Plasma Cutting Technical-Cutting tips and Safety tips

Plasma cutting is a form of cutting metal using gas and an electric current forming an extremely high temperature to cut medal with extreme precision. Increasing the temperature of a gas creates a chemical reaction where the electrons collide at a very high speed giving off enormous amounts of energy. Controlling pressurized gas through a small channel combined with an electrical charge alters the state of the gas turning it into plasma. The electrical arc produced by the gas-electric combination reaches a temperature over 20,000 degrees Fahrenheit and moves at the speed of 20,000 feet per second.

As can be imagined, altering the natural state of a gas compound using electricity to create such high temperatures and speed is fraught with numerous dangers yet plasma cutting has been an important part of our lives since World War II. It is vital to follow the directions of the manufacturer when purchasing a plasma cutter and to follow some basic safety guidelines:

  • Protective clothing
  • Avoid electric shock using appropriate grounding safety devices
  • Ear protection
  • Use in well ventilated areas
  • Gas supply safety

Protective clothing – Using protective clothing including, welding helmets, insulated boots and gloves, fire resistant clothing and pants without cuffs is extremely important for your safety. The extreme heat produced while plasma cutting can cause serious burns. Shielding your eyes from the ultra-violet and infrared waves can prevent your eyes from irreparable damage.
Electric shock – A plasma cutter uses more voltage than a regular welder ranging from 100-200 volts. Standard electrical safety procedures should always be followed when using electricity of this magnitude:

  • Wear dry clothing at all times
  • Do not weld or stand in areas with water accumulated in puddles
  • Do not touch wet surfaces while welding

Furthermore the use of the grounding clamp is a life saving measure. This clamp, similar to that of battery jumper cable clamp, is used to protect the user and the plasma cutting machine. It is attached to the piece being work on to complete the circuit preventing the cutter from shorting out. It also prevents the danger of electrical current passing through the body of the user. This will not prevent electric shock if you touch the torch body!
Ear protections – The noise of a plasma cutter is a deafening 120 decibels. The decibel level of a jet taking off is 110 for comparison and a rock concert about 108 decibels; therefore any extended use of a plasma cutter will cause permanent hearing loss without the use of ear protection.
Good ventilation – Working with gases and metals at such extreme temperatures can produce toxins that will harm your lungs. Having a well-ventilated work area is extremely important for you respiratory health. If you are working in a closed space, it is highly recommended to wear a respirator.
Gas Supply – Using gases like nitrogen requires the use of tanks. It is important to keep the tanks chained upright in support carts at all times. Check the regulator and hoses often, keeping hoses off the ground avoiding, kinks and damage. Any leaky hoses should be replaced or spliced but never with tape as this is insufficient and not recommended for any type of gas hose repair.
Once you are properly suited, grounded and equipment inspected you are ready to start using your plasma cutter. Despite the numerous safety warnings and precautions that need to be taken, plasma cutting is quite straightforward and simple to do. Here are a few tricks to the trade to help you get going:

  • Make sample cuts
  • The longer the cut the harder it is to control
  • Use a drag shield
  • Output and travel speed
  • Standoff

Sample Cuts – The old adage of “measure twice, cut once” can be twisted a little to apply to plasma cutting by using the same type of metal of which you are cutting, make a sample cut to check for the settings and travel speed. This will save frustration on your final project by having all the settings correct.
Distance and control – In plasma cutting, continuity is king. The design of plasma cutters is to give precise cutting. Cutting is the key word. Stopping mid cut will make for an unclean work product. Practice your cut making sure you have freedom to move the entire distance and nothing is in the way to break a continuous cut.
Drag shield – Drag shields are placed on the cutting surface to give the optimal 1/8th inch standoff (distance from the surface being cut and the tip of the cutter.) They act as a guide and spacer for optimal cutting. A drag shield is often used in cutting patterns. If you don’t have a drag shield using your non-cutting hand as a guide and stability is also an option.
Output and travel speed – Quality cuts rely on output and travel speed. The type and thickness of the metal being cut will determine both output and travel speed. Thinner metals like aluminum require lower amp, smaller streams and more rapid travel speed, while thicker metals will require higher amps, wider streams and a slower travel speed. Learning the proper tips to use with your plasma cutter will help in not only reducing the amount of consumables used but will improve your ability to make clean cuts. Your machine’s manual should have a table showing travel speeds for various types and thicknesses of metal.
Standoff – Finally standoff, the distance between the tip and the surface being cut, is important for not only clean, efficient cuts but for maintaining the integrity of your equipment. A standoff that is too high or low can make your machine work harder than needed reducing its lifespan. This is where drag shields come in handy. Again checking the operating manual of your machine will help guide you in knowing what tips and standoffs should be used for each metal.

Plasma cutters have been around for decades. The practicality of a machine that can alter the state of a gas turning it into a precise cutting tool can never be underestimated. The uses for cutting metal are unlimited. Being that the power of this tool is so great, safety has to come first. Once the safety issues are addressed, learning some basics of plasma cutting will provide you with years of skill.

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One Comment

  1. Using a plasma cutter on metal sheets sounds and looks very dangerous. I think learning the basics is very important. It always seems like the basic and simple rules are the ones that will keep you safer.

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