Page 36 - MetalForming-Nov-2018-issue

Welding Well
ing variables to productivity and quality results and then push those variables out to an entire fleet or enterprise.
It also enables them to spot anom- alies, such as low arc-on time or wire consumption, then determine a root cause. If, for example, an operator spends too much time grinding, is it because of spatter or a poorly prepared bevel? If so, then a low-spatter wire or automated plasma-beveling system
might make sense. As noted, estimates based on inaccurate data can cost a company money. By capturing actual operator time, consumable and material use, companies can precisely estimate job costs and increase profit margins.
Documentation and Traceability
Documentation and traceability, often required by customers in the
power, wind-tower, offshore, pressure- vessel and other industries, generates reams of paper. Most fabricators look at it as unproductive time, yet the need for traceability and documentation is growing.
New technology enables using a smart-phone app to scan a barcode for every component, operator, power source, consumable and shielding-gas cylinder used in a weld session. Cou- pled with weld-parameter monitoring (more on this shortly), a fabricator can automate what is a tedious and costly process prone to human error.
Quality
A first step toward consistent weld quality is linking production variables with results. Even then, weld-quality monitoring happens after a part is completed or sent farther down the production line. A quality-assurance system based on looking in the rearview mirror is costlier, especially if multiple parts have defects.
Conversely, a data-monitoring sys- tem can provide the operator or man- ager with feedback in real time. Imag- ine the value of immediately identifying a weld flaw on the root pass of a 1-in.- thick joint instead of after making the cap pass. On an automated system, because travel speed also would be captured, the operator would be able to identify the location of the flaw.
The type of online management sys- tems discussed so far can capture and log data at a rate of up to 1 Hz (and sometime much slower). The data is generally higher level (e.g., the welding arc shut off and the system recorded an error). The micro details required by engineers and quality assurance per- sonnel require a real-time weld quali- ty-assurance system that captures data at rates of 23 kHz or faster. By comparing measured parameters with reference curves, the system calculates quality marks for each weld seam and provides an instant notification when an irregu- larity occurs. Faults detected can include poor arc ignition, porosity, burnthrough, seam length (too long or short) and seam interruption. M F
34 MetalForming/November 2018
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