Updating Your Aging Welding Equipment can Drastically Improve Quality, Productivity - and Often a Quick ROI
March 1, 2008
What was state-of-the-art 10 years ago may bear little resemblance to today's equipment and the advantages it offers. 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, today's power sources, especially inverters, offer increased power efficiency, which alone may justify their cost.
“If it’s not broke, don’t fix it,” is a common mantra and, unfortunately, one that can lead to you losing your competitive edge. What was state-of-the-art 10 years ago may bear little resemblance to today’s equipment and the advantages it offers. This is especially true in the area of welding.
In fact, if your welding equipment is more than 10 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, today’s power sources, especially inverters, offer increased power efficiency, which alone may justify their cost.
Old conventional welding machines convert incoming line power to welding output power at 60 - 70% efficiency. New generation solid-state machines are much more efficient, with about an 80% efficiency. Inverter-based welding power sources are even better, operating at an average efficiency of 85%, which reduces utility bills. In fact, swapping out old machines for inverters typically may save a company $500 - $1,200+ per year, per machine.
Performance tests by independent consultants consistently confirm that replacing an old power source with an energy efficient inverter provides a proven return on investment.
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) power factor will not only decrease energy usage, but increase you system capacity. Today’s leading inverters, such as Miller’s XMT multi-process inverters and Invision MPa 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 – equipment such as the XMT. One fabricator, Team Industries, received a $413 rebate per machine– up to a total of $7,434 ¾ from its utility company when it acquired 18 new XMTs.
“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 states.
Double Your Machines Without Rewiring
|By switching to a pulsed MIG power source, Iron Grip Barbell Company of Santa Ana, Calif., eliminated the need to apply anti-spatter, increased productivity 16% and reduced scrap by 20. For the full story, visit MillerWelds.com
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 Miller XMTs. 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–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 Miller’s Auto-Line™ and 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.
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-le
vel 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
|JPG Brad Hooper, supervisor for the NERM (NorthEast Regional Maintenance) overlay for Covanta Energy, and his team recently switched to Miller XMT 350 MPa multi-process inverters, allowing them to run five power sources from a 100-amp breaker where before they could only run four.
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 and its associated costs.
While pulsed MIG used to be 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, such as Miller Invision (manufacturing) or XMT 350 MPa multi-process (fabrication), 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. (To see an example of this, visit the on-line simulator: Invision_350 or XMT_350)
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 requires. 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 10 years old, don’t wait for a machine to break to examine your options.