Choosing the Right Plasma Cutting Table & Options to Get the Job Done Right

The plasma cutting process is a staple of the fabrication shop providing accuracy and efficient cuts in steel for further processing. When selecting a new plasma cutting table you need to know what the important factors are and how to apply them to your decision making. Here we discuss what plasma cutting machines are, the various types of plasma cutters available, what they are used for and hot to choose the right system for your needs

What Are Plasma Cutters?

Plasma Cutters are a power source and related hoses and electrical equipment to attach a torch to that power source. These plasma cutters utilize the extreme heat of a plasma stream to vaporize conductive materials. Although there are many adaptations of the Plasma torch for use in today's manufacturing world the primary use is on that of a computerized (CNC) controlled cutting table. Below we will take a look at the types of plasma cutters available and how to choose the right one for your needs. 

Types of Plasma Cutters

There are 3 main types of plasma cutting torches and uses: 

1. Hand Held: Plasma cutting power sources can be hand held allowing for free form cutting, parting or gouging. This is a common method used in scrapping large assemblies using the power of the plasma to easily cut off fabricated components into smaller pieces for transport. 
2. Mechanized: A plasma cutter can be mounted on a track to allow for motorized control of the cutting process. This allows large plate cutting and bevel cutting.
3. Computer Controlled: The thyroid and most common way of utilizing a plasma cutter is by mounting to a computer driven (CNC) Controlled gantry frame which controls the on/off cycle of the plasma cutter but also allows for cutting complex shapes in metals.  

How to Choose the Right Plasma Cutter For Your Needs

Selecting the right CNC Plasma Cutting System for your needs comes down to determining what is the result you want to achieve from the machine first. Factors like material type, accuracy and quality of the plasma cut edge. Knowing these things in advance will greatly help you zero in on the right machine and options you will need to make your plasma cutting system a success.

1) Identify the Materials You're Cutting

Material type is incredibly important in plasma cutting as each material reacts differently to the plasma stream. Carbon steel yields fairly easily and as it is most common most of the plasma cutter system is designed to cut this material best. Stainless Steel can also be cut with a plasma plasma cutter but with less efficiency and only in thinner material than in standard carbon steels. Aluminum also can be cut with a plasma cutter but due to its inherent heat absorption properties, plasma cutting aluminum is not a preferred method.

The thicknesses of the materials you can cut on a plasma cutter are based on the amperage that the plasma cutter can produce. The higher the amperage, the thicker the material that can be effectively processed. We must also know that there are several “types” of cuts we can get with a plasma which include:

• Severance: Poor Quality, Edge of hole start. Plasma cannot penetrate material of this thickness on its own. Maximum thickness the plasma can cut.
• Pierce Capacity: The plasma has sufficient power to create a start hole and begin cutting but parts maye retain dross and rougher quality edges.
• Production Cutting: Best Quality edge at maximum thickness. Easiest plasma cutter pierce. This is the cut we most likely expect with a smooth usable edge. 

As a rule we use the carbon steel capacity settings to save a plasma cutter power source and generally it is pretty easy to select the amperage for effective cutting as follows:

Capacity of Plasma Power Source = Decimal Thickness of Material = ½ the amperage output of the plasma cutting power source. Stainless and Aluminum capacitors will be a third less than that of carbon steel.

Here are a couple examples: 

• If you are cutting 1” Carbon Steel maximum you should select a 200 AMP (or higher power source) as this will be enough power to pierce and cleanly cut, dross free carbon steel. 
• If you are going to be cutting 2.0” Carbon Steel you should select a Plasma Power Source not less than 400 AMPs.

2) Determine Your Desired Results

Another important factor in selecting the right plasma cutting power source and machine is to determine what type of results you will need on the cut parts once removed from the table. The plasma power source , if selected correctly will yield clean, dross free quality cuts but, it will not yield accurate and square parts. Accuracy in your parts is a function of the correct plasma  power source AND the CNC Motion system driving it. For the best results ensure you have a servo fed closed loop drive system (as opposed to stepper motors) that provides accurate feedback to the CNC controller. Also for best results ensure your plasma torch is driven on both sides of the bridge to avoid lag and whip when the controller reverses directions (as when cutting circles). 

3) Consider All Aspects of Plasma Cutters

Once you have considered the correct power source and the correct table drive system you need to look at all the options available for your plasma table like: 

• Table Size: The table size is more important than you may initially realize and getting a longer table then your material likely will only be realized after you have been running your machine a while. If your lateral is 1” plate 5’ X 12’ in length you may easily consider a table size to match but consider that when you plasma cut your torch generates an enormous amount of heat into the material making it untouchable for up to several hours after the cut is finished.
  In cases like this you may want to consider a table length of 24’ or longer to allow you to stage material and continue cutting while the first sheet cools and is unloaded then that section, reloaded.
• Table Type: There are several different types available for machines today including water tables and dry downdraft. A water table provides efficient smoke/dust reduction in a much less expensive investment, however it poses many problems such as more slag on cut pieces, messy and stinky tanks filled with dirty water. Rusty Parts etc.
  A Dry Downdraft table is always recommended & preferred by plasma cutting table users in production scenarios. The material stays clean and dry and the dross is minimized. There is not dirty rotten water smelling up the shop and cleanout is much easier and safer. 
• Additional Cutting Torches: One of the advantages of plasma cutting machines by design is the fairly simple process of adding additional plasma torches or Oxy-Fuel torches to increase capacity. Adding more plasma torches and power suppliers is a great way to maximize your machines efficiency with heavy production cutting needs. 
• Bevel Cutting/5-Axis: Another great adaptation that can be made to the CNC plasma table is the addition of a bevel cutting or 5-AXis cutting attachment. This CNC Controlled device holds the plasma torch manipulating it to cut bevels, on or through the material which can make the machine much more efficient when cutting complex workpieces. The only precaution you should note in advance is the material thickness grows larger the more the torch leans over in a bevel thus your plasma power source output should be selected accordingly. 
• Tube Cutting Attachment: Another great option to consider is a plasma tube cutting attachment. Mounted alongside the table and connected to the CNC controller a rotary axis clamps and rotates a pipe to provide for proper orientation to the plasma cutter. This attachment allows a shop to greatly increase the effectiveness and versatility of not only the machine but of their own shops capabilities.

4) Narrow Down Your Options for New Plasma Cutters

Once you have selected the right plasma power source, machine type, table sizes and options you will need to select the right supplier. Although there are many machine builders there are only a few that can provide all the options listed above on a quality and supportable table built for longevity and accuracy. BendmakUSA provides the most complete selection of plasma cutting systems from Bendmak available with many options and in a range of sizes to suit any need. 

Find the Best New Plasma Cutters at Bendmak USA

BendmakUSA has simple 2 axis cutting tables or dual tabled 5-Axis bevel cutting designs. Also we can easily integrate the rotary device allowing for production tube or pipe cutting increasing your productivity like never before. Visit our website at www.bendmakusa.com or call us directly at 833-BENDMAK (833-236-3625) for immediate assistance.