From Design to Reality: A Deep Dive into CNC Plasma Cutting
Contents
The dozens of metal fabrication processes, ranging from cutting, drilling, punching, milling and forming, can now be done with extreme precision, at much higher speeds with greater consistency and at higher volumes due to the growing use of CNC machines. Machines can autonomously perform one or a range of fabrication methods using programmed software or ‘Computer Numerical Control’ and a variety of machine tools to remove parts or layers in the workpiece and bring it to a specified finish. There are dozens of CNC machines in terms of what they do, but if high-speed precision cutting in any type of metal is your goal, then look no further than a CNC plasma cutter.
What is CNC Plasma Cutting?
Plasma cutting is a cutting technique that can make precision cuts in conductive metals. This includes some of the most common metals and alloys. such as steel, aluminium, titanium, copper and copper alloys like brass and bronze. The process can be done manually with a handheld plasma cutter, or be fully automated, using a preprogrammed CNC plasma cutting machine for large-scale industrial uses. The high precision, speed and ease of use means this is an affordable alternative to other CNC cutting techniques, specifically laser and water jet cutting.
source: mac-tech.com
How It’s Done
CNC plasma cutting machines work by forcing an inert gas (such as nitrogen and argon) or compressed air through a torch nozzle at very high speeds. An electric arc is combined with the gas to essentially create an ionised gas or plasma (and the fourth state of matter). This superheated gas can reach temperatures above 20000 C, and muster enough energy and electrical conductivity to melt or evaporate metals of any thickness, The pressure created in the nozzle forces the plasma downwards onto the workpiece surface, effectively removing or cutting the targeted area.
source: thefabricator.com
Specifics of CNC Plasma Machines
With CNC-programmable torches and torch controllers to adjust movement, and software that can read part geometry and interpret coded software instructions, this makes for extreme precision and speed, with repeatable and consistent results that remove the possibility of human error. Machines have a drive system, comprising motors working on the X and Y-axis, drive amplifiers, encoders and cabling. Each axis uses an encoder to generate a signal and inform how far the axis has travelled. Cables direct power to the motors, and carry the position signals from the encoder back to the CNC. There is also an electrical input and output system, to control the generation of plasma, the movement of the torch or turn the system off at the required time.
The whole process is done on a dedicated platform or table. Tables come in a variety of sizes, but most industrial-grade machines average 1500 by 3000mm. The table contains the molten metal that’s been cut away. Two types of tables can feature in a CNC plasma cutter machine. Downdraft tables have integrated ventilation systems to absorb fumes and burnt metal pieces, combined with incisions or holes to deal with finer particulates. Water tables cut metals underneath a bed of water and use an air chamber to restrain the the spread of fumes during cutting.
source: mac-tech.com
Where is CNC Plasma Cutting Used?
CNC cutting machines utilising plasma are seen in fabrication shops, auto parts repair, construction, and scrapping tasks. Moreover, the technique is extensively used in commercial signage, wall art, outdoor furniture, sculptures, decorative interior panels and more. CNC machines are a quick and precise way to fabricate metal frames, mounting hardware, large building and structural elements in buildings or bridges, precision metal components in machinery…the list goes on.
source: cncmasters.com
Benefits These Machines Provide
There are various ways and methods of cutting through metals. CNC plasma cutting rivals and substitutes water jet and laser cutting in industrial and commercial applications. All processes have their set of unique applications and advantages, depending on the metal used, their thickness, cutting speed and edge quality.
For CNC plasma cutting, fabricators can benefit with:
- Ability to cut through thicker metals – plasma can cut pieces of nearly 150mm, meaning versatility with a range of metal thicknesses. This is almost 10 times more than what water jets and lasers can muster.
- Very fast cutting speeds – a CNC plasma cutting machine delivers very fast results regardless of workpiece thickness, The method is exceptionally useful in thinner sheets, but also more effective and faster than both laser and water jet cutting in thicker workpieces.
- Low machine and operating costs – fabricators will be shelling out considerably less cash to get their hands on a decent plasma cutter, and will have less to worry about when fabricating and during machine upkeep.
- Safety and ease of use – CNC machining doesn’t require a steep learning curve, meaning cutting machines are relatively easy to use, and the automated process does most of the work for you. As a result, there are fewer safety risks.
- Precision – the CNC controls offer very high precision, especially when compared to plasma cutting with smaller, handheld machines. While edge quality and tolerances are very good, water jets and lasers do offer slightly better results. For that privilege though you’ll be paying much more.
- Versatility – for the most common conductive metals, the process offers unmatched versatility. It’s particularly suited to large-scale jobs with high volume turnout. Moreover, this is one of the more environmentally friendly fabrication processes and produces little to no waste.
