CNC plasma cutting is a technique that uses a plasma torch controlled by a CNC machine to cut parts from sheet metal. Manual plasma cutting is slow and the cuts made are not very neat but with the aid of this tool, the cutting is elegant and is done in a shorter time.
Here is an overview of how CNC plasma cutting works and is done:
Understanding Plasma Cutting
Before going further in explaining CNC plasma cutting, it is essential to explain what plasma cutting is all about. Plasma cutting uses a compressed gas ejected through a small nozzle in the plasma torch to create a high-energy plasma arc; this plasma stream can easily cut through metal.
The plasma is hot enough to melt the metal being cut during the cutting process. Subsequently, a stream of compressed air blows the molten metal to the side, thereby leaving a smooth and straight cut. Plasma can cut through steel, aluminum, copper and other metals that are highly conductive with ease and with a high level of precision.
What is a CNC Plasma Cutter?
A CNC plasma machine consists of a plasma torch mounted on a mechanical structure referred to as the gantry system. It employs a plasma torch to act on the workpiece in the X, Y & Z directions as per the CNC commands from its inbuilt machine controller.
CNC allows plasma cutter to cut through metal repetitively and with an accuracy of up to +/- 0. 001 inches. It can be easily programmed to make accurate cuts on complex shapes at higher speeds. The operator is only required to input or transfer the necessary shapes into the software.
Steps in CNC Plasma Cutting
Here are the basic steps to carry out CNC plasma cutting:
Design the Parts
The first step is to sketch the shapes and parts that you want to cut on the computer using a CAD tool. Convert the CAD designs or CAD drawings into formats that are acceptable by CNC plasma machine software. The most common formats are dxf and dwg.
Prepare the Machine
There are specific preparations on the machine that have to be made before it can be used to cut. Scrub all slags, dirt, and oil from previous cuts with a brush and alcohol/acetone. Make sure that the correct torch consumables are fitted. Level the cutting table. Refuel the compressed air tank and cooling system. Convey the metal workpiece to the machine in a proper manner.
Input CNC Program
Copy your CAD cutting patterns to the CNC software. Fix the correct dimensions and coordinates. It is important to also specify the cut sequence when cutting different parts. Enter more CNC codes for the cut setting such as cutting speed, plasma current, standoff height, pierce delay etc. Check the correct paths programmed.
Perform Test Cuts
It is recommended that a test cut be made on a piece of the same metal before making the actual cuts to be used in production. This will assist in setting the correct cut settings. Review the test piece and modify such parameters as plasma current, cutting speed, etc., if necessary, before running the production.
Start Cutting
When ready to start, begin the operation of the CNC cutting cycle. The machine will first translate the plasma torch to the programmed pierce point of the steel to be cut. The high voltage spark will be used to ionize the compressed air and consequently, create the plasma arc which will melt through the metal and follow the designed cutting path. This compressed air will blow the molten slag away from the cut. As controlled by the program, this machine will cut all the parts that are programmed to be cut.
Part Removal & Cleanup
Once cutting is over, the cut parts must be removed from the workpiece either by hand or using the part extraction hooks. Scrape off any residual slag or burrs with grinding or sanding equipment. The parts are now ready for further finishing or for use as they are.
Benefits of CNC Plasma Cutting
Compared to manual plasma cutting, CNC plasma offers the following advantages:
– A higher level of cutting accuracy and cutting benefits
– It is capable of making cuts of both curves and angles as well as holes.
– Since the process of cutting comes under automation, it results in much faster cutting time as compared to manual cutting.
– Standardized components in large quantities
– Substantial decrease in the likelihood of making mistakes and fatigue among the operators
– Improved efficiency and profitability
– Convenient to use when in the process of manufacturing many similar components.
It is easy, efficient, and much more consistent to get high quality cut metal parts once the plasma cutting process is automated using CNC. It also opens up the possibility of making detailed designs with the plasma, something that was not possible before. CNC plasma cutting machine is one of the best machines that a fabrication shop can own.