Plasma Cutting
JPen (John Patrick Engineering)

Plasma cutting is a very popular means of cutting metals that grew into maturity during the 1980s. The concept evolved from the already established plasma welding that was developed in the late 1950s by Robert M Gage.

Original plasma machines have evolved from being able to only cut repetitive patterns for mass production into highly articulated CNC controlled systems that offer superior flexibility and design possibilities with the added bonus of saving on waste material.

What can JPen provide by way of plasma cutting services?

The largest machine in operation at JPen has the following features:


Cutting bed measuring 6m X 2.5m


Full CNC control system with network to print capability


Dross free upto 32mm (stainless steel) with a maximum cutting capacity of 50mm


Aluminium, mild and stainless steel cutting options


Cutting speed 3850mm per minute for 12mm thickness


Maximised productivity through rapid process cycling


Minimal operating cost, long life technology without compromise of quality


High definition cutting on thin stainless steel 3-6mm depth

The plasma technology in use at JPen transfers much less heat than previous generations of plasma devices. The cut edges of profiled steel have very small heat affected zones, under the control of the CE (BSEN 1090) compliance and standards system, JPen are allowed to cut mild and stainless steels upto a thickness of 30mm for use in fabrications upto and including category EX3.

How does plasma cutting work?

Essentially the system relies upon a narrow feed nozzle to channel a focused channel of gas at high velocity. The gas is heavily ionized with an electrical charge to form an arc, naturally the gas is compressed to create a high flow speed and this is required in order for a successful arc to be formed. The ionization acts like a conduit to a stream of plasma; the current that flows through it is capable of generating enough heat to melt steel and other metals used in fabrication. The gas also performs a secondary role in blowing away the molten metal to leave a clean edge.

Why use plasma cutting in preference to other long standing methods?

Traditional flame cutting has some unwanted drawbacks, the most negative of these is that the cut region is susceptible to higher levels of surface oxidation, the heat changes the physical properties of the metal matrix at the cut region. Flame cutters also need very precise mixing of the oxygen gas, as even the smallest flow inconsistency can affect the cutting rate drastically. Whilst plasma and flame cutting require good standards of health and safety, plasma cutting does not require a volatile, dangerous gas unlike the flame method.
The rate at which plasma cutters can carry out their operations is considerably faster than flame cutting and certainly less expensive than high powered water jet or laser methods. Certainly there is minimal dross (molten slag) with plasma over flame.

Time and money

With greatly reduced production rates and less cost to operate than other means of metal cutting, the plasma solution continues to prove its worth for the company and the consumer.