Openair^® plasma is a revolutionary form of plasma
Traditionally, to create plasma particular conditions were needed. These included one or a combination of low pressure, extreme heat or high currents. The technology was sometimes difficult to control precisely and the high temperatures and voltages could be dangerous.

In 1994 our company pioneered the technology to create plasma in a small chamber through which air is blown. This system creates a beam of relatively low-temperature plasma that is voltage-free. The system operates using electricity and compressed air. No vacuum or special gases are required.

Openair^® plasma has enabled us to introduce the exciting world of plasma chemistry into manufacturing along with its many benefits. Production lines can operate at higher speeds, solvent cleaning can be eliminated and solvent-based inks and adhesives can be replaced with water-based forms. Also personnel safety is enhanced.

How Openair^® plasma is generated
Openair^® plasma is created in a jet through the action of a stepped, high-frequency, pulsed current that turns compressed air into a beam of plasma. The plasma can then be directed onto the material surface.

All that is required to generate Openair^® plasma is electricity and clean, compressed air. The beam of plasma is relatively cool such that if a sheet of paper is held in front of it, eventually the beam will blast a hole through it, but it is unlikely to catch fire.

Openair® plasma is created inside a chamber using a stepped, high-frequency pulsed current. A gas is blown through the chamber creating a beam of plasma that can be directed onto the surface of a material to change its properties.

Comparison between different plasma technologies
There are four commonly used plasma technologies. For delicate applications and research, vacuum plasma has generally been employed. For less critical applications, flame treatment and corona and blown corona systems have been employed. Now an alternative exists. Our patented Openair^® system generates plasma at atmospheric pressures without the need for expensive process gases, and with low power consumption. It is ideal for high throughput, in-line manufacturing operations.

Here is a generalized comparison between the different features of the four technologies.

Feature	Vacuum plasma	Flametreatment	Corona /blown corona	Openair® plasma
Description	The plasma is formed in a sealed chamber at low pressures. Sometimes specialty gases are required like helium, argon or nitrogen	This form of plasma requires the lowest level of technology. Burning gas generates a low concentration of plasma	An electric discharge creates an arc, generating plasma. A current of air or gas can be used to blow the arc towards the work surface. In some cases the arc touches or penetrates the material	The patented Openair® process generates a high density plasma inside a jet that is then directed onto the work surface
Special process gases required	Specialty gases required	No	Air is generally used	Air is used. For unusual applications a process gas might be used to add functionality
Energy consumption	Low for small batches	High. A lot of heat is produced, which can be disagreeable in summer	Low, typically 300 Watts	Low, 500 to 1000 Watts
Running cost	Labor intensive, because of batch process	Energy costs and venting costs because unit creates heat and humidity	Low	Low, only 10 to 20¢ per hour per jet for electricity and air
Temperature	20 - 40°C	Flame can be 900 - 1,000°C, surface is less	Arc can be 1,500°C which can cause pitting and streamers	Plasma beam is typically 40 - 125 °C. Surface of material can often rise 1 - 10°C
Voltage at material surface	0 - 800 volts	0 - 10 volts	500 - 2,000 volts	0 - 10 volts (or with a special jet to treat sensitive electronics less than 1 volt)
% plasma	10 - 100% but due to vacuum actual plasma density is 200 times lower than Openair® plasma	Less than 3%	Likely less than 3%	10% atomic oxygen at the exit from the jet
Wettability achievable (dynes/cm)	70	30 - 70	40 - 60	60 - 120
Suitability for in-line production	Batch processes only	Yes	Yes	Yes
Suitability for 3D components	Yes	Yes, but produces uneven results	Uneven treatment, does not cover the inside of flanges	Yes
Suitability for metal/plastic combinations	Yes	Yes, but not satisfactory for foam	No - danger of arcing	Yes
Treat thin walled containers	Yes	Thin walled moldings can warp and glass filled plastics develop a rough surface	Can create pinholes in thin materials	Yes
Safety	Generally safe	Flammable gas explosion hazard. Extra insurance costs	Danger of electrical shock, burn and ozone toxicity	Relatively safe
Emissions	Depends on process gases used	Can produce high concentrations of partially combusted organic compounds and greenhouse gases	Produces ozone	No ozone produced nor other pollutants
Suitability for high volume production	No - a high labor batch process	Yes	Yes	Yes can run at line speeds up to 3,000 feet per minute
Monitoring for quality control	Yes	Results vary with the composition of the gas and can vary through the year, and diminish when humidity is high	Difficult to monitor	Yes, suitable for QS9000, can verify treatment effectiveness

Contact our specialists to find out how Openair^® plasma can be incorporated into your production system.