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Spot welding is the most basic and generally, the most economical of all resistance welding techniques and lends itself to many forms of mechanization and automation. It can be used where speed is not a critical factor, double-thick lapped joints are acceptable, and normal electrode maintenance time is tolerated.
Spot Welder FEATURES
|Coil Width||80” (2030mm)|
|Coil Thickness||.250” (6.3mm)|
Single Row Spot
Single Row Spot- Welds for heavier gauges were double the thickness is acceptable
Double Row Spot
Double Row Spot- Welds for heavier gauges were double the thickness is acceptable and weld will not be recoiled
The top 3 types of spot welders are listed below:
The forces required for flash-butt welding are established by the forge strength of the materials being welded. The strength classifications of steel are:
- Low Forging Strength: (10,000 psi) SAE-1020, 1112, 1315, NAX9115, along with trade names such as Cor-Ten, Yoloy, Ductiloy, Cromansil, etc.
- Medium Forging Strength: (15,000 psi) SAE-1045, 1065, 1335, 3135, 4130, 4140, NE- 8442, 8640, 9440, 9540, 9640, etc.
- High Forging Strength: (25,000 psi) SAE-4340, 4640, Stainless steel of the 400 series (13% CHROMETYPE), 300 series stainless steel (18% CHROME-8% NICKEL), high speed steel, Sil-Chrome, special tool and die steels.
- Extra High Forging Strength: (35,000 psi) Any special steel having extra high compressive strength at elevated temperatures. NOTE: Hardenable steels may require pre/post-heating either in the welder or a furnace.
The selection of a standard machine or the design of a special welder will be determined by the upset forces, along with the necessary clamp forces required as a result of the sectional area of the material being welded.
Flash welders consist of the three main sections each of heavy duty construction.
The MAIN FRAME is made of heavy duty welded construction and designed for maximum accessibility for ease of maintenance and adjustability. Mounted to the frame are the welding transformer, upsetting mechanism, upset slide/clamp, stationary clamp, four sealed main bearing boxes with precision roller bearings.
The WORK CLAMPING MECHANISMS are normally vertically operated pivoting lever-arms mounted integral with the fixed and movable platens. Each consists of steel clamping levers on heavy duty hardened and ground pivot pins and bushings. The ends of the pivot-pin bearings are sealed to protect them from weld flash. Lubrication of the bearings is through single point Alemite fittings.
The clamp levers are usually operated by double acting direct cylinders, either pneumatic or hydraulically operated. The piston rods are protected by sewn leather bellows. Depending on the application, these clamp levers are designed to provide from .5 to 2.5 times the upset force. Other types of clamping mechanisms are available optionally as required.
The Upper Electrodes are recessed in the clamping levers. They can be arranged for adjustable/fixed or self-equalizing alignment with the lower dies/work piece.
The Lower Electrodes are often supplied so that the electrode on the movable platen is adjustable horizontally and the electrode on the stationary platen is adjustable vertically. This allows precision alignment of the welded parts.
UPSETTING MECHANISM: The motor operated device for controlling the flashing and upset movement of the upset slide is a gear box mounted Flashing Cam on which a steel roller runs. The cam shaft is supported by an outboard anti-friction bearing with the flash/upset cam located between the outboard bearing and the first bearing in the gear box.
A variable speed 3 phase, 60 hertz, 230/460 volt motor provides a flashing time range of approximately 3 to 1. The cam shaft carries timing cam switches to turn off and on the welding power and stop the motor after each weld cycle. The upset slide is returned to the load die position by a single acting air cylinder.
When welding non-ferrous materials the upsetting action may be controlled by the addition of necessary pneumatic devices between the flashing cam and the upset slide to increase the upset speed for greater control of the forging force.
The flash and upsetting action may also be controlled hydraulically by use of a double acting hydraulic cylinder in place of the motor driven gear box and flash cam. An electro-hydraulic servo control with provisions for multiple welding programs and data recovery is available.
All welders are provided with control interlocking features to provide maximum safety to the operator and to prevent damage to the welder or work spoilage because of improper operator actions.
Welding Power Supply
These welders may be provided with one of three types of power sources.
SINGLE PHASE welder transformer rated at 50% duty cycle per RWMA standards selected for KVA rating based on power required for welding and production considerations.
SINGLE PHASE D.C. power pack with silicon diodes arranged for full wave rectification of the weld transformer secondary current.
THREE PHASE D.C. power pack with silicon diodes arranged for full wave rectification of the weld transformer secondary current.
The power supplies are mounted at the rear of the main frame and are sealed to prevent flash particles from entering the power supply area. They are connected to the stationary and movable platens by heavy water-cooled copper buss bars and flexible band connectors. Transformer primary tap switches are included for a wide range of welding applications.
Welder sizes range from the B-2.5 Butt welder for band saws, providing 2.5 KVA, 1 phase transformer and 1200 pounds upset force, to the B-1600 Butt welder with 1600 KVA transformer and 1 million pounds upset force for aircraft landing gear.
Machine frame sizes are standardized according to upset force such as 5000, 10,000, 20,000, 40,000, etc.; the electrical rating varies proportionally with the power required and the duty cycle of the machine.
Taylor-Winfield’s heavy-duty, power traversed spot welder has found wide acceptance in heavy gauge processing lines. The welding gun is moved by a manually controlled motorized drive. The operator thus controls spot spacing and the quality of spots.