Teknologi Dan Rekayasa AUTOMATED WELDING

AUTOMATED WELDING Objective : After studying this lesson, the student can be identify the automated welding.

AUTOMATED WELDING For many years manual or stick welding was used predominantly for jointing metal. With the development of gas shielded-arc welding equipment it became possible to resort to semi-automatic techniques.

AUTOMATED WELDING Although stick welding per se will always play a useful role in many fabricating processes, particularly in small jobs shops and maintenance work, industries in general have to a large extent adopted semi-automatic equipment.

AUTOMATED WELDING Now many metal fabricating manufacturers are beginning to realize the necessity of moving even beyond the semi-automatic processes and going to fully automatic welding systems, even to the extent of using computers to control the automated equipment.

ADVANTAGES OF AUTOMATED WELDING Studies have shown that the best stick welding operators working under the most ideal conditions rarely with get more than 25 to 30 percent arc time, that is, in any given work period only 25 to 30 percent of the time is actually spent welding. On the other hand, semi-automatic operators usually can achieve 50 to 75 percent arc time.

ADVANTAGES OF AUTOMATED WELDING However, management is finding that even this increase in production efficiency is not enough to meet the present-day technological demands on industry.

ADVANTAGES OF AUTOMATED WELDING The need for more serviceful and quality goods at greater savings is forcing industries to adopt better control techniques and more functional manufacturing procedures. Specially, industry is facing the task of boating production, turning out products of better quality, at lower labor cost and greater safety.

ADVANTAGES OF AUTOMATED WELDING By resorting to fully automated welding, poor and ineffectual welds, operator inefficiency, and high manufacturing cost are reduced. Automated welding not only ensures faster deposition rates but repeatedly produces welds of consistent quality.

ADVANTAGES OF AUTOMATED WELDING Although the initial cost of converting to automated welding may be relatively high at the outset, the consensus of welding engineers is that “we cannot afford not to”. The eventual savings in manufacturing cost, by and large, will more than make up for any expense incurred in setting up a modern automated system.

AUTOMATED WELDING SYSTEMS In general, there are two basic systems for automated welding. With one, the welding equipment is stationary and the work flows around the welders. With the alternate plan, the work remains stationary and the welding equipment moves on a track to the designated position where welds are to be made.

AUTOMATED WELDING SYSTEMS Either system is designed to give precise control over every welding factor, such as presurge time, hot start level, pulsation delay, initial current, upslope, weld taper delay, weld current, pulse level, high and low pulse time, final taper current, final current, postflow time and post heat.

AUTOMATED WELDING SYSTEMS There are virtually no limits as to the kind of welding that can be automated. Submerged arc, resistance, and Tig and Mig processes can readily be automated. Mig welding is often preferred because of its greater versatility. This includes spray arc, short arc, cored wire and CO2.

TYPES OF AUTOMATED WELDING SYSTEMS Generally speaking, there are no conventional or standard types of automated welding systems. Outside of the regular welding units, most systems are specifically designed to function for an existing work flow configuration.

TYPES OF AUTOMATED WELDING SYSTEMS Therefore, the type of system used depends on the product being manufactured, the manner in which production is processed, and the existing type of plant facilities. Accordingly, automation is strictly an engineering design problem of individual plants. Several examples to illustrate this point follow.

TYPES OF AUTOMATED WELDING SYSTEMS In one automotive industry, increased production is achieved by means of traversing robot which moves on floor-mounted tracks or overhead rails and performs welding operations on car bodies or parts on an assembly line. Affixed to the robot, a spot welding gun is carried down the assembly line and automatically performs the desired welds.

TYPES OF AUTOMATED WELDING SYSTEMS Another example is the manufacturer of motor stators which developed an automated system that : picks up and orients the correct number of laminations and hands them to the operator

TYPES OF AUTOMATED WELDING SYSTEMS joins the laminations with four simultaneous Tig welds at 90-degree intervals around the circular stator and presses a cap ring over the stator and gas metal-arc spot welds it in place.

TYPES OF AUTOMATED WELDING SYSTEMS Connected to the power sources are four stationary tig welding torches. Welding is accomplished under the torches on a turntable. A ram smoothly lifts the stator unit past the torches.

TYPES OF AUTOMATED WELDING SYSTEMS A further example is that of a manufacturer of hydraulic equipment. Here an automated submerged arc system was designed to weld cylinders. This welding system moved on a floor track 50 feet long. The ram which carries a welding head has an eight-foot stroke.

TYPES OF AUTOMATED WELDING SYSTEMS Welding current is supplied by a constant voltage power source which is mounted on the frame of the headstock to allow it to move with the system. Air brakes hold the entire unit at any point on the track.

TYPES OF AUTOMATED WELDING SYSTEMS The fact that one man can often do 80 percent of the work of two men led a manufacturer of dual wheels for all types of farm equipment to develop an automated welding system. In this case, the automatic welders are used to join strips of metal into cylindrical rim blanks. These blanks are first run through an expander to form the proper configuration.

TYPES OF AUTOMATED WELDING SYSTEMS A fixture clamps the rim blanks in place and holds the joint sides together during welding. A welding head which is mounted on a carriage moves over the rim and welds the joint.

PROGRAMMED WELDING The ultimate in any automated welding system is programmed welding where numerically controlled (N.C.) equipment is utilized. Just as N.C. is currently used in many machining operations, industries are finding that further economies are achieved by resorting to numerically controlled units for production welding.

PROGRAMMED WELDING With programmed welding, all of the welding operations are preset and the entire welding process is initiated with the press of a button. The sequence of operations can be pre-programmed on punched tape to weld numerous different configurations automatically.

PROGRAMMED WELDING A typical example is the manufacturer of heat exchangers who, when converting to automatic numerical control, found that welds could be executed ten times faster.

PROGRAMMED WELDING The N.C. unit automatically aligns the fixture containing the heat exchanger, inserts a shot pin, clamps the fixture, positions the assembly for welding, initiates the welding torch guidance system, and returns the exchanger to the start position.

PROGRAMMED WELDING The only manual operation required is turning the fixture 180 degrees for welding the opposite end of the exchanger. While one unit is being welded, another is being loaded in a second fixture. This new system requires only 10 percent of the 70 to 80 minutes needed to do the work manually.

PROGRAMMED WELDING The old method required putting parts together manually, placing them on a hand-turned spindle, then Mig-welding manually one side of the spiral at a time. With the new system, the parts are rotated past two stationary Mig welding torches feeding 1/16 ʺ flux-core wire.

PROGRAMMED WELDING Torches positioned on both sides of the helix operate simultaneously, producing a stronger weld than before because of better heat penetration and the flux-core shield.

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