Plasma cutters are machines that utilize a torch in the form of an expedited jet of hot plasma to cut through electrifying conductive materials. The plasma is formed when a gas is passed through a compressed opening (torch) at a very high speed shaping an electric arc on the level below. And the plasma cutter welders are the certain types of machines that combine what welder and plasma cutter machines can do into one single machine’s function, they can also be called as multi-process welder, plasma cutter with welder combo options, plasma cutter and welder, or welders& plasma cutters.
Plasma cutters works by shipping an electric arc through a gas that is passing through a compressed opening. The gas can be shop air, nitrogen, Argon, oxygen, et cetera, depending on the metal being cut. This raises the temperature of the gas to the degree that it enters a 4th stage of matter. We all are familiar with the first three: i.e., solid, liquid, and gas. Scientists call this additional stage plasma. Since the metal being cut is part of the circle, the electrical conductivity of the plasma results in the arc to transfer to the work. The compressed opening (or nozzle) the gas passes through gives rise to it to squeeze by at a high speed, like air swiftly passing through a venturi in a carburetor. This high-speed gas cuts from end to end of the molten metal. The gas is steered around the perimeter of the cutting area to protect the cut as well.
Most entry-level plasma cutters use shop air simply fed via an air compressor. High accuracy plasma cutters such as those found in complex manufacturing shops need pressurized gas such as Argon or a mixture of gases. The materials that can be cut with a plasma cutter include steel, stainless steel, copper, brass, aluminum, and among other conductive metals. Because if its high speed and very hot localized "cone", a plasma cutter is utilized to cut sheet metal with angled or curved shapes, and it is widely used in large-scale CNC (computer numerical control) applications and small DIY shops. A pilot arc between the electrode and nozzle is utilized to ionize the gas and initially generate the plasma previous to the arc transfer in many of today's improved plasma cutters. Other methods that have been utilized are touching the torch tip to the work to create a spark, and the use of a high-frequency starting circuit. Neither of these latter two methods is compatible with CNC (automatic) cutting.
Plasma cutting torches often use a copper nozzle to compress the gas stream with the arc flowing through it. That arc jumps from an electrode in the torch to somewhere else, and usually the conductive material is the one being cut. That’s a ‘transferred arc’. There are some systems that use a ‘non-transferred’ arc where it jumps from the electrode back to the nozzle, yet those are not often utilized for cutting. So that means that plasma cutting is solely utilized for materials that are conductive, primarily mild steel, aluminum, and stainless steel. But tons of other alloys and metals are conductive too, such as copper, brass, titanium, and cast iron, et cetera. The pickle is that the melting temperature of some of those metals makes them not easy to cut with a good quality edge. Why use oxygen in a plasma torch? The same reason you use Oxygen in an acetylene torch, oxygen in the plasma stream reacts with mild steel. That is why pure oxygen is only utilized when cutting mild steel, or ‘carbon steel’. That chemical reaction between the Oxygen in the plasma gas and the base metal helps to expedite the cutting process and enhance the edge quality. But since Oxygen doesn’t have the same reaction with stainless steel or aluminum, cheaper gases can be utilized for those metals, like nitrogen or compressed air, but mostly just nitrogen.
● Power Supply
The plasma power supply transforms single or three phase AC line voltage into a smooth, constant DC voltage ranging from 200 to 400VDC. This DC voltage is accountable for keeping the plasma arc throughout the cut safely. It also controls the current output required based on the material type and thickness being processed.
● Arc Starting Console
The arc starting console circuit produces an AC voltage of approximately 5,000 VAC at 2 MHz in which produces the spark inside of the plasma torch to create the plasma arc.
● Plasma Torch
The function of the plasma torch is to offer adequate alignment and cooling of the consumables. The chief consumable parts required for plasma arc generation are the swirl ring, nozzle, and electrode. An additional protective cap may be exerted to further better cut quality, and all the parts that are held together by outer and inner retaining caps.
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