The key manufacturing process for polishing tungsten rods

(1) Raw material selection

Purity: High purity tungsten rods with a purity of 99.95% or higher are usually used (such as ASTM B777 standard).

Initial state: sintered or hot-rolled state, with a diameter range of Φ 1mm~Φ 100mm and a length of up to 1000mm.

(2) Precision grinding (cylindrical grinder)

Equipment: CNC cylindrical grinder (diamond/CBN grinding wheel).

Process parameters:

Grinding wheel grain size: coarse grinding (# 180~# 400) → fine grinding (# 600~# 1200).

Feed rate: 0.005~0.02mm/time, to avoid tungsten brittleness causing edge breakage.

Coolant: Special tungsten processing cooling oil to prevent thermal stress cracking.

(3) Ultra precision polishing (mirror level)

Mechanical polishing:

Using diamond polishing paste (0.5-3 μ m) and non-woven polishing wheel, the Ra can reach 0.05 μ m.

Electrolytic polishing (EP):

Suitable for ultra-high smoothness (Ra<0.01 μ m), using NaOH or KOH electrolyte, voltage 5-20V.

(4) Testing and Packaging

Size inspection: laser caliper (± 0.002mm), roundness tester (≤ 0.005mm).

Surface inspection: white light interferometer (Ra), electron microscope (microcrack).

Packaging: Vacuum oxidation resistant packaging or inert gas protection.

Key performance parameters of polished tungsten rod

Parameters                              ordinary polishing                              high-precision polishing                              ultra precision polishing

Surface roughness                       Ra 0.1~0.4 μ m                                         0.05~0.1 μ m                                                 ≤ 0.01 μ m

Diameter tolerance                          ± 0.01mm                                               ± 0.005mm                                                  ± 0.002mm

Straightness                                   ≤ 0.05mm/m                                           ≤ 0.02mm/m                                                ≤ 0.01mm/m

Application examples: electrodes, weighted medical collimators, semiconductor probes

Main application areas

(1) Semiconductor and Electronics Industry

Probe Card: Ultra high precision tungsten rod used for wafer testing, requiring Ra<0.05 μ m.

Sputtering target support shaft: High straightness (≤ 0.01mm/m) ensures coating uniformity.

(2) Medical equipment

Radiation therapy collimator: The tungsten rod is processed into a multi leaf grating (MLC), and the surface smoothness affects the accuracy of ray focusing.

Gamma Knife Core Components: High Density+High Polishing to Reduce Scattering.

(3) High temperature industry

Single crystal furnace thermal field component: tungsten rod as heater support rod, resistant to high temperatures above 2000 ° C.

Vacuum furnace heating element: mirror polishing reduces volatile pollution.

(4) Military Industry and Scientific Research

Armor piercing core material: high-density tungsten rod (Φ 5-20mm) is precision ground to enhance ballistic consistency.

Synchrotron radiation beamline: Ultra high straightness tungsten rod used for X-ray guidance.