When choosing a wire feeder for the first time, the numerous factors to consider may seem overwhelming. Following are answers to buyers’ most frequently asked questions.
Q: Can I add a wire feeder to any type of power source?
A: Wire feeders can be paired with three basic categories of DC power sources: Constant Voltage (CV), Constant Current (CC), or one with both capabilities (CV/CC). Wire feeders are not recommended for use with AC output-only machines. Generally speaking, CV-only power sources are dedicated for wire welding, typically the MIG or flux cored processes. They do not have, nor can they be converted for, Stick or TIG capabilities. CC-only power sources are often initially purchased for Stick or TIG welding, but a wire feeder can be added. CC/CV power sources can inherently perform all three processes.
Q: What is the difference between a constant speed wire feeder and voltage sensing wire feeder?
A: Wire feeders come in two categories: Constant Speed or Voltage Sensing. A constant speed wire feeder is used with a CV power source. Voltage is set at the power source, while the wire feed speed (which controls amperage) is set at the constant speed feeder. A voltage sensing wire feeder (sometimes called voltage following or variable speed) can be paired with either a CC or a CV power source. When a voltage sensing wire feeder is paired with CC power source, amperage is adjusted at the power source and voltage varies directly with the distance (arc length) between the electrode and the work piece. The welder is usually limited to the globular and spray transfer MIG welding processes.
Q: Should I use a bench feeder or a portable feeder?
A: If all welding occurs inside a shop or facility where the power source is in a dedicated location, chances are that an open/bench type feeder or a boom mounted feeder will best suit your needs. An open/bench type feeder gives the greatest flexibility with respect to diameters and types of wire, spool size, and the number of drive rolls. If the welding will be done in the girders of the job site on Monday, from the back of a pick-up truck on Tuesday, and in the shop on Wednesday, a portable “suitcase style” wire feeder is best. Portable feeders have a durable enclosure that permits easy carrying and protects the feeder from dust and other elements.
Q: Should my feeder have two drive rolls or four drive rolls?
A: Small diameter, hard wires like .035 in. or .045 in. (.9 mm or 1.2 mm) steel feed fine with a two roll drive system in most cases. Consider a wire feeder with four drive rolls when using hard and flux cored wires 3/32 in. (2.4 mm) and larger, when using a gun with a long cable (say 25 ft./7.6 m), or when using large “pay-off paks” where the wire is pulled through a manifold system. In a four roll feeder, the first set of drive rolls almost acts as a straightener, helping to remove the helix (longitudinal twist) and cast (spiral), while the second set of drive rolls helps smooth wire feeding performance. When using very soft wires, such as aluminum and certain flux cored wires with a low columnar strength, a two drive roll system is best. “Over-driving” and over pressuring soft wire can crush and flatten it, resulting in poor feeding and possible bird’s nesting (tangling) of the welding wire. Properly adjusting the drive roll pressure is critical when running soft wires.
Q: What feeders are best for aluminum?
A: One pound spoolguns and push-pull systems offer exceptional portability and provide optimum feeding performance for difficult-to-feed welding wires, such as aluminum and other soft alloys. Spoolguns, such as Miller’s Spoolmatic, are a portable lightweight wire feeder/gun combination normally equipped with a 25 ft. (7.6 m) cable assembly. Designed for 4 in. (10 cm) diameter spools of welding wire, they are ideal for lower duty applications requiring mobility and access. Push-pull systems, like Miller’s XR feeder, utilize a torque motor in the push feeder synchronized with a drive motor in the pull gun to optimize feeding performance when using 12 in. (30 cm) diameter spools of welding wire. Welders use push-pull systems for higher duty cycle and higher wire deposition applications.
Q: What are the advantages of having a dual feeder?
A: Having dual drive assemblies allows you to accommodate two different diameters or types of wire, and several of Miller’s open/ bench type and boom mounted wire feeders permit this option. For example, many metal fabrication shops can perform nearly all their jobs by using a dual wire feeder equipped with one spool of .035 in. (.9 mm) wire and one spool of .045 in. (1.12 mm) wire. Dual feeders can eliminate or reduce change-over time, increasing productivity, and they are ideal when a standby gun is desired.
Q: Can some wire feeders provide pulsed-MIG capabilities?
A: In addition to conventional MIG, some wire feeders, like Miller’s 60M series combined with an inverter-based power source, allow users to select from factory-set programs or create a finely-tailored pulsed-MIG arc without separate pulsing controls. With these wire feeders, welding technicians can adjust all four major characteristics of the pulsed arc wave form – peak current, background current, pulse time, and pulse frequency – to optimize it for specific applications or welding positions.
When selecting a wire feeder, allow for flexibility, growth, and future needs. Don’t just think about how you are using your welder now – try to anticipate how you will be using it in three or five years. Think of a wire feeder as a long-term investment, and plan accordingly.
Information courtesy of Miller Electric