Single Gas or High Definition Plasma Cutting?
- Peter Dawber
Need to invest in plasma but unsure of whether you need single gas plasma or a high definition plasma?
For many applications single gas plasma cutting will produce a perfectly satisfactory cut although there are some limitations that you need to be aware of. In general a single gas plasma will create more bevel on the cut edge at production speeds and can only produce acceptable holes at a higher diameter to plate thickness ratio than high definition plasma.
Single Gas Plasma Cutting
When cutting with a single gas plasma, cut speed, dross levels and cut quality are played off against each other. Parts cut at lower amps and lower speed will have less bevel on the cut but will have an increased level of dross which can be harder to remove. By increasing the cutting amps productivity can be greatly increased and the parts will have a lower level of dross which is easily removed; however the edge bevel will increase and hole quality will reduce. With single gas plasma, hole diameter as a ration of the material thickness is normally no less than a ratio of 1.5:1 i.e. 15mm diameter in 10mm material.
Are there applications where single gas is preferred?
Only cutting thin mild steel up to 3mm thick? Specific consumables are available such as FineCut® from Hypertherm. These consumables give a fantastic finish quality which rivals even high definition plasma at this thickness. If this is the majority of your work then this solution is well worth considering.
High Definition Plasma Cutting
So when do you need high definition plasma? This process comes into its own on thicker materials, high speed low dross cutting and when cutting materials such as stainless steel and aluminium. The hole diameter to material thickness can come down to as little as 1:1 still with acceptable bolt hole quality. This is also enabled by cutting strategies such as TrueHole from Hypertherm and OptiHole from Ajan CNC.
The gas mixes available when high definition cutting allow much closer control of the cutting arc which in turn allows higher speed cutting with little dross and significantly reduced edge bevel. The acid test is the ability to stand a part on edge after cutting which can be done successfully with high definition cutting. By using different gasses stainless can be cut without an oxidised edge as you will get when using air.
What’s next after high deifniton?
New technology from Hypertherm - known as X-Definition - takes high definition cutting a stage further by adding the opportunity to use 3 gas mixing and even use water as the arc shield. This is particularly beneficial when cutting stainless steel and aluminium and for the lowest levels of dross and edge bevel with increased hole accuracy.
Making a decision
There are many more features that could be explored but the ultimate test is running cuts on each of the different technologies for a direct comparison. At Bison Machinery we are committed to giving our customers the opportunity to make a truly informed decision and with this in mind we have invested in each type of technology in our showroom. At the time of writing we are able to demonstrate the following technologies; Single gas plasma from Morgan Rushworth running Hypertherm Powermax 85, High definition plasma cutting from Ajan CNC built entirely in their own factory, and High definition plasma cutting from Morgan Rushworth running Hypertherm XPR300 plasma featuring X-definition technology.
In addition to this, why not also put fibre laser cutting into the mix and cut the same part using four different processes?
Contact us here to arrange a demonstration or alternatively just send us a drawing and we will happily cut samples and send them back to you.