The equipment needed to generate a low-pressure plasma for surface modification is basically as follows:

  • Vacuum chamber
  • Vacuum pump
  • Gas supply
  • Middle or high frequency generator
  • Electrode
schematic of a low pressure plasma chamber for plasma cleaning or surface modification

A vacuum chamber is evacuated with the vacuum pump to produce a low-pressure environment in the chamber.

The process gas 0² for example is introduced in a controlled manner.

Generally, the pressure in the chamber is now at 0.1 to 1.0 mbar. The gas is then ionized by introducing energy via the electrode creating a plasma.

Fresh gas is continuously bled into the chamber and the used gas is pumped out via the vacuum pump.

Depending on the desired process the plasma surface treatment can take anywhere from less than 1 min to 30 minutes.

On completion of the process air is allowed into the chamber and once atmospheric pressure is achieved the parts or material can be removed.

Advantages of low-pressure plasma systems

  • Cost-effective and durable
  • Minimal material consumption
  • High process reliability
  • Capable of treating complex shapes and delicate substrates
  • Efficient and environmentally friendly
  • Extremely versatile
  • Metal
  • Plastics /Polymers
  • Elastomers
  • Polymers combined with other materials, metals for example
  • Textiles

Parts with complex geometries can be treated or cleaned as the plasma penetrates even the smallest gaps.

Textiles and roll goods can be treated in special roll to roll plasma chambers.

We offer this as a service at our factory in Herrenberg.

The size of the parts and the quantity determine the vacuum chamber size.

The maximal throughput for parts is dependent on the plasma process.

For example, surface activation usually only takes about 5 min whereas cleaning and etching may take up to 30 minutes.

Dependent on the components to be treated it may be possible to bulk treat large quantities in a rotating drum system.

Flat parts can be treated on multiple racks at various levels in the vacuum chamber. Textiles and foils can be treated on a roll to roll system.

It is also no problem to design a chamber for large complex parts.

  • Oxygen
  • Hydrogen
  • Argon
  • Nitrogen
  • Fluor gas

Dependent on the desired treatment either a mixture, or even other gases may be used. We will advise you on the best option.

For the larger production systems, you will need a 400V supply.

For the small table top Laboratory / small production systems you will need a 230-volt socket.

Plasma etching is the process by which the surface is accurately roughened hence greatly increasing the surface area available for adhesive or paint to bond to.

Time taken to complete this process is dependent on power and the gas used. Generally, between 10 and 100 µm is removed.

Plasma activation process creates functional groups on to the surface of the work piece. This is carried out relatively quickly (up to 5 min).

The treated areas ensure an optimal bonding of paints and adhesives even on difficult materials.

The areas on the surface that should not be treated can be masked, so that only selected areas of the work piece are treated.

Our Plasma-spot ® offers an alternative.

This employs a specially designed delivery system that focuses the plasma on to the specific areas to be treated.

An advantage of the Plasma-spot ® process method is the extremely short cycle time due to the short time needed to evacuate the chamber.

The low-pressure process is extremely environmentally friendly.

Due to the very small amounts of process gas used there is no danger of creating a poisonous or explosive environment.

Where fluorinated gases are used a special filter, technique is used to eliminate any last risk due to the exhaust gases.

No heath damaging radiated energy is given off from the process.

Plasma is a naturally occurring state of matter, the “Northern lights” being a popular visible example.