TAKE YOUR PULSE: TIME TO EXAMINE YOUR WELDING EQUIPMENT

"If it's not broke, don't fix it" is a common belief, but one that can lead you to lose your competitive edge. What was state-of-the-art ten years ago bears little resemblance to the newest welding equipment and the advantages it offers.

The truth of the matter is if your welding equipment is more than ten years old and still running as good as new, it is likely costing you money – and may be making it more difficult for you to train new welders. The reason: today's welding power sources provide many benefits that can help shorten prep time, increase deposition rates, decrease training time, and/or reduce weld defects and rework time.  In addition, the newest power sources – especially inverters – offer increased power efficiency, which alone may justify their cost.

POWER EFFICIENCY

Old conventional welding machines convert incoming line power to welding output power at 60 to 70 percent efficiency. New generation solid-state machines are much more efficient, with about an 80 percent efficiency. Inverter-based welding power sources are even better, operating at an average efficiency of 85 percent, which reduces utility bills. In fact, swapping out old machines for inverters typically may save a company $500 to $1,200+ per year, per machine. To determine your particular savings, visit the online power calculator at www.millerwelds.com/resources/. Performance tests by independent consultants consistently confirm that replacing an old power source with an energy efficient inverter provides a proven return on investment.

POWER FACTOR

Efficiency is only part of the savings equation. Your equipment's Power Factor also affects your energy usage. Power factor is defined as the ratio of real (working) power to apparent (total) power. In a purely resistive circuit, voltage and current waveforms are in phase, and the ratio of real power to apparent power is near to, or equal to 1. In circuits with inductors and capacitors, the amp and voltage waveforms are out of phase and not all of the power is available to do useful work; some of it is returned to the source. Although the power company charges you for the apparent power, you are only receiving the benefits of the real power.

A high (close to 1.0) power factor will not only decrease energy usage, but increase your system capacity. Today's leading inverters, such as newer multi-process inverters and MIG inverters, offer power factors of 0.95.
Some utilities provide rebates to facilities that swap out old, inefficient equipment for equipment with good power factor. One fabricator, TEAM Industries, received a $413 rebate per machine – up to a total of $7,434 –  from its utility company when it acquired 18 new machines.

"Saving energy is a win-win proposition for us and the customer," says James J. Brown, Kaukauna Utilities' customer service representative and Team consultant. He explains that when customers reduce energy demand, the utility can generate fewer kilowatt hours and/or reduce the amount of electricity purchased on the open market. "Our ?avoided cost' is converted into rebates for customers that use energy efficiently," he adds.

DOUBLE YOUR MACHINES WITHOUT REWIRING

If you've reached the maximum capacity of your incoming electrical service, but still want to add more welding stations, inverters may offer an alternative to rewiring your facility. One Wyoming fabricator faced this dilemma. The utility company informed the shop manager that he could not place any more loads on the line . . . yet he wanted to add eight welding stations. One alternative would have been to add a transformer with greater capacity. Changes of this magnitude could have cost tens of thousands of dollars and the fabricator would still be stuck with outdated technology.

Instead, the shop manager retired old, inefficient machines and purchased new equipment. This allowed him to quickly add eight new welding stations without changes to the incoming service. It also helped him improve weld quality.

POWER AFFECTS QUALITY

Conventional power sources are tied directly to the input power, which means that a brown out, spike or dip in the power supply (such as when a large motor starts) can directly affect weld quality. This can lead to costly weld defects, which may need to be ground out and reworked, or cause the part to be scrapped ¾ time and money, which could better be spent elsewhere.

Inverters, on the other hand, are much better suited to managing primary power fluctuations and better suited to handling a variety of power input. Inverters can keep welding output constant even if input power varies by ± 10 percent. Some current technology, such as line voltage compensation, allow for any input voltage from 208-575 volts, single- or three-phase, without relinking. And at 460 VAC, the compensation ranges from +37 percent to -59 percent. This helps ensure that weld output remains consistent, improving weld quality.

BETTER QUALITY

Today's inverters also provide other advantages. Perhaps most importantly, operators enjoy welding with them. The consistent arc starts, smooth and stable arc and improved puddle control make welding easier and often lead to better bead quality. Plus, these results are achievable with fewer controls to set on the machine. This is part of an on-going trend to relieve the operator from having to fine-tune parameters, allowing him to concentrate on welding technique. (Even some of today's entry-level and hobbyist machines feature technology that only requires the operator to know the thickness of the metal being welded and the size of the wire.)

With a welder shortage that is only expected to grow in coming years, these advances have been shown to make it easier to train non-welders to produce quality welds.

TAKE YOUR PULSE

With today's inverter technology, pulsed MIG welding has come of age. In pulsed MIG, the power source switches between a high peak current and a low background current. This lowers the heat input into the part, yet maintains the good fusion of spray transfer. Good applications for pulsed MIG include those prone to such problems as lack of fusion, warpage, burn through, spatter, lack of puddle control and poor bead appearance. In some cases, pulsed MIG has eliminated the need to apply anti-spatter.

While pulsed MIG was once complicated and required expert knowledge to fine-tune, today's implementation allows the user to achieve the benefits of pulsed MIG easier than ever before. Some pulsed MIG machines come with built-in programs for the wire types most commonly used, while allowing the operator to easily control weld puddle fluidity, weld bead profile and arc length.

REVISITING YOUR WELDING OPERATION

With these thoughts in mind, take a moment to review your welding operation. Today's state-of-the-art welding machines operate so efficiently that they easily create payback within the five-to-seven years industry standard requirements. Even better, they produce high-quality weld beads, provide multiple process capabilities and operators enjoy welding with them more.

If your welding equipment is more than ten years old, don't wait for a machine to break to examine your options.

Jeff Herb is a product manager for Miller Electric Mfg. Co., 1635 West Spencer Street, PO Box 1079, Appleton, WI 54912-1079, www.millerwelds.com.

TEAM Industries, 18880 Dan Street, Detroit Lakes, MN 56501, 218-847-9582, Fax: 218-847-1052, www.team-ind.com.