Machine tools for fabricating structural steel have advanced over the past 100 years, from basic handheld motorized drills and saws to cutting edge, fully-automated “heat cutting” machines. Steel fabricators today stand at a technological “fork in the road” of sorts – whether to continue using traditional cutting-tool-based methods or embrace the new heat-cutting-based methods. The choice is one that must be considered from many perspectives, based on both where the fabricator has been and where they want to go. There are many companies supplying fabrication machinery to structural steel shops, but of these, the most recognized name is Peddinghaus. Their philosophy has been one of specialization – dividing up the myriad different functions that are commonly done into distinct groups and then building equipment focused on the resulting groups. Following this way of thinking, Peddinghaus has come up with a collection of machines that fabricates beams, plate, angle, hollow structural sections according to the requisite operations of cutting, drilling holes and making variable shapes of different sizes. This philosophy results in features such as high cutting spindle speed, workpiece indexing, specialized clamping, and others that make any individual machine especially efficient at the tasks it was designed to accomplish. However, the possible downside for this specialization is that an individual workpiece may have to visit multiple machines in order to have all its operations competed. That calls for extra time and material conveyance around the shop. Only recently has a fundamentally different method to this equipment specialization philosophy emerged. The core of this approach is using thermal cutting via robot or similar automated means to accomplish multiple fabrication functions. In this case, the “flame” is the familiar plasma arc – ordinarily used to cut steel plate – rather than an oxy fuel torch or laser cutting. In this case the plasma cutter has been placed in the grip of sophisticated industrial robot, which decides what and how to cut based on a cutting sequence made by proprietary software. The new system, known by the brand name PythonX, is the first of these structural fabrication machines. Early in its introduction (2005) the common complaint about the PythonX plasma cutting approach was certain operations – like making bolt holes – were somehow not done as well by flame cutting as by metal-against-metal drilling. That concern has since been shown to be unfounded, since plasma cut bolt holes satisfy all pertinent requirements for both roundness and dimensional precision. The PythonX philosophy stands the Peddinghaus approach on its head, by using one plasma cutting system to perform the work of four traditional machines plus a manual torch setup. The net effect is less capital investment and less floorspace to host the equivalent fabrication capability of those five machines. Some consider reductions in material handling are the strongest benefit of the PythonX philosophy. Since all operations can be performed on a single machine, there is vastly reduced need to transfer WIP from one machine to another, as is so commonly done in the multiple specialized machines approach to structural fabrication. Fabricators facing the prospect of acquiring new production machinery now find themselves at this “crossroads” that begs the decision whether to follow the path of multiple, specialized machines to sequentially perform the different functions needed, or the path of a single versatile machine that completes all the needed operations. In several cases, there is likely to be a place for each fabrication philosophy approach. Cases that call for a large number of bolt holes drilled into steel beams don’t require much more than a beam drill line and bandsaw. On the other hand, jobs that involve more complicated steel workpieces – copes, notches, flange flush cuts, piecemarks – will be quickly and completely processed on a single robotic plasma cutting machine. Each structural steel fabrication company will take the path that matches their business needs. The question is, if you can only choose one fabrication system, what would it be?
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