Microwave Applications of Industrial Free Electron Lasers

IFELs are tuneable, high output power, low cost sources of microwaves operating in the frequency range 1 to 100GHz and 10s kW powers, continuous or pulsed. For material processing the microwaves can be used directly or converted into microwave plasma or UV radiation.
Projects being undertaken within the Network involve processing of polymers, ceramics, metals, water, waste products and food.
An hybrid laser/microwave plasma has all the advantages of the laser material processing, but at a very much lower cost per product.

Link to the MAIFEL project Home Page

The IFEL is a low cost compact source of microwaves producing high powers (~ 10kW) within the frequency range 1 to 100GHz. The Network is investigating microwave applications and in the area of material processing and two main areas have been identified based upon the direct use of microwaves and the conversion of microwaves into plasma and UV radiation.

1. Direct Use of Microwaves

Advantages compared with conventional furnaces.

2. Microwave Plasma

Advantages compared with conventional plasma sources.

3. Microwave UV Sources

Advantages compared with conventional plasma sources.

4. Microwave Applications in connection with Material Processing

4.1 Polymers

- Curing of adhesives.

- Surface treatment.

- Joining of plastics with and without priming agents.

4.2 Inorganic Materials

- New ceramics for the aerospace and automotive industries

- Classic materials with new micro or macro structures such as nano-powders or microporus materials

- Surface treatment

- Casting and sintering of ceramics and piezoceramics

- Ferrite sintering

- Joining of ceramics

- Fibres in various shapes such as fleece, felt/braid, tow, sausage and curly form for a wide range of materials including:-

4.3 Metals

Use with aerospace materials (e.g. titanium alloys including titanium aluminide) and automotive materials (high strength steels)

- Welding

- Cutting

- Surface cleaning

- Heat treatment

- Surface coating

- Chipless machining

4.4 Clean Technologies

Microwaves Only

- Pattern marking on cloth

- Waste water cleaning and drinking water purification

- Vitrification of nuclear materials

- Decommissioning of concrete structures

Microwave Plasma

- Automotive plasma catalyst for conversion to remove NOx’s exhaust gases

- Efficient lighting for highways, stadiums etc.

Microwave UV

- Waste water cleaning and drinking water purification

- Food processing for longer shelf life

- Air filters for hospitals, aircraft, factories etc.

- Curing printing ink

- Bonding adhesives

- Surface preparation for painting

4.5 Combination of Laser and Microwave Technologies

Microwave plasma is cheap compared with laser produced plasma but cannot be focussed to the small size attainable by lasers. A combined system produces material preheat with the microwave plasma thus allowing material processing with low power lasers thus giving considerable cost saving per product. Applications are with:-

- Pure metals

- Ceramics

- Coated steels for automotive industries to improve cut quality in terms of good finish reduced kerf width and dross.