WELDING SHOP

The submerged arc welding machine is a versatile arc welding machine that performs groove or fillet welds in the down-hand position. The submerged arc welding machine has an automatic wire feeding mechanism, flux feeder and recovery unit, and a trolley for automatic welding speed. The device can operate on constant current (CC) and constant voltage (CV) modes. DC power source, which is also known as a self-regulatory arc system. With this setup, students should be able to:

• The setting of welding parameters/Understand the effect of welding variables like current, voltage and travel speed according to the workpiece thickness.
• Preheating of fused flux to avoid porosity.
• Control of heat input by regulating the welding speed of the trolley system.
• Evaluate the performance of the system through experiments.
• Learn about the applications and limitations of the process.

The Gas Tungsten Arc Welding machine consists of a rectifier with an HFHV unit and a gun-torch arrangement with an inert gas supply used under a controlled flow rate. The process is also popular for its low heat input. Therefore, it is used for joining thin sheets with or without filler rods. Inert gas is provided to protect the molten material from atmospheric oxidation. An electrode of Tungsten which is non-consumable is used to generate the welding arc. With this setup, students should be able to:

• Set welding current and voltage according to the workpiece thickness.
• Application and selection of inert gas or gas mixture as per requirement and process economy for shielding purposes.
• Evaluate the system's performance through experiments carried out at different voltage and current settings.

The Gas Metal Arc Welding machine consists of a rectifier, wire feeding mechanism and gun-torch arrangement with an inert gas supply under controlled pressure/flow rate. The machine uses a rectifier to convert AC into DC power and utilizes it at low voltage and high current. The process is equally applicable for thin and thick cross-sections to be welded. Inert gas is provided to protect the molten material from atmospheric oxidation. Automatic wire feeding is supplied through a hand-held welding torch gun. Capable of feeding wires of three different diameters 0.8mm, 1mm, and 1.2mm. With this setup, students should be able to:

• The welding current and arc voltage are set according to the workpiece dimensions, especially thickness.
• The selection of shielding gas, i.e., inert or active gas, for shielding purposes depends on the job material.
• Evaluate the system's performance through experiments carried out at different voltage and current settings.
• Generally, GMAW is performed in CV mode.

The Shielding Metal Arc Welding machine consists of a transformer and electrode holder. Consumable electrodes are flux coated which serves the purpose of shielding. The process is versatile as it allows the electrode material anytime during the operation. However, productivity is not comparable to other arc welding processes. It is a manual arc welding process where electrode feeding and welding speed depend on the operator's skill. With this setup, students should be able to:

• Vary the welding current and voltage according to the diameter of the electrode.
• The selection of electrode material depends on the job material.
• Evaluate the system's performance through experiments carried out at different voltage and current settings.

The spot welding is a resistance welding machine that is one of the oldest welding processes whereby two or more metal sheets are welded together without using any filler material. The process involves applying pressure by spring expansion which generates a force of 200 KGF and heat to the weld area using shaped alloy copper electrodes which convey an electrical current through the weld pieces. The material comes at the plastic stage, fusing the mating parts; after a few seconds, the current is turned off, pressure from the electrodes is maintained, and the "nugget" solidifies to form the joint. The equation can express this heat: Q = I²Rt. In this equation, "Q" is heat energy, "I" is current, "R" is electrical resistance and "t" is the time for which the current is applied. With this setup, students should be able to:

• The setting of welding time according to the workpiece thickness.
• Understand the resistance heat generation process.
• Understand why cooling of the electrode is necessary.
• Evaluate the performance of the process through experiments.

A resistance seam welding is a welding machine whereby two or more metal sheets are welded together without using any filler material. Resistance seam welding can be used to make gas- or fluid-tight joints in various sheet metal fabrications. Steel fuel tanks for motor vehicles are a prime example. The process involves applying pressure by spring expansion and heat to the weld area using shaped alloy copper wheels (act as an electrode) which convey an electrical current through the weld pieces. The material comes at the plastic stage, fusing the parts, and a continuous seam solidifies to form the joint. The equation can express this heat: Q = I²Rt. In this equation, "Q" is heat energy, "I" is current, "R" is electrical resistance and "t" is the time for which the current is applied. With this setup, students should be able to:

• Setting of current and pressure according to the workpiece thickness.
• Understand the resistance heat generation process.
• Evaluate the performance of the process through experiments.
• Learn about the process's applications and limitations necessary for selecting electrode material according to the material to be welded.

A mechanical power press is a machine used to cut, bend, punch, or shape metal sheets and other materials into required forms. It operates by applying mechanical force through a punch and die. Mechanical power presses are commonly used in manufacturing industries for producing components such as brackets, panels, washers, and metal parts. They provide high speed, accuracy, and consistency, making them suitable for mass production. Proper machine guarding, safe operating procedures, and regular maintenance are essential to prevent accidents and ensure efficient operation.

A power hacksaw machine is used for cutting metal bars, rods, pipes, and other solid materials into required lengths. It operates with a reciprocating hacksaw blade that moves back and forth over the workpiece. The workpiece is securely clamped in the machine vice, and the blade cuts the material during its cutting stroke. It is commonly used in workshops and industries for accurate and efficient metal cutting.