How To Select and Operate a Hand-Held Plasma Cutter

Before firing an arc, learn about choosing the plasma cutter and accessories that best suit your application.

Advances in Plasma Cutting

The cut is often all it takes. Manufacturers, suppliers, service personnel, artists and DIY enthusiasts who have experienced the benefits of a portable plasma cutter rarely want to return to oxyacetylene cutting processes or to mechanical cutting processes such as cutting, knife cutting, shears and shears.

Plasma cutting can improve productivity and reduce cutting costs. The advantages of plasma cutting include:

Cut faster

  • A preheat cycle is not necessary
  • Shut off all metallic conductive electricity (except bone fuel which cannot be cut into stainless steel or aluminum)
  • Allows handover around tasks
  • Reduce the heat affected area and cut it to a small level (cutting width).
  • Plasma devices can also drill, drill, tilt, cut holes and record shapes.

The actual process of using a portable plasma cutter is relatively simple. In fact the hardest part before cutting the arc – choose the car that best suits your application and choose the right accessories.

What is plasma cutting?

Plasma looks and behaves like a high-temperature gas, but with one key difference: it conducts electricity and cuts through any electrically conductive metal.

Plasma arcs are the result of electrical heating of a gas, usually air, to a very high temperature. It ionizes its atoms and makes them conduct electrical current. The plasma arc is a rotating ring that rotates the gas around the electrode. The gas is heated in the chamber between the electrode and the flash point, ionizing the gas and creating plasma. As a result, the plasma gas expands significantly in volume and pressure. The small, narrow hole in the tip of the torch confines the plasma and accelerates it in the work area at high speed (20,000 feet per second) and temperature (up to 30,000 degrees Fahrenheit).

High intensity plasma radiation melts a highly localized area. The force of the plane (or arc) pushes the workpiece and removes molten metal. This loop is easy to cut into metals with low thermal conductivity (stainless steel) or excellent conductivity (aluminium).

In response to plasma cutting, the flame generated by the torch has no concentration and degrades poorly to stainless steel and aluminum. Arcplasma cutting is considered standard procedure for these metals.

Choose a plasma cutter

There are several factors to consider when buying a plasma cutter.

Thickness of the material:

When choosing the right plasma cutter, the thickness of the metal you cut regularly and the maximum metal thickness are important. As a source of welding energy, the current and voltage of the plasma cutter can determine its size. The plasma process requires relatively high and low ampere voltages, unlike soldering. Many people misjudge an electricity-only plasma machine. Although it is an important indicator, keep in mind that the total output power (in watts) is equal to the voltage. Calculate to get a more accurate product comparison. The plasma cutting capability of a machine of a given size varies widely from manufacturer to manufacturer.

Cutting speed

Once you know the cutting speed of the expected metal thickness, you can calculate the production speeds, usually in parts per second. O’clock. This helps ensure that the cutting portion of the operation does not become a constraint. Many manufacturers provide cutting speed charts that allow you to compare cutting speed performance.

While there is no universal standard, Miller allows for comparisons by qualifying for two standards: slicing and graduated slicing.

The nominal cut is the thickness of the metal that the operator can cut manually 15 IPM. This is considered the minimum speed at which the operator achieves a smooth, stable cut and the best possible cut quality.

Sharp cutting means the operator can push the machine to its maximum thickness (1-1/4 in. for a 55 amp unit). Cutting speeds will be very slow and cutting will require significant cleaning. Fortunately, the cutting speed increases as the material becomes thinner.

Main power:

Plasma cutting requires two basic elements – air and electricity – so the next question is what kind of input energy is available. Many 30 amp plasma cutters, such as the Spectrum® 375 X-TREME®, operate at 120 or 240 volts. In fact, if your input circuit has a 30 amp circuit breaker, you get the same switching power at both voltages (with a 20 amp circuit breaker, the circuit breaker power drops by 20 percent). Miller offers a key power management solution called Auto-Line technology, which allows cars to receive input voltages from 190 to 630 volts, single-phase or three-phase, 50 or 60 hertz. And although the primary power increases and decreases, but still remains between 190 and 630 volts, the devices with Auto-Line technology offer a stable, equal arc and full cutting power. Similar devices without an automatic line suffer from unstable circuit breakers, frequent circuit breakers, open circuits, and are prone to premature transformer failure. These problems usually occur because when the plasma cutter is activated, it charges the line so much that the voltage levels fall below the operating range of the plasma cutter.

Environment and air supply

In environments with a lot of dust and metal chips (for example due to grinding), the reliability of the Miller® machine with tecnulugia wind technology and a fan generator on demand increases. Thanks to the air tunnel technology, cold air passes through the machine without being blown through the electronic components, so that the grinding material is not deposited in the critical components. Fan-On-Demand means that the cooling fan only works when needed, which reduces the amount of dirt entering the unit. In terms of air supply, most portable manufacturers of plasma cutters recommend the use of ordinary air as the cutting gas. In mobile applications, suppliers often choose to pack nitrogen because it costs less than bottled air. When waiting for stainless steel, some people think that nitrogen causes a little less oxidation because it dries out from compressed air.

The principle of high frequency or the principle of contact

Plasma cutters use high frequency (RF) activation technology or contact activation to activate the pilot arc. If you plan to use the plasma cutter near telephones, computers, CNC machines or other electronic devices, keep in mind that HF ​​interferes with electronic work. To avoid potential HF problems, all Miller plasma openers have a contactless disconnect design. The ignition mode also creates a visible control arc to better position the igniter.

Plasma cuts costs and accessories

Frequent and elongated cuts: Choose a regular or enlarged cut. For plasma units larger than 40 amps, the integrated trailer protection protects the standard tip and automatically keeps it 1/8 inch away from the work surface (for units smaller than 40 amps, the tip can be placed directly on the piece) . If you want to draw straight edges or pattern traces or patterns, many people choose this setting because they can simply join the edge of the drawing screen to the conductor (railing, piece of wood, cardboard pattern, etc.) and start cutting. with

Extensive tips: To cut slopes, angles and a better view of the cutting arch, some operators prefer an extended point. This point extends 1/2 to 1 inch behind the coupling cup so that the operator can better direct the flow of the plasma mask and reach it at angles. Importers it is important to have a strong hand, because if you touch the top of the top three or four times, the hole in the top is so large that it no longer limits the bow.

Roll and Circular Cutter Guide: This section reflects every movement of the hand, so if you do not have a stable arm, consider using a roller and circular cutter. These guides hold the lamp, prevent the tip from touching the work piece, and make it easier to travel in a straight line or cut a perfect circle.

Gold Tips: Use old glue tips to remove old or imperfect welds. The hole at one point is three to four times wider than the normal point. The shape of the cone pushes the plasma arc, which removes much more material than the narrow hole at the usual tip. Many people don’t believe that plasma works well for cutting, but that the perception is based on older machines with weaker arcs. The more powerful Miller Spectrum plasma cutters have a stronger design that creates an arc from 1 to 1-1/2 inches.

In addition to cutting power and speed, consumption time varies widely between manufacturers. Miller outperformed its competitors in a test that reduced the number of 12-inch and 1/2-inch mild steel strips with a single consumable.

cutting technique

 Now that you have selected your plasma cutter and completed your preliminary list, you can do the following:

1. Place the guard on the edge of the base metal, or leave space in the holes (usually 1/8 inch) and level the arc straight.

2. Lift the trigger lock and pull the trigger – and the pilot arc will start as soon as the trigger is pulled.

3. Once the cutting arc starts, the torch will begin to move slowly on the metal.

4. Adjust the speed so that the sparks pass through the base metal and exit at the end of the cut.

5. At the end of the cut, rotate the torch slightly to the end edge or stop just before releasing the trigger to cut the metal completely.

6. To cool the burner, hold the air for 20 to 30 seconds after the trigger is released. Depressing the trigger during reverse current starts the arc immediately.

If you switch to plasma cutting, you can achieve excellent results. If you choose the right plasma cutter and use it correctly, you can enjoy many years of trouble-free life.

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