How Plasma Cutting Works

Metal cutting breaks down into two categories there is mechanical cutting and then thermal cutting.  Plasma cutting falls underneath the thermal cutting method that relies on ionized gas to cut through metals.  Plasma cutting is one of the most widely used techniques to cut thick metal plates and sheet metal.  Below we weigh the benefits and disadvantages of plasma cutting.  

What is Plasma?

It is possible to find plasma in nature but mainly in the upper parts of Earth’s atmosphere.  The beautiful polar lights that everyone has heard of are actually made up of solar winds made of plasma.  There is plasma found in other areas too such as our bodies, and even lightning.  Plasma is all around us in the universe everywhere we look.   

Plasma is an electronic conductive ionized gas-like substance.  Gas can be transformed into plasma if it is introduced to intense heat.  Similar to gasses, plasma atoms are not in constant contact with each other.  At the same time it holds similar qualities of behavior as liquid with the ability to flow when subjected to an electrical and magnetic field.  

How Does Plasma Cutting Work?

Plasma cutters use compressed air and gasses like nitrogen.  Once the gas ionizes they become plasma.  With the mixture of plasma making contact with electrodes it creates pressure.  Then, a build up of pressure begins to push the plasma towards the cutting head.  The cutting force is then directed towards the workpiece.  While the plasma is contacting the metal the high temperature begins to melt it.  Lastly, the gasses traveling at a high speed blow away the molten metals.  

The Cutting Process

Now, even though not all cutting processes are the same there are different variations of plasma cutting.  Ones that are a lot less costly.  Like, the high frequency method, the pilot arc, or even the spring loaded plasma torch head.  There are pros and cons for each method and a time to choose which one is best for your project.  

Advantages vs. Disadvantages

Advantages 

  • Able to cut all conductive materials
  • Great quality for thickness up to 50 mm
  • Maximum thickness up to 150 mm 
  • Comparative cheap for thick metal cutting
  • Best way to cut medium thickness stainless steel and aluminum
  • Can cut in water 
  • Smaller cutting kerf compared to flame cutting 
  • Quick cutting speed

Disadvantages

  • Larger Haz compared to laser cutting 
  • Quality with thinner sheets and plates is not as good as laser cutters.  
  • Tolerance is not as precise 
  • Does not reach thickness like flame cutting or waterjet cutting 
  • Wide kerf

Choosing a Cutting Method

The recommended cutting thickness for plasma cutting is between 15 and 50 mm.  The recommended upper limit of material thickness for a plasma cutting service is around 50 mm for both carbon and stainless steel.  Aluminum should never go beyond 40 mm.  Everything that exceeds these limits should be done with either flame cutting or waterjet cutting.  When it comes to thinner metals like sheet metals laser cutting is the ideal choice.  

Contact Markham Metals Today:

For more information on plasma cutting contact our team of professionals at Markham Metals.  Our team is more than happy to help with both small and big projects.  To get in touch with us call us at 978-658-1121 or by filling out an online contact form directly on our website.  We look forward to speaking with you.  

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