Mon. Feb 6th, 2023

If you are a primary time buyer or have existing installations of plasma and/or oxy-fuel shape cutting systems, continuous advancements in technology and an increasing landscape of low-cost manufacturers and integrators has clouded the automated plasma shape cutting machinery landscape.

Plasma cutting is the result of introducing a power arc by way of a gas that’s blown by way of a nozzle at high pressure, evoking the gas to develop into plasma and making a focused flame that reaches temperatures of 50,000 degrees Fahrenheit. Automated plasma cutting systems are classified as either conventional or precision (high-definition), on the basis of the characteristics of the cutting flame. Precision plasma systems are capable of producing parts to tighter tolerances, achieving faster cut rates, and producing less kerf and bevel than conventional plasma systems. The expense of these units can also be significantly greater than conventional plasma systems. It’s therefore extremely important to properly match the design cutting machine with the right plasma cutting system.

One of the very most common and costly pitfalls buyers encounter is when manufacturers or integrators mismatch machines and power sources. That is often the result of manufacturers not taking the time to know the buyer’s requirements, having a limited or single-product line of machines, limited OEM access to power sources, and/or too little industry/application knowledge. These manufacturers will often sell with an emphasis on lowest price in place of cheapest of ownership, highlighting the strong point of the plasma system or the equipment without regard to the limitations of the other. The very best precision plasma power source available won’t provide users with the desired cut quality and accuracy when it is not mated to a suitable base machine.

You will find various types of plasma shape cutting machines available available in the market today. The most frequent machines are bridge or gantry style machines produced from either fabricated steel or extruded aluminum. Construction of the equipment is extremely important in accordance with your application. Machines constructed of extruded aluminum are usually regarded as hobbyist or artisan machines and most appropriate when performing a limited quantity of cutting or when cutting light gauge materials. The plasma and oxy-fuel cutting processes create large levels of heat that is retained in the materials being cut and could cause deflection or warping of aluminum machine components traveling within the hot cutting surfaces, greatly effecting accuracy and cut quality. Fabricated steel machines are recommended for almost any continuous cutting process, cutting of plate steel, and where auxiliary oxy-fuel torches might be used. Auxiliary heat shields may also be available to help protect the equipment and components from extreme heat conditions.

Cutting machines can be found with many different drive systems including single-side drive, single-motor dual-side drive, and true two-motor dual-side drive systems.  digital fabric flatbed cutter CNC A well constructed single-side drive system or single-motor dual-side drive system will perform well in conventional plasma applications. The advantage of the extra precision provided by two-motor dual-side drive systems won’t be realized in conventional plasma applications because of the limitations in the precision of the standard plasma cutting process itself. Two-motor dual-side drive systems will give you the accuracy and performance required to attain optimal results from a precision plasma process.

Sizing of the motors and gear boxes in accordance with the mass of the equipment can also be extremely important. Undersized motors and gearboxes won’t manage to effectively change the direction of the mass of the equipment at high traverse and cut speeds, leading to un-uniform cut quality and washed-out corners. This not only affects the cut quality, but will also cause premature mechanical failures.

The CNC control is the unit that ties together every one of the functionality and top features of the equipment and plasma source. You will find basically two classes of controls used on these types of machines today. Most industrial applications use industrial PC-based control systems such as those created by Burny or Hypertherm. These units have user-friendly touchscreen display control panels and are housed in enclosures that will stand up to the harsh environments they operate in. Smaller machines of the hobbyist or artisan types often utilize standard PCs with I/O cards to control the drives and plasma systems. Industrial based controls are recommended for almost any application, were created for industry specific requirements, are less prone to the normal PC problems, but could be cost prohibitive in smaller applications.

Another important, and often overlooked, feature to consider when selecting a machine is the construction of the rail system. Plasma cutting machines produce and reside in a harsh environment. It’s therefore critical that the components found in the construction of the rail system be robust enough to exist in this environment. All rail surfaces should be constructed of hardened materials and cleaned frequently so they don’t become pitted and gouged by the splatter of molten steel that may inevitably fall on them. Self-cleaning wheels will also be a recommended feature to help keep the wheels clean between regular preventive maintenance (PM) cycles. Sizing of the rails should also be robust enough to avoid deflection as the equipment travels across them.

The mixture of every one of the above factors results in the precision and accuracy of a system. Unlike other mechanical machining processes, it is difficult to assign a regular tolerance to plasma cutting processes. Many manufacturers will strongly promote the truth that their machines have positional accuracy of +/-0.007 in. and repeatability of +/-0.002 in.. Truth be told that nearly any machine on the market can hold tolerances that far exceed the tolerance and capability of the plasma cutting process itself. There are numerous factors that may influence the cut quality you will achieve on your parts including: the characteristics of the part itself, power settings, consumables, gases used, material type, gauge/thickness of material, part layout on plate, etc.. Ask producer to give you cut examples of your parts or parts that closely approximate the parts you is likely to be cutting, made on a machine/plasma combination that’s comparable as to the you’re looking at. This will give you probably the most realistic representation of what to expect from a particular machine/plasma combination and the plasma cutting process itself.

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