Las Busur Kd 4 (32) Ingg

Teknologi Dan Rekayasa

SHIELDED METAL ARC WELDING(SMAW)

Teknologi dan Rekayasa

SHIELDED METAL ARC WELDING EQUIPMENT

OBJECTIVE :After studying this lesson, the students can be to :1. identify of welding equipments2. explain the name of welding equipments3. select for welding equipments 4. explain welding equipments setting



UNDERSTANDING :

Shield metal arc welding is a process where coalescence is achieved by generating an electric arc between a coated metallic electrode and the work piece.


SHIELDED METAL ARC WELDING SHIELDED METAL ARC WELDING EQUIPMENTEQUIPMENT

Fig. 1. Shield metal arc welding process


Application :

The Shielded Metal Arc Welding process is used extensively in welding both ferrous and non ferrous metals.

Shielded Metal Arc Welding is universal in repairing and servicing equipment.



The general of welding equipment are three kinds :

1. Main equipment

2. Assist equipment

3. Health and safety equipment



The basic units of any shielded metal arc welding system consist of :

1. Power Supply

2. Electrode holder

3. Ground clamp

4. Power cable

5. Protective shield

THE MAIN WELDING EQUIPMENT


1. Power SupplyThe three basic welding machines are referred to as generators, transformers and rectifiera. DC generator : The direct current power supply consist of a generator driven by an electric motor or a gasoline engine. One of the characteristics of a direct current welding generator is that the welding can be done with straight or reverse polarity


To identify this DC machine


Fig. 2. DC-welding machine


In straight polarity the electrode is negative and the work piece positive and electrons flow from the electrode to the work piece.


STRAIGHT POLARITY (DCSP)

GENERATOR

+ -

WORK

Fig. 3. DCSP-welding machine connections


In reverse polarity the electrode is positive and the work piece negative and the electrons flow from the work piece to the electrode.


GENERATOR

+ -

WORK

Fig. 4. DCRP-welding machine connections

REVERSED POLARITY (DCRP)


b. Transformer : The transformer type of welding machine produces alternating current where power is taken directly from a power supply line and transformed into a voltage required for welding. In its simplest form an AC transformer consists of a primary and secondary coil with an adjustment to regulate the current out put.




Fig. 5. AC-welding machine

To identify this AC machine



c. Rectifier :

Rectifier is essentially transformers containing an electrical device which changes alternating current into direct current.

Rectifier are made to provide DC current only or both DC and AC welding current.


To identify this AC/DC machine


Fig. 5. AC/DC welding machine.


2. Electrode HolderThe electrode holder is used to hold the electrode and guide it over the seam to be welded.


Fig. 6. Electrode Holder


3. Ground Clamp

A very important unit of any electrical welding equipment is the ground clamp. Without proper grounding the full potential of the circuit will fail to provide the required heat for welding


Fig.7. Ground Clamp


4. Power cablePower cable selection that will be used should appropriate with the burden, it is ampere and input tension voltage regulator includes : wire size, long wire and type wire (fiber or not)


Fig. 8. Power cable


5. Protective shieldA suitable helmet or handshield is required for all arc welding.An electric arc produces a brilliant light and also gives invisible ultraviolet and infrared rays which are extremely dangerous to the eyes and skin.Both the helmet and hand shield are equipped with special colored lenses that reduce the brilliancy of the light and screen out the infrared and ultraviolet rays.



Lenses come in different shades and the types used depends on the kind of welding done.

In general, the recommended practice is:Shade 5 : for light spot weldingShade 6 and 7: for welding up to 30 amperesShade 8 : for welding 30 to 75 amperesShade 10 : for welding 75 to 200 amperesShade 12 : for welding 200 to 400 amperesShade 14 : for over 400 amperes



Fig. 9. Protective Shielded

Lens

Clear lens

Clear lensFilter lens


WELDING TABLE

CHINDER HAMMER

CURVE HAMMER

HAND GRINDSTONE

1

2

3

4

ASSIST WELDING EQUIPMENT

1. Welding table Welding table is place to put work think in position


2. Chinder hammer

Chinder hammer is a tool for cleaning chinder from welding product


3. Curve hammer

Curve hammer is used to straighten, levelling the surface of curve or bend work think.


4. Hand Grindstone

Its function is to prepare materials that will be welding, it is preparing welding shawl, it is also used to support in welding process specially in cleaning welding product


HEALTH AND SAFETY EQUIPMENT

1. WELD 1. WELD CLOTHES

2. APPRON (2. APPRON (CHEST PROTECTOR)

3. 3. GLOVES

4. LEATHER 4. LEATHER SHOES

1. Weld Clothes

By wearing this clothes, welder will fill comfort and free in movement


2. Apron (Chest protector)

Appron is used to protect welder chest from UV ray, infra red, weld fire work sprinkling and the hot of welding.


3. GlovesGloves it used to protect welder hand from electricity, the of welding and sharp material.


4. Leather ShoesThis shoes made of leather that there is metal in top of it, this shoes will protect welder from electricity, downfall material, hot material and sharp material.



Las Busur Kd 4 (32) Ingg

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