Investing in new equipment always comes down to analyzing budget vs. benefits. This tutorial will help readers looking to purchase their first automated plasma-arc cutting (PAC) system, as well as those considering an upgrade to more productive technology. This article is particularly relevant for operations cutting mild and stainless steel and aluminum sheet and plate, from gauge thickness to 1⁄4 in., and who would be well suited with a 5- by 10-ft. cutting table, appropriate for cutting 4- by 8-ft. plate.
Automation makes sense for fabricators that repeatedly make the same cuts, have a high degree of rework with manual operations, struggle with poor fitup, need weld-ready parts, and face labor shortages or labor-cost issues. Addressing one or more of these issues through automation improves productivity and ultimately lowers per-part cost. Automation also can decrease order lead times, and an inhouse cutting system enables fabricators to cut parts at their own convenience rather than based on the schedule of a metal service center.
Many fabricators evaluating automated cutting systems also may evaluate waterjet and laser technology. Both offer tighter tolerances and better cut quality than plasma, but plasma cuts faster. And, comparatively speaking, plasma has the lowest initial cost.
The plasma industry generally divides cutting technology into two categories: standard definition and high precision. Standard-definition systems suit those who plan to cut only a few hours per day and a few days per week, or when tolerances of ±0.02-0.03 in. are acceptable. Fabricators that anticipate a cutting-table utilization rate of at least 50 percent or that need a cut accuracy of ±0.01-0.05 in. should select a high-precision system.
This article also includes information on integrated systems, consumable costs, investment costs, and cut quality.
> Read more by Dirk Ott, MetalForming Magazine, July 2016