, TPIC switch fuse unit 500 V, 15 Amps,
with fuses of 5 Amps for D.C. motor Drive system. COMPRESSED AIR :
Supply of air recommended flow volume at minimum pressure of 5.6 kg/cm2
(80 psi) by the customer.
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Projection Welding Machine
- Spot and nut projection possible on the same machine
- Robust construction – less vibrations – no maintenance of controller broad / connectors.
- Controlled delivery of welding current by made constant current feedback controller.
- Quantity watch on every spot. Weak or faulty spot highlighted instantly.
- Error and weak spot alarm buzzer.
- Fused copper laminate flexible links for lifetime use
- High speed cylinder operations gives better cylinder follow up.
- Electrode movement made precise by LM bearing.
- Engineered for minimum downtime.
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Spot Welding Machine
- High weld abilities are achieved with special type of transformer.
- Ability to weld thick material at low speed using short length arms.
- In Manually operated machine at low speed using short length arms.
- Easy maintenance.
Construction
The unit is of robust construction sturdy heavy rigidly reinforced welded steel construction. It combines a compact streamlined appearance with maximum resistance to mechanical deflection. The transformer enclosed in the main frame and is easily accessible, for inspection.
Welding Transformer
Manufactured from high grade materials of copper strips and sections, water cooled with class ‘F’ insulation with standing continuous temperature rise of 140`C. The coils are impregnated and tropicalised.
Current Control
By tap method with 8 tap adjustments on primary of the main transformer having current control from 50% to 100% in 8 steps.
Cooling system
By tap link method with 8 tap adjustments on primary of the main transformer having current control Electrodes, Electrode holders, Arms, Transformer are all water cooled with one single water-cooling circuit.
Electrode Control System
Upper electrode is actuated by foot lever or by air cylinder. The electrode force can easily be calculated in both systems. Air system is provided with gauge and manual system with calibrated spring. All air accessories such as filter, lubricator, regulator, gauge, solenoid valve and speed valve are incorporated.
Maximum Operating Speed
Machine is mechanically capable of attaining 60 spots per minute.
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MIG Welders
VIRDI's MIG welders are used universally in light and heavy fabrication workshops, shipbuilding & auto industries, in manufacture of stainless steel, mild steel, copper vessels & container in chemical and allied industries.
These VIRDI CO2/ MIG equipment are designed and engineered for CO2 welding of mild steel, low alloy steels and MIG welding of high alloy steels and light metals.
Salient Features
- Welds mild steel, stainless steel wires & bronze alloy wires ,/
- Suitable for solid wires as well as fluxed cored wires
- Easy connection system for torch plug-in to wire feeder
- Most reliable / easy / maintenance wire feeder with roll / quick release type
- Adjustable spot time control available on request
- Coarse / Fine controls for proper selection of voltage
- Sleek & most flexible torch
- Wire feeder units are normally supplied as separate unit to give greater area of operation & flexibility. However in-built version is also available (on request)
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Hot Staking Welders
- Solid-state digital timer for precision time control.
- Highly productive process (welds 60 Armatures of 24 segments within 60 minutes)
- High weld abilities are archived with special type of transformer.
- In manually operated machine special mechanism is incorporated in order to increase production by reducing fatigue to operator.
- The joints are very strong, durable and can withstand upto 650`C (whereas solder joints can stand only upto 160`C to 200`C)
- No need to clean enamel on winding wires.
- Weld strength of each segment is same and quality of each weld is far superior than that achieved by soldering.
Salient Features
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- Precise control of time eliminates :
Damage to inter segment insulation.
Sparking or flashing of segment material.
Damage to insulation of wire.
- No automation and no air operation makes it virtually simple and facilitates every manufacturer to enhance production even manually.
Electronic Timer System
Control of precision electronic timer, synchronous with power frequency giving exact number of cycle set on the dial. The timer heat control unit is completely solid state ageing type and having modular construction to replace the timer easily.
Mechanical System
The construction is like simple bench drill machine. Pressure system is with calibrated spring and adjustable over wide range to suit the staking of various combination of wires and segments of machine.
Water-cooling is provided for electrodes. The system is of course a closed loop type with water inlet and outlet brought out for external connections where customer has to provide clean water through completely closed water tanks pumps etc.
Since commutators do not have slots exactly in center, the automatic indexing facility is not provided. But the position of armature is so adjusted that the manual synchronism of both hand movement provides indexing as fast as automatic. The staking time for one segment being as low as 0.5 to 0.8 secs and total cycle time for staking one armature of 24 segments being only 15 to 20 secs.
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Arc Welding
In arc welding, the intense heat needed to melt metal is produced by an electric arc. The arc is formed between the actual work and an electrode (stick or wire) that is manually or mechanically guided along the joint. The electrode can either be a rod with the purpose of simply carrying the current between the tip and the work. Or, it may be a specially prepared rod or wire that not only conducts the current but also melts and supplies filler metal to the joint. Most welding in the manufacture of steel products uses the second type of electrode.
Basic Welding Circuit
An AC or DC power source, fitted with whatever controls may be needed, is connected by a work cable to the work piece and by a "hot" cable to an electrode holder of some type, which makes an electrical contact with the welding electrode.
An arc is created across the gap when the energized circuit and the electrode tip touches the work piece and is withdrawn, yet still with in close contact.
The arc produces a temperature of about 6500ºF at the tip. This heat melts both the base metal and the electrode, producing a pool of molten metal sometimes called a "crater." The crater solidifies behind the electrode as it is moved along the joint. The result is a fusion bond.
Arc Shielding
However, joining metals requires more than moving an electrode along a joint. Metals at high temperatures tend to react chemically with elements in the air - oxygen and nitrogen. When metal in the molten pool comes into contact with air, oxides and nitrides form which destroy the strength and toughness of the weld joint. Therefore, many arc-welding processes provide some means of covering the arc and the molten pool with a protective shield of gas, vapor, or slag. This is called arc shielding. This shielding prevents or minimizes contact of the molten metal with air. Shielding also may improve the weld. An example is a granular flux, which actually adds deoxidizes to the weld.
The extruded covering on the filler metal rod, provides a shielding gas at the point of contact while the slag protects the fresh weld from the air.
The arc itself is a very complex phenomenon. In-depth understanding of the physics of the arc is of little value to the welder, but some knowledge of its general characteristics can be useful.
Nature of the Arc :
An arc is an electric current flowing between two electrodes through an ionized column of gas. A negatively charged cathode and a positively charged anode create the intense heat of the welding arc. Negative and positive ions are bounced off of each other in the plasma column at an accelerated rate.
In welding, the arc not only provides the heat needed to melt the electrode and the base metal, but under certain conditions must also supply the means to transport the molten metal from the tip of the electrode to the work. Several mechanisms for metal transfer exist. Two (of many) examples include:
Surface Tension Transfer® - a drop of molten metal touches the molten metal pool and is drawn into it by surface tension.
Spray Arc - the drop is ejected from the molten metal at the electrode tip by an electric pinch propelling it to the molten pool. (Great for overhead welding!)
If an electrode is consumable, the tip melts under the heat of the arc and molten droplets are detached and transported to the work through the arc column. Any arc welding system in which the electrode is melted off to become part of the weld is described as metal-arc. In carbon or tungsten (TIG) welding there are no molten droplets to be forced across the gap and onto the work. Filler metal is melted into the joint from a separate rod or wire. More of the heat developed by the arc is transferred to the weld pool with consumable electrodes. This produces higher thermal efficiencies and narrower heat-affected zones.
Since there must be an ionized path to conduct electricity across a gap, the mere switching on the welding current with an electrically cold electrode posed over it will not start the arc. The arc must be ignited. This is caused by either supplying an initial voltage high enough to cause a discharge or by touching the electrode to the work and then withdrawing it as the contact area becomes heated. Arc welding may be done with direct current (DC) with the electrode either positive or negative or alternating current (AC). The choice of current and polarity depends on the process, the type of electrode, the arc atmosphere, and the metal being welded.
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T.I.G./ ARGON Welding Machine
Welding rectifiers are forced air-cooled, silicon type and are designed to provide a DC Welding current where 3 Phase, 50 Hz AC mains power is available at voltage ranging from 380 to 440. Arc welding is one of several fusion processes for joining metals. By applying intense heat, metal at the joint between two parts is melted and caused to intermix - directly, or more commonly, with an intermediate molten filler metal. Upon cooling and solidification, a metallurgical bond is created. Since the joining is an intermixture of metals, the final weldment potentially has the same strength properties as the metal of the parts. This is in sharp contrast to non-fusion processes of joining (i.e. soldering, brazing etc.) in which the mechanical and physical properties of the base materials cannot be duplicated at the joint.
Welding rectifiers are suitable for manual arc welding particularly for the welding of :
Technical Specification :
- Pipes in all positions.
- Non-ferrous metals.
- Low alloy, corrosion, heat and creep.
- Mild steel and low alloy steel at site where welds of high radiographic standards are required.
- Mild steel and low alloy steel is lighter gauge resisting steel i.e. stainless steel.
- Also suitable for argon arc welding where DC is necessary and are supplied with built in high frequency suppressor.600 FC welding rectifier is suitable for arc gouging also.
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