|D/F Automatic & Robotic MIG Tandem Torch - High Deposition, Continuous Duty Cycles, .035"-1/8"|
D/F Tandem Torch - MIG Water-Cooled Remote Machine Torch
The D/F Machine Specialties specially designed high amperage MIG Tandem welding torch is a critical component of the MIG tandem welding system, engineered with specific spacing and alignment of adjustable two contact tips to achieve proper arc control. The torches are usually rated in terms of combined current flowing through both wires due to the demands of high amperage, high duty cycle production runs. This rating is typically in the 600-1300 amp range. D/F's patented MIG Tandem Wire Torch has been developed for heavy-duty welding, where the requirements relating to heavy-duty applications and long welding times are rigorous. The D/F tandem wire welding torch is designed to provide excellent cooling of the nozzle, gas cup, body and the current tips. Two wire electrodes electrically insulated from one another must run through a common gas nozzle and share a common welding torch. Efficient cooling of the round shaped tandem gas cup prevents welding spatter easily sticking to the gas cup. The separate water-cooling of the nozzle reduces spatter and prolongs gas cup life. Because a lot of heat is generated in the tandem process it must be subsequently dissipated all the way to the front area of the contact tubes. Each body assembly is also separately water-cooled ensuring tip life and arc stability. The insulation of the two separate tandem torch inner bodies of the single common torch is done according to existing D/F standards, guaranteeing no electric flash-over between the two electric systems. The distance between the tandem contact tips (the wires) can vary by removing the body screws of one or both of the inner bodies. This allows rotation of each inner body increasing or decreasing the distance between the two welding wires. The D/F Tandem Barrel inner bodies can be either straight or bent to desired degrees to help achieve different center-point distances between the two tandem contact tips and are easily changeable.
To provide maximum resistance to the abuses of day to day service, the tandem torch is of heavy duty construction with all metal parts well insulated from current carrying members. The compact in-line body allows the D/F Tandem Torch to be used in a variety of applications with ease of maneuverability and can access hard to reach areas of operation. To facilitate maneuverability, all service lines are internally connected to the tandem torch bodies and exit from the rear of the torch barrel. The tandem torch uses threaded (HTM) contact tips. The D/F Tandem Torch, like all D/F torches, is easily reparable, thus reducing downtime and increasing productivity.
The D/F Machine Specialties Tandem Water-Cooled MIG Machine Torch is configured to provide individual parameter control for each of two separate, and electrically isolated, welding arcs. This requires a pairing of all equipment; two specially designed high-speed inverter power sources, two wire drives, two separate welding wire pay-off sources and a D/F Tandem welding torch.
The D/F Machine Specialties Tandem Water-Cooled MIG Machine Torch can also be used as a Twin Wire Torch (1200 amp high current machine torch). When used as a MIG Twin Wire welding torch (two wires used with one power source), It can increase deposition rates by 20 to 30 percent versus single wire welding without significantly increasing heat input. The increase comes from the greater current density achieved by pushing a similar current over smaller, cross-sectional areas of wire.
Each D/F automatic welding torch head is fully assembled and ready to install. In order to make the installation complete, the code number, wire size, make/model automated welding system (Thermadyne Thermal Arc Wire Feeders, Lincoln wire feeders, Miller wire feeders, Linde/ESAB wire feeders), and inlet as needed must be specified when ordering. If special welding tools or accessories other than those listed previously are required, please consult with the factory. Get the right feeder adapter connection to fit your MIG wire feeder.
The D/F Tandem Torch Welding Process
The tandem process is a GMAW automated process that increases the application range of traditional single-wire GMAW processes: Two electrically isolated wire electrodes are positioned in line, in the direction of travel. The first electrode, the 'Lead' (Mode A), controls the majority of the base plate penetration. The second electrode, the 'Follow' (Mode B), controls weld bead appearance and contour, edge wetting, and adding to the overall deposit rate. The spacing between the two wires is usually less than 15mm so that both welding arcs are delivering to a common weld puddle, but can be adjusted for job requirements and different applications. The process uses a true tandem configuration of dual power sources and two wire feeders to generate two separate welding arcs. The output of the two power sources are coordinated by either a robot controller for robotic applications, or by a Tandem interface for dedicated hard automated work cells. The two arcs are positioned to operate in a common weld puddle by a specially designed high amperage D/F Machine Specialties patented Tandem Water-Cooled "MIG" welding torch. Operation of the welding arcs in the close proximity of a common weld puddle is made possible by the use of high-speed dual power source output coordinating the interaction of the welding arcs. This unique operating arrangement promotes productivity, often greater than two separate wire electrodes, while providing the operating convenience of a single torch process.
The tandem process establishes a means for increasing both the travel speed and deposition rate without compromising the weld quality. The ability of the process to control heat input and bead wetting further enhances weld quality and minimizes weld repair associated with burn-through on thin components, or distortion on thick members. The process works best with a large diameter 'Lead' (Mode A) wire and a small diameter 'Follow' (Mode B) wire. The larger 'Lead' wire may represent as much as 65% of the total deposition rate, while providing greater penetration. The smaller, trail welding wire is focused on the trail edge of the weld puddle. The trail wire is typically smaller in diameter and therefore draws less current. This helps to control the shared weld puddle and aids in keeping it cool. A common compromise is to specify the 'Lead' and 'Follow' welding wires to be the same diameter to satisfy inventory constraints or because the direction of welding must be reversed somewhere on the weldment.
The Most Common Variants of the Tandem Process:
It was vital that the two power sources communicate with each other for the synchronization of the two electric arcs. An additional requirement was that the robot could activate the two power sources as a single power source.
In conclusion, for all applications a substantial increase in productivity can be obtained. The rule of thumb sometimes mentioned, "double-wire = double speed", appears to be correct compared with conventional single-wire welding. The welding speed, the weld quality and the process tolerances must however be balanced (evaluated for each case). It is also interesting to note that the tandem welding process has a much higher penetration capacity than single-wire welding. D/F's Tandem torch, will help reach maximum output of the welding process by increased weld speeds, increased arc stability for optimum weld quality and consistency, higher deposition, and Maximum number of hours of welding contact/current tip life, thus reducing shut downs and start ups also reducing the amount of scrap produced.