Vacuum coating and metallizing (PVD, sputtering, evaporation) run in high vacuum, so they use a turbomolecular or diffusion pump backed by a rotary vane or Roots backing pump. The high-vacuum pump reaches the process pressure; the backing pump exhausts it to atmosphere.
What vacuum does coating need?
Most coating processes work in the high-vacuum range (10-3 to 10-6 mbar) – see vacuum ranges. That is beyond any single positive-displacement pump, so a two-stage pump set is used.
Turbomolecular vs diffusion
Both reach the required vacuum. Turbomolecular pumps (e.g. Leybold TURBOVAC, Edwards nEXT) are clean and controllable; diffusion pumps are robust and cost-effective for larger loads. See turbomolecular vs diffusion.
The backing pump & boosters
A rotary vane backing pump, often with a Roots booster for larger chambers, handles roughing and backing. Correct sizing of the whole set is critical to throughput.
Supply & support
Girovac supplies and services coating pump sets from Edwards and Leybold. Tell us your chamber and process and we’ll specify the set.
Specifying a coating pump set?
Give us your chamber size, process and target pressure and we’ll size the turbo/diffusion and backing pumps. Email [email protected] or request a quote.
Frequently asked questions
What vacuum pump is used for coating and metallizing?
A high-vacuum pump – turbomolecular or diffusion – backed by a rotary vane or Roots backing pump. Coating typically runs in the 10^-3 to 10^-6 mbar range.
Turbomolecular or diffusion pump for coating?
Both reach the required vacuum. Turbomolecular pumps are cleaner and more controllable; diffusion pumps are robust and cost-effective for large loads. The choice depends on process and budget.
Do coating systems need a backing pump?
Yes. The high-vacuum pump needs a rotary vane or Roots backing pump to rough the chamber down and exhaust it to atmosphere.
Written by the Girovac technical team. Girovac Ltd has supplied and serviced industrial and laboratory vacuum equipment from its North Walsham workshop since 1983. Last updated: July 2026.