Thermal Evaporation Tungsten Filament for Vacuum Coating Applications

1. Why Twist Tungsten Wire? Structural Advantages

Single-strand tungsten wire can become brittle and limited under extreme heat conditions.

Twisting multiple strands provides four key engineering advantages:

Capillary Effect (Liquid Retention)

Molten low-melting-point metals such as aluminum are held within twisted valleys of the filament.

This allows controlled evaporation instead of dripping.

Larger Surface Area

Stranding multiple wires significantly increases surface area compared to a single wire.

This improves thermal radiation efficiency and evaporation capacity.

Enhanced Thermal Uniformity

Current distribution becomes more balanced across strands.

This reduces hot spots and improves filament stability.

Superior Mechanical Flexibility

Twisted structure distributes stress more evenly.

It allows safe bending, coiling, and shaping into heating geometries.

2. Common Stranded Configurations

Twisted Tungsten Wire is classified by strand count and wire diameter.

2-Strand (2-Ply): Balanced flexibility with deep capillary grooves.

3-Strand (3-Ply): Stable triangular structure with strong liquid retention.

4-Strand to 9-Strand+: Heavy-duty evaporation and heating element applications.

RFQ Example: 3-Strand x 0.76mm means three wires of 0.76mm diameter twisted into one filament.

3. Primary Applications